Irap 2016 Is Jointly Organized By

THE 12TH INTERNATIONAL SYMPOSIUM ON IONIZING RADIATION & POLYMERS

Many thanks to our support and sponsors

INTERNATIONAL SYMPOSIUM POLYMERS & IONIZINGON RADIATION September 25-September 30, 2016 TH

Presqu’île de Giens, France THE 12 THE 12TH INTERNATIONAL SYMPOSIUM ON IONIZING RADIATION & POLYMERS

IRaP 2016 is jointly organized by

Centre de recherche sur les Ions, Commissariat à l’Énergie Atomique les Matériaux et la Photonique (UMR 6252) et aux Énergies Alternatives

In collaboration with

INTERNATIONAL IRRADIATION ASSOCIATION Welcome address

Dear Colleagues,

On behalf of the organizing committee, it is my great pleasure and honor to welcome you to the 12 th symposium on Ionizing Radiation & Polymers, IRaP 2016, in Giens, France.

Polymers can be submitted to ionizing radiations in various situations, either intentionally or in the course of their normal use. Ionizing radiations of polymers have been used for decades for various industrial applications, either to improve polymer properties or to design new materials. As a consequence, the radiation chemistry of polymers has been intensely studied. Despite the growing scientific and technical interest of radiation-induced modifications on polymers, there was no dedicated meeting where scientists dealing with the effect of ionizing radiations on polymers would exchange and disseminate their knowledge. To fill this gap, Dr. N. Betz and Dr. A. Le Moël, from the French Atomic Commission (CEA), and their coworkers from Germany decided to organize an international conference addressing this subject. The IRaP meetings were initiated with the threefold objective to 1) bring together scientists from research centers, universities and industry, 2) to provide a forum to exchange knowledge and information in this field, and 3) to promote innovative applications.

Thanks to your abstracts, during the next 5 days, we will be exchanging valuable knowledge and learning about innovative applications related to “polymers under ionizing radiation”. We will be harvesting information from 21 invited lectures, 43 contributed lectures, a course on the specific effects of ion beams on polymers, a keynote lecture and a tribute to Natacha Betz. Besides, more than 50 posters will be presented during the two poster sessions scheduled.

The International Irradiation Association (IIA) has granted three young scientists for their contribution to the advancement of the science of ionizing irradiation. This award includes, apart from a bursary for IRaP2016, an invitation to attend IMRP 2016 in Vancouver on November together with a travel bursary. Thanks to the cooperation of IRaP with IAEA, we were able to fund five young scientists on the basis of their work.

We gratefully acknowledge the financial support received from all the institutions, organizations and companies: IAEA, CEA, IIA, Andra, CNRS, Université de Caen, Caen la Mer, IONISOS and Agilent Technologies. Many thanks to the companies having funded an exhibition booth: AERIAL, NIST, Synergy Health-Stearis, and Thermo Scientific. Please make sure to visit them during the conference.

We warmly thank each of you for attending IRaP 2016 on this beautiful location of Belambra “les Criques”.

Dr. Yvette Ngono-Ravache Chair of IRaP 2016

IRaP conference locations

Since its creation in 1994, IRaP has been organized in different countries, starting in France, and different continents. We are proud and happy to welcome back IRaP in France for this edition.

1994: Saint-François Guadeloupe, France

1996: Saint-François Guadeloupe, France

1998: Weinböhla, Germany

2000: Gouvieux, France

2002: Saint-Adèle, Canada

2004: Houffalize, Belgium

2006: Antalya, Turkey

2008: Angra dos Reis, Brazil

2010: College Park, USA

2012: Cracow, Poland

2014: Jeju Island, South Korea

2016: Presqu’île de Giens, France

2018: ?

IRaP Committees

Conference chairs

Chair: • Y. Ngono-Ravache CIMAP (CEA/CNRS/ENSICaen/UCBN) Bvd H. Bequerel, BP 5133, 14070 Caen cedex 5 Tel office: +33 (0) 2 31 45 47 51 Email: [email protected]

Co-chairs: • M.-C. Clochard (LSI CEA/CNRS/Ecole Polytechnique Université Paris-Saclay) Laboratoire des Solides Irradiés Ecole Polytechnique F-91128 PALAISEAU Tel office: + 33 (0) 1 69 33 45 26 E-mail: [email protected]

• M. Ferry CEA/DEN/DPC/SECR/LRMO CEA Saclay 91191 Gif sur Yvette Cedex Tel office: + 33 (0) 1 69 08 27 34 Email: [email protected]

Steering committee

Scientific committee

• M. Al-Sheikhly (University of Maryland, USA) • G. Burillo (Instituto de Ciencias Nucleares, Mexico) • A.G. Chmielewski (Institute of Nuclear Chemistry and Technology, Poland) • M.-C. Clochard (LSI CEA/CNRS/Ecole Polytechnique Université Paris-Saclay) • X. Coqueret (University of Reims, France) • O. Güven (Hacettepe University, Turkey) • P-H. Kang (Korea Atomic Energy research Institute, Korea) • P. Minbiole (E-beam Services, USA) • J.-J. Pireaux (University of Namur, Belgium) • J.M. Rosiak (Technical University of Lodz, Poland) • S. Sabharwal (IAEA, Austria) • G. Spadaro (University of Palermo, Italy) • E. Takacs (Institute of Isotopes and Surface Chemistry, Hungary) • P. Ulanski (Technical University of Lodz, Poland) • Y. Maekawa (Japan Atomic Energy Agency, Japan) • M. Mahmoud Nasef (Universiti Teknologi Malaysia, Malaysia) • Y. Ngono-Ravache (CIMAP, France) • Y.-C. Nho (Korea Atomic Energy Research Institute, Korea) • W. Pasanphan (Kasetsart University,Thailand) • D. Poster (NIST, USA) • S. Tagawa (Osaka University, Japan) • M. E. Toimil-Molares (GSI, Germany) • G. Wu (Shanghai Institute of Applied Physics, China) • M. Zhai (Peking University, China)

Local organizing committee

• C. Aymes-Chodur (Université Paris-Sud, Faculté de Pharmacie) • M.-C. Clochard (LSI CEA/CNRS/Ecole Polytechnique Université Paris-Saclay) • F. Cochin (AREVA NC) • X. Coqueret (Université de Reims Champagne-Ardenne) • B. Fayolle (Arts et Métiers ParisTech) • M. Ferry (CEA/DEN/DPC/SECR/LRMO) • S. Legand (CEA/DEN/DPC/SECR/LRMO) • Y. Ngono-Ravache (CIMAP CEA/CNRS/ENSICaen/UCBN) • F. Nizeyimana (Areva TN International) • D. Ricard (Andra)

Session topics

I. Fundamentals on ionizing radiation interactions with polymers

II. Polymer ageing: defects creation, chemical modifications

III. Nanostructuration, composites

IV. Energy

V. Polymer curing and grafting

VI. Instruments and installations for irradiation

VII. Hydrogels Past present and futur (devoted to Pr. J.M. Rosiak)

VIII. Gels and biopolymers

IX. Polymer-based medical and pharmaceutical devices

X. Lifetime prediction

XI. Polymer ageing: property modifications

XII. Membranes

XIII. Radiolysis

XIV. Surface effects

XV. Bio-based polymers and environmental concerns

XVI. International cooperation activities

Time table

25th Sept. (Sun) 26th Sept. (Mon) 27th Sept. (Tue) 28th Sept. (Wed) 29th Sept. (Thur) 30th Sept. (Fri) 09:00 - 09:15 Opening session M. Negrin G. Przybytniak E. Bucio J.A. LaVerne 09:15 - 09:30 S. Bouffard (Tribute to R. Sonnier 09:30 - 09:45 Natacha Betz) L.M. Ferreira T. Fekete F. Nizeyimana 09:45 - 10:00 D.F. Parra K. Furtak-Wrona K. Cieśla Y. Hosaka 10:00 - 10:15 M. Driscoll 10:15 - 10:30 E. Balanzat M. Barsbay M. Jonsson A. Dannoux-Papin 10:30 - 10:45 Coffee break Coffee breakCoffee break Coffee break 10:45 - 11:00 Coffee break IAEA: S. Sabharwal 11:00 - 11:15 X. Coqueret A. Whittington R. Papaléo IIA: Y. Hénon 11:15 - 11:30 ERASMUS: X. Coqueret V. Feldman 11:30 - 11:45 S. Saiki M. Grasselli J. Portillo Casado Closing session 11:45 - 12:00 K. Tran R. Wach 12:00 - 12:15 Y. Yoshida Group photo G. Varca 12:15 - 12:30 S. Kadlubowski 12:30 - 12:45 Lunch Lunch / Lunch boxes 12:45 - 13:00 13:00 - 13:15 Lunch Lunch Lunch 13:15 - 13:30 13:30 - 13:45 13:45 - 14:00 14:00 - 14:15 E. Dantras L. Karam M. Celina 14:15 - 14:30 14:30 - 14:45 E. Fromentin S. Rouif A. Sidi 14:45 - 15:00 R. Thomaz H. Michel H. Kudo 15:00 - 15:15 Registration 15:15 - 15:30 T. Oka M. Bielmann M. Cabalka (Registration desk 15:30 - 15:45 will be open during Coffee break Coffee break Coffee break 15:45 - 16:00 office hours until the Excursion end of the 16:00 - 16:15 (Porquerolles Island) conference) M.E. Toimil-Molares P. Ulański G. Teyssèdre 16:15 - 16:30

16:30 - 16:45 A. Zezin O. Güven M. Ito 16:45 - 17:00 M. Al-Sheikhly G. Burillo B. Fayolle 17:00 - 17:15 A. Lugão 17:15 - 17:30 Y.C. Nho S.D. Sütekin C. Dispenza 17:30 - 17:45 Y. Maekawa V. Labed 17:45 - 18:00 J.M. Rosiak 18:00 - 18:15 S.-H. Oh D. Klimov 18:15 - 18:30 G. Melilli 18:30 - 18:45 - - 18:45 - 19:00 D. Poster 19:00 - 19:15 Welcome reception 19:15 - 19:30 19:30 - 19:45 Dinner 19:45 - 20:00 Dinner Dinner 20:00 - 20:15 Banquet & Student Dinner 20:15 - 20:30 Traditionnal danses & Award ceremony music 20:30 - 20:45 20:45 - 21:00 21:00 - 21:15 Poster session II 21:15 - 21:30 Poster session I 21:30 - 21:45 21:45 - 22:00

Fundamentals on ionizing Polymer curing and Bio-based polymers and radiation interactions with Gels and biopolymers Radiolysis grafting environmental concerns polymers Polymer ageing: defects Photo of the conference Polymer-based medical and International cooperation creation, chemical Surface effects participants pharmaceutical devices activities modifications

Nanostructuration, Instruments and Lifetime prediction composites installations for irradiation

Hydrogels past present Polymer ageing: property Energy and futur (devoted to Pr. modifications Rosiak)

Membranes

Conference events

Welcome and registration: Sunday September 25, 2016 from 3.00 pm Welcome Reception: Sunday September 25, 2016; 6.30 pm-8.00 pm

Course, keynote and lectures All lecturers are kindly reminded to respect the time they were allocated: 25+5 min for invited talks, 15+5 min for contribution talks and oral presentation in special sessions on gel and international cooperation activities, 50+10 min for the course and 40 + 5 min for the keynote lecture.

A computer will be available in the conference room. The authors are invited to prepare their talk as a pdf format, when possible, for smooth operation.

The speakers will be allowed to use their personal laptop, provided they have checked the compatibility with the operation system in advance of the session, or more adequately the day before. They are also requested to bring the adapting connector. This last point is particularly applicable to Macintosh laptops.

Poster sessions Two poster sessions are scheduled, on Tuesday September 27 after dinner for odd numbers and on Wednesday 28 after dinner for even numbers. Each poster should be displayed on the assigned numbered board. Poster pins will be available at the conference desk. The authors are invited to respect the assigned boards.

Special sessions A course addressing the specificity of the interaction of Swift Heavy Ions with polymers will be delivered by Dr. Emmanuel Balanzat on Monday morning, just after the tribute to late N. Betz.

A special session on gels, devoted to Pr. Rosiak and chaired by his colleague Dr. Ulanski is scheduled on Tuesday afternoon.

Conference Outing We will be visiting the wonderful island of Porquerolles. We hope that the weather will be nice enough for us to take all the advantages of this gorgeous place.

Conference Dinner, Awards celebration and other celebration No formal dress is requested for the gala. During this gala, young scientists granted by the IIA and the IAEA will receive their awards and future retirees will be celebrated.

Table of contents: oral presentations

Monday September 26, 2016 (09:00 – 12:35) Opening session O1. Tribute to Natacha Betz, by S. Bouffard Session I. Fundamentals on ionizing radiation interactions with polymers Chaired by Dr. E. Takacs (Hungary) O2. Radiation-induced modifications of polymers: influence of the nature of the projectile (Course ) E. Balanzat

O3. Basic mechanisms of the radiation damage in polymers at cryogenic temperatures: model studies and implications (Keynote ) V. Feldman

O4. Electron dynamics in primary process of radiation chemistry studied by femtosecond pulse radiolysis Y. Yoshida

O5. New system for time-resolved pulse radiolysis with multi-angle light scattering detection S. Kadlubowski, B. Rokita, K.-D. Bures, J.M. Rosiak, P. Ulanski

Monday September 26, 2016 (14:00 – 15:30) Session II. Polymer ageing: defects creation, chemical modification Chaired by Dr. F. Nizeyimana (France) O6. Inorganic fillers influence on the radiation-induced crosslinking of a silicone elastomer: chemical structure and electrical properties (Invited lecture ) A. Roggero, E. Dantras, T. Paulmier, C. Tonon, S. Lewandowski, S. Dagras, D. Payan

O7. Study of the hydrolysis of an industrial radio-oxidized poly(ester urethane) E. Fromentin, M. Ferry, S. Legand, D. Lebeau, J.J. Pielawski, S. Esnouf, P. Reiller, D. Doizi, C. Aymes-Chodur

O8. Effect of spatial confinement of the radiolytic efficiency of high-energy ions in polymers R. Thomaz, L.I. Gutierres, J. Morais, P. Louette, J. J. Pireaux, D. Severin, C. Trautmann, R.M. Papaléo

O9. Oxidative degradation of polyethylene studied by positron annihilation lifetime spectroscopy T. Oka, K. Onodera, Y. Kino, T. Sekine

Monday September 26, 2016 (16:00 – 17:10) Session III. Nanostructuration, composites Chaired by Prof. O. Güven (Turkey) O10. Recent developments on etched ion-track membranes for sensor applications (Invited lecture ) M.E. Toimil-Molares, A. Spende, N. Ulrich, M. Carrillo-Solano, C. Trautmann

O11. Generation and growth of copper and silver nanoparticles in irradiated poly(acrylic acid) and polyvinyltriazol based systems A.A. Zezin, V.I. Feldman, G.V. Danielyan, E.A. Zezina, S.S. Abranchuck, G.F. Prozorova

O12. Different architectures of hydrogels based on chitosan and dimethylacrylamide D. Tinoco, A. Ortega, L. Islas, G. Burillo

Monday September 26, 2016 (17:10 – 19:10) Session IV. Energy Chaired by Prof. M. Al-Sheikhly (USA) O13. Performance of polyethylene separator modified by radiation for lithium secondary battery (Invited lecture ) Y.C. Nho, J.Y. Sohn, J.H. Shin, J.S. Park, Y.M. Lim, J.P. Jeun, P.H. Kang

O14. Mechanism study of radiation-induced graft polymerization for application in fuel cells Y. Maekawa

O15. Development of hybrid materials with electron beam treatment as an interfacial layer for efficient polymer based photovoltaic devices S.-H. Oh, H.B. Kim, J.-M. Yun, P.H. Knag

O16. E-beam irradiation beneficial effect on PVDF piezoelectricity G. Melilli, D. Lairez, D. Gorse, E. Garcia-Caurel, A. Peinado, O. Cavani, B. Boizot, M.-C. Clochard

O17. Enhancement of the extraction of the uranium from seawater (Invited lecture ) T. Dietz, Z. Tsinas, I. Pazos, A. Barkatt, D. Poster, F.B. Bateman, L.T. Cumberland, M. Adel-Hadadi, M. Al-Sheikhly

Tuesday September 27, 2016 (09:00 – 10:30) Session V. Polymer curing and grafting Chaired by Prof. Y. Maekawa (Japan) O18. Radiation-induced processes in aliphatic polyesters as seen by EPR spectroscopy and their physicochemical implications (Invited lecture ) G. Przybytniak, M. Walo

O19. Hybrid materials prepared by gamma irradiation for consolidation of ancient ceramic artefacts: morphology and preliminary biocide activity studies L.M. Ferreira, A.P. Rodrigues, S.C. Verde, L.C. Alves, M.H. Casimiro, J.J.H. Lancastre, A.N. Falcão, F.M.A. Margaça, M.F. Araújo

O20. Reinforcement of radiation-cured PUR acrylate networks by cellulose nanocrystals K. Furtak-Wrona, P. Kozik-Ostrowka, K. Jadwiszczak, J.-E. Maigret, G. Tataru, V. Aguié-Béghin, X. Coqueret

O21. Controlling of crosslinking in the radiation-induced polymerization of styrene in the presence of a RAFT agent and a crosslinking agent M. Barsbay, T. Ovalıo ğlu, O. Güven

Tuesday September 27, 2016 (11:00 – 12:30) Session V. Polymer curing and grafting Chaired by Prof. J.M. Rosiak (Poland) O22. Kinetic and structural features of radiation-initiated crosslinking polymerization: a comparison between free radical and cationic chemistries (Invited lecture ) G. Ranoux, C. Kowandy, M. Krzeminski, A. Berquand, M. Molinari, X. Coqueret

O23. Radiation-induced grafting method with an addition of organophosphorous compounds S. Saiki, N. Seko

O24. Study of styrene-free unsaturated resins and acrylic monomers for the consolidation of wooden cultural heritage artefacts by radiation-curing K. Tran, C. Salvan, M. Bardet

Tuesday September 27, 2016 (14:00 – 15:30) Session VI. Instruments and installations for irradiation Chaired by Y. Hénon (IIA) O25. International traceability for ionizing radiation: NIST measurement standards (Invited lecture ) L.R. Karam

O26. Selection of radiation strategy for polymer modification: case of grafting phosphorus compounds on flax fibers S. Rouif, R. Sonnier, B. Otazaghine, I. Chala

O27. Qualification of the properties of highly crosslinked UHMWPE, to be routinely processed with a 7 MeV X-Ray irradiator H. Michel, H. Hartmann, M. Allen

O28. Electron beam lab unit and systems – How accessibility will change the market M. Bielmann

Tuesday September 27, 2016 (16:00 – 18:10) Session VII. Hydrogels, past, present and future (devoted to Pr. Rosiak) Chaired by Prof. P. Ulanski (Poland) O29. Radiation engineering of polymeric biomaterials (Invited lecture ) J.M. Rosiak, P. Ulanski

O30. From bulk hydrogels to functional nanogels (Invited lecture ) O. Güven

O31. Synthesis and modification of functional polymer nanogels using pulsed- alectron beam ionizing irradiation (Invited lecture ) I. Pazos, J.-C. An, N. Grimald, P.Y. Takinami, D. Poster, C. Dispenza, N. del Mastro, W. Vreeland, M. Al-Sheikhly

O32. Are wound dressings based on Rosiak's process still a technical challenge? The Brazilian experience (Invited lecture ) A.B. Lugão

O33. Radiation-induced synthesis of nanogels: advances in research and application (Invited lecture ) C. Dispenza

Final remarks and conclusions, by J.M. Rosiak

Wednesday September 28, 2016 (09:00 – 10:30) Session VIII. Gels and biopymers Chaired by Prof. G. Burillo (Mexico) O34. Novel thermos and pH-sensitive poly(N-vinylcaprolactam-co - 4vinylpyridine) onto silicone rubber by one step method for drug delivery (Invited lecture ) V.H. Pino-Ramos, C. Alvarez-Lorenzo, A. Concheiro, E. Bucio

O35. Synthesis of cellulose derivative/acrylic acid hydrogels by radiation- initiated crosslinking T. Fekete, J. Borsa, E. Takács, L. Wojnárovits

O36. The effects of some compositional factors and ionizing radiation on the properties of starch-PVA-nanocellulose films K. Cie śla, A. Abramowska, J. Drewnik, M. Buczkowski

O37. On the mechanism of radiation synthesis of nanogels C. Dispenza, L.A. Ditta, M.A. Sabatino, M. Jonsson

Wednesday September 28, 2016 (11.00 – 12.30) Session IX. Polymer-based medical and pharmaceutical devices Chaired by Dr. C. Dispenza (Italy) O38. Response of medical polymers to therapeutic levels of ionizing radiation A.R. Whittington

O39. Radiation-induced preparation of gold/albumin core/shell nanoparticles C.Y. Flores, E. Achilli, M. Grasselli

O40. Sterilization of a biodegradable medical device comprising supramolecular polymers - is radiation technique appropriate? R.A. Wach, W. Mozalewska, A. Adamus, A.K. Olejnik, M. Ramos Gallego, J. Vange, A.W. Bosman, T. Mes, J.M. Rosiak

O41. Radiation crosslinked albumin capped gold nanoparticles for theranostics G.H.C. Varca, J.A.G. Barros, J. G. dos Santos Batista, K.V. Katti, A.B. Lugão

Wednesday September 28, 2016 (14:00 – 15:30) Session X. Lifetime prediction Chaired by Prof. B. Fayolle (France) O42. Challenges and options for the prediction of polymer degradation under combined aging environments (Invited lecture ) M. Celina, K. Gillen (ret.)

O43. Thermo and radiooxidation of model materials of cable insulation used in nuclear power plants A. Sidi, J.-F. Larche, A. Rivaton, F. Bot-Robin, J. Colombani

O44. Influence of color pigments on degradation of polymer materials for cables in nuclear power plants upon thermal and/or radiation ageing H. Kudo, G. Mizerova, V. Pla ček

O45. Cable materials in harsh environment and radiolytic gas formation M. Cabalka, V. Pla ček

Wednesday September 28, 2016 (16:00 – 17:10) Session XI. Polymer ageing: property modifications Chaired by Dr. D. Poster (USA) O46. E-beam as prototype source for investigating electrical ageing of insulating polymers (Invited lecture ) G. Teyssèdre, V. Griseri, M. Banda, S. Le Roy, C. Laurent

O47. Changes in heat resistant properties of LLDPE by pre-irradiation M. Ito, G. Nishio, Y. Watanabe, T. Kosaka

O48. Coupling between chemical degradation under irradiation and mechanical properties B. Fayolle, E. Richaud, X. Colin, J. Verdu

Wednesday September 28, 2016 (17:10 – 18:20) Session XII. Membranes Chaired by Dr. M.C. Clochard (France) O49. Amphiphilic block copolymer synthesis by RAFT-mediated radiation- induced polymerization (Invited lecture ) S.D. Sütekin, O. Güven

O50. Ageing under gamma irradiation of a reverse osmosis membrane: properties and structure modifications N. Combernoux, V. Labed, L. Schrive, E. Carretier, Y. Wyart, P. Moulin

O51. Preparation of bimetallic nanoparticles with controllable core-shell ratio in irradiated interpolyelectrolyte complexes D.I. Klimov, A.A. Zezin, S.S. Abramchuk, E.A. Zezina, M. Yang

Thursday September 29, 2016 (09:00 - 10:30) Session XIII. Radiolysis Chaired by Dr. Emmanuel Balanzat (France) O52. Gas yields and relative sensitivity of various polymers (Invited lecture ) J.A. LaVerne

O53. Effect of temperature on gas release during thermal oxidation of gamma- irradiated polymer based neutron shielding O. Okamba-Diogo, M. Cornaton, V. Dauvois, D. Durand, M. Ferry, D. Lebeau, S. Legand, J.L. Roujou, F. Nizeyimana, S. Esnouf

O54. Pulse radiolysis in concentrated solution by using alpha-allyloxymethyl acrylic copolymer Y. Hosaka, C. Wang, Y. Soeta, Y. Saito, T. Kondoh, Y. Yoshida, A. Oshima, M. Washio

O55. Radiolytic degradation of ionic exchange resins: water effect I. Boughattas, Y.Ngono-Ravache , V. Labed, A. Dannoux-Papin

Thursday September 29, 2016 (11:00 – 11.50) Session XIV. Surface effects Chaired by Pr. A.B. Lugão (Brazil) O56. Ion irradiation of polymer thin and ultrathin films: effects of spatial confinement in one dimension (Invited lecture ) R.M. Papaléo

O57. Electron beam curing of acrylic elastomers for medical products J. Portillo Casado, G. Gotzmann, Fh. Rögner, H.L. Bui, W. Meyer, H. Zeidler, G. Glowa

Friday September 30, 2016 (09:00 -10:20) Session XV. Bio-based polymers and environmental concerns Chaired by O58. Gamma radiation effects on random copolymers based poly(butylene succinate) for packaging applications M. Negrin, E. Macerata, G. Consolati, F. Quasso, L. Genovese, M. Soccio, M. Giola, N. Lotti, A. Munari, M. Mariani

O59. Functionalization of flax fibres by radiation-grafting R. Sonnier, B. Otazaghine, C. Longuet, A. Viretto, I. Chala, S. Rouif

O60. Mechanical properties and thermal behavior evaluation of experimental dental composited filled with irradiated montmorillonite D.F. Parra, L.M.P. Campos, T. Zaharescu, L.C. Boaro, L.K.G. Santo, A.B. Lugão

O61. G-values of wood polysaccharides and lignin M.S. Driscoll, J.A. LaVerne, M. Al-Sheikhly

Friday September 30, 2016 (10:50 – 11:50) Session XVI. International cooperation activities Chaired by Dr. L. Karam (USA) Erreur ! Radiation processing for advanced materials: IAEA perspectives Source du (Invited lecture ) renvoi S. Sabharwal introuvable. O63. IIA presentation (Invited lecture ) Y. Hénon

O64. Introducing the ERASMUS + educational program for “enhancing the development and transfer of knowledge for the application of ionizing radiation material processing” (Invited lecture ) X. Coqueret

Closing session

Table of contents: poster presentations

P1. The mechanical and physicochemical properties of EPDM cable polymer after thermal and radiochemical ageing T. Šarac, J. Deveaux, N. Quiévy, A. Gusarov, M.J. Konstantinovi ć

P2. Analysis of the space environment influence on the electrical resistivity of a silicone adhesive A. Roggero, E. Dantras, T. Paulmier, C. Tonon, S. Lewandowski, S. Dagras, D. Payan

P3. High-dose irradiation and long-term thermal ageing of (U)HMWPE A. Kömmling, E. Chatzigiannakis, V. Wachtendorf, U. Braun, K. von der Ehe, M. Jaunich, J. Beckmann, U. Schade, D. Wolff

P4. Modification of cellulose nanocrystals by radiation-induced graft polymerization of N-isopropyl acrylamide S.F. Mohamad, B. Kurek, V. Aguie-Beghin, X. Coqueret

P5. An approach to the sterilization of β-alanine by ionizing radiation L. de Souza Gonçalves, G. Giannini Artioli, M.B. Mathor, A.B. Lugão, G.H.C. Varca

P6. High melt strength polypropylene (HMSPP) nanocomposite under photo and thermal ageing L.G.H. Komatsu, D.F. Parra, W.L. Oliani, A.B. Lugão

P7. Attenuation properties of PCDF / CNT and metal oxides nanocomposites for low energy X-Rays E.L.M. Pereira, A.S.M. Batista, F.A. S. Ribeiro, A.P. Santos, L.O. Faria

P8. Radiation synthesis of bioactive hydrogel and hydrocolloid dressings B. Rokita, S. Kadlubowski, K. Luzniak, P. Ulanski, J.M. Rosiak

P9. Effect of radiation grafting parameters in the morphology and mechanical properties of FEP-based films for alkaline anion-exchange membrane for fuel cell applications C.C. Pereira, M.C. Salvadori, L.G.A. Silva, E.I. Santiago

P10. Ionizing radiation effects mechanical and thermal properties in polyamide 6 with colloidal silicone dioxide (Aerosil®) C.A. Amorim, W.P. Ferro, J.L. Moura, L.G.A. Silva

P11. Synthesis and characterization of novel polyelectrolyte hydrogels of different types based on vinyl ethers G.A. Mun, B.B. Yermukhambetova, V.K. Yu, G.S. Irmukhametova, D. Kaldybekov, A.K. Tokhtabayeva

P12. Development of radiation technology production of the new hydrogel materials for bio-medical application G.A. Mun, B.B. Yermukhambetova, G.S. Irmukhambetova, Z. Beksultanov, R. Rakhmetullayeva, I.E. Suleimenov

P13. Poly(N-vinyl-2-pyrrolidone) (PVP) and neomycin hydrogels as wound dressing obtained by gamma irradiation A.T. Zafalon, V. Juvino dos Santos, A.B. Lugão, D.F. Parra

P14. Determination of the impact of radiation ageing on the global ageing of PE-EPDM polymers in service by a sensitivity study R. Maurin, M. Berveiller

P15. The effect of PVA type and radiation treatment on the properties of starch-PVA films K. Cie śla , A. Abramowska, J. Boguski, J. Drewnik

P16. The effect of gamma-radiation on biodegradability of synthetic PHB structural foams PP/HMSPP based E.C.L. Cardoso, S.R. Scagliusi, A.B. Lugão

P17. Polymers degradation under radiolysis: adaptations of devices for irradiating samples dedicated to analytical methods perspectives J-L. Roujou, V. Dauvois, M. Ferry, D. Durand, M. Cornaton, S. Esnouf, D. Lebeau, S. Legand, Y. Ngono-Ravache, J-M. Ramillon

P18. Radiation synthesis of hydrogels of dextran methacrylate K. Szafulera, R.A. Wach, P. Ulanski, J.M. Rosiak

P19. Loading and release of ciprofloxacin from plasma polymerized acrylic acid coatings T. Tapia-Esquivel, B. Segura-Bailon, J.-C. Ruiz

P20. Removal of Cd(II) ions form aqueous media using porous cellulosic adsorbent M. Barsbay, P. Akka ş Kavaklı, S. Tilki, C. Kavaklı, O. Güven

P21. Comparison of gamma radiation effects on natural corn and potato starches and modified cassava starch B.S. Teixeira, P.Y. Takinami, N. del Mastro

P22. Ecologic particleboard based on HDPE/EVA blend reinforced with corncob fiber and zinc oxide nanoparticle treated by electron-beam radiation F. Lainetti, R.R. Oliveira, R.C.L.B. Rodrigues, E.A.B. Moura

P23. Preparation and characterization of EVA/clay/TiO 2 flexible film modified by electron beam radiation M.V. de S. Seixas, J.A. Santos, V.K. Rangari, F. Valenzuela-Díaz, H. Wiebeck, E.A.B. Moura

P24. Mechanical, thermal and barrier properties of EVOH/graphene oxide treated by electron beam radiation J.G. Santana, A.V. Ortiz, M. Akbulut Söylemez, V.K. Rangari, F. Valenzuela- Díaz, O. Güven, E.A.B. Moura

P25. Effects of bio-CaCO 3 nanoparticles and graphene nanosheets on properties of PBA/PLA flexible films treated by ionizing radiation P.R.S. Reis, E.C.L. Cardoso, F.R. Lourenço, A.V. Ortiz, V.K. Rangari, E.A.B. Moura

P26. Determination of Arrhenius coefficients of N-vinylpyrrolidone polymerization in aqueous solution by pulsed electron polymerization - Size Exclusion Chromatography (PEP-SEC) P. Sawicki, S. Kadłubowski, P. Ula ński

P27. A study of radical decays and radiation-induced grafting of irradiated polyethylene nonwoven fabric at various storage conditions S. Saiki, K. Okaya, N. Seko, H. Kudo

P28. Molecular dynamics simulation of polymer-like thin films irradiated by fast ions: a comparison between FENE and Lennard-Jones potentials N.W. Lima, R. Gonzalez, L.I. Gutierrers, R. Thomaz, S. Muller, R. M. Papaléo, E. M. Bringa

P29. The effect of electron beam radiation on mechanical ans physico-chemical properties of P(TMC-co -LA) A. Adamus, R.A. Wach, P. Ulanski, J.M. Rosiak

P30. The role of hydrogels in the radical production of Fricke gels irradiated at low temperature S. Lazzaroni, G.M. Liosi, R. Marconi, G. D’Agostino, M. Mariani, A. Buttafava, D. Dondi

P31. Chitosan-containing hydrogel dressings prepared by radiation technique W. Mozalewska, R. Czechowska-Biskup, A. K. Olejnik, R.A. Wach, J.M. Rosiak

P32. Synthesis of cellulose derivative based superabsorbent hydrogels E. Takács, T. Fekete, J. Borsa, L. Wojnárovits

P33. Radiation formation of nanogels based on poly(acrylic acid) for applications in radiation therapy M. Matusiak, S. Kadlubowski, P. Ulanski

P34. Radiation and sonochemical formulation of gold nanoparticles R. Czechowska-Biskup, B. Rokita, P. Sawicki, P. Komorowski, P. Ula ński, J.M. Rosiak

P35. Poly(acrylic acid) grafted PET track-etched membranes as nanoscale template for gamma-radiation synthesis of silver and gold nanoparticles I. Korolkov, O. Güven, A. Mashentseva

P36. Use of experimental irradiatiors for products specification validations H. Michel, C. Johnson , B. McEvoy

P37. Removal of uranyl ions from water by sodium alginate-acrylamide semi- interpenetrating networks S. Demir, M. Torun, D. Şolpan

P38. Preparation of ion-exchange adsorbent by radiation-induced grafting of 4-vinyl pyridine onto cellulose microsphere for Cr(VI) removal H.-L. Ma, Y. Zhang, J. Peng, J. Li, L. Wang, X. Zeng, M. Zhai

P39. Preparation of immunoglobulin adsorbents by radiation-induced grafting of cellulose fibers G. Torchio, M.L. Carbajal, M. Grasselli

P40. The effect of gamma irradiation of the properties of poly(3- hydroxybutyrate-co -3-hydroxyvalerate) blends Y. Liu, B. Li, H. Yu, L. Wang, X. Zeng, B. Guo

P41. Preparation of chitosan/poly vinylpyrrolidone matrices by gamma irradiation: characterization and preliminary cell response studies M.H. Casimiro, S.R. Gomes, G. Rodrigues, J. Paulo Leal, L.M. Ferreira

P42. Construction of multi-purpose irradiation facility at KACST B. Han, T.S. Alkhuraiji, W.-G. Kang, C.M. Kang, A.A. Alwatban

P43. Synthesis of hydrogels based on DMAPMA-co -IA by gamma radiation for the retention of heavy ions J. Apango, A. Ortega

P44. Radiation effects in the PVDF/graphene oxide nanocomposites J.V. Pereira, A.S.M. Batista, J.P. Nascimento, C.A. Furtado, L.O. Faria

P45. P(VDF-TrFE) / Nanosized Bi 2O3 Polymer-composites for X-Ray shielding C.C.P. Fontainha, A.T.B. Neto, L.O. Faria

P46. Truths and myths about aging and fading of PADC radon detectors J.M. Wasikiewicz

P47. Fabrication of thermo-responsive membrane for medical devices by radiation grafting Y. Yamahara, T. Hinata, N. Nagasawa, A. Oshima, M. Washio

P48. Calibration of radiation survey meters using the braking rays of an electron beam A. Chapon

P49. Formation of nanowires via solid state polymerization/crosslinking reactions of organic materials induced by swift heavy ion irradiation A. Horio, T. Sakurai, S. Seki

P50. Preparation of well-defined erytromycine imprinted non-woven fabrics via gamma irradiation induced grafting M. Akbulut Söylemez, M. Barsbay, O. Güven

P51. Template effect on the size and size distribution of free volume holes in the molecularly imprinted networks synthesized via gamma irradiation M. Akbulut Söylemez, O. Güven

P52. Evaluation of electron beam energy spread variation and its influence on radiation processing Z. Zimek, V.M. Lazurik, V.T. Lazurik, G. Popov

P53. Acrylic polymer grafted onto polypropylene sutures for antimicrobial materials F. López-Saucedo, E. Bucio

P54. Synthesis and characterization of polymeric films rich in primary amines for cell cultures, by gamma radiation M.P. Pérez-Calixto, G. Burillo

P55. Development of thermos-responsive hydrogels membranes: N-isopropyl acrylamide and N-vinyl caprolactam by ionizing radiation for biomedical application J.E. López-Barriguete, E. Bucio

P56. Radiation resistance assessment of EPDM formulation for electrical insulation S.R. Scagliusi, E.C.L. Cardoso, T. Zaharescu, A.B. Lugão

P57. Polyethylene as a benchmark for advanced first principles calculations of optical properties of polymers G. Roma, D. Moodelly, L. Martin-Samos, F. Bruneval

P58. Characterization of radiolytic ageing of EVA/EPDM polymer by ATR- FTIR spectroscopy and Principal Component Analysis A. Levet, J. Colombani, L. Duponchel

P59. Effect of radiation on mechanical properties of FKM rubber before and after vulcanization H.A. Zen, A.B. Lugão

P60. Vulcanization of cis-1,4-polybutadiene rubber (CPBR)/nature rubber (NR) by 60 Co gamma radiation W. Wang, Y. Jiao, Y. Lu, A. Ren, J. Liu, X. Zeng, L. Wang, Y. Zhang, Y. Guo

P61. Grafting of N-vinylcaprolactam and 2-hydroxyethyl methacrylate onto polypropylene films for biomedical applications G. González-Hernández, E. Bucio

P62. Preparation of nanogels by radiation-induced crosslinking of interpolymer complexes of poly(acrylic acid) with poly(vinyl pyrrolidone) and poly(vinyl imidazole) in aqueous medium and their characterization M. Ghaffarlou, O. Güven

P63. Evaluation of MAGAT polymer gel with CBCT P. Sathiyaraj, E.J.J. Samuel

P64. Radiation-induced crosslinking of polyamide 11 in presence of triallyl isocyanulate T. Tago, N. Nagasawa, H. Kudo, M. Taguchi

P65. How much ionizing radiation may induce negative effects on resistence properties of double packaging for medical products protection? K.M.B.G. Porto, S.I. Borrely

P66. Irradiation influence on the properties of HMS-polypropylene clay/AgNPs compounds masterbatches W.L. Oliani, D.F. Parra, L.G.H. Komatsu, V.K. Rangari, N. Lincopan, A.B. Lugão

P67. Radical processes induced in collagen by radiation sterilization G. Przybytniak, E. Kornacka, J. Sadło, Z. Zimek

P68. Comparative study of the polypropylene irradiated versus polypropylene with pro-degradant additive exposed to the natural aging R.S. Grecco Romano, W.L. Oliani, D.F. Parra, A.B. Lugão

Oral presentations

O1. TRIBUTE TO NATACHA BETZ

S. Bouffard 1,*

1 CIMAP, CEA-CNRS-ENSICAEN-UCBN, BP 5133, F-14070 Caen cedex 5, France 55* [email protected]

Session I. Fundamentals on ionizing radiation interactions with polymers

O2. RADIATION-INDUCED MODIFICATIONS OF POLYMERS: INFLUENCE OF THE NATURE OF THE PROJECTILE

Emmanuel Balanzat 1,*

1 CIMAP, CEA-CNRS-ENSICAEN-UCBN, BP 5133, F-14070 Caen cedex 5, France * [email protected]

Polymers could undergo irradiation by a wide variety of projectiles (X or γ rays, electrons, ions and neutrons) of very different energies. The aim of this lecture is to put forward the influence of the projectile in the radiation-induced modifications. This influence is due to the differences in the energy deposition at the nanometer scale.

The first part of this lecture will consist in remembering the bases of the energy losses of the mentioned projectiles (nuclear reactions, photoelectric and Compton effects, excitation ionization, elastic displacements) as function of the nature and energy of the projectiles. The consequences at the macroscopic level (penetration and Linear Energy Transfer (LET) depth profiles) and nanometer level (electron spurs, blobs and short tracks, ion tracks and their radial dose distribution, ion velocity effect).

The second part will be a synthetic review of the principal consequences of changing the LET in polymers (mainly polyolefins) by using Swift Heavy Ions (SHI). We will address both the oxic and anoxic conditions and consider the gas release and the changes in the polymer chains and network. Finally the applied contexts where SHI are involved (alpha radiolysis and Ion Track Technologies) will be recalled.

Session I. Fundamentals on ionizing radiation interactions with polymers

O3. BASIC MECHANISMS OF THE RADIATION DAMAGE IN POLYMERS AT CRYOGENIC TEMPERATURES: MODEL STUDIES AND IMPLICATIONS

Vladimir I. Feldman 1,*

1 Department of Chemistry, Lomonosov Moscow State University, Moscow 119991 Russia * [email protected]

The studies on the radiation-induced transformations in macromolecules at low and ultra-low temperatures (4 to 100 K) are directly related to various advanced applications, including space technology, development of the radiation-resistant insulation materials for superconducting magnets, X-ray crystallography of biomacromolecules, etc. Meanwhile, the most important basic aspect of these studies is concerned with modeling the mechanisms of early stages of the radiation-induced effects. Generally it is supposed that the secondary processes (in particular, radical reactions) are completely frozen at cryogenic temperatures, whereas the primary events (positive hole and excitation migration, ion-electron recombination) are virtually unaffected by temperature. However, a detailed consideration reveals more complicated effect of temperature and shows hidden mechanisms, which may lie behind the observed features of the radiation-induced damage. This lecture summarizes basic findings in this area over several decades and presents an overview of the state-of-art situation, with particular impact on the extensive experimental studies carried out in our laboratory using a combination of FTIR and EPR spectroscopy. The following aspects are considered:

(i) model studies on the radiation-induced transformations of small molecules under the conditions of matrix isolation, identification of primary ionic and radical intermediates; (ii) the role of “hot” reactions in the radiation chemistry at ultra-low temperatures; (iii) long-range hole and electron migration at cryogenic temperatures; (iv) impact of spatial distribution on the raditaion-induced reactions in solid polymers; (v) low-temperature dynamics and peculiarities of the local radical site migration.

In summary, it can be concluded that the studies of the radiation effects at cryogenic temperatures may provide unique insight into basic mechanisms, localization and selectivity of the radiation-induced processes in polymers. Finally, some paradoxes and unresolved issues are discussed.

Financial support from the Russian Science Foundation (project no. 14-13-01266) is acknowledged.

Session I. Fundamentals on ionizing radiation interactions with polymers

O4. ELECTRON DYNAMICS IN PRIMARY PROCESS OF RADIATION CHEMISTRY STUDIED BY FEMTOSECOND PULSE RADIOLYSIS

Y. Yoshida 1,*

The Institute of Scientific and Industrial Research, Osaka University, Japan * [email protected]

Although the dynamics of electrons after the ionization is very important for understanding the primary process of radiation chemistry, it has been difficult to observe the dynamics, because of the lack of time-resolution of pulse radiolysis. However, the recent progress of femtosecond pulse radiolysis [1] enables us to observe the electron behaviours directly. The dynamics of electron in femtosecond and picosecond time regions were studied in polar and non-polar liquids.

In water and alcohols, several kinds of electrons, such as a dry electron, a pre-solvated electron and a solvated electron, exist in femtosecond and picosecond time regions, which make the primary process to be complicated. Their formation times [2-3] and reactivities with solutes were obtained and the solvation model was proposed [3].

In non polar liquid, such as alkane, the geminate ion recombination of a relaxed cation radical with a thermalized electron is an important reaction. However, their precursors, the excited state of the radical cation [4] and the high mobile electron have been observed. These precursors should be considered in the geminate process, because the decomposition process of alkane is closely related with the geminate process.

References [1] J. Yang, et al., Nucl. Instr. Meth., A 556 (2006) 52. [2] J. Yang, et al., Nucl. Instr. Meth., A 629 (2011) 6. [3] T. Toigawa, et al., Radiat. Phys. Chem., 23 (2016) 73 [4] T. Kondoh, et al., Radiat. Phys.Chem., 84 (2013) 30.

Session I. Fundamentals on ionizing radiation interactions with polymers

O5. NEW SYSTEM FOR TIME-RESOLVED PULSE RADIOLYSIS WITH MULTI-ANGLE LIGHT SCATTERING DETECTION

Slawomir Kadlubowski 1,* , Bozena Rokita 1, Klaus-Dieter Bures 2, Janusz M. Rosiak 1, Piotr Ulanski 1

1 Lodz University of Technology, Institute of Applied Radiation Chemistry, Wroblewskiego 15, 93-590 Lodz, Poland 2 WGE Dr Bures GmbH&Co KG, Hauptstr. 19-20, 14624 Dallgow-Doeberitz, Germany * [email protected]

Time-resolved pulse radiolysis, utilizing short pulses of high-energy electrons from accelerators, is an effective method for rapidly generating free radicals and other transient species in solution. Combined with fast time-resolved spectroscopic detection (typically in the ultraviolet/ visible/ near-infrared), it is invaluable for monitoring the reactivity of species subjected to radiolysis on timescales ranging from picoseconds to seconds. When used for polymer solutions, pulse radiolysis can be coupled with light-scattering detection, creating a powerful tool for kinetic and mechanistic analysis of processes like degradation or crosslinking of macromolecules. Changes in the light scattering intensity (LSI) of polymer solutions are indicative of alterations in the molecular weight and/or in the radius of gyration, i.e., the dimensions and shape of the macromolecules. In addition to other detection methods, LSI technique provides a convenient tool to study radiation-induced alterations in macromolecules as a function of time after the pulse. Prerequisite for the application of the LSI method is the property of a polymer to scatter light of a given wavelength much stronger than the neat solvent. First attempts to combine light scattering technique and pulse radiolysis were made by Schnabel et al. in 1970’s. [1] Second system of this type has been built at the Institute of Applied Radiation Chemistry (IARC) in Lodz by Rosiak and co-workers. [2] Both of them were measuring intensity of light scattered at one (right) angle. Another setup, constructed at the Max-Planck-Institute for Radiation Chemistry, was able to detect scattered light at a single low angle. [3] Nowadays an advanced pulse radiolysis & multi-angle light- scattering-intensity system is being built at IARC. Idea of its operation and preliminary results will be shown. Implementation of the proposed system will provide a novel research tool, which is expected to contribute to the expansion of knowledge on free-radical reactions in monomer- and polymer solutions, by delivering precise kinetic data on changes in molecular weight and size, and thus allowing to formulate or verify reaction mechanisms. The proposed method is universal and can be applied for studying both natural and synthetic polymers. The developed system can be also valuable in studies of the border of biology and medicine, especially on radical reactions of biopolymers and their conformational transitions. Furthermore, capability to follow fast changes in mass and dimensions of nanoobjects may be of significant importance for nanoscience and nanotechnology.

References [1] W. Schnabel (1974); Eur. Polym. J. 10, 106. [2] R. Lubis, J. Olejniczak, J. Rosiak, J. Kroh (1990); Radiat. Phys. Chem. 36, 249 [3] M. Adinarayana, E. Bothe, D. Schulte-Frohlinde (1988); Int. J. Radiat. Biol. 54, 723.

Acknowledgements This project was supported by the National Science Centre, Poland (grant no. 2012/07/B/ST4/01429)

Session II. Polymer ageing: defects creation, chemical modification

O6. INORGANIC FILLERS INFLUENCE ON THE RADIATION- INDUCED CROSSLINKING OF A SILICONE ELASTOMER: CHEMICAL STRUCTURE AND ELECTRICAL PROPERTIES

Aurélien Roggero 1, Eric Dantras 1,* , Thierry Paulmier 2, Claire Tonon 3, S. Lewandowski 2, S. Dagras 3, Denis Payan 4

1 Physique des Polymères CIRIMAT, Université Paul Sabatier, 108 route de Narbonne, 31062 Toulouse Cedex 9, France 2 ONERA, The French Aerospace Lab F-31055, France 3 Airbus Defence and Space, 31 Avenue des Cosmonautes, 31402 Toulouse, France 4 Centre National d’Etudes Spatiales, 18 Avenue Edouard Belin, 31400 Toulouse, France *[email protected]

In the geostationary space environment, satellites are exposed to high fluxes of electrons and protons. These ionizing radiations interact with the surface materials, causing bond scission and recombination in polymers. Chemical ageing is likely to induce evolutions of the physical properties of the material during the spacecraft lifetime (15 years). This study focused on the space radiation-induced ageing of a filled silicone adhesive. The structural evolutions and associated degradation mechanisms were identified and their influence on the electrical resistivity analyzed so as to propose empirical structure-electrical properties relationships. In order to assess the filler influence on both structural and electrical degradations, neat samples (isolated polysiloxane matrix) were studied in parallel with the filled ones. Upon 400 keV-electronic irradiation (~10 6 Gy), mechanical and calorimetric analyses led to the conclusion that the fillers induce further crosslinking than in the isolated polymer matrix. Solid- 29 state Si NMR spectroscopy allowed identifying T-type SiO 3 as the main crosslinks formed under irradiation. In conjunction with solvent swelling tests, NMR also gave insight into an additional crosslinking process occurring at the filler-matrix interfaces and involving the formation of Q-type SiO 4 crosslinks, which resulted in a more pronounced increase in mechanical modulus 1. The electrical resistivity of both samples was found to increase upon irradiation, over more than one order of magnitude (e.g., from 10 13 up to 10 15 Ω. m in the filled samples). Similarly to the degree of crosslinking, a more pronounced increase in resistivity was observed in the filled samples than in the neat ones. Moreover the activation energy of charge transport (Arrhenius temperature dependence 2) doubled for the filled samples whereas it remained constant in the neat case. These filler-induced discrepancies were associated with the additional crosslinking process at the filler-matrix interfaces. The framework of the electronic percolation allowed proposing empirical structure-electrical resistivity relationship coherent with the evolutions observed upon irradiation. On one hand, the increase in resistivity was explained in terms of an increasing number of electron traps (crosslinking sites) in series. On the other hand the Q-type crosslinks at the filler-matrix interfaces were considered as deeper electron traps than the regular T-type SiO 3 formed in the polymer matrix, resulting in increased activation energy. These results stress the importance of the choice of a polymer formulation for space applications: fillers that were initially incorporated for mechanical reinforcement induce further degradation of the electrical resistivity, resulting in higher failure risk (electrostatic discharges) in the long run.

References [1] Roggero, A.; Dantras, E.; Paulmier, T.; Tonon, C.; Dagras, S.; Lewandowski, S.; Payan, D. Polym. Degrad. Stab. 2016; In Press. [2] Roggero, A.; Dantras, E.; Paulmier, T.; Tonon, C.; Balcon, N.; Rejsek-Riba, V.; Dagras, S.; Payan, D. J. Phys. D. Appl. Phys. 2015, 48 (13), 135302.

Session II. Polymer ageing: defects creation, chemical modification

O7. STUDY OF THE HYDROLYSIS OF AN INDUSTRIAL RADIO- OXIDIZED POLY(ESTER URETHANE)

E. Fromentin 1, *, M. Ferry 1, S. Legand 1, D. Lebeau 1, J.J. Pielawski 2, S. Esnouf 1, P. Reiller 3, D. Doizi 1, C. Aymes-Chodur 4

1 Den-Service d’Etude du Comportement des Radionucléides (SECR), CEA, Université Paris- Saclay, F-91191, Gif-sur-Yvette, France. 2 AREVA E&P, 1 place Jean Millier, F-92084 La Défense Cedex, France. 3 Den-Service d’Etudes Analytiques et de Réactivité des Surfaces (SEARS), CEA, Université Paris-Saclay, F-91191, Gif-sur-Yvette, France. 4 Université Paris-Sud, Laboratoire Matériaux et Santé, EA 401, IFR141, F-92296 Châtenay- Malabry, France. * [email protected]

Polymers are widely used in the nuclear industry and will be found in Intermediate Level Waste Long Lived (ILW-LL) nuclear waste packages. In the French context, the ILW-LL packages are to be disposed of in a geological repository. During disposal, polymers will undergo radiooxidation from radionuclides present in the packages, and alkaline hydrolysis because of the water re-saturation of the repository and water percolation through the concrete backfill [1]. Very few studies focus on the hydrolysis of radio-oxidized polymers, and for the safety assessment of the repository it seems important to improve this knowledge. Indeed, some hydrosoluble degradation products (HDPs) are able to increase the mobility of radionuclides [2-5]. In this study, an industrial poly(ester urethane), used as glove for glove-boxes, is irradiated with γ-rays under air at room temperature at a dose rate of 0.9 kGy ·h-1 up to 1000 kGy. Non- irradiated and irradiated materials are hydrolyzed in alkaline (KOH/NaOH) or pure water, at different temperatures (room temperature, 40, and 60°C). Two series of experiments are performed: first, to obtain concentrated HDP solutions, pH of the solutions is kept constant by KOH addition. Second, the hydrolysis solution is regularly renewed to evaluate the release kinetics of HDPs. The obtained hydrolysis solution are analyzed using total organic carbon analyzer, ionic chromatography, gas chromatography coupled with mass spectrometry, liquid chromatography etc. It is observed that the HDPs release rate increases with hydrolysis temperature. At room temperature and at 40°C, the higher the absorbed dose, the more concentrated the HDP. Mass balances are established through the total organic carbon and organic molecules quantifications . Adipic acid is one of the main HDP: other molecules such as diacids, alcohols, diols and ketones are also detected in the solution.

References [1] Berner, U.R., Waste Management, 1992. 12(2–3): p. 201-219. [2] Colombani, J., Herbette, G., Rossi, C., Joussot-Dubien, C., Labed, V., and Gilardi, T., Journal of Applied Polymer Science, 2009. 112(3): p. 1372-1377. [3] Dannoux, A., Esnouf, S., Amekraz, B., Dauvois, V., and Moulin, C., Journal of Polymer Science Part B: Polymer Physics, 2008. 46(9): p. 861-878. [4] Fromentin, E., Pielawski, M., Lebeau, D., Esnouf, S., Cochin, F., Legand, S., and Ferry, M., Polymer Degradation and Stability, 2016. 128: p. 172-181. [5] Glaus, M.A. and Van Loon, L.R., Environmental Science & Technology, 2008. 42(8): p. 2906-2911.

Session II. Polymer ageing: defects creation, chemical modification

O8. EFFECT OF SPATIAL CONFINEMENT ON THE RADIOLYTIC EFFICIENCY OF HIGH-ENERGY IONS IN POLYMERS

R. Thomaz 1,* , L. I. Gutierres 1, J. Morais 2, P. Louette 3, J. J. Pireaux 3, D. Severin 4, C. Trautmann 4,5 and R.M. Papaléo 1

1Faculdade de Física, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil. 2 Instituto de Física, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil. 3 Université de Namur, Namur, Belgium. 4 Materials Research, GSI Helmholtz Centre, Darmstadt, Germany. 5 Technische Universität Darmstadt, Darmstadt, Germany. * [email protected]

In this work, the radiolytic efficiency in polymer thin films has been quantified, following the chemical damage induced by MeV-GeV heavy ions as the layer thickness h of the films is systematically reduced (2< h<200 nm). X-ray photoelectron spectroscopy (XPS) was the employed to evaluate bond-breaking in the polymer thin films after ion irradiation. We evaluated the rate of decrease of C-O and C-Cl XPS peaks in PMMA and PVC films as a function of the thickness of the polymer layers. Bond breaking cross sections, estimated from XPS data were found to be insensitive to thickness reductions, even in layers as thin as 5nm. The damage cross-sections for PMMA were ~1.5x10 -13 cm 2 (for O-C-O bonds) and ~2.3x10 -13 cm 2 (for C=O bonds) for the 2.2 GeV Bi irradiation, whilst for 2 MeV H irradiation the values were ~2.7x10 -16 cm 2 and ~4.4x10 -16 cm 2, for O-C-O and C=O bonds, respectively. Meanwhile, PVC damage cross-sections for C-Cl bonds were estimated as ~1.5x10 -15 cm 2 for 2 MeV H irradiation. Films thinner than ~5 nm become difficult to analyse, because of the non-negligible influence of the adventitious carbon on the substrate, combined to changes caused by the ion beam (such as roughening and thinning). These findings indicate that most of the bond-breaking induced by the ions is related to short-range events close to the track core. The absence of a decrease in the damage cross section in ultrathin layers is somewhat surprising, considering that radiation chemistry of heavy ion tracks is, to a large extent, controlled by the energy spread by secondary electrons, which may escape from the ultrathin films before they thermalize, lowering the effective radial dose, especially at high ion velocities. Our observations are also in contrast to recent studies showing that surface effects, such as mass transport and cratering formation, are substantially weakened when individual ion tracks are confined into polymeric ultra-thin films due to the suppression of cooperative effects of excited atoms along the ion track.

Session II. Polymer ageing: defects creation, chemical modification

O9. OXIDATIVE DEGRADATION OF POLYETHYLENE STUDIED BY POSITRON ANNIHILATION LIFETIME SPECTROSCOPY

T. Oka 1,2,* , K. Onodera 2, Y. Kino 2, T. Sekine 1

1 Institute for Excellence in Higher Education, Tohoku University, Japan 2 Department of Chemistry, Tohoku University, Japan * [email protected]

Polyethylene (PE) is widely used for an insulator, a covering material, etc., in various radiation environments such as nuclear plants, accelerators, and so on. The irradiation effect and the degradation of PE have been studied because they are very important for the safety of the equipment and the facilities. In this work, we investigated the irradiation effect and degradation of PE using positron annihilation lifetime spectroscopy (PALS), which is a powerful tool to measure sub-nanometer holes in polymers called free volume [1] non-destructively. Additive free high density polyethylene (HDPE) and low density polyethylene (LDPE) were used. An electron beam was irradiated up to 1000 kGy under vacuum at room temperature. Change of the chemical structure and the nanostructure of both PEs were periodically examined by micro-FT-IR spectroscopy, gel fraction measurement, and PALS. Application of PALS relies on the fact that some of the positrons injected into a polymer combine with an electron to form the hydrogen-like bound state, positronium. In a polymer, spin-parallel ortho -positronium (o-Ps) annihilates by pick-off annihilation in a free volume with one of the surrounding electrons and the lifetime of o-Ps increases with increasing hole size [2,3], so we can estimate the free volume size from the lifetime of o-Ps. The o-Ps lifetime for immediately after the irradiation and during the long-term storage did not change whereas the o-Ps relative intensity clearly decreased with dose and also decreased during the storage. On the other hand, the degree of cross-linking estimated by gel fraction test increased with dose but no change was observed with time. These results suggest that the crosslinking of the PE can lead the decrement of the o-Ps intensity but not for the long-term storage. The carbonyl groups increased after the irradiation and those gradually increased with time due to the auto-oxidation. It is known that the carbonyl groups are one of the inhibitor for o-Ps formation, so that the increase of the carbonyl groups probably lead the decrement of the o-Ps intensity during the storage. The o-Ps intensity systematically decreases with increasing the total carbonyl groups absorbance for HDPE, suggesting that one can evaluate the degradation of the HDPE non-destructively from the point of view of the oxidation using PALS. In addition, the nanostructure change near the surface of the sample measured by the variable-energy positron beam will be also discussed.

A part of this work was supported by AIST Nanocharacterization Facility (ANCF) platform as a program of "Nanotechnology Platform" of the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan.

References [1] Oka T., Oshima N., Suzuki R., Uedono A., Fujinami M., Kobayashi Y. Free volume change of elongated polyethylene films studied using a positron probe microanalyzer. Appl. Phys. Lett. 101 (2012) 203108. [2] Tao S. J. Positronium snnihilation in molecular substances. J. Chem. Phys. 56 (1972) 5499-5510. [3] Eldrup M., Lightbody D., Sherwood J. N. The temperature dependence of positron lifetimes in solid pivalic acid. Chem. Phys ., 63 (1981) 51-58.

Session III. Nanostructuration, composites

O10. RECENT DEVELOPMENTS ON ETCHED ION-TRACK MEMBRANES FOR SENSOR APPLICATIONS

M.E. Toimil-Molares 1,* , A. Spende 1,2 , N. Ulrich 1,2 , M. Carrillo-Solano 1, C. Trautmann 1,2

1 Materials Research Department, GSI Helmholtz Centre for Heavy Ion Research, Darmstadt, Germany 2 Materials Science, Technical University Darmstadt, Germany * [email protected]

In the past decades, multichannel etched ion-track membranes have been widely used for applications in filtration, surface protection, and life sciences, and as templates for the formation of nanowires and nanotubes [1]. Their fabrication involves two separate processing steps: (i) Irradiation of the template material with swift heavy ions and creation of latent tracks; (ii) selective ion-track dissolution and formation of channels by chemical etching. Control over the irradiation and etching conditions enables the production of various membranes with channels of predefined geometries, sizes and aspect ratios [2]. More recently, single etched ion-track membranes have been developed and characterized as nanofluidic diodes. Currently, efforts are being particularly devoted to develop surface modification techniques that confer specific surface functionalities to the nanochannels. In this talk, we will present recent results obtained on the surface modification of etched ion- track membranes by atomic layer deposition (ALD) [3,4]. By ALD, we have successfully and conformally coated membranes with few nm thin SiO 2, TiO 2, and Al 2O3 layers. The coatings have been characterized by scanning electron microscopy after dissolution of the polymer template in an organic solvent. Figure 1 shows representative images of the resulting cylindrical and conical tubes, as well as nanotube networks. Ionic transport studies of cylindrical and conical single nanochannels before and after ALD will be discussed, explaining in particular how the isoelectric point of the deposited surface layer affects the ionic transport at different pH values. In addition, recent examples of polymer-based nanochannel sensors based on different surface modification methods will be discussed.

Figure 1. Scanning electron microscopy images of a) Al 2O3 cylindrical nanotube, b) SiO 2 conical nanotube c) TiO 2 nanotube network, visualized after dissolution of the polycarbonate etched ion-track membrane.

References [1] C. Trautmann, Particle Acceleration and Detection Ion Beams in Nanoscience and Technology 2010, p. 369-387 R. Hellborg, H. J. Whitlow and Y. Zhang Springer Berlin Heidelberg [2] M.E. Toimil-Molares, Beilstein J. of Nanotechnology 3 (2012) 860. [3] N. Sobel et al. Beilstein J. of Nanotechnology 6 (2015) 472. [4] A. Spende et al. Nanotechnology 26 (2015) 335301 .

Session III. Nanostructuration, composites

O11. GENERATION AND GROWTH OF COPPER AND SILVER NANOPARTICLES IN IRRADIATED POLY(ACRYLIC ACID) AND POLYVINYLTRIAZOL BASED SYSTEMS

Alexey A. Zezin 1,2,* , Vladimir I. Feldman 2, Gurgen V. Danielyan 1, Elena A. Zezina 2, Sergei S. Abranchuck 2, Galina F. Prozorova 3

1 Enikolopov Institute of Synthetic Polymer Materials of the Russian Academy of Sciences, Profsoyuznaya ul. 70, Moscow, 117393 Russia. 2 Department of Chemistry, Lomonosov Moscow State University, Moscow, 119991 Russia. 3 Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, Irkutsk, 664033, Russia. * [email protected]

Polymer composites with copper and silver nanoparticles are of considerable interest due to their optical, antibacterially and fungicidal properties, catalytic and electrocatalytic activity.The key problem for obtaining of nanocomposites is tunning of the size and spatial distribution of nanoparticles [1,2]. The difference in the ability of functional groups of poly(acrylic acid) (PAA) and polyvinyltriazol (PVT) to bind metal ions/surface provides the interest for study of effects of these polymer matrices on the formation of nanoparticles. The nanoparticles were obtained in solutions and suspensions of PAA and the PVT or in the films of PAA-PVT interpolymer complexes with of copper or silver ions which were irradiated in aqueous-ethanol medium. The electron microscopy, XRD and optical spectroscopy were used for study the structure of nanoparticles. In solutions linear and star shape PAA [3] the pH increase leads to the change of the mechanism of nanoparticles assembly. For aquacomplexes of Cu(II) ions (at pH 2.9), the formation of the Cu- nanoparticles proceeds through homogeneous nucleation. When Cu(II) ions are localized inside PAA stars (at pH 4.3), the ripening of Cu-nanoparticles is considered to occur from the preformed Cu 2O seeds (heterogeneous nucleation). Such localization and concentrating of Cu(II) ions provides a specific regime for the formation of Cu nanoparticles. In this case for star shape PAA macromolecules, each PAA star acts as an individual nanoreactor where in such nanoparticle is generated. Irradiation of PAA solutions with Ag(I) in pH range 3-6 leads to formation of nanoparticles with wide size distribution. On the other hand suspension PVT provide size control for silver nanoparticles and poor stabilization for copper nanoparticles. Silver and copper nanoparticles may be successfully obtained in PAA- PVT complexes. The role of interaction PAA or PVT functional groups with metal ions/surfaces is under discussion.

The support from the Russian Foundation for Basic Research (project no. 15-03-04886) is gratefully acknowledged.

References [1] Belloni J. Nucleation, growth and properties of nanoclusters studied by radiation chemistry: Application to catalysis. Catal Today 113 (2006), 141 [2] Pergushov D.V., Zezin A.A., Zezin A.B.; Müller, A.H.E. Advanced functional structures based on interpolyelectrolyte complexes. Adv. Polym. Sci. 255 (2014), 173 [3] Zezin A.A., Feldman V.I., Abramchuk S.S., Danelyan G.V., Dyo V.V., Plamper F.A., Müller A.H., Pergushov D.V.. Efficient size control of copper nanoparticles generated in i rradiated aqueous solutions of star-shaped polyelectrolyte containers. Phys. Chem. Chem. Phys. 17 (2015), 11490.

Session III. Nanostructuration, composites

O12. DIFFERENT ARCHITECTURES OF HYDROGELS BASED ON CHITOSAN AND DIMETHYLACRYLAMIDE

Daniel Tinoco 1, Alejandra Ortega 1, Luisa Islas 1, Guillermina Burillo 1,*

1 Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de México, Av. Universidad#3000 Ciudad de México 04510, México * [email protected]

The present work focuses on the interpretation of metal ion adsorption mechanisms in relation with CS hydrogels modified with dimethylacrylamide (DMAAm) in three different architectures: comb type grafting hydrogels ( net-CS)-g-DMAAm, interpenetrating networks of CS and DMAAm ( net-CS) -inter-(net -DMAAm), and semi-interpenetrating hydrogels ( net- DMAAm)-inter-CS. These compounds were chosen because in acidic solutions, the amino groups of CS protonate and there is an electrostatic attraction of metal anions, while DMAAm gives more hydrophilicity and better mechanical properties to the different systems. The synthesis of different polymeric architectures was carried out with ionizing radiation from gamma rays of a 60 Co source.

The crosslinking of DMAAm was performed by gamma radiation of a DMMAm aqueous solution in glass ampoules that were previously bubbled with argon to eliminate oxygen. To form the ( net -CS)-g-DMAAm comb type system, solutions of different concentration of CS (2% w/v) and DMAAm (2-10% vol) in acetic acid were place in glass ampoules, bubbled with argon, sealed and irradiated at different doses. To synthesize the graft copolymer CS-g- DMAAm, without DMAAm gel formation, this copolymer was dissolved in acetic acid (2% vol), and formaldehyde was added to the solution as a CS crosslinking agent. Semi- interpenetrating networks of CS in DMAAm hydrogels ( net -DMAAm)-inter-CS were synthesized by irradiating DMAAm (10-50% vol) in the presence of CS. The interpenetrating networks were synthesized by mixing DMAAm, CS and formaldehyde in an acetic acid solution; the crosslinking reaction of CS was carried out by the presence of formaldehyde, the ampoules were then bubbled with argon to eliminate the oxygen and sealed, followed by irradiation at different doses for the DMAAm crosslinking. The chromate retention studies were realized by UV spectroscopy at 375 nm and pH 7, at different chromate concentrations in the limit of retention time, and in different studied systems.

Acknowledgments The authors thank L.M. Valdes, F. Garcia and M.L. Escamilla from ICN UNAM for their technical support and DGAPA UNAM IN200214 for financial support.

Session IV. Energy

O13. PERFORMANCE OF POLYETHYLENE SEPARATOR MODIFIED BY RADIATION FOR LITHIUM SECONDARY BATTERY

Y.C. Nho 1,* , J.Y. Sohn 1, J.H. Shin 1, J.S. Park 1, Y.M. Lim 1, J.P. Jeun 1, P.H. Kang 1

1 Radiation Research Division for industry & Environment, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, 1266 Sinjeong-dong, Jeongeup-si, Jeollabuk-do, Korea * [email protected]

Though polyolefin-based separators for lithium secondary batteries are widespread and have many advantages, their thermal shrinkage and mechanical strength have raised serious concerns with their ability to maintain the necessary electrical isolation between electrodes, particularly under vigorous conditions such as abnormal heating or mechanical rupture. A various approaches for overcoming these technical drawbacks of polyolefin-based separators have been investigated, including polyethylene terephthalate nonwoven fabrics, nanofiber- based separators by electrospinning and self-standing inorganic separators. In this study, radiation technology was tried to reduce the thermal shrinkage of the polyethylene separators. Firstly, polyethylene separators were irradiated by electron beam to investigate the radiation effect on polyethylene separators. In another attempt, porous poly(vinylidenefluoride- hexafluoropropylene) involving silylated γ-Al 2O3 was introduced onto polyethylene separators by a dip coating under various relative humidity condition and followed by a EB irradiation.

The prepared separators were characterized with FT-IR, surface morphology, electrolyte uptake, ion conductivity, thermal shrinkage and battery performance. In battery performance test, the coin cell assembled with silylated γ-Al 2O3/PVDF-HFP/TTT(95/5/2)-coated polyethylene separator showed excellent properties compared to that with the others. Especially, the prepared separators containing crosslinker (TTT) and irradiated by electron beam showed improved thermal resistance.

Acknowledgement This work was supported by Nuclear R & D Program through the National Research Foundation of Korea funded by the Ministry of Science, ICT and Future Planning.

References [1] D.W. Kim, K.A. Nho, J.H. Chun, S.H. Kim, J.M. Ko, Solid State Ionic 2001, 144 , 329 [2] J.S. Oh, Y. Kang, D.W. Kim, Electrochim. Acta 2006, 52 , 1567 [3] W.H. Seol, Y.M. Lee, J.K. Park, J. Power Sources 2006, 163 , 247 [4] K.Yamanoto, H. Tanaka, M. Sakaguchi, S. Shimada, Polymer 2003, 44 , 7661 [5] A.M. Stepahn, D. Teeters, J. Power Sources 2003, 119 , 460

Session IV. Energy

O14. MECHANISTIC STUDY OF RADIATION-INDUCED GRAFT- POLYMERIZATION FOR APPLICATION IN FUEL CELLS

Yasunari Maekawa 1,*

1 Takasaki Advanced Radiation Research Institute, National Institutes for Quantum and Rogiological Science and Technology (QST), Japan * [email protected]

Radiation-induced graft polymerization (RGP) has been intensively investigated in the last 2 decades using thermally and mechanically stable fluorinated polymer substrates for application to fuel cells because of its intrinsic characteristics; “a new functional graft polymers (grafts) are directly introduced into the substrates while maintaining the initial crystallinity and mechanical strength”. However, the detailed mechanism of unique solid state RGP have not been revealed due to the insolubility of the grafted films even in strong solvents. Recently, we found that the polymer grafts in fluorinated polymer substrates can be isolated by the swelling induced detachment of the grafts without decomposition [1]. Taking advantages of this method, we investigated detailed mechanism for RGP of styrene onto a fluorinated polymer film, poly(ethylene-co-tetrafluoroethylene) (ETFE) by simple kinetics and phase transition phenomena; (1) The kinetic model includes only initiation, propagation, and bimolecular termination of radical polymerization even under very restricted viscous reaction media in the film state. (2) The phase transition of the films induced by the incorporation of the polystyrene (PS) at the grafting degrees (GDs) of 70-80%, which is confirmed by small-angle X-ray/neutron scattering (SAXS/SANS), restarts the propagation steps, probably because of the liberation of dormant initiation radicals in the crystalline state [2]. We had developed proton- and anion-conducting electrolyte membranes (PEM and AEM) for fuel cells. For PEM, the polystyrene (PS)-grafted-ETFE films were sulfonated to give PS- sulfonic acid (PSSA)-grafted films (ETFE-PEMs), which exhibited high proton-conductivity with high mechanical strength under low and high relative humidity (RH) conditions. The ETFE-PEMs showed three times higher power density than that of Nafion under low RH at 80 °C [3]. We recently applied this grafting technique to AEMs using vinylimidazole-type (VIm) monomers for application in non-noble metal alkaline-type fuel cells. The VIm-type AEM exhibited moderate basicity, resulting in the requirement conductivity with low water uptakes and high alkaline fuel durability (> 1000 hours) at 80 °C. Noted that even after the abovementioned phase transition with a large amounts of the grafts (GDs > 100%), the grafted films maintain the crystallinity at a certain level; this is the origin of high thermal and alkaline durability of the graft-type membranes.

References [1] K. Enomoto, S. Takahashi, T. Iwase, T. Yamashiata, Y. Maekawa, J. Mater. Chem. , 2011, 21 , 9343-9349. [2] T. D. Tap, S. Sawada, S. Hasegawa, K. Yoshimura, Y. Oba, M. Ohnuma, Y. Katsumura, Y. Maekawa, Macromolecules , 2014, 47(7) , 2373-2383. [3] T. Hamada, S. Hasegawa, H. Fukasawa, S. Sawada, H. Koshikawa, A. Miyashita and Y. Maekawa, J. Mater. Chem. A , 3, 20983-20991 (2015)

Session IV. Energy

O15. DEVELOPMENT OF HYBRID MATERIALS WITH ELECTRON BEAM TREATMENT AS AN INTERFACIAL LAYER FOR EFFICIENT POLYMER BASED PHOTOVOLTAIC DEVICES

Seung-Hwan Oh 1, Hyun Bin Kim 1, Jin-Moon Yun 1, Phil Hyun Kang 1,*

1 Korea Atomic Energy Research Institute (KAERI), 29 Geumgu-gil, Jeongup-si, Jeollabuk- do 56212, South Korea * [email protected]

Polymer based photovoltaic devices (PVs) have the merits of low-cost, lightweight and flexibility, which enable their mass production, large-area production and roll-to-roll process. As an effort to obtain a better power conversion efficiency, a hole- and electron-transporting layer is introduced between the electrode and active layer to improve the efficiency of carrier transport in PVs. To improve efficiency of PVs, 1) a hole-transporting hybrid material and 2) an electron-transporting material were developped using electron beam energy, respectively.

1) For hole-transporting material, we synthesized composite consisting of water-soluble conjugated polymer and graphene oxide (GO). The water-soluble conjugated polymer and GO hybrid material has been irradiated with an electron beam to improve the electrical conductivity for efficient hole-transporting property. This hybrid material was then used as a hole-transporting layer (HTL) between the active layer and anode. 2) And for electron-transporting material, ZnO prepared by sol-gel method is regarded as considerable promising electron transport material. However, high temperature annealing process and low carrier mobility are problems to realize flexible PVs. ZnO sol-gel solution was modified by electron beam radiation to use as an efficient electron transporting layer (ETL) in PVs.

As a result of the introduction of hole- and electron transporting materials with electron beam, power conversion efficiency of PVs was enhanced. In the presentation, we will discuss the effect of electron beam about development of water-soluble conjugated polymer and GO hybrid material, and modified ZnO used as an interfacial layer in PVs.

References [1] S. Bae, H. Kim, Y. Lee, X. Xu, J. -S. Park, Y. Zheng, J. Balakrishnan, T. Lei, H. Kim, Y. I. Song, Y. -J. Kim, K. S. Kim, B. Ozyilmaz, J. -H. Ahn, B. Hong, S. Iijima, Roll-to-roll production of 30-inch graphene films for transparent electrodes, Nat. Nanotech. 5 (2010) 574-578 [2] S. -H. Oh, S. -I. Na, J. Jo, B. Lim, D. Vak, D. -Y. Kim, Water-Soluble Polyfluorenes as an Interfacial Layer Leading to Cathode-Independent High Performance of Organic Solar Cells Adv. Mater. , 20 (2010) 1977-1983.

Session IV. Energy

O16. E-BEAM IRRADIATION BENEFICIAL EFFECT ON PVDF PIEZOELECTRICITY

G. Melilli 1, D. Lairez 2, D. Gorse 1, E. Garcia-Caurel 3, A. Peinado 3, O. Cavani 1, B. Boizot 1, M.-C. Clochard 1,*

1 Laboratoire des Solides Irradiés, CNRS UMR 7642, CEA-DRF-IRAMIS, Ecole polytechnique, Université Paris-Saclay, 91128 PALAISEAU cedex, France 2 Laboratoire Léon Brillouin, CNRS UMR 12, CEA-DRF-IRAMIS, 91191 GIF-SUR- YVETTE cedex, France 3 Laboratoire de Physique des Interfaces et des Couches Minces, CNRS UMR 7647, Ecole polytechnique, 91128 Palaiseau, Cedex, France * [email protected]

Poly(vinylidene fluoride) (PVDF), is one of the most attractive semi-crystalline polymer owing to its remarkable pyro-, piezo- and ferro-electric properties. These thermal and electrical properties results of an appropriate crystalline phase arrangement inside PVDF bulk. PVDF polymorphism is well-known and consists of four crystallines phases, named α, β, γ and δ phases. In β phase, PVDF chains are arranged in pairs adopting an all-trans planar zigzag conformation, resulting in a significant net dipole moment. Whatever the phases, poling is a necessary ultimate step to align whole microscopic net dipole moment to the direction of the electric field.

Since the discovery of the piezoelectric properties of PVDF in 1969, many research groups immediately understood the potential applications of the polarized β-PVDF as sensors and actuators. In the recent years piezoelectric PVDF membranes have experienced a resurgence of interest for energy harvesting. However, their use as electrical generators has remained rather limited due to their relatively low power output. With the decrease of portable electronic devices energy consumption, this limitation has nowadays become less critical.

Although its power output is generally lower than that of commonly used PZT ceramics, PVDF has the advantage that it can generate piezoelectric power under large reversible elastic deformation. We have shown that high irradiation energy is a competitive way to modify structural components of the piezoelectric polymer to enhance electro-active properties. Homemade pressure-cell system was realized to correlate the bending deformation on the PVDF membrane with the output voltage. Respect to commercial PVDF, the irradiated one exhibited twice as large output voltage. FT-IR technique gives new insights on which crystalline part or structural change contributes at the surplus output voltage. The results suggest that the state of crystalline region of the material after irradiation is composed of nano- polar regions which may explain the enhancement of electrostriction and relaxor ferroelectric behavior in electron-irradiated PVDF films.

Session IV. Energy

O17. ENHANCEMENT OF THE EXTRACTION OF THE URANIUM FROM SEAWATER

Travis Dietz 1, Zois Tsinas 1, Ileana Pazos 1, Aaron Barkatt 2, Dianne Poster 3, Fred B. Bateman 3, Lonnie T. Cumberland 3, Mohammad Adel-Hadadi 1, Mohamad Al-Sheikhly 1,*

1 Department of Materials Science and Engineering, University of Maryland, College Park, USA 2 Department of Chemistry, The Catholic University of America, Washington, USA 3 National Institute of Standards and Technology, Gaithersburg, Maryland, 20899, USA * [email protected]

The oceans contain significantly more dissolved uranium than currently known terrestrial sources. By developing technology to harvest this uranium, the technological complexity and environmental impact of conventional mining techniques can be avoided and the uranium stockpile can be expanded to allow for the nuclear fuel cycle to continue for many more centuries. While a number of methods for extraction dissolved uranium have been developed in the past, current interest in this technology has focused on the development of adsorbent fabrics produced using radiation-induced polymerization after Japanese groups collected over a kilogram of uranium with this method. This initial experiment however did not provide a commercially viable way for uranium to be harvested, and so the need remains for the development of more efficient adsorbents. Advanced adsorbent materials are being developed using polymeric substrates with high chemical stability, excellent degradation resistance and improved mechanical properties. Fabrics include polypropylene, nylon and advanced Winged Fibers™ from Allasso industries featuring extremely high surface areas for improved grafting density. Using a 60 Co gamma source or a 10-32 MeV electron beam linear accelerator, the various fabrics have been irradiated over a wide range of dose rates, total doses and temperatures and subsequently analyzed with EPR for determination of free radical concentration. Also being utilized are innovative allyl-functionalized phosphate monomers with high distribution coefficients and selectivity for uranium with excellent potential for free radical polymerization. Optimization of the grafting procedure involves precise control over reaction temperature, duration and methodology. Attachment of the chelating adsorbent to the substrate polymer is maximized by use of high monomer concentrations and quantified by determination of the grafting density of the sample. In order to test the effectiveness of oxalate-based polymeric adsorbents in the recovery of uranium from seawater, diallyl oxalate (DAOx) was grafted onto nylon 6 fabrics by exposing the fabric, immersed in pure liquid DAOx or in a surfactant-stabilized dispersion of DAOx in water, to electron beam or gamma radiation. Following drying and weighing to determine the degree of grafting (DoG), the presence of oxalate in the fabrics was verified using XPS. Zeta potential measurements indicated the fabric surfaces are negatively charged. The fabrics were tested by rotating them for 7 days in a rotary agitator with actual seawater spiked with 0.2 or 1.0 mg ·L-1 uranium. The fraction of uranium in the solution which was removed due to uptake on the fabrics was found to rise with increasing DoG at both uranium concentrations. EDS measurements were used to map the distribution of adsorbed uranium on the polymeric fibers. Current work includes optimization of irradiation conditions in addition to material characterization on the molecular level and analysis of the sample microstructure. Testing in synthetic seawater will be conducted to compare the selectivity of the adsorbent fabric towards uranium compared to that of other species, in addition to determining the loading and adsorption rates under various conditions such as pH, temperature and salt concentration. Experiments in real seawater will consider effects of organics on the adsorbent materials, test for durability and reusability and determine kinetics and efficiency of the uranium extraction as a function of degradation. 40

Session V. Polymer curing and grafting

O18. RADIATION-INDUCED PROCESSES IN ALIPHATIC POLYESTERS AS SEEN BY EPR SPECTROSCOPY AND THEIR PHYSICOCHEMICAL IMPLICATIONS

Gra żyna Przybytniak 1,* , Marta Walo 1

1 Institute of Nuclear Chemistry and Technology, Dorodna 16 str., 03 195 Warsaw, Poland * [email protected]

Aliphatic polyesters are widely used in many applications in the form of homopolymers or as segments in various types of copolymers. In the last decades aliphatic polyesters and their copolymers have been widely studied due to their significant contribution in biomedical applications as scaffolds in tissue engineering, biodegradable implants, carriers for anti-cancer drugs, components of drug delivery systems, etc. The growing interest of these type of materials has resulted in the development of new generation products known under the trade names of Ecoflex®, Bionolle™, Ecovio®, CAPA™, Biopol™ and others. The character of innovative products with tailored functional properties depends on the molecular architecture and composition. These factors determine also effects of high energy irradiation which can have beneficial or unfavorable consequences. In the second case, extensive material degradation or deformation make radiation sterilization impossible in relation to the medical grade polymers based on polyesters. The influence of chemical structure on the response of aliphatic polyesters to high-energy ionizing radiation is reported. Various surroundings of the ester group in homopolymers, poly(ester urethane) and aliphatic-aromatic copolyesters subjected to ionizing radiation determine the competitive chain scission and crosslinking reactions. The protective nature of aromatic groups would be demonstrated with the example of aliphatic-aromatic copolyester Ecofex. The radiation generated radicals were identify on the basis of EPR spectra which also allowed to follow the radical decay processes. The mechanisms of radiation induced processes involving ester groups and their proximity were proposed. It was found that the relative concentration of paramagnetic species in poly(ester-urethane) determined in each segment is not proportional to its weight contributions and almost all radicals are localized in the dominant component, i.e. either in soft or hard segment. In the ester soft domains following intermediates were confirmed by EPR method: radical anion, α-ester radical, alkyl radical and peroxyl radical whereas in the regions of urethane groups the species generated via scission of N-C bond and their subsequent products were postulated. The influence of aliphatic adipate segment on the radiation susceptibility in the copolyester and poly(ester urethane) was compared. Changes in thermal feature and extend of oxidative degradation were monitored applying TGA, DSC, GC and DRS methods. There are significant differences between extents of oxidation in the studied macromolecules. The process is particularly interesting in the case of Ecoflex for which, despite high yield of oxygen absorption, degradation processes are very limited during six months storage in an air atmosphere. This presentation is focused on our recent work concerning the structural changes and their functional role by reference to ester group located in various polymers.

Session V. Polymer curing and grafting

O19. HYBRID MATERIALS PREPARED BY GAMMA IRRADIATION FOR CONSOLIDATION OF ANCIENT CERAMIC ARTEFACTS: MORPHOLOGY AND PRELIMINARY BIOCIDE ACTIVITY STUDIES

L.M. Ferreira 1,* , A.P. Rodrigues 1,2 , S.C. Verde 1, L.C. Alves 1, M.H. Casimiro 1, J.J.H. Lancastre 1, A.N. Falcão 1, F.M.A. Margaça 1, M.F. Araújo 1

1 Centro de Ciências e Tecnologias Nucleares (C2TN), Instituto Superior Técnico, Universidade de Lisboa, EN 10 (km 139.7), 2695-066 Bobadela, LRS, Portugal. 2 Departamento de Conservação e Restauro, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal * [email protected]

Ormosils (o rganically modified silicates ) are a special class of hybrid materials which consists of an organic compound chemically bonded to a silica network. These type of materials may conjugate unique properties such as: transparency, robustness, high temperature resistance, water-repellency, anti-reflection, UV and environment-resistance [1]. Taking advantage from our previous studies [2], nanostructured PDMS based ormosils have been now being prepared and functionalized by gamma irradiation from a Co-60 source aiming its application, alone or as additives, in the consolidation processes of ancient ceramic artefacts. Apart from its origin/localization, type and respective human frame, ceramic artefacts are strongly influenced by weathering and bioactivity effects [3]. For this reason, special attention was given to hybrid materials surface properties (morphology, wettability) and biocide activity. The influence of composition, precursors ratios, irradiation conditions and synthesis procedure on these properties was evaluated, showing that they can be used in a real manner to tailor the molecular struture and consequently the surface characteristics of the hybrids. Results obtained regarding the organization of inorganic clusters in the polymeric matrix also give us good perspectives for a good compatibility between these materials and the damage ceramic artefacts. Early results from microbiological innactivation studies show the necessity to increase the biocide activity of the hybrid materials in study by introduction of another active component in the materials formulation.

Acknowledgements: This work was financially supported by the International Atomic Energy Agency (IAEA) under the Research Contract No. 18982/RO and by the Portuguese funding institution FCT - Fundação para a Ciência e a Tecnologia under PhD Research Grant PD/BD/114410/2016.

References [1] C. Sanchez, B. Julien, P. Belleville and M. Popall. Applications of hybrid organic-inorganic nanocomposites. J. Mater. Chem. 15 (2005) 3559-3592. [2] J.J.H. Lancastre, A.N. Falcão, F.M.A. Margaça, L.M. Ferreira, I.M. Miranda Salvado, L. Almásy, M.H. Casimiro, A. Meiszterics. Nanostructure of PDMS-TEOS-PrZr hybrids prepared by direct deposition of gamma radiation energy. Appl. Surf. Sci. 352 (2015), 91-94. [3] J.A. Gil, C. Saiz-Jimemez. Biodeteoration of Roman mosaics by bryophites. International Congress on Deterioration and Conservation of Stone (1992), 511-520, LNEC, Lisbon, Portugal.

Session V. Polymer curing and grafting

O20. REINFORCEMENT OF RADIATION-CURED PUR ACRYLATE NETWORKS BY CELLULOSE NANOCRYSTALS

Kamila Furtak-Wrona 1,* , Patrycja Kozik-Ostrowka 1, Karolina Jadwiszczak 1, Jean-Eudes Maigret 2, Gabriela Tataru 1, Véronique Aguié-Béghin 2 and Xavier Coqueret 1

1CNRS UMR 7312, Université de Reims Champagne-Ardenne, Institut de Chimie Moléculaire de Reims, BP 1039, 51687 Reims, France 2 INRA, UMR FARE 614 Fractionnement des Agro-Ressources et Environnement INRA/URCA, BP 224, 51686 Reims, France * [email protected]

The growing interest for green and sustainable chemistry covers the various constituents of biomass as a promising, renewable and vast source of chemicals and materials. In particular, nanocrystalline cellulose (NCC) obtained by controlled acid hydrolysis of natural fibers exhibit outstanding structural and mechanical properties. These features have been recently exploited for obtaining nanocomposites by blending NCC with various thermoplastic or thermoset materials [1-3]. Only few articles report on the use of such nanofillers in UV-cured formulations [4].

In the present work, aqueous suspension of cellulose nanocrystals was prepared by sulfuric acid hydrolysis of Ramie fibers [5]. As the matrix precursor a commercial water – based polyurethane acrylate (PURa) emulsion was selected. This approach allows for the use of water as a common phase for mixing and casting the curable formulations in molds. Films of thickness ranging from 1 to 2 mm could be easily obtained by this method. Two types of radiation commonly used for the processing of paints, coatings, inks and adhesives were applied, (i) high intensity UV-vis LED emitting at 395 nm and (ii) low energy Electron Beam (EB). A photoinitiator was introduced to the formulations prepared for UV-vis curing. FTIR in the medium (MIR) and near visible range (NIR) was used for determining the conversion of monomer. The influence of the amount of nanoparticles (1 to 10 wt%) was studied by various physical and mechanical measurement including DMA and tensile tests.

The results show that significant improvements of Young’s modulus and strength at break were achieved by introducing cellulose nanocrystals in amount as low as 1 wt% in the PURa material. The profile of the reaction kinetics measured during UV-initiated polymerization was not significantly altered by the presence the nanocrystals in the coalesced material. The mechanical performances of the nanocomposites cured by EB irradiation were significantly higher than those observed for UV-vis-cured materials of same composition and same level of polymerization, very probably as the result from grafting reactions between the nanofiller and the PURa matrix that occur under high energy radiation.

References [1] M. Samir, F. Alloin, A. Dufresne, Biomacromolecules 2005 , 6, 612-626. [2] A. Dufresne, Materials Today 2013 , 16, 220-227. [3] G. Siqueira, J. Bras, A. Dufresne, Polymers 2010 , 2, 728-765. [4] B. Poaty, V. Vardanyan, L. Wilczak, G. Chauve, B. Riedl, Progress in Organic Coatings 2014 , 77, 813-820. [5] A. Hambardzumyan, L. Foulon, B. Chabbert, V. Aguié-Béghin, Biomacromolecules 2012 , 13, 4081-4088.

Session V. Polymer curing and grafting

O21. CONTROLLING OF CROSSLINKING IN THE RADIATION- INDUCED POLYMERIZATION OF STYRENE IN THE PRESENCE OF A RAFT AGENT AND A CROSSLINKING AGENT

Murat Barsbay 1,* , Tu ğçe Ovalıo ğlu 1, Olgun Güven 1

Department of Chemistry, Hacettepe University, 06800 Beytepe, Ankara, Turkey * [email protected]

In conventional free-radical polymerizations, the molecular weight, molecular weight distribution and structure of the resultant polymers cannot be controlled. Irradiations applied in conjunction with Controlled Radical Polymerization (CRP) techniques, on the other hand, may yield polymers with low dispersities and controlled molecular weights. Benefits of this combination have been investigated for various homo-and graft-polymerization systems [1]. However, outcomes of a CRP method, e.g. RAFT polymerization, on the formation of crosslinked network structures under irradiation have not been investigated. This study presents, for the first time, the benefits of utilizing a CRP method during the synthesis of crosslinked polymer structures via ionizing radiation, i.e. gamma rays. RAFT mediated polymerization of styrene was carried out in the presence of a crosslinking agent (divinylbenzene, DVB). In order to investigate the influence of RAFT mediation, polymerizations were performed under conventional crosslinking conditions as well. Soluble polymers formed in pre-gel region were characterized by GPC. The proportions of high and low molecular weight polymers formed were qualitatively estimate by GPC traces in Figure 1. It has been extracted from these analyses that at low monomer conversions, the chromatograms are all relatively narrow and well controlled, suggesting that there is

Figure 1. SEC trace evolution of polystyrene synthesized minimal branching in this regime. In in the presence of DVB and RAFT agent. Percentages contrast, after a conversion value of ca. 35 %, show the individual amounts of each crosslinked fraction . the SEC trace develops a shoulder at short retention times. As the reaction progresses, this shoulder becomes a population of very high molecular weight polymers, indicating branched polymers formed through the pendant vinyl group on the polymers. Also, increasing amount of crosslinking agent yields higher molecular weight and dispersity. After gelation, characterization of the insoluble gels were carried out by calculating cross-link density and average molecular weight between the crosslinks using the results of rheological analyses, compression tests and swelling analyses. Average molecular weights between the crosslinks were higher, and hence the crosslinking density was lower, for the gels synthesized by RAFT compared to non-RAFT process. DSC, TGA and SEM techniques were also used for the characterizations. The gels synthesized by the combination of radiation and RAFT polymerization were found to have more homogenous network structure at low DVB concentrations compared to those synthesized by conventional crosslinking method.

References [1] Barsbay M., Güven O., Radiat. Phys. Chem. 78 (2009), 1054-1059.

Session V. Polymer curing and grafting

O22. KINETIC AND STRUCTURAL FEATURES OF RADIATION- INITIATED CROSS-LINKING POLYMERIZATION: A COMPARISON BETWEEN FREE RADICAL AND CATIONIC CHEMISTRIES

G. Ranoux 1, C. Kowandy 1, M. Krzeminski 1, A. Berquand 2, M. Molinari 1,2 and X. Coqueret 1,*

1 Université de Reims Champagne-Ardenne, CNRS UMR 7312, Institut de Chimie Moléculaire de Reims, BP 1039, 51687 Reims Cedex 2, France 2 Université de Reims Champagne-Ardenne, CNRS UMR 7312, Laboratoire de Recherche en Nanosciences, BP 1039, 51687 Reims Cedex 2, France * [email protected]

The radiation-induced polymerization of multi-acrylate monomer compositions is known to proceed heterogeneously at various dimension scales, depending of monomer composition. In radiation-cured materials based on a single type of monomer, the network were shown to display heterogeneities of cross-link densities resulting from a complex interplay between mechanistic and kinetic factors along the solidification process [1, 2].

Compared to free-radical chain polymerization, radiation-initiated cationic polymerization exhibits peculiarities at the different steps of the chain process (complex initiation and propagation mechanisms, pseudo-living character…). The influence of these features on the reactivity and on the microstructure of multifunctional aromatic epoxy monomers and of their acrylate analogs has been examined using various types of radiation (UV, visible, EB, X-ray). Complementary spectroscopic and analytical methods were implemented in order to correlate the changes of network physical properties as a function of the polymerization degree.

AFM analysis of the networks in the topographic, phase contrast and indentation modes provides quite informative data with indications on the actual dimensions of the soft and rigid domains and of their evolution, as the curing level is driven to higher values.

Solid-state proton T 2 NMR relaxation experiments were also performed on radiation-cured materials with valuable quantitative information on the local mobility in the nanoheterogeneous samples as well as on the associated fraction of material, as polymerization proceeds.

On the basis of these observations and measurements, a consistent scenario for the build-up of radiation-cured networks is proposed. The influence of this general behavior is discussed with respect to radiation curing, either of epoxy or acrylate monomers, for demanding applications [3, 4].

References [1] M. Krzeminski, M. Molinari, M. Troyon, X. Coqueret, Macromolecules 43 3757–3763 (2010). [2] M. Krzeminski, M. Molinari, M. Troyon, X. Coqueret, Macromolecules 43 8121–8127 (2010). [3] M. Krzeminski, M. Molinari, B. Defoort, X. Coqueret, Radiat. Phys. Chem. 84 79–84 (2013). [4] B. Vissouvanadin, G. Teyssedre, ·S. Le Roy, C. Laurent, G. Ranoux, X. Coqueret, IEEE Trans. Dielectr. Electr. Insul. 22 1142–1149 (2015).

Session V. Polymer curing and grafting

O23. RADIATION-INDUCED GRAFTING METHOD WITH AN ADDITION OF ORGANOPHOSPHOROUS COMPOUNDS

Seiichi Saiki 1,* , Noriaki Seko 1

1 Quantum Beam Science Research Directorate, National Institutes for Quantum and Radiological Science and Technology, Japan * [email protected]

Pre-irradiation method of radiation-induced grafting polymerization has been utilized for various fields. In the grafting polymerization process, dissolved oxygen in a reaction solution should be removed by bubbling with inert gas like nitrogen gas because oxygen inhibits polymerization and reduces polymerization efficiency. In a laboratory scale, nitrogen gas bubbling in a reaction solution is very useful; however it costs much for appropriate equipment on an industry scale. On the other hand, some additives have been used for reducing oxygen inhibition for polymerization process, for example, in a field of gel dosimetry for radiation therapy and UV curing. In this study, an addition effect of organophosphorous compounds on radiation-induced grafting polymerization was examined to reduce oxygen inhibition instead of nitrogen gas bubbling. As a result, we could reduce oxygen inhibition for radiation-induced grafting polymerization and get high degree of grafting by adding organophosphorous compounds without nitrogen gas bubbling. This fact may lead to realize an easy handling of radiation-induced graft polymerization. In this presentation, we will introduce some results about radiation-induced grafting with some additives and various parameters.

Session V. Polymer curing and grafting

O24. STUDY OF STRYENE-FREE UNSATURATED RESINS AND ACRYLIC MONOMERS FOR THE CONSOLIDATION OF WOODEN CULTURAL HERITAGE ARTEFACTS BY RADIATION-CURING

Khôi Tran 1,* , Claudia Salvan 1, Michel Bardet 2

1 ARC-Nucléart, CEA-Grenoble, France 2 INAC-Laboratoire de Résonance Magnétique, CEA-Grenoble, France * [email protected]

Since the seventies, ARC-Nucléart is using a styrene unsaturated polyester resin for the consolidation of degraded wooden artefacts from cultural heritage, following a process called “Nucléart ” by resin impregnation under vacuum/pressure, and then in-situ polymerization of the resin under gamma irradiation. However, this method is irreversible due to the crosslinked solid state resin which is insoluble in any solvent. Moreover, the consolidation of wood by such 100% reactive resin fills almost completely the wooden pore structure, creating in fact a wood-plastic composite which density is much higher than untreated wood one. These features constitute some drawbacks of this method going against two well-known criteria of the conservation of artefacts: the reversibility of the treatment and the minima intervention in order to avoid the denaturation of the original and unique object.

Furthermore, even if this technique had proved during many decades its effectiveness for saving from destruction numerous highly degraded artefacts, another drawback of the current process is the toxicity and the relatively high vapour pressure of the styrene monomer. Moreover, since the safety regulation is becoming more severe, our research is focused on the improvement of our radiation method in two directions: the use of already available styrene- free resins, and the development of hydroxyl-acrylic monomers, whose polymers are in principle reversible.

In this paper, we will describe first the irradiation conditions for a complete polymerization of the resins and monomers, the formulations of monomers in order to obtain polymers presenting appropriate glass transition temperature T g (around 40° to 60°C), and their polymerization in selected solvents in order to modulate their content in the wood. Structural characterizations are carried out by using FTIR and solid state NMR spectroscopies.

The second part of our work will present the impregnation of two species of wood, beech and fir, by the styrene-free selected resin and by the new-formulated monomers. They are characterized by various techniques such as colorimetry, dimensional changes, scanning electron microscopy, X-ray radiography, computed tomography CT, and mechanical resistance measurements. Last but not least, the interaction or not of the resins or monomers with various polychromies (pigments, colorants) has to be checked, and it is important to assess the feasibility of their use for consolidation of samples of artefacts presenting gilded or polychrome surface layers.

Session VI. Instruments and installations for irradiation

O25. INTERNATIONAL TRACEABILITY FOR IONIZING RADIATION: NIST MEASUREMENT STANDARDS

Lisa R. Karam 1,*

1 Radiation Physics Division, Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD USA. * [email protected]

As other National Measurement Institutions (NMIs) around the world, the National Institute of Standards and Technology (NIST) provides the US National measurement standards for a variety of quantities, including for ionizing radiation dosimetry, radioactivity, and neutron measurements. Such standards play a key role in enabling commerce and safety by providing a level of confidence in measurements in a variety of applications from health care to radiation processing. To develop and disseminate recognized measurement standards, however, requires a metrological infrastructure not only at an NMI such as NIST, but also internationally. Mutual recognitions of measurement standards, such as is facilitated by the Committee on Weights and Measures (CIPM) Mutual recognition Arrangement (MRA), are supported by both the measurement capabilities within a laboratory and also in how those capabilities compare with those at other NMIs and Designated Institutions (DIs). This presentation will address how international radiation metrology is organized, the configuration and capabilities of the ionizing radiation measurement standards program for the United States at NIST, and how the entire structure sustains international measurement traceability for ionizing radiation.

Session VI. Instruments and installations for irradiation

O26. SELECTION OF RADIATION STRATEGY FOR POLYMER MODIFICATION: CASE OF GRAFTING PHOSPHORUS COMPOUNDS ON FLAX FIBERS

Sophie Rouif 1,* , Rodolphe Sonnier 2, Belkacem Otazaghine 2, Ichem Chala 2

1 IONISOS – Parc Dombes Côtière Activités – F - 01120 Dagneux 2 C2MA, Ecole des Mines d’Alès, 6, avenue de Clavières, F - 30100 Alès * [email protected]

Radiation processing with ionizing rays enables different types of chemical modification of polymers, without adding an initiator : − Polymerization of composites − Crosslinking of thermoplastics − Functionalization of polymer substrates by grafting

In this work, we highlight the impact of the radiation strategy chosen to induce the radiation chemistry. Indeed, it is possible with radiation processing to operate by 2 ways: simultaneous irradiation and pre-irradiation .

We focus on the most largely used technologies: Electron Beam and Gamma rays. Due to their different natures, they differ on penetration and on dose rate. In presence of oxygen, the low dose rate of Gamma rays (about 2 kGy / h) is particularly suitable to quench the free radicals into hydroperoxide derivates.

Our work is based on the example of the grafting of phosphorus-based molecules onto flax fibers in order to impart flame retardancy to flax fabrics, used as reinforcements.

This work is included in the French project called BIONICOMP, headed by IONISOS, with a consortium gathering of academic and industrial partners, in order to improve the performances of composites reinfor ced by natural fibers fabrics.

Session VI. Instruments and installations for irradiation

O27. QUALIFICATION OF THE PROPERTIES OF HIGHLY CROSSLINKED UHMWPE, TO BE ROUTINELY PROCESSED WITH A 7 MEV X-RAY IRRADIATOR

Hervé Michel 1,* , Hans Hartmann 1 and Mark Allen 2

1 Synergy Health Däniken AG, now part of Steris Applied Sterilization Technologies, Hogenweidstrasse 6, CH-4658 Däniken, Switzerland 2 Orthoplastics Limited, Grove Mill Todmorden Road, OL13 9EF Lancashire, England * [email protected]

Ultra high molecular weight polyethylene (UHMWPE) is used in orthopaedic industry to manufacture implants. Currently, both Electron beam and Gamma technology are used for the crosslinking process.

Due to density and functional properties specification of the UHMWPE, Gamma and Electron beam process have some limitations, namely, (i) The process requires a tight dose range (Dose uniformity ratio <= 1.2) which limits the use of electron beam processing (ii) The process requires a high dose (typically> 70kGy) which challenges the use of Gamma irradiation as this dose range is atypical to the routine dose window of most of the industrial Gamma facility.

X-Ray irradiation technology in routine use by STERIS Applied Sterilization Technologies at Däniken, Switzerland since 2010 is used to process different type of products at different dose ranges. The processing characteristics are between Gamma and Electron beam in terms of dose rate and treatment time. Such characteristics positively impact processing criteria in terms of processing scheduling & flexibility, dose range, dose uniformity and ozone impact. Most importantly, the process has shown improved results in terms of dose uniformity ratio and heat development when comparing same product and process load treated with Gamma or Electron beam.

As with any change of radiation processing modality, a number of factors & criteria must be assessed, in particular the functional properties of the material.

The purpose of this paper is to present the results of the study performed to compare the characteristics of UHMWPE processed through X-ray and Gamma ( 60 Co) irradiation at incremental doses. The presentation shows the performance qualification results made on the same configuration for Gamma and X-Ray processing, and results of experimental analysis of the impact of both process on material property included Izod Impact Strength, tensile testing, Elongation Trans- Vinylene Index analysis, Oxidation Index analysis. The paper also presents the result of the performance qualification to validate the X-Ray routine process. This example is also be used as a case study to present challenges facing by industry to change their current process even when results show evidence that new process is equal or better than the current one.

Session VI. Instruments and installations for irradiation

O28. ELECTRON BEAM LAB UNIT AND SYSTEMS – HOW ACCESSIBILITY WILL CHANGE THE MARKET

M. Bielmann 1,*

1 ebeam Technologies, COMET AG, Herrengasse 10, 3175 Flamatt, Switzerland * [email protected]

Electron Beam treatments are successfully used in industrial processes for over 50 years. Today, it is a common technology to many products and services with its main applications in Polymer and Rubber Crosslinking, Sterilization and Photoinitiator-free Ink Curing as a solid alternative for UV-curing. Why is the technology not yet common-place?

While in the early days, High Voltage Systems (1MeV and higher) and therefore High Volume Clients and Service Centres dominated the technology. Since 1980, Low Energy EB Systems have seen tremendous growth due to their ability to be implemented directly inline in processes - but remained a technology for very high production volumes. Since 2009, hermetically sealed EB units emerged on the market, opening up new potentials for application due to unprecedented compact designs. With these sealed units, one crucial bottleneck for EB can be resolved: Accessability to the technology.

In this presentation, a short overview on Low Energy EB Systems and its applications is given. Especially, EBlab Systems based on sealed technology allow formulators and researchers to conduct their work quickly and efficiently in their trusted environment - work that currently was cumbersome and therefore was reserved only to the truly committed scientists and companies. Systems based on ultracompact designs now fill the bottleneck in scale-up and creates new market opportunities inaccessible by large systems. Sealed EB systems are the missing link to large scale adoption of EB technolog y - and it has been filled.

Session VII. Hydrogels, past, present and future (devoted to Pr. Rosiak)

O29. RADIATION ENGINEERING OF POLYMERIC BIOMATERIALS

J.M. Rosiak 1 and P. Ulanski 1,*

1 Institute of Applied Radiation Chemistry, Faculty of Chemistry, Lodz University of Technology, Wroblewskiego 15, 93-590 Lodz, Poland * [email protected]

One of indispensable requirements related to biomaterials is their sterility. Ionizing radiation seems to be a very convenient and useful tool to achieve that, especially in relation to polymeric components of medical devices and their packaging. However, in parallel to destruction of living microorganisms radiation treatment causes changes in physicochemical properties of irradiated materials. Both electron beam and gamma radiation used for sterilization may initiate all types of fundamental polymer reactions in biomaterials, i.e. polymerization, degradation, crosslinking, grafting, oxidation, gases formation, etc. The presence of water in irradiated systems enhances the observed changes by indirect effect of radicals formed in water at high yield. Some of such changes are undesirable from the point of view of properties of biomaterials and have to be suppressed, e.g. by introducing into composition of materials selected additives, as it is done for polypropylene syringes or UHMW polyethylene applied for total joint arthroplasty.

On the other hand, such “additional” reactions during terminal sterilization of biomaterials can be utilized for achieve their final, desired properties.

In the last 30 years, our research group led by Prof. Rosiak has created a number of radiation technologies of polymeric biomaterials. Some of them have been commercialized and are used, modified and developed by other laboratories and companies all over the world, some of them still await industrial investments. The comprehensive review of such biomaterials will be presented including hydrogels dressings, hydrogel systems for induction of childbirth, hydrogel-based dietary product, hydrogel-based hybrid artificial organs, hydrogel implants for intervertebral discs, hydrogel dosimeter for radiotherapy, hydro-nanogels, degradable and/or non-degradable scaffolds for regeneration of peripheral nerve and formation of animal neural tissue in 3D, thermoresponsive surface for cultivation of skin cells as well as the method for preservation of biological activity of peptides undergoing radiation sterilization in aqueous solution.

The above mentioned biomaterials and new methods have been achieved using a typical radiation chemistry methodology and experimental techniques, e.g. sol-gel analysis, molecular weight measurements, pulse radiolysis with spectrophotometric and light scattering detection methods (LSI) as well as specific tests recommended for biomaterials by ISO 10 993. Both the developed technologies as well as the area of their applications have formed a new direction of radiation research – radiation engineering of biomaterials [1].

References [1] http://mitr.p.lodz.pl/biomat

Session VII. Hydrogels, past, present and future (devoted to Pr. Rosiak)

O30. FROM BULK HYDROGELS TO FUNCTIONAL NANOGELS

Olgun Güven 1,*

1 Hacettepe University, Department of Chemistry, Beytepe, 06800, Ankara, Turkey * [email protected]

Hydrogels are synthetic or natural biomaterials playing significant role in different areas of health-care. This is due to their important properties like hydrophilicity, biocompatibility, non toxicity and tissue-like properties. Hydrogel synthesis routes and their applications showed tremendous increases during the last two decades. Hydrogels are formed from the three-dimensional networks of randomly crosslinked hydrophilic polymers. The crosslinks can be formed with the aid of crosslinking agents in the case of chemical crosslinking or via strong physical interactions leading to the formation of noncovalent crosslinks. Ionizing radiation is known to induce polymerization of vinyl monomers or crosslinking of most of the water soluble polymers when irradiated in water. The latter method is utilized in hydrogel synthesis due to its biomedically safe nature.

The Odyssey of radiation synthesis of hydrogels in the laboratories of the author (www.polymer.hacettepe.edu.tr ) started in 1978[1] by investigating the gelation behavior of gamma irradiated aqueous poly(ethylene oxide) solutions and currently continuing with the synthesis of nanogels with well-defined sizes and different chemical functionalities[2]. This presentation will highlight some of our results on the preparation and application of various hydrogels synthesized from PEO, PVP, PAAm homopolymers as well as random copolymers of PVP, PAAm, PNiPAAm with maleic and itaconic acids. The results of our recent parametric studies on the radiation synthesis of nanogels in the size range of 30-200 nm composed of PVP and PNiPAAm homopolymers and those prepared from interpolymer complexes of PEO/PAA, PVP/PAA and PVIm/PAA will be presented and discussed with a future outlook.

References [1] O. Güven and C. Şenvar, “On the gelation of aqueous poly(ethylene oxide) solutions with gamma rays” Makromol. Chem ., 180 (1979) 847-850. [2] S.D. Sütekin and O. Güven unpublished results.

Session VII. Hydrogels, past, present and future (devoted to Pr. Rosiak)

O31. SYNTHESIS AND MODIFICATION OF FUNCTIONAL POLYMER NANOGELS USING PULSED-ELECTRON BEAM IONIZING IRRADIATION

Ileana Pazos 1, Jung-Chul An 1, Natascia Grimald 1,2 , Patricia Yoko Takinami 1,3 , Dianne Poster 4, Clelia Dispenza 2, Nelida del Mastro 3, Wyatt Vreeland 4, Mohamad Al- Sheikhly 1,*

1 University of Maryland College Park, Maryland, USA 2 Università di Palermo, Palermo, Italy 3 Nuclear and Energy Research Institute -Ipen/CNEN/SP - Brazil 4 National Institute of Standards and Technology, Gaithersburg, Maryland, USA * [email protected]

Nanogels made of bio-compatible hydrophilic polymers can be used in various medical applications such as targeted nano-medicine delivery and imaging agents. Intravenously introduced nanogel-drug conjugates may accumulate in tumors through the enhanced permeability and retention effect. We present our latest results on the synthesis and kinetic analysis of two nanogel systems (1) poly(vinyl pyrrolidone) (PVP) and (2) gelatin/polyethylene (GEL/PEG) using ionizing irradiation ( γ-ray, electron beam). The characteristics of nanogels depend on the radiation synthesis parameters (e.g., total dose, pulse repetition rate, etc.) as well as physical parameters (e.g., solution concentration, irradiation temperature, etc.). Specifically, one may tune the parameters to promote the crosslinking reaction within the same polymer chain (intra-crosslinking) and to suppress the crosslinking between two different chains (inter-crosslinking). At higher temperatures (> 60 °C), there is a disruption of polymer-water hydrogen-bonds resulting in a collapsed form. Smaller nanogels can be produced with high repetition rates of the pulsed electron beam irradiation while low dose rate pulses favor inter-molecular crosslinking. The nanogels were analyzed using asymmetric flow field-flow fractionation coupled to multi- angle static light scattering and dynamic light scattering detectors. The measured hydrodynamic radius (R h) of the PVP hydrogels were concentration dependent with a range from 15 to 80 nm with a polydispersity index of 0.2– 0.3 and molecular weight of 0.4– 13 MDa. On the other hand, the R h of the GEL/PEG mixed nanogels decrease from 350 to 20 nm as a function of dose. Additionally, atomic force microscopy images confirm the synthetic approach results in globular shapes. X-ray photoelectron spectroscopy (XPS) measurements confirm that the chemical structure of these nanomaterials closely resemble that of the un-irradiated polymers. Moreover, XPS also provides data on the level of oxidation and enables confirmation of chemical grafting. In addition, pulse radiolysis elucidates the mechanism that leads to nanogels generation. The second order reaction rate constants (k 2) of PVP radical recombination are determined to be -1 -1 -1 -1 ca. 1.1–2.8 E9 L mol s (PVP-H, ε390 nm = 510 ± 30 L mol cm ). The activation energy (E a) of this reaction is calculated from the Arrhenius plot of PVP radical decay rate constants at the series of temperatures and show 1.0 kcal mol -1 below 60 °C and 6.8 kcal mol -1 above 60 °C. These two measured E a constants can be explained by the different rate-determining mechanism of PVP radical recombination reaction at two temperature regions. Below 60 °C, the low E a reflects the diffusion controlled polymer radical reaction in a good solvent. But at higher temperatures, above 60 °C, polymer chains are segregated from the aqueous solution by micro-phase separation and collapse.

Session VII. Hydrogels, past, present and future (devoted to Pr. Rosiak)

O32. ARE WOUND DRESSINGS BASED ON ROSIAK’S PROCESS STILL A TECHNICIAN CHALLENGE? THE BRAZILIAN EXPERIENCE

A.B. Lugão 1,*

1 Nuclear and Energy Research Institute, University of São Paulo, Brazil. * [email protected]

The benefits of a moist wound for faster and more comfortable healing was only acknowledged after the remarkable works of George Winter published in Nature in 1962. It took some years to consolidate the concept among medical teams, and so the industry. Soon hydrogel dressings started to appear in the market place, but they were very expensive and inadequate in many aspects. Hydrogel dressings based on the simultaneous crosslinking and sterilization of the hydrophilic mixture of medical grade polymers was developed in the late 1980’s by Janusz M. Rosiak and its team of Lodz Polytechnic. The clever and elegant process, so-called “Rosiak’s process”, attracted the attention of industries and many laboratories in Poland and the rest of the world. However, wounds are multiple in depths, infection and production of body fluids. Therefore it is not feasible to have a dressing for all and we have to face the reality of a tropical under development country and its national system of health. A very good dressing for the Brazilian needs would require some added features, such as enhanced swelling of body fluids, better anti-inflammatory effect and stronger ability to kill microorganisms. Silver nanoparticle are excellent well known microbiocidal agent and recently it was demonstrated an important anti-inflammatory effect independent from the microbiocidal one. The control of infection and inflammation has a marked effect in the exudation rate; however some infected tropical wounds are extremely proliferous in the generation of body fluids. Therefore there is a need to improve the swelling capacity without jeopardizing the excellent mechanical properties and without any significant added cost. Our presentation will address the challenges some of progress.

Session VII. Hydrogels, past, present and future (devoted to Pr. Rosiak)

O33. RADIATION-INDUCED SYNTHESIS OF NANOGELS: ADVANCES IN RESEARCH AND APPLICATION

Clelia Dispenza 1,2,*

1 Università degli Studi di Palermo, Dipartimento di Ingegneria Chimica, Gestionale, Informatica e Meccanica, Viale delle Scienze, 90128 Palermo, Italy. 2 School of Chemical Science and Engineering, Department of Fibre and Polymer Technology, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden. * [email protected]

From their first appearance in 1969, when Schnagel and Borwardt reported the radiochemical synthesis of poly(ethylene oxide) microgels by gamma-irradiation, the possibility of generating crosslinked micro- and nanoparticles from ”pure” aqueous solutions of macromolecules, have triggered the imagination of material scientists on the search for ”clean” processes and products for biomedical applications. Thanks to the seminal studies of Rosiak and co-workers, who have clarified, both experimentally and mechanistically, the key role of intra-molecular crosslinking in controlling the particle size, the scientific community has now a powerful tool to design and manufacture radiation-synthetized nanogel particles with a terrific potential in targeted drug delivery therapies.

We have recently demonstrated that nanogels can be produced by e-beam irradiation with industrial accelerators and with the typical set-ups and doses applied for sterilization; therefore, the synthesis may not even represent an additional cost in the production process. Particle size, molecular weight and functionalization can be controlled, hence tuned, by selecting the dose rate, the polymer concentration and the total dose imparted, without necessarily adding other chemicals but the crosslinking polymer. The generated functionalized nanocolloids are amenable of decoration with (bio)molecules and cell receptors-specific ligands of therapeutic and/or diagnostic relevance. In particular, the prospects of using insulin-conjugated radiation-synthetized poly(N-vinyl pyrrolidone) nanogels for achieving brain targeted insulin delivery for the treatment of Alzheimer's disease will be presented.

Session VIII. Gels and biopolymers

O34. NOVEL THERMO AND PH-SENSITIVE POLY(N- VINYLCAPROLACTAM-CO-4VINYLPYRIDINE) ONTO SILICONE RUBBER BY ONE STEP METHOD FOR DRUG DELIVERY

Victor H. Pino-Ramos 1, Carmen Alvarez-Lorenzo 2, Angel Concheiro 2, and Emilio Bucio 1,*

1 Departamento de Química de Radiaciones y Radioquímica, Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, México DF 04510, México. 2 Departamento de farmacia y Tecnología Farmacéutica, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, España. * [email protected]

This work focuses on the use of modified silicone rubber to synthesize novel thermo and pH sensitive materials using gamma irradiation, grafting of N-vinylcaprolactam (NVCL) and 4- vinylpyridine (4VP) by a one-step method. The aim is to evaluate the effect of radiation conditions such as the dose on the grafting yield, and monomers concentration; factors that determine the characteristics of a material with potential application in drug delivery systems. Biomaterials were characterized by FTIR-ATR, Raman, DSC, TGA, and swelling degree in order to study silicone pristine and modified films. The stimuli response was carried out using buffer solutions for pH critical point and temperature changes for Upper Critical Solution Temperature (UCST) behavior. Graft copolymers of SR-g-(NVCL-co-4VP) showed good cytocompatibility against BALB/3T3 cells; the amount of drug loaded showed dependence of solution drug concentration. Drug release studies were performed at pH 7.4 and 37 °C (simulating physiological conditions). The grafted films showed bacteriostatic activity and released diclofenac in a sustained way for at least 48 hours.

Session VIII. Gels and biopolymers

O35. SYNTHESIS OF CELLULOSE DERIVATIVE/ACRYLIC ACID HYDROGELS BY RADIATION-INITIATED CROSSLINKING

Tamás Fekete 1,2,* , Judit Borsa 3, Erzsébet Takács 1,3 , László Wojnárovits 1

1 Centre for Energy Research, Hungarian Academy of Sciences, Budapest, Hungary 2 Budapest University of Technology and Economics, Budapest, Hungary 3 Obuda University, Budapest, Hungary * [email protected]

Hydrogels are special polymer networks containing large amounts of water. Due to their special properties there is a large interest in their application in various fields like drug delivery, agriculture or water treatment. While the majority of commercially available gels are synthetic polymer-based, there is an increasing focus on the use of various natural polymers, like cellulose, starch or chitosan. Cellulose is the most abundant, low cost renewable material. While its use for gel preparation was widely investigated, most studies focus on the application of its derivatives due to their water solubility.

In our work we prepared gels with superabsorbent properties from aqueous solutions of various cellulose derivatives by radiation-initiated crosslinking. The effect of synthesis parameters such as the absorbed dose and solute concentration on the gel properties was investigated. We also tried to improve the gel properties by partially replacing the cellulose derivative with acrylic acid. Our goal was to achieve superior properties compared to pure cellulose derivative gels while keeping the acrylic acid content as low as possible. The samples were mainly characterized with the degree of swelling and the gel fraction. The gel morphology was studied by scanning electron microscopy, while FTIR-ATR provided information about the chemical composition of the samples.

The derivative type had a major impact on the gel properties when the gels were synthesized from pure cellulose derivative solutions. Carboxymethylcellulose-based gels showed the best swelling properties. The gelation also improved with the molecular weight: derivatives with low molecular weight could not form gels. The properties showed a significant dependence on the synthesis conditions. Improving of the gel properties proved to be difficult because high gel fraction was usually achieved at the expense of low water uptake.

The partial replacement of the cellulose derivative with acrylic acid improved the gelation. Significantly milder synthesis conditions were adequate for the gel formation. Moreover, gels prepared at such conditions had both higher water uptake and gel fraction compared to their pure cellulose derivative counterparts. The acrylic acid proved to be very effective even in very low concentrations. The presence of the monomer also affected the sensitivity of the swelling to the presence of salt in the water, especially for non-carboxymethylcellulose gels.

Session VIII. Gels and biopolymers

O36. THE EFFECTS OF SOME COMPOSITIONAL FACTORS AND IONIZING RADIATION ON THE PROPERTIES OF STARCH-PVA- NANOCELLULOSE FILMS

Krystyna Cie śla 1,* , Anna Abramowska 1, Joanna Drewnik 1, Marek Buczkowski 1

1 Institute of Nuclear Chemistry and Technology, Dorodna 16 str., Warsaw, Poland * [email protected]

The studies are connected to the increasing interest in substitution of traditional packaging by the materials prepared basing the natural and biodegradable polymers. Starch appears the appropriate substrate, however preparation the films with good properties needs using of the modified starches, addition of hydrophobic compounds, blending starch with the other polymer, introduction of the reinforcing or structuring agents, or application of additional physico-chemical treatment. Due to perspective of radiation technologies for polymers modification and due to potential application of the materials for packaging of the products predicted for radiation decontamination/sterilization, the necessity appeared for studying the radiation effects in such materials. In particular, our results obtained till now have shown that ionising radiation enables to modify the properties of starch, starch surfactant or starch-PVA films [1-4]. Our current studies deals with search of new biodegradable materials based on starch-PVA and starch-PVA-nanocellulose systems. These studies concerns the effects of using different starch and PVA substrates, addition of several differently structured nano- and micro-sized celluloses, changing of the starch:PVA ratio and nanocellulose content in the composite materials, and addition of the selected natural substances that are known to reveal antioxidant activity. Moreover, the sensitivity of the films with modified composition to gamma and electron irradiation (performed with doses in the range from 1 kGy till 75 kGy), was compared. Mechanical and hydrophilic/hydrophobic properties of the non-irradiated and the irradiated films, and migration phenomena taking place in liquid food simulants depend on the sample composition and on the conditions applied during syntheses and irradiation. The results were related to the chemical processes involved in films and to their modified microstructure and showed the potential of using the selected compositions for packing some groups of food, including the products predicted for radiation decontamination.

The work was sponsored in the frame of the International Atomic Energy Agency research contract No: 17493, co-funded by Polish Ministry of the Science and the Higher Education

References [1] Cie śla K.A., Nowicki A., Buczkowski M.J. Radiation modification of the functional properties of the edible films prepared using starch and starch – lipid system. Nukleonika , 55(2) (2010), 233-242. [2] Cie śla K., Watzeels N., Rahier H. Effect of gamma irradiation on thermophysical properties of plasticized starch and starch surfactant films. Radiat. Phys. Chem , 99 (2014 ), 18-22. [3] Cie śla K., Sartowska B. Modification of the microstructure of the films formed by gamma irradiated starch examined by SEM, Radiat. Phys Chem 118(2016), 87-95. [4] Abramowska A. , Cie śla K.A. , Buczkowski M. J., Nowicki A., Głuszewski W.J. The influence of ionizing radiation on the properties of starch-PVA films. Nukleonika 60 (3) (2015), 669-677.

Session VIII. Gels and biopolymers

O37. ON THE MECHANISM OF RADIATION SYNTHESIS OF NANOGELS

Clelia Dispenza 1, Lorena Anna Ditta 1, Maria Antonietta Sabatino 1 and Mats Jonsson 2,*

1 Dipartimento di IngegneriaChimica, Gestionale, Informatica, Meccanica, UniversitàdegliStudi di Palermo, VialedelleScienze, Edificio 6, 90128 Palermo, Italy 2 School of Chemical Science and Engineering, Applied Physical Chemistry, KTH Royal Institute of Technology, SE – 100 44 Stockholm, Sweden * [email protected]

Radiation-engineered poly( N-vinyl pyrrolidone) nanogels are very interesting biocompatible nanocarriers for i.v.administration of therapeutics and contrast agents for bioimaging among other applications. Nanogels are usually produced upon irradiation of dilute aqueous polymer solutions. Under these conditions, the polymer radicals formed primarily react via intramolecular radical-radical combination forming intramolecular crosslinks. The manufacturing process is fast and effective and grants excellent control of particle size and simultaneous sterilization of the formed nanogels. Interestingly, primary amino groups and carboxyl groups, useful for (bio)conjugation, are also formed in a dose-dependent fashion when manufacturing PVP-nanogels. In this presentation, the origin of nanogel size control and functionalization are discussed in relation to dose, dose rate, polymer concentration and chemical conditions. The latter can be directly altered by purging the solutions with N 2O or N2 or indirectly through the formation of H 2O2 in systems with low polymer concentration. The discussion is based on recent experimental work and kinetic simulations. This understanding offers a new dimension for the design and production of radiation-sculptured multifunctional nanocarriers from aqueous solutions of polymers. In addition, the inherent boundaries of these systems in terms of processing parameters are explored.

Session IX. Polymer-based medical and pharmaceutical devices

O38. RESPONSE OF MEDICAL POLYMERS TO THERAPEUTIC LEVELS OF IONIZING RADIATION

Abby R. Whittington 1,*

1 Departments of Chemical Engineering and Materials Science and Engineering Virginia Tech, Blacksburg, VA USA * [email protected]

Polymeric medical devices are becoming commonplace in the treatment of cancer patients to provide fluids and medications, to offer insight into diagnosis, and to fill the voids created by removal of the tumor. Therefore there is a growing need to understand how the materials respond and are influenced by the hostile environment of generated around the tumor during cancer treatment. This talk will discuss the design and characterization of polyurethane devices for medical applications and how therapeutic radiation commonly used in cancer therapy influences the critical properties of such materials. Therapeutic radiation is utilized in both imaging and radiotherapy. The doses for imaging, while very low, pose a risk when repeated multiple times as in the case of placement and monitoring of peripherally inserted central catheters (PICC) for neonates. In radiotherapy, the dose levels are sufficiently high to cause cross-linking and/or degradation of many polymers when exposed in the aqueous environment of the body. An example of both applications will be explored.

Session IX. Polymer-based medical and pharmaceutical devices

O39. RADIATION-INDUCED PREPARATION OF GOLD/ALBUMIN CORE/SHELL NANOPARTICLES

Constanza Y. Flores 1, Estefania Achilli 1 and Mariano Grasselli 1,*

1 Laboratorio de Materiales Biotecnológicos– Grupo vinculado al IMBICE – CCT La Plata, Departamento de Ciencia y Tecnología, UNQ, Roque Saenz Peña 352, Bernal, Bs. As, Argentina * [email protected]

Functionalization of the surface of Gold nanoparticles ( AuNPs ) with different biomolecules has been used for several decades in rapid diagnostics tests. In last decades, AuNPs have been demonstrated they use in therapy and imaging. This is due to their biocompatibility and their unique properties, dependent on their size, shape and coating. Those characteristics will allow preparing nanomaterials as platforms by therapy and diagnoses, or combinating both, to generate theragnostic nanoparticles. Preparation of AuNPs with a single monolayer coating of protein is easy to achieve by physisorption methods. However, the main core of the protein is denatured and the stability of the nano-constract is relatively low. In addition interaction with a dynamic ‘ protein corona’ has been described when these NPs are in presence of high concentrations of proteins, such as in the plasma. Recently, our research group has described for the first time the preparation of protein NPs using radiation-induced crosslinking with 60 Co gamma rays and accelerated electrons [1,2]. The ethanol/water mixture of Albumin solution generates a dynamic equilibrium between free and aggregate proteins, which can be stabilized by ionizing radiation [2]. In this work is proposed a novel method to prepare Au/Albumin NPs by radiation-induced crosslinking. First, AuNPs of 30 nm diameter are prepared by chemical reduction of Au salt in aqueous medium. AuNPs were pre-treated with dilute protein solution to stabilize semi- denatured forms of the protein (monolayer coating) and subsequently addition of higher amount of Albumin followed by cold ethanol to induce the aggregation. The water/ethanol suspension is irradiated in a 60Co source with a minimum of 5 kGy dose under oxygen free atmosphere, to obtain a stable coating. A similar crosslinking mechanism than in protein NPs preparation is expected. The Au/Albumin NPs were characterized by UV-visible and infrared spectroscopy, transmission electron microscopy (TEM) and dynamic light scattering (DLS). By DLS, it was found a new NP population with an average diameter of about 60 nm. Moreover, TEM images showed that the NPs have spherical shape and the presence of a low-density halo around the metal core confirms the presence of Albumin. Au/Albumin NPs showed better stability under physiological conditions and the Albumin coating do not interfere with the optical properties of Au.

References [1] Espinoza, S. L. S., Sánchez, M. L., Risso, V., Smolko, E. E., & Grasselli, M., Radiation synthesis of seroalbumin nanoparticles. Radiat. Phys. Chem., 81 (2012), 1417-1421. [2] Achilli, E., Casajus, G., Siri, M., Flores, C., Kadłubowski, S., Alonso, S. D. V., & Grasselli, M. Preparation of protein nanoparticle by dynamic aggregation and ionizing-induced crosslinking. Coll. Surf. A, 486 (2015), 161-171.

Session IX. Polymer-based medical and pharmaceutical devices

O40. STERILIZATION OF A BIODEGRADABLE MEDICAL DEVICE COMPRISING SUPRAMOLECULAR POLYMERS - IS RADIATION TECHNIQUE APPROPRIATE?

Radoslaw A. Wach 1,* , Wiktoria Mozalewska 1, Agnieszka Adamus 1, Alicja K. Olejnik 1, Monica Ramos Gallego 2, Jakob Vange 2, Anton W. Bosman 3, Tristan Mes 3, Janusz M. Rosiak 1

1 Institute of Applied Radiation Chemistry, Lodz University of Technology, Wroblewskiego 15, 93-590 Lodz, Poland 2 Coloplast A/S, Holtedam 1-3, DK-3050, Humlebaek, Denmark 3 SupraPolix BV, Horsten 1, 5612 AX Eindhoven, The Netherlands * [email protected]

Common terminal sterilization methods applicable for medical devices encompass moist heat, formaldehyde, ethylene oxide, radiation and plasma. Particularly, implants based on biodegradable synthetic polymers require special concern with regards to their sterilization. In principle, only low-temperature methods are acceptable. Simple implants, designed for load bearing applications, i.e. of polylactides, are typically treated with EO. Other chemical methods should be avoided since sterilizing agents may interact with polymers in terms of chemical reactions, or modify greatly its surface chemistry, e.g. hydrogen peroxide plasma. On the other hand, radiation is not inert to properties of polymeric biomaterials. Irradiation of a polymer by an electron beam or gamma rays generates radicals which are precursors of reaction leading in turn either to crosslinking or degradation. The latter case is usually detrimental to polymer physical-chemical properties, thus a number of polymers cannot withstand sterilization with radiation. Nevertheless, the limited extent of changes may be acceptable. Polyesters degrade when exposed to ionizing radiation, yet those possessing in their chemical structures secondary carbon atoms may simultaneously undergo crosslinking. A good example is poly( ε-caprolactone) (PCL) in which radiation causes broadening of molecular weight distribution but eventually, at doses sufficiently high, a gel fraction could be separated. Supramolecular polymers having ureidopyrimidinone (UPy) groups responsible for intermolecular, labile crosslinking bonds, can be processed by common techniques, such as thermal methods at relatively mild conditions, or by electrospinning. This, combined with their perfect biocompatibility and bio-degradative character are main advantages of UPy materials having PCL mainchain. Since UPy-PCL is sensitive to elevated temperature, only low-temperature methods can be considered for sterilization of this biomaterial. Selection of the most suitable method, i.e. the least harmful to the biomaterial properties is determined, besides the nature of the polymer, by the device design. While considering production of large quantities of the device one should also consider validation of sterilization process. In this work some basic requirements for application of low temperature sterilization methods to UPy-PCL implantable electro-spun mesh for reinforcement and repair of soft tissue were addressed. Studies on radiation sterilization by either electron beam or gamma rays of the implant will be presented. Changes in physical-chemical properties caused by sterilization will be discussed along with basic biocompatibility. This work has been partially financed by the European Commission within FP7 project ‘BIP- UPy’ NMP-2012-LARGE-6 310389.

Session IX. Polymer-based medical and pharmaceutical devices

O41. RADIATION CROSSLINKED ALBUMIN CAPPED GOLD NANOPARTICLES FOR THERANOSTICS

Gustavo H. C. Varca 1,* , Janaína A. G. Barros 1, Jorge Gabriel dos Santos Batista 1, Kattesh V. Katti 2, Ademar Benévolo Lugão 1

1 Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP) - Avenida Lineu Prestes, 2242, Cidade Universitária, 05508-000, Sao Paulo, SP, Brazil. 2 Departments of Radiology, Physics and Chemistry, University of Missouri, Columbia, MO, United States. * [email protected]

Gold nanoparticles (AuNP) are being investigated for diagnostic and therapeutic nanomedicines considering their low toxicity and stability against oxidation, among other features. AuNP may be administered site-specifically or intravenously for diagnostic imaging by computed tomography or for therapy [1, 2]. Albumin functionalization of AuNP, whether linked by chemical or physical processes, may provide unique features to the system regarding biopharmaceutical aspects [3]. Recently albumin crosslinking has been studied by radiation induced methods [4, 5]. This work aimed the development of radiation crosslinked bovine serum albumin (BSA) capped AuNP for improved administration of the nanoparticles. For such purpose AuNP were synthesized using 2.5 mM sodium tetrachloroaurate (III) dehydrate and 1 mM resveratrol in water. The mixture was allowed to stand for 12 hours. AuNP capping was performed by BSA addition followed by slow addition of ice-cold ethanol to reach 5 mg mL -1 BSA in a 30% (v/v) ethanol solution. The mixture was allowed to rest overnight at ± 4 oC. BSA crosslinking onto AuNP was performed by gamma irradiation [4] at doses of 2.5, 5, 7.5, 10 and 15 kGy. AuNP were synthesized in the range of 60 nm, whereas BSA Capped AuNP presented size over 100 nm, as revealed by dynamic light scattering. AuNP and BSA capped AuNP morphology was evaluated by transmission electron microscopy using negative staining and revealed protein aggregation onto AuNPs and its surroundings. Irradiation led to no shifts in maximum absorbance for both nanoparticles. Protein crosslinking was confirmed by bityrosine and increased with dose. Future steps address biological evaluation of the BSA capped AuNP.

References [1] Viator, J.A., Gupta, S., Goldschmidt, B.S., Bhattacharyya, K., Kannan, R., Shukla, R., Dale, P.S., Boote, E., Katti, K. Gold Nanoparticle Mediated Detection of Prostate Cancer Cells Using Photoacoustic Flowmetry with Optical Reflectance. J. Biomed. Nanotechnol. 6 (2010), 187 -191. [2] Kattumuri, V., Katti, K., Bhaskaran, S., Boote, E.J., Casteel, S.W., Fent, G.N., Robertson, D.J., Chandrasekhar, M., Kannan, R., Katti, K.V. Gum arabic as a phytochemical construct for the stabilization of gold nanoparticles: In vivo pharmacokinetics and X-ray-contrast-imaging Studies. Small. 3 (2007), 333-341. [3] Cañaveras F., Madueño, R., Sevilla, J.M., Blázquez, M., Pineda, T. Role of the Functionalization of the gold nanoparticle surface on the formation of bioconjugates with human serum albumin. J. Phys. Chem. C. 116 (2012), 10430-10437. [4] Queiroz, R.G., Varca, G.H.C., Kadlubowski, S., Ulanski, P., Lugao, A.B. Radiation-synthesized protein-based drug carriers: Size-controlled BSA nanoparticles. Int. J. Biol. Macromolec. 85 (2016), 82-91. [5] Achilli E., Casajus G., Siri, M., Flores, C., Kadłubowski, S., Alonso, S. del V., Grasselli, M. Preparation of protein nanoparticle by dynamic aggregation and ionizing-induced crosslinking. Colloids. Surf. A. Physicochem. Eng. Asp . 486 (2015) 161-171.

Session X. Lifetime prediction

O42. CHALLENGES AND OPTIONS FOR THE PREDICTION OF POLYMER DEGRADATION UNDER COMBINED AGING ENVIRONMENTS

Mathew Celina 1,* , Kenneth Gillen (ret.) 1

1 Organic Materials Science Dept. 1853, Sandia National Laboratory, Albuquerque, New Mexico, 87185, USA * [email protected]

The key material behaviors that result in complexity for lifetime prediction of polymer degradation under thermal-radiation conditions are reviewed. Complications arise due to inverse temperature, diffusion limited oxidation and dose rate phenomena, often part of limited aging studies under only highly accelerated aging conditions (either through temperature or high dose rates). We compare existing experimental data with extended exposure studies under low dose rate conditions for oxidation rates and their correlation with mechanical property changes for an XLPO cable insulation material.

Accelerated aging models are needed when two environments impact degradation and we therefore consider combined radiation-temperature environments. A viable model described in the past is the dose to equivalent damage (DED) model which assumes that by accelerating the thermal-initiation rate by a factor x (from Arrhenius T-only analysis) and raising the radiation dose rate by x leads to an identical increase in the combined degradation rate. We critically review the DED model, using a 2-D plot that describes the model’s underlying framework and how its assumptions can be tested using so-called matched accelerated conditions (MAC) which reflect the simple acceleration factor assumption above. Historical data on several elastomers not only confirms the model assumptions, but shows that substantial degradation chemistry changes occur as one transitions from thermo-oxidative dominated to radiation-dominated degradation. This not unexpected observation is handled appropriately in the DED approach, but conflicts with the primary assumption used in an alternative but highly-empirical past model.

Given the chemical changes that depend upon the particular mix of radiation plus temperature, accelerated aging simulations should ideally choose accelerated conditions along the MAC line that intersects the ambient conditions, leading to more confident lifetime predictions. These same concepts also allow the remaining lifetimes of ambiently aged samples to be derived using a 2-D analogy to the 1-D Wear-out approach developed previously for thermo- oxidative aging. Sandia is a multi-program laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy’s National Nuclear Security Administration under Contract DE-AC04-94AL85000. Unlimited release under SAND2016- 3540 A.

To be presented at IRaP “12 th meeting of the Ionizing Radiation and Polymers Symposium” Sept 25 – 30, 2016, Giens, France

Session X. Lifetime prediction

O43. THERMO AND RADIOOXIDATION OF MODEL MATERIALS OF CABLE INSULATION USED IN NUCLEAR POWER PLANTS

A. Sidi 1,* , J.-F. Larche 4, A. Rivaton 2,3 , F. Bot-Robin 1, J. Colombani 1

1 Laboratoire Expérimentation Environnement et Chimie -IRSN CEN Cadarache - 13115 St- Paul-Lez-Durance - France 2 Clermont Université, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, Equipe Photochimie, BP 10448, F-63000 Clermont-Ferrand, France 3 CNRS, UMR 6296, ICCF, Equipe Photochimie, BP 80026, F-63171 Aubière, France 4 NexansResearch Center, 29 rue du PréGaudry, 69353 Lyon Cedex 07- France * [email protected]

The ability of I&C cables used in Nuclear Power Plants (NPP) to support both normal operating conditions and accidental situations is a major challenge for nuclear safety, particularly within the scope of extending the life time operation of French NPP. The I&C cables can be exposed to two main degradation triggers: gamma radiation and temperature. The electrical functionality of I&C cables being strongly dependant on the ageing of the polymers composing them, the study of thermal and radiochemical ageing of cable insulation is therefore of major interest. The present work focuses on the ageing of model materials whose composition are well known and are very close to the main components of the I&C cable insulation. These model materials are based on a cross-linked blend of EVA (Ethylene Vinyl Acetate) and EPDM (Ethylene Propylene Diene Monomer) filled with ATH (Aluminum trihydroxide). The aim of this study is to understand the ageing phenomena of these materials and to highlight particularly:

− the influence of the filler (ATH) on the ageing degradation mechanisms, − the degradation mechanisms induced by the impact of the gamma irradiation on one hand, and the impact of temperature on the other hand, − the correlations between the evolutions of the chemical, physical and mechanical properties of the material occurring during the ageing process.

Results show that the incorporation of a high amount of fillers (60%) drastically modifies the structure and morphology of the model material. Thermoporosimetry measurements reveal the presence of large size pores in the filled material compared to the unfilled material. In addition, XRD data suggest that the filler is modified during the pre-crosslinking step of the material by dicumyl peroxide. Based on both thermoxidative and radiooxidative ageings results, it can be stated that degradation mechanisms are governed by chain scission processes starting on the EVA units. The consequences on the mechanical properties are only observed for the filled material with a rapid drop of the elongation at break after thermooxidation at 100°C. SEM images although confirm the significant degradation of the polymer in the filled material. This drop of the mechanical properties is correlate with the evolution of the quantity of carbonyl compounds in the model material, this evolution being itself linked to the chain scission process.

Session X. Lifetime prediction

O44. INFULENCE OF COLOR PIGMENTS ON DEGRADATION OF POLYMER MATERIALS FOR CABLES IN NUCLEAR POWER PLANTS UPON THERMAL OR/AND RADIATION AGEING

Hisaaki Kudo 1,* , Gabriela Mizerova 2 and Vit Pla ček 2

1 Nuclear Professional School, School of Engineering, the University of Tokyo, Japan 2 UJV, Rez, Czech Republic * [email protected]

Aging of Nuclear Power Plant (NPP) has been of serious concern and cable is one of the important equipments, and cable insulation aging has been extensively studied so far [1]. Cable insulation aging is attributed to thermal and /or radiation degradation of polymer materials that constitute of jacket and insulators of cable. Degradation is well indicated by elongation at break (EtB) through tensile test; EtB decreases with aging time or absorbed dose as a consequence of oxidation, scission, cross-linking, etc.

However, the commercial cable materials contain miscellaneous coexisting chemicals such as anti-oxidant, plasticizer, filler etc. (and sometimes such information is not available), which would make the situation very complicated. Influence of additives, especially pigments to exhibit specific colors, to polymer degradation has been pointed out [1-3].

Influence of color pigments on polymer degradation is analyzed in this work. Provided five kinds of commercial cables having four insulations with different pigments, were subjected to, thermal aging, radiation aging, and simultaneous thermal and radiation aging. Afterwards, tensile tests to obtain Elongation at break (EtB) were carried out, according to the International Standard (IEC 62582-3). The sequential aging (thermal ageing followed by radiation aging) or reverse sequential aging (radiation ageing followed by thermal aging) are planned, but not completed yet.

Although some data has large standard deviation (scattering), especially for whole cable, or jacket which may be reasonable for preparing of specimens, and also some important data are missing because it was not possible to prepare specimens, the conclusion is that it seems not- very significant effect of pigments (from comparison from different colors with the same base polymer). Results concern the tested system base polymer material and pigment. They may differ for another material combination.

References [1] T. Yamamoto and T. Minakawa, Final report of -“Assessment of Cable Aging for Nuclear Power Plants”, Japan Nuclear Energy Safety Organization (JNES) report, Report No. JNES-SS-0903 (2009). [2] G. Mizerova and V. Placek. “Influence of pigments on cable life time”, presentation at an IAEA- CRP meeting on Cable ageing , Shanghai, China (2014). [3] T. Z. M. AlShaketheep. “Study on Ageing Degradation of Nuclear Power Plants Cables using Accelerated Tests”, ph. D Thesis, the University of Tokyo (2015).

Acknowledgements The authors thank Mr. Micael LINDBERG of Habia, Sweden, and Mr. Richard NEDVED of Lamela, Czech Republic.

Session X. Lifetime prediction

O45. CABLE MATERIALS IN HARSH ENVIRONMENT AND RADIOLYTIC GAS FORMATION

Martin Cabalka 1,* , Vít Pla ček 2

1 Nuclear Research Institut, Řež, Czech Republic 2 Nuclear Research Institut, Řež, Czech Republic * [email protected]

Long-term influence of stressors – elevated temperature and irradiation – has the negative effect on mechanical, electrical and other properties of polymer materials (cables) and consequently it may has the dominant impact on functionality during accidental conditions at NPP. Deterioration of cable materials (jacket and insulations) is demonstrated appreciably by fragility and surface cracks, therefore the measured mechanical properties fall down to minimal value of strain at break. Surface changes are clearly evident for example in the pictures of scanning electron microscope. Similarly, these stressors are the cause of radiolytic gas formation. The researchers of ÚJV Řež made special cylinders, which were placed into irradiation facility in average dose rate position of 2 kGy·h -1. First of all, experiments were concentrated on detection of explosive gases – hydrogen and methane, determined by mass spectrometry and gas chromatography. The samples of cable types NSKA (NSKFA) and CXFE were chosen for these experiments. Degradation of samples was carried out with simultaneous ageing at 75 °C and 5 Gy·h -1 over a period 2.5 years and the comparison between non-aged and aged samples. The gas formation was monitored by measuring of pressure in cylinders, at the room temperature (30 °C – due to irradiation heating) and at elevated temperature of 67 °C. The nitrogen was carrier gas was and the foil balloons were used for the gas sampling. For both analytic methods, the results were comparable. The experiments has shown, that gas formation in cable materials NSKA (NSKFA) and CXFE depending on dose (dose rate) and temperature was similar, even for aged and non-aged materials. The experiments with whole cables sealed with shrink tubes have validated the same upward trend of pressure.

Figure 1: Determination of pressure dependent on temperature and dose

This project was solved under the terms of project TA ČR02010218.

Session XI. Polymer ageing: property modifications

O46. E-BEAM AS PROTOTYPE SOURCE FOR INVESTIGATING ELECTRICAL AGEING OF INSULATING POLYMERS

Gilbert Teyssèdre 1,* , Virginie Griseri 1, Mallys Banda 1, Séverine Le Roy 1, Christian Laurent 1

1 Université de Toulouse & CNRS; LAPLACE, Toulouse, France * [email protected]

Insulating polymeric materials are used in a large variety of applications in electrical engineering either as bulk insulation or in thin films form, e.g. high-voltage insulated cables, capacitors, windings of coils for electrical machines, power electronic modules, etc. One of the main threats for the insulation ageing is the existence of partial discharges (PD) eroding the polymer. However, progresses made along materials processing and systems design are such that the limits in insulation endurance very often move to intrinsic field withstanding. Under such circumstances, ageing processes have to be unraveled, and one of the candidate mechanisms is the onset of hot electrons generation able to break atomic bonds and to generate defects. However, the proof and demonstration of such process is not an easy task owing to the slowness of the phenomena. Our purpose in this paper is to present some diagnosis results on insulating polymers obtained using e-beam as a source of energetic carriers likely to create impact-excitation and impact-ionization into materials. The material under investigation is mainly polyethylene, used traditionally as insulation of power cables.

A first part of the talk addresses cathodoluminescence –CL- measurements, excited by electrons of a few keV in energy, with a comparison to electroluminescence – EL excited under high AC field. Common optical signatures can be found in the related spectra: different important mechanisms for the stability of the material properties under electric field can be investigated such as the onset of hot electrons, recombination phenomena and chemiluminescence. One of the components in the emission has not been identified although it represents the main emission peak. It might be due to a by-product generated under an excited form or excited during charge recombination.

The second part of the talk will concern electron implantation in polyethylene under electron source of up to 100keV, focusing on primary electron deposition along with ionization effects associated with e-beam energy deposition. Through space charge density profile measurements, we clearly demonstrate the generation of electron-hole pairs and/or ionization in the irradiated area, surviving in post-irradiation conditions. The behavior of such charges is investigated under field stress and put in relation to delayed radiation induced conductivity.

Session XI. Polymer ageing: property modifications

O47. CHANGES IN HEAT RESISTANT PROPERTIES OF LLDPE BY PRE-IRRADIATION

Masayuki Ito 1,* , Genki Nishio 1, Yuto Watanabe 1 and Tomomi Kosaka 1

1 Tokyo gakugei university, Japan * [email protected]

Introduction: Electric wire and cable used in the container vessel of nuclear power plant are exposed by radiation and heat during the lifetime. IEEE Std. [1] recommended the sequential addition of radiation and heat for the convenience of the test. This article studied the effect of pre-irradiation on the thermal resistant properties of LLDPE using the simple method [2].

Experiment: Antioxidant reagent (4,4’ thio bis-(3-methyl-6-tert-buthyl phenol) was blended with LLDPE using mixing roll. The sheet whose thickness was about 0.15mm was obtained by heat press. Irradiation was performed by Co-60 γ ray at room temperature. Dose rate was 3.0 kGy/h. After irradiation the sample was aged at constant temperatures.

Result and discussion: The weight change of LLDPE by isothermal aging was studied at from 90˚C to 170˚C. Figure 1 shows the weight change of LLDPE which contains different concentration of antioxidant reagent along with thermal gaining at 140˚C. Relationship between concentration of antioxidant reagent and induction period was found to be linear in all of the temperatures. Fig.2 shows the effect of pre-irradiation of γ ray. Pre-irradiation of 320 kGy to LLDPE decreased remarkably the period of induction period of thermal aging. The pre-irradiation accumulate hydroperoxide in LLDPE and this initiate autoxidation at the early stage of thermal aging.

Fig. 1. Effect of concentration of antioxidant Fig. 2. Effect of pre-irradiation on weight change by reagent on changes in weight by thermal aging at thermal aging at 140°C. 140°C Dose of pre-irradiation: 320 kGy

Reference [1] IEEE Std.323-1974, IEEE standard for type test of class IE electric cables, field splices and connections for nuclear power generating stations, IEEE (1974) [2] Ito M., Inayoshi S. and Moriyama K., Polym. Deg. Stab . 93 1935(2008)

Session XI. Polymer ageing: property modifications

O48. COUPLING BETWEEN CHEMICAL DEGRADATION UNDER IRRADIATION AND MECHANICAL PROPERTIES

B. Fayolle 1,* , E. Richaud 1, X. Colin 1, J. Verdu 1

1 Arts et Métiers ParisTech, CNRS, PIMM UMR 8006, 151 bd de l'Hôpital, Paris, France. * [email protected]

Lifetime of polymers under irradiation is mainly limited by an embrittlement process due to chemical ageing. Since non-arrhenian behaviors or dose rate effects make more complicated lifetime predictions, we have been involved for many years exploring alternative multi-scale approaches based on kinetic modeling and structure-properties relationships that may provide a basis for predictions of curvature in extrapolations. An integral part of this approach is knowledge of the coupling between chemical degradation and mechanical properties in order to predict mechanical behavior changes during long-term aging.

Since chemical ageing leads to macromolecular modifications due to chain scission or crosslinking processes, we propose here to review the relationships available between macromolecular modifications and mechanical properties (modulus, properties at failure) as a function of polymer families. In the case of radiooxidative ageing, for instance, polymers such as polyolefins or polyoxymethylene are degraded by a random chain scission process, whereas elastomers such as polydienes undergo crosslinking. Specific aspects for epoxy systems under irradiation will be investigated.

Session XII. Membranes

O49. AMPHIPHILIC BLOCK COPOLYMER SYNTHESIS BY RAFT- MEDIATED RADIATION-INDUCED POLYMERIZATION

S. Duygu Sütekin 1,* , Olgun Güven 1

1 Hacettepe University, Department of Chemistry, Beytepe, 06800, Ankara, Turkey * [email protected]

Among various polymeric nanoparticles the micelle-like nanoparticles assembled from amphiphilic block copolymers have received growing attention in recent years. It is well- known that an amphiphilic block copolymer in a selective solvent can form micelle-like structures through association of less soluble segments enabling their use in many applications, especially in biomedical field [1]. Block copolymers are usually prepared by sequential living anionic polymerization which is known to require stringent polymerization conditions and limited to monomers that can be polymerized by ionic mechanism. Classical free radical polymerization can hardly be used for block copolymer synthesis due to difficulty in finding monomer pairs with appropriate reactivity ratios. With the introduction of a controlling mechanism in otherwise irreversible free radical polymerization it has been possible to synthesize vinyl polymers with predetermined molecular weight and very narrow distributions. Moreover due to the reactivity of the end groups present at growing chains it is possible to extend the chains using different monomers leading to the formation of block copolymers with precise molecular weights. One of these controlled radical polymerization methods namely; Reversible Addition-Fragmentation chain Transfer (RAFT) is a method that offers the essential features of “living”/ controlled systems under conventional free radical reaction conditions. The versatility of RAFT allows for the synthesis of various well-defined AB block copolymers with different segment lengths provided that the correct RAFT agent, solvent and other parameters for both monomers have been considered. As a source of radical generation ionizing radiation has proved to be very convenient tool in RAFT-mediated polymerization, grafting and copolymerization [2]. Here we shall present details of the synthesis of amphiphilic block copolymers of poly (tert- butyl acrylate) and poly (N-vinyl pyrrolidone) (PtBA-b-PVP) by radiation-induced RAFT polymerization and preparation of terpolymers by partial conversion of tBA blocks into poly (acrylic acid). Since N-VP cannot be polymerized by ionic mechanism its block copolymers can only be synthesized by RAFT polymerization. The chain lengths of PtBA blocks can be used to tune the hydrophilic/hydrophobic balance of the copolymer and can be easily converted to poly (acrylic acid) to prepare pH responsive amphiphilic block copolymers. Thus PtBA-b-PVP block copolymers would allow the preparation of amphiphilic (PtBA-b-PVP), double hydrophilic (PAA-b-PVP) and amphiphilic polyelectrolyte [PtBA(PAA)-b-PVP] copolymers. The main challenge of such a work is to synthesize these copolymers with controlled segment lengths. The preparation of amphiphilic block copolymers of PtBA-b-PVP was achieved by the chain extension of RAFT synthesized PtBA as a macrotransfer agent via addition of NVP to active chain end. The formation of self- assembled structures from these block copolymers will be presented.

References [1] Rösler A., Vandermeulen G.W., Klok H.A. Adv. Drug Deliv. Rev. 64 (2012) 270-279. [2] Barsbay, M., Güven, O. Radiat. Phys. Chem. 78 (2009) 1054-1059. [3] Duan X., Li Y., Small 9 (2013) 1521-1532.

Session XII. Membranes

O50. AGEING UNDER GAMMA IRRADIATION OF A REVERSE OSMOSIS MEMBRANE: PROPERTIES AND STRUCTURE MODIFICATIONS

Nicolas Combernoux 2,3 , Véronique Labed 1,* , Luc Schrive 2, Emilie Carretier 3, Yvan Wyart 3, Philippe Moulin 3

1 CEA, DEN, DTCD, SPDE, LP2C, F-30207 Bagnols-sur-Cèze, France. 2 CEA, DEN, DTCD, SPDE, LPSD, F-30207 Bagnols-sur-Cèze, France. 3 Aix Marseille Université, CNRS, Centrale Marseille, M2P2 UMR 7340, Equipe Procédés Membranaires (EPM), Europôle de l’Arbois, BP80, Pavillon Laennec, Hall C, 13545 Aix en Provence Cedex, France * [email protected]

Reverse osmosis (RO) is currently one of the most used desalination process to produce drinking water. This process, based on membrane separation, is developing more and more to treat different types of effluents. For now, membranes are organics polymers and composed on a superposition of three polymers: Polyamide, Polysulfone and Polyester.

Recently, RO was chosen as the final treatment of the seawater used to cool the damaged nuclear reactors. Only very few studies and data has been published yet about RO applied to radioactive wastewater. In an industrial process of radioactive liquid waste treatment one should expect that the RO membranes can be degraded by the irradiation induced by the presence of the radionuclides in the effluents. However, data about the ageing of the membranes under these operating conditions are very difficult to obtain even if RO seems to be efficient in the process used in Fukushima.

Thus, the goal of this work was to understand the degradation mechanism of the membrane and quantify the effect of the irradiation during the filtration of radioactive wastewater. The radionuclides spectra after nuclear disasters revealed mainly gamma and beta emitters, as 137 Cs, 90 Sr and 131 I. Consequently, in this study, membranes were exposed to a gamma irradiation source with dose and dose rate chosen closely to the value observed in a realistic case like Fukushima and Tchernobyl.

Some experimental parameters were varied (contact with oxygen, with water, irradiation dose and dose rate) to quantify the impact on physico-chemical properties and separation performances of the membrane. The results showed that the main degradations appeared above a dose higher than 100kGy and had some consequences on the intrinsic properties of the polymers and on the separation performances of the RO membrane. Furthermore, presence of oxygen and increase in dose rate were identified as significant parameters that affect the threshold of the membrane degradation. All these conclusions resulted from the development of an innovative and complementary analytical protocol.

Session XII. Membranes

O51. PREPARATION OF BIMETALLIC NANOPARTICLES WITH CONTROLLABLE CORE-SHELL RATIO IN IRRADIATED INTERPOLYELECTROLYTE COMPLEXES

D.I. Klimov 1,* , A.A. Zezin 1, S. S. Abramchuk 2, E. A. Zezina 2, M. Yang 3

1 Enikolopov Institute of Synthetic Polymeric Materials, a foundation of Russian Academy of Sciences, Profsoyuznaya ul. 70, Moscow, 117393 Russia 2 Department of Chemistry, Lomonosov Moscow State University, Moscow, 119991 Russia 3 Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China * [email protected]

The bimetallic nanostructures (BNs) are of considerable interest for various prospective applications. Radiation-chemical methods have been proved to be extremely useful for preparation of nanoparticles and detailed studies are concentrated on the mechanisms of their formation [1]. The poly(acrylic acid)–polyethyleneimine (PAA–PEI) interpolyelectrolyte complexes (IPEC) were shown to be particularly suitable precursors for preparation of metal- polymer nanocomposites via reduction of metal ions using chemical and radiation-chemical methods [2]. Cu shell /Ag core and Cu shell /Au core nanoparticles were synthesized in situ in films of interpolyelectrolyte complexes containing both Ag (or Au) and Cu ions by irradiation with x- ray and e-beams accelerator. HRTEM data show the core-shell structure of nanoparticles. XRD data exhibits that irradiation led to formation of the nanoparticles cores (Ag or Au) at early stage of irradiation while increase of the irradiation dose resulted in the growth of copper shell. On the BNs sizes and core-shell ratio affect the irradiation doze and initial concentration of metal ions in IPEC. In summary, we have demonstrated that the radiation-induced reduction of metal ions in the IPEC matrices can be used for the single-stage preparation of nanocomposite films containing the bimetallic nanoparticles with controllable core-shell ratio [3].

Figure 1. a) TEM images of Cu shell /Ag core and Cu shell /Au core nanoparticles with initial content of copper ions 10 wt% and silver ions 1 wt%, irradiation dose 250 kGy b) XRD patterns of patterns of irradiated films of interpolymer complexes containing 10 wt% of copper ions and 1 wt% of silver, irradiation dose 125,250,500 kGy.

The support from the Russian Foundation for Basic Research (project no. 15-03-04886) is gratefully acknowledged.

References [1] J. Belloni, Catal. Today. 113 (2006) 141 [2] D.V. Pergushov , A.A. Zezin , A.B. Zezin , A.H.E. Müller, Adv. Polym. Sci. 255 (2014) 173 [3] D. I. Klimov , E. A. Zezina, S. B. Zezin, M. Yang, F. Wang, V. I. Shvedunov, V. I. Feldman, A. A. Zezin, Radiation-induced preparation of bimetallic nanoparticles in the films of interpolyelectrolyte complexes, Mat. Letters, In press 74

Session XIII. Radiolysis

O52. GAS YIELDS AND RELATIVE SENSITIVITY OF VARIOUS POLYMERS

Jay A. LaVerne 1,*

1 Radiation Laboratory and Department of Physics, University of Notre Dame, Notre Dame, Indiana, USA. * [email protected]

Research has long shown that some organic molecules are more sensitive to radiation than others. A short discussion on the fundamentals of organic radiolysis and application to polymers will be followed by more detailed examples of the relative radiation sensitivity of a wide variety of polymers. The majority of the focus will be on gas production, which gives a good indication of the relative radiation sensitivity. Gas production is also important for determination of explosive hazards in practical applications. Other aspects of polymer radiolysis will be presented in a few specific instances. The fundamental processes occurring in the radiolysis of a few polymers and resins in their dry state will be discussed as well as with associated water to illustrate interfacial effects. The final part of the discussion will consider the radiolysis of various siloxanes. Comparisons and variations with the more common organic polymers will be examined.

Session XIII. Radiolysis

O53. EFFECT OF TEMPERATURE ON GAS RELEASE DURING THERMAL OXIDATION OF GAMMA-IRRADIATED POLYMER BASED NEUTRON SHIELDING

O. Okamba-Diogo 1, M. Cornaton 1, V. Dauvois 1, D. Durand 1, M. Ferry 1, D. Lebeau 1, S. Legand 1, J.L. Roujou 1, F. Nizeyimana 2, and S. Esnouf 1,*

1 DEN/DANS/DPC/SECR – Laboratoire de Radiolyse et de la Matière Organique, CEA Saclay, 91191 Gif-sur-Yvette, France 2 AREVA-TN, 1 Rue des Hérons, 78180 Montigny-le-Bretonneux, France * [email protected]

Transportation and storage casks for nuclear material contain polymer matrix-based neutron shielding. For safety reasons, neutron shielding capability is guaranteed by polymer composites such as unsaturated polyester or vinylester. These composites are naturally rich in hydrogen atoms which slow down neutrons by elastic collisions. The hottest temperature can reach 160 °C inside the cask. Therefore, in addition to irradiation, polymer materials can undergo thermal oxidative degradation that might affect the integrity of the neutron shielding especially by hydrogen consumption. Radiological protection implies the accurate determination of the cask’s lifetime, consequently the durability of the polymer-based neutron shielding. The aim of the present work collectively completed by CEA and AREVA is to investigate the influence of temperature on the quantity and the composition of gas released during thermal oxidation of gamma pre-irradiated neutron shielding polymers.

In this study, we present more specifically the effect of gamma-irradiation on thermal oxidation of additive-free unsaturated polyester and vinylester matrix. Our approach is aimed at determining which process rules our polymers durability between thermal oxidation and irradiation.

Films (200 µm thick) were placed under various atmospheres (helium and oxygen) in sealed ampoules then gamma-irradiated at room temperature under air at 1 kGy h -1 (500 and 1000 kGy). Then, the irradiated samples were oxidized at 160 °C and under oxygen (2 bars) in sealed ampoules. The gas release was analyzed by high-resolution mass spectroscopy. The polymer was characterized by infrared spectroscopy and the mass loss was determined. The decomposition activation energy was determined by thermal gravimetric analysis (TGA).

Session XIII. Radiolysis

O54. PULSE RADIOLYSIS IN CONCENTRATED SOLUTION BY USING ALPHA-ALLYLOXYMETHYL ACRYLIC COPOLYMER

Yuji Hosaka 1,* , Chucheng Wang 1, Yushi Soeta 1, Yutaro Saito 1, Takafumi Kondoh 2, Yoichi Yoshida 2, Akihiro Oshima 1,† , Masakazu Washio 1

1 Research Institute for Science and Engineering, Waseda University, Japan. 2 the Institute of Scientific and Industrial Research, Osaka University, Japan. † Current address: Graduate School of Engineering, Osaka University, Japan. * [email protected]

Alpha-allyloxymethyl acrylic copolymer (AMA) is a resin composition which has a tetrahydrofuran (THF) ring in the main chain, as shown in Fig. 1. [1] AMA is radical curable and has high solubility in organic solvents. Thus, it is applicable for various industrial fields such as the surface curing and an adhesive materials. Recently, it was suggested that radiation- induced direct ionizations of solute are observed by pulse radiolysis in THF because of rapid decay of radical cations in THF. [2] It means that early reactions in radiation chemistry in solid state can be simulated by experiments in solution. As AMA has a high solubility in THF, the high viscosity samples in THF can be easily prepared. Therefore, pulse radiolysis experiments in concentrated solution with low mobility that are more close to in solid state than in diluted solution are expected to be performed by using AMA. In the study, the radiation-induced early events in highly concentrated AMA solution were studied by means of pulse radiolysis. Transient absorption spectra of 1 M AMA and 0.25 M polystyrene mixed solution in THF (t = 0, 20 ns) obtained by the pulse radiolysis are shown in Fig. 2. A long-lived broad absorption band of dimer radical cations of polystyrene were observed at 1100 nm. The yield and the decay time of dimer radical cations of polystyrene were independent of the concentration of AMA in an additional experiment. As the yield remained the same at each concentration, the radical cations of polystyrene were generated only by direct ionization of solute. Therefore, it suggests that early reactions in radiation chemistry in solid state can be simulated more precisely by using AMA.

Figure 1. A chemical structure of methyl AMA Figure 2. Transient absorption spectra of mixed solution

The authors would like to acknowledge gratefully NIPPON SHOKUBAI CO., LTD. for providing AMA sample and Dr. Gohdo for making pulse radiolysis measurement system.

References [1] Tomomasa Kaneko. α-allyloxymethylacrylic acid-based copolymer, resin compositions, and use thereof. US Patent (2013), 8497332 B2. [2] Yuji Hosaka, et al. Pulse radiolysis study on a highly sensitive chlorinated resist ZEP520A. J. Photopolym. Sci. Tec. 26 [6] (2013), 745-750. 77

Session XIII. Radiolysis

O55. RADIOLYTIC DEGRADATION OF IONIC EXCHANGE RESINS: WATER EFFECT

I. Boughattas 1, Y.Ngono-Ravache 2, V. Labed 1, A. Dannoux-Papin 1,*

1 CEA, DEN, DTCD, SPDE, LP2C, F-30200 Bagnols sur Céze, France. 2 CIMAP, UMR CEA-CNRS-ENSICAEN-UCBN, BP 5133, F-14070 Caen cedex 5, France. * [email protected]

Exchange Ionic Resins (IERs) are organic waste mainly issued from water treatment plants of used nuclear fuel pools. Or, these IERs are submitted to beta, gamma, and alpha auto- irradiation. Liquid or gaseous radiolytic compounds are produced as hydrogen which radiolytic yield depends on hydration of IERs. In the aim to immobilize these IERs in a cementitious matrice, it is necessary to characterize their physical state and to quantify hydrogen production according to the dose, the water content and the atmosphere. Even if radiolytic degradation of IERs is well known under gamma rays nowadays, only Baidak and al. [1] have studied the evolution of hydrogen production as a function of water content using alpha particles irradiation. The aim of the present work is firstly to study the effect of hydration on hydrogen emission, in anionic and cationic resin irradiated under inert atmosphere, using Swift Heavy Ions and gamma rays as a function of water content. Secondly, we are interested in the radiolytic degradation of IERs in aerobic conditions irradiated at 1, 2, 3 and 4 MGy as a function of water content. Measurements of swelling, crosslinking rate and soluble fraction were performed to characterize their physical state. The result obtained concerning gas production showed that the release of hydrogen takes place in three steps depending on the water form(free or bonded) whatever the ionic form of IERs (H +, OH -). Concerning the physical state, the water uptake of the resin bead for H + form cationic resin irradiated at 1 MGy is more efficient when the resin was irradiated under moist conditions whereas literature data show a release of water during irradiation of IERs due to crosslinking process. The dried resins irradiated at 1 MGy have the same behavior as non- irradiated IERs (Figure 1). Consequently, it appears that the initial water content have an impact on hydrogen emission but also on the radiolytic degradation of the skeleton of IERs.

Figure 1: Swelling rate of cationic resins irradiated at 1MGy as a function of water content

References [1] Baidak, A. and J.A. LaVerne, Radiation-induced decomposition of anion exchange resins. Journal of Nuclear Materials, 2010. 407 (3): p. 211-219. 78

Session XIV. Surface effects

O56. ION IRRADIATION OF POLYMER THIN AND ULTRATHIN FILMS: EFFECTS OF SPATIAL CONFINEMENT IN ONE DIMENSION

Ricardo M. Papaléo 1,*

1 Faculty of Physics, Catholic University of Rio Grande do Sul, Porto Alegre, Brazil * [email protected]

In the past 30 years, basic damage mechanisms and the physico-chemical changes observed in polymers irradiated by energetic ions have been thoroughly investigated for a multitude of polymeric systems and irradiation conditions. However, very little has been reported so far on nanoscale polymer systems and, in particular, on studies aiming a direct comparison of the magnitude of radiation effects under bulk and confinement conditions. In this talk, I´ll briefly review recent results in our group on ion irradiation of polymer thin and ultrathin films, used as a model system to investigate confinement effects of ion tracks in one dimension. We followed the changes in radiation effects as the thickness is systematically reduced from ~ 100 nm down to ~2 nm. Two types of experiments were performed for ions in an energy range from 2 MeV up to 2 GeV: one involving individual ions (surface effects, such as cratering and mass transport in single ion impacts) and another based on average effects of high-fluence irradiations (to get information on bond- breaking rates or chemical damage cross sections via XPS). Surface effects produced by swift heavy ions associated to mass transport and particle ejection are weakened when the length of the ion track is spatially confined. The deviation from bulk-like behavior starts at a critical thickness as large as 40 nm in PMMA, initially because long-range effects associated to cooperative action of excited material along the ion track are reduced. Contrary to the strong confinement effects found for the surface modifications, chemical damage cross sections were found to be insensitive to thickness reductions, even in layers as thin as 5 nm. There are however several challenges for the extraction of bond breaking rates in ultrathin layers, coupled to the reduced sensitivity of the experimental techniques, growth of carbonaceous contaminants during irradiation and thinning and morphological changes due to sputtering.

Session XIV. Surface effects

O57. ELECTRON BEAM CURING OF ACRYLIC ELASTOMERS FOR MEDICAL PRODUCTS

J. Portillo Casado 1,* , G. Gotzmann 1, Fh. Rögner 1, H. L. Bui 2, W. Meyer 2, H. Zeidler 2, G. Glowa 2

1 Fraunhofer FEP, Winterbergstr. 28, 01277 Dresden, Germany 2 Beckmann-Institut für Technologieentwicklung e. V., Turleyring 15, 09376 Oelsnitz/Erzgebirge, Germany * [email protected]

The need for personalized medical devices increased during the last few years rapidly. In the same way, the technology of 3D printing and rapid prototyping evolved. The medical technical field is a great area of application for these techniques and besides metallic and ceramic materials also polymer based materials are processed. Most of these polymer materials come in a liquid state and are cured by UV-polymerization. A main problem for these materials is the cytotoxic effect caused by residues of the photo initiator and its debris after polymerization. They lead to reduced biocompatibility in contact with biological environment. By application of non-thermal electron beam irradiation (eBeam), it was possible to polymerize standard elastomers. The thickness of the polymerized layers was in the range of some hundred micrometers, which makes this technique potentially suitable for 3D-printing applications. In contrast to UV-polymerization after polymerization by eBeam no odor and stickiness of the polymerized material was observed and the polymerized material occurred clear and transparent. The main improvement compared to standard polymerization is the enhanced biocompatibility of the material after eBeam treatment (Fig. 1). Besides the improvement of biocompatibility, the eBeam treatment in parallel can be used for surface sterilization of products according to DIN EN ISO 11137. With these findings, the use of eBeam polymerization of elastomersfor biomedical applications becomes utilizable. Due to its relatively low shielding requirements the non- thermal eBeam technology could be integrated in small laboratories and is compatible for inline production processes as well. In a next step, its combination with AM technologies should be assessed.

Figure 1: Metabolic activity of fibroblasts seeded on commercially cured elastomer and eBeam cured elastomer.

Session XV. Bio-based polymers and environmental concerns

O58. GAMMA RADIATION EFFECTS ON RANDOM COPOLYMERS BASED ON POLY(BUTYLENE SUCCINATE) FOR PACKAGING APPLICATIONS

M. Negrin 1,* , E. Macerata 1, G. Consolati 2, F. Quasso 2, L. Genovese 3, M. Soccio 3, M. Giola 1, N. Lotti 3, A. Munari 3, M. Mariani 1

1 Department of Energy, Politecnico di Milano, Piazza L. da Vinci, 32, 20133 Milano, Italy. 2 Department of Aerospace Science and Technology, Politecnico di Milano, Piazza L. da Vinci, 32, 20133 Milano, Italy. 3 Department of Civil, Chemical, Environmental and Materials Engineering, Università di Bologna, Viale Risorgimento 2, 40136 Bologna, Italy. * [email protected]

The high stability of conventional synthetic plastics and their increasing accumulation in the environment nowadays has intensified the need of biodegradable polymers, especially in those fields they rapidly become waste, such as packaging industry. Currently, great efforts are still devoted to develop new biodegradable plastics with suitable properties, in order to favor their production and application. It is well-known that ionizing radiation could affect polymer properties and/or enhance polymer biodegradability, therefore radiation-induced effects on polymers for packaging applications should be deepened because in such industry they often undergo radiation treatments for different purposes, such as in food irradiation[1]. Within this context, the present research work deals with novel copolymers of poly(butylene succinate) (PBS), a biodegradable polyester with similar processability as LDPE and suitable for processing into films[2]. In particular, the research focused on the behavior under irradiation of four new poly(butylene/tiodietylene succinate) random copolymers (PBS- PTDGS)[3]. Films and layers of the considered polyesters were exposed to gamma radiation at absorbed doses up to 500 kGy and subsequently fully characterized by different techniques, in order to evaluate the polymer radio-resistance as well as a possible positive impact on their biodegradability. GPC analyses were performed to correlate molecular weight decreases with absorbed dose, taking into account the copolymer composition and thickness. The effect of radiation on the thermal behavior were investigated by DSC and TGA, while PALS analyses were exploited to study changes in morphology affecting polymer permeability. Furthermore, SEM images and water contact angle measurements were carried out in order to reveal post- irradiation superficial alterations that could affect polymer biodegradability in compost. Results confirmed that radiation-induced degradation dominates for all the aliphatic systems under study. The presence of thioether linkages seems not to significantly affect the polymer stability towards radiation, while superficial modifications lead us to suppose a positive impact on the copolymers biodegradation rate in compost.

References [1] Haji-Saeida M., Sampaa M.H., Chmielewskib A.G. Radiation treatment for sterilization of packaging materials. Rad. Phys. Chem. 76 (2007), 1535–1541. [2] Ichikawa Y., Mizukoshi T. Bionolle (polybutylenesuccinate). Adv. Polym. Sci. 245 (2012), 285- 314. [3] Genovese L., Lotti N. et al. Novel biodegradable aliphatic copolyesters based on poly(butylene succinate) containing thioether-linkages for sustainable food packaging applications. Polym. Degrad. Stab. (2016), http://dx.doi.org/10.1016/j.polymdegradstab.2016.02.022.

Session XV. Bio-based polymers and environmental concerns

O59. FUNCTIONALIZATION OF FLAX FIBRES BY RADIATION- GRAFTING

Rodolphe Sonnier 1,* , Belkacem Otazaghine 1, Claire Longuet 1, Amandine Viretto 1, Ichem Chala 1, Sophie Rouif 2

1 C2MA, Ecole des Mines d’Alès, 6 avenue de Clavières, 30100 Alès, France 2 IONISOS – Parc Dombes Côtière Activités – F - 01120 Dagneux, France * [email protected]

The use of natural reinforcements in composite materials has considerably increased due to numerous advantages. However, some drawbacks limit their industrial applications such as their hydrophilic character, their low thermal stability and also their flammability.

Among different strategies to functionalize natural fibers, the radiation grafting appears promising. In this work, the grafting by simultaneous irradiation was used to improve the flame retardancy and the hydrophobicity of flax fabrics. As an example, Figure 1 shows the procedure to radiation-graft phosphorus compounds on flax fabrics. The influence of various experimental conditions on the grafting efficiency was assessed.

Figure 1. Scheme showing the procedure to radiation graft phosphorus compounds onto flax fabrics, the grafting location of phosphorus and the fire behavior of modified fabrics according to the phosphorus content

It is possible to control precisely the grafting efficiency and the location of phosphorus in order to achieve the desired level of flame retardancy. Self-extinguishing behavior of fabrics can be achieved [1]. Hydrophobic fibers were also prepared according to similar procedure.

This work is partly included in the French project called BIONICOMP, headed by IONISOS, with a consortium gathering of academic and industrial partners, in order to improve the performances of composites reinforced by natural fibers fabrics.

References [1] Sonnier R., Otazaghine B, Viretto A., Apolinario G., Ienny P. Improving the flame retardancy of flax fabrics by radiation grafting of phosphorus compounds. European Polymer Journal 68 (2015), 313-325.

Session XV. Bio-based polymers and environmental concerns

O60. MECHANICAL PROPERTIES AND THERMAL BEHAVIOR EVALUATION OF EXPERIMENTAL DENTAL COMPOSITES FILLED WITH IRRADIATED MONTMORILLONITE

Parra D.F.1,* , Campos L.M.P.1, Zaharescu T.2, Boaro L.C.3, Santos L.K.G.1, Lugão, A.B. 1

1 Nuclear and Energy Research Institute, University of São Paulo, Brazil. 2 Nacional Research Institute on Electrical Engineering, INCDIE ICPE, Romania. 3 Department of Biomaterials, School of Dentistry, University of Santo Amaro, Brazil. * [email protected]

The effects of pre-irradiation treatment (dose ranged from 25 - 50 kGy) of MMT nanoclay added as filler (50 wt%) in experimental dental composites based on Bis-GMA / TEGDMA, was studied. The thermal stability of resulting material was tested by thermogravimetry analysis (TGA) ranging from 50 to 800 ºC. Elastic modulus and flexural strength was determined by the three point bending test (n=10). Data for elastic modulus were analyzed using two way ANOVA/ Tukey’s test. Data for flexural strength were analyzed using Kruskal- Wallis/ Tukey’s test. For all tests, the global significance level was 5%. The modifications in elastic modulus and flexural strength with applied dose were characterized. XDR and TEM analysis allows depicting the intercalation phenomenon between base-polymer and nanophase. The polymeric system modified with MMT nanoparticles showed higher thermal stability by delaying in the thermal degradation, compared to the control group and the radiation dose influenced directly this thermal behavior. However, the applied dose was not sufficient to improve significantly the mechanical properties, which is related to the interaction between MMT and polymeric matrix. The pre-irradiation treatment of MMT nanoclay phase was useful for the attaining efficient interaction between the two constitutive phases of the systems bis-GMA/TEGDMA modified with MMT nanoparticles, because the polymer component was not affected.

Session XV. Bio-based polymers and environmental concerns

O61. G-VALUES OF WOOD POLYSACCHARIDES AND LIGNIN

Mark S. Driscoll 1,* , Jay LaVerne 2, Mohamad Al-Sheikhly 3

1 State University of New York College of Environmental Science and Forestry, USA 2 University of Notre Dame, USA 3 University of Maryland, USA * [email protected]

Ionizing radiation has been studied as a pretreatment process for a wood based bio refinery. Ionizing radiation treatment of wood chips has been shown to increase the amount of hemicellulose and lignin removed from the chips by hot water extraction. Ionizing radiation treatment has also been shown to decrease the molecular mass of cellulose. To try and better understand the process of wood irradiation, g-values were determined for cellulose, micro crystalline cellulose, xylan, organosolv lignin, cottonwood, glucose and amylopectin. Also studied was the “protective effect” that lignin has on cellulose and hemicellulose in wood.

Session XVI. International cooperation activities

O62. RADIATION PROCESSING FOR ADVANCED MATERIALS: IAEA PERSPECTIVES

S. Sabharwal 1,*

1 International Atomic Energy Agency, Vienna International Centre, PO Box 100, 1400 Vienna, Austria * [email protected]

Session XVI. International cooperation activities

O63. IIA PRESENTATION

Yves Hénon 1,*

1 International Irradiation Association, Hardwick House, Prospect Place, Swindon Witshire, UK SN1 3LJ, United Kingdom * [email protected]

Session XVI. International cooperation activities

O64. INTRODUCING THE ERASMUS + EDUCATIONAL PROGRAM FOR “ENHANCING THE DEVELOPMENT AND TRANSFER OF KNOWLEDGE FOR THE APPLICATION OF IONIZING RADIATION MATERIAL PROCESSING”

Xavier Coqueret 1,*

1 Université de Reims Champagne Ardenne, UMR CNRS 7312, BP 1039, 51687 REIMS Cedex 2, France * [email protected]

This project coordinated by the Institute of Nuclear Chemistry and Technology (INCT), in Warsaw (Poland), aims at developing a high level training course (syllabus, lectures, lab exercises, supporting material and dissemination tools) for MSc and PhD students from the seven participating institutions [1]. The students will acquire basic knowledge on radiation physics, radiation chemistry and radiation technology, together with an introduction to the advanced concepts and analytical methods for studying the applications of radiation processing to various sectors of materials science and technology. Since the kick-off meeting of the project, in December 2014, the academic or institutional partners from six different countries eligible for EU programs [1] have involved almost 50 of their collaborators (18 professors, 10 senior scientists, 10 junior researchers and 10 technicians) for preparing and implementing the training activities that were offered to 40- 50 students each year [2,3]. About 90 hours of classes and 12 hours of laboratory practice and demonstrations at research and industrial facilities are included in each intensive course, which lasts for 19 days, and ends up with an exam (9 ECTS credits granted to successful trainees). The new training module "Applications of ionizing radiation in materials processing" has been prepared, implemented, self-evaluated and improved all along the process, with two intensive courses hosted in the partner institutions or universities, in Italy, Poland (year 2015), and in France and Lithuania (year 2016). The elaborated course structure, the teaching materials, as well as a new text book written in English by the lecturers, will be adopted in the future as a regular training program. The knowledge gained during the project will help participants (mainly learners) to improve their impact and influence in this field of radiation science and technology applied to polymer materials. A new generation of scientists will be trained to the latest concepts and to the most recent techniques for elaborating materials with specific properties by using radiation processing.

References [1] Consortium including Hacettepe University (Turkey), Institute of Nuclear Chemistry and Technology (Poland), National Research Center (Italy), Petru Pone Institute of Macromolecular Chemistry (Romania), Technical University of Kaunas (Lithuania), University of Palermo (Italy), University of Reims Champagne Ardenne (France). [2] http://tl-irmp.eu/en/ [3] https://www.facebook.com/TL.irmp

Poster presentations

P1. THE MECHANICAL AND PHYSICOCHEMICAL PROPERTIES OF EPDM CABLE POLYMER AFTER THERMAL AND RADIOCHEMICAL AGEING

T. Šarac 1,* , J. Deveaux 2, N. Quiévy 3, A. Gusarov 1, and M. J. Konstantinovi ć1

1 SCK.CEN, Nuclear Materials Science Institute, Boeretang 200, B-2400 Mol, Belgium 2 Universite Catholique de Louvain, Place de l'Universite 1, 1348 Louvain-la-Neuve, Belgium 3 Laborelec, Rodestraat 125, B-1630 Linkebeek, Belgium * [email protected]

Mechanical and physicochemical properties of simultaneously thermal and gamma-irradiation ageing of industrial EPDM polymer are analyzed. Accelerated ageing, covering the wide range of dose rates, doses and temperatures, is performed on EPDM polymer samples extracted from the cables that are in use in Belgian Nuclear Power Plants. In this work the focus is given to the study of dose rate effect and on the correlation between the tensile test and thermogravimetry results.

Dose rate effect is observed as the change of the crossover between cross-linking and chain scission in the ultimate tensile stress data, as well as the change of the reduction of the elongation at break data as a function of the dose. The dose rate effect is found to be strongly enhanced at high temperatures.

Thermogravimetry tests are performed in both air and nitrogen atmosphere, which indicated the existence of different polymer decomposition processes in aged samples. Namely, the polymer decomposition curves in the oxygen are found to be dose dependent in a way that the increase of dose shifts the decomposition toward higher temperatures, while no difference in the polymer decomposition is observed under nitrogen atmosphere. The decomposition rates, analyzed by derivative thermogravimetry, also indicate the existence of the dose rate effect which fully mimics the elongation at break data.

These results are explained on the basis of thermal and radiation mediated oxidation degradation process.

References [1] T. Šarac, A. Gusarov, N. Quiévy, and M. J. Konstantinovi ć, Influence of γ-irradiation and temperature on the mechanical properties of EPDM cable insulation, Radiation physics and chemistry 25, 151 (2016). [2] T. Šarac, A. Gusarov, N. Quiévy, J. Devaux, M. J. Konstantinovi ć, The mechanical and physicochemical properties of EPDM cable polymer after thermal and radiochemical aging, Polymer degradation and stability, submitted.

P2. ANALYSIS OF THE SPACE ENVIRONMENT INFLUENCE ON THE ELECTRICAL RESISTIVITY OF A SILICONE ADHESIVE

Aurélien Roggero 1, Eric Dantras 1,* , Thierry Paulmier 2, Claire Tonon 3, S. Lewandowski 2, S. Dagras 3, Denis Payan 4

Space environment is held responsible for 11% of on orbit satellite failures. Materials used on their surface, such as adhesives or thermal insulators, are exposed to high flows of charged particles trapped in the geomagnetic field. On one hand, low energy electrons are deposited at the surface of insulating materials, building up high potentials that may lead to the initiation of disruptive electrostatic discharges. On the other hand, highly energetic particles can break chemical bonds. The subsequent reorganization of matter, known as chemical ageing, leads to irreversible evolutions of the physical properties of these materials.

This study focuses on a commercial filled silicone elastomer currently used in a variety of aerospace applications, such as solar cells adhesive or connectors potting. It aims at correlating between the evolutions of chemical structure and electrical properties.

Dynamical mechanical analysis, differential scanning calorimetry, solvent swelling tests and solid-state NMR spectroscopy evidenced an anticipated crosslinking process upon exposure to 400 keV-electron irradiation (~10 6 Gy), mainly proceeding through the formation of T-type SiO 3 crosslinks. The inorganic fillers incorporated in the matrix were shown to greatly enhance the material crosslinking via the formation of Q-type SiO 4 crosslinks at the filler- matrix interfaces 1.

The electrical resistivity of this material was found to increase upon irradiation, over more than one order of magnitude (e.g., from 10 13 up to 10 15 Ω. m at 30 °C) 2. Similarly to the degree of crosslinking, a more pronounced increase in resistivity was observed in the filled samples than in the isolated matrix. The framework of electron percolation allowed proposing an empirical structure-electrical resistivity relationship coherent with the evolutions observed upon irradiation. On one hand, the increase in resistivity was related to the densification of electron traps (crosslinking sites) in series. On the other hand the Q-type crosslinks at the filler-matrix interfaces were considered as deeper electron traps than the regular T-type SiO 3 formed in the polymer matrix, resulting in a greater increase in resistivity. It is believed that these results highlight the importance of the choice of a polymer formulation for space applications, as the incorporation of fillers may induce unexpected and undesired evolutions of the materials’ properties.

References [1] Roggero, A.; Dantras, E.; Paulmier, T.; Tonon, C.; Dagras, S.; Lewandowski, S.; Payan, D. Polym. Degrad. Stab. 2016, 128, 126–133. [2] Roggero, A.; Paulmier, T.; Dantras, E.; Dirrassen, B.; Tonon, C.; Dagras, S.; Lewandowski, S.; Payan, D. J. Spacecr. Rockets 2016, In press.

P3. HIGH-DOSE IRRADIATION AND LONG-TERM THERMAL AGEING OF (U)HMWPE

Anja Kömmling 1,* , Emmanouil Chatzigiannakis 1, Volker Wachtendorf 1, Ulrike Braun 1, Kerstin von der Ehe 1, Matthias Jaunich 1, Jörg Beckmann 1, Ulrich Schade 2, Dietmar Wolff 1

1 Federal Institute of Materials Research and Testing (BAM), 12200 Berlin, Germany 2HZB Helmholtz-Zentrum Berlin für Materialien und Energie,12498 Berlin, Germany * [email protected]

Two polyethylene types with ultra high (UHMWPE) and high molecular weight (HMWPE), which are used as neutron radiation shielding materials in storage casks for radioactive waste, were subjected to gamma irradiation doses up to 600 kGy and subsequent thermal ageing at 125 °C for up to one year. One material was a medical grade UHMWPE and the other a HMWPE containing an antioxidant. Degradation effects in the materials were characterized using colorimetry, UV-Vis spectroscopy, MIR and FTIR measurements, DSC and, in the case of HMWPE, insoluble content determination. Both materials exhibited a yellowing upon irradiation. The discoloration of UHMWPE disappeared again after thermal ageing, which is why it was attributed to annealable color centers in the form of free radicals entrapped in the crystalline regions of the polymer that recombine during thermal ageing. Furthermore, oxidation species were observed with MIR and FTIR spectroscopy. For HMWPE, the yellowing occurred during both irradiation and thermal ageing and was correlated to antioxidant decomposition. Additionally, black spots were observed after thermal ageing of HMWPE that were attributed to reaction products of antioxidant derivatives and catalyst residues. While only little evidence of oxidation species was found in the light material parts, oxidation is expected to concentrate in the black spots as the catalyst residue promotes hydroperoxide decomposition and thus radical formation that initiate polymer oxidation.

P4. MODIFICATION OF CELLULOSE NANOCRYSTALS BY RADIATION-INDUCED GRAFT POLYMERIZATION OF N- ISOPROPYL ACRYLAMIDE

Siti Fatahiyah Mohamad 1,2,3,* , Bernard Kurek 2, Véronique Aguie-Beghin 2 and Xavier Coqueret 1

Surface modification is a key strategy for tailoring the properties and the behavior of nanoparticles in specific environments. Cellulose nanocrystals (CNC) exhibit at their surface a large density of potentially reactive anhydroglucose units, while having a very stable core structure and unique aspect ratio. Various methods have been used to convert the hydrophilic and polar surface of the CNC by ionic interactions with surfactants, by chemical coupling to hydroxyl groups or by polymer grafting. However, radiation grafting onto NCC seems to have received little attention in the literature, in spite of its unique advantages.

We are currently studying the graft polymerization of N-isopropyl acrylamide (NIPAM) onto cellulosic materials. The presence of thermo-responsive grafts at the surface of the nanowhiskers is expected to induce new properties such as colloidal stability at high ionic strength, surface activity, and thermally triggered dispersion and aggregation in aqueous media.

CNCs were synthesized from pre-treated ramie (Boehmeria nivea ) fibres by appropriate hydrolytic fractionation in concentrated sulfuric acid.

Preliminary experiments conducted onto microcrystalline cellulose allowed us to compare the efficiency of various radiation-grafting methodologies. The so-called pre-irradiation process in aerated proved to be superior, allowing for the formation of surface peroxides that can be activated on-demand by the Fenton reaction in a subsequent grafting stage.

The grafting procedure was successfully applied to ramie CNCs. The effects of pre-irradiation dose, Mohr’s salt concentration, temperature, polymerization time and NIPAM concentration were investigated in details. Chemical and structural features of starting and modified CNCs were determined using a variety of analytical and spectroscopic techniques supporting good control of NIPAM graft polymerization.

P5. AN APPROACH TO THE STERILIZATION OF Β-ALANINE BY IONIZING RADIATION

Lívia de Souza Gonçalves 1,* , Guilherme Giannini Artioli 1, Monica B. Mathor 2, Ademar B. Lugão 2, Gustavo H. C. Varca 2,*

1 Faculdade de Medicina da Universidade de São Paulo (FMUSP) - Av. Dr Enéas Carvalho de Aguiar,15, 05403-000 – São Paulo – SP, Brazil. 2 Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP) - Av. Lineu Prestes, 2242, Cidade Universitária, 05508-000 – São Paulo – SP, Brazil. * [email protected]; [email protected]

The amino acid β-alanine is the rate-limiting point for the endogenous synthesis of carnosine (beta-alanyl-L-histidine) in skeletal muscle. Carnosine has a wide range of biomedical applications, including improved exercise tolerance and athletic performance [1]. While some questions regarding the physiological roles of carnosine in humans remain to be clarified [2], the use of β-alanine for infusion in humans is one aspect to be considered for biomedical purposes at laboratorial level. Sterilization is mandatory when it comes to parenteral or intravenous routes of administration. The aim of this work was to evaluate the viability of the use of ionizing radiation for the sterilization of β-alanine, as radiation sterilization stands as a powerful technique for the sterilization in a single process inside the final package. For this purpose, β-alanine was transferred to sealed glass vials and then sterilized. Irradiation was performed in a 60 Co multipurpose irradiator, at a dose rate of 8.5 kGy.Hour -1 totalizing the pre-established doses of 5, 10, 15, 20, 25 30, 40 and 50 kGy, as confirmed by Harwell Type 4034 dosimetry. The samples were characterized by X-ray diffraction in the seek for structural changes and β-alanine content was determined by UV-HPLC analysis. Sterility assurance was evaluated by inoculation assay as described in the US Pharmacopeia [3] and performed in accordance to the ISO 11737-2 [4]. All assays were performed before and after irradiation. Irradiation resulted in no significant changes in the crystal structure of β-alanine, although such effects were more pronounced as irradiation dose increased. No new peaks were identified bellow 40 kGy. In addition, no changes in β-alanine content were detected using up to 40 kGy. Sterility levels were already acceptable at 5 kGy. Our results indicate that irradiation may be performed at the standardized dose for sterilization [5] without causing relevant damage to its molecular structure or content. In summary, high energy irradiation was found to be suitable technique for the sterilization of β-alanine without any compromise to β-alanine structure or causing its degradation.

References [1] Harris RC, Tallon MJ, Dunnett M, et al. The absorption of orally supplied A-alanine and its effect on muscle carnosine synthesis in human vastus lateralis. Amino Acids . (2006), 279–89. [2] Artioli GG, Gualano B, Smith A, Stout J, Lancha Jr AH. Role of beta-alanine supplementation on muscle carnosine and exercise performance. Medicine and Science in Sports and Exercise. (2010),1162-73 [3] United States Pharmacopeia – National Formulary – USP 38 NF 33. [4] ISO 11737-2:2009, Sterilization of medical devices - Microbiological methods - Part 2: Tests of sterility performed in the definition, validation and maintenance of a sterilization process. 2009. [5] ISO 11137-2:2012, Sterilization of health care products- Radiation - Part 2: Establishing the sterilization. 2012.

P6. HIGH MELT STRENGTH POLYPROPYLENE (HMSPP) NANOCOMPOSITE UNDER PHOTO AND THERMAL AGEING

L. G. H. Komatsu 1,* , D. F. Parra 1,* , W. L. Oliani 1, and A. B. Lugão 1

1 Nuclear and Energy Research Institute, IPEN-CNEN/SP, Av. Prof. Lineu Prestes, 2242 – Cidade Universitária – CEP 05508-000 São Paulo – SP - Brazil * [email protected] ; [email protected]

HMSPP was synthesized by gamma irradiation under acetylene atmosphere. The nanocomposite of HMSPP with montmorillonite clay was obtained by twin-screw extrusion. The compatibilizer agent was the polypropylene graft with maleic anhydride. The samples were submitted to photo and thermal ageing. After ageing assay, the thermal properties of the samples were analyzed by Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). The chemical alterations were investigated by Fourier Transformed Spectroscopy (FT-IR), Carbonyl Index (CI) and Melt Flow Index (MFI) and Energy Dispersive Spectroscopy (EDS) through the technique of Scanning Electron Microscopy (SEM). When the nanocomposites were submitted to photo ageing, they showed higher decomposition level at 1 year of assay. At lower concentrations (<5 wt%) the higher values of MFI corroborate with the chain scission mechanism of the polymer This evidence was confirmed by CI values and oxidation level of surfaces observed by EDS spectroscopy. Under photo ageing the sample with higher content of clay (10 wt%) showed more intense cracks in the surface compared to the others, while, under thermal ageing the same sample showed more intense cracks in the surface only after the period of 56 days of assay. The results suggested that the ageing occurs with scission and oxidation in the terminal of chains.

P7. ATTENUATION PROPERTIES OF PVDF / CNT AND METAL OXIDES NANOCOMPOSITES FOR LOW ENERGY X-RAYS

Esther Lorrayne M. Pereira 1, Adriana S. M. Batista 2, Fabíola A. S. Ribeiro 3, Adelina P. Santos 3, Luiz O. Faria 3,*

1 Depto. de Engenharia Nuclear (DEN / UFMG), Av. Antônio Carlos 6627, 31270-970 Belo Horizonte, MG, Brazil. 2 Depto. de Anatomia e Imagem (IMA / UFMG), Av. Alfredo Balena 190, 30130-100 Belo Horizonte, MG, Brazil. 3 Centro de Desenvolvimento da Tecnologia Nuclear, Av. Antônio Carlos 6627, C.P. 941, 31270-901, Belo Horizonte, MG, Brazil. * [email protected]

Poly(vinylidene fluoride) [PVDF] is a semicrystalline linear homopolymer composed by the repetition of CH 2–CF 2 monomers. The combination of multi–walled carbon nanotubes [MWCNTs], metal oxides and PVDF homopolymer makes produces multifunctional nanocomposite materials, with potential for several applications [1]. In this work nanocomposites made of PVDF/MWCNT/ZrO 2 were synthetized aiming application as X- rays attenuators. The samples were exposed to three different X-rays sources with different energies: Cobalt (6.5 keV), Molybdenum (17.5 keV) and Silver (24.3 keV) tubes. PVDF/MWCNT/ZrO 2 samples were tested in different proportions of MWCNTs (0.5 mg, 1.0 mg and 1.5 mg), maintaining the amount of PVDF homopolymer and ZrO 2 constant, i.e. 150 mg and 2 mg, respectively. The mass attenuation coefficient for the sample filled with 0.33% of MWCNT show anomaly behavior for X-rays with energy of 24.3 keV, as it can be seen in the Figure bellow. It has the same value found by Fujimore et al. at 17.5 keV for the C-textile with 8% of MWCNT. The results are discussed in terms of attenuation of X-rays and characterization of the materials produced by differential scanning calorimetry (DSC), X-ray diffraction techniques (XRD), Fourier transform infrared spectroscopy (FTIR) and ultraviolet–visible spectroscopy (UV-Vis).

References [1] Toshihiko Fujimore et al.Materials Express (2011),273-278.

P8. RADIATION SYNTHESIS OF BIOACTIVE HYDROGEL AND HYDROCOLLOID DRESSINGS

Bozena Rokita 1,* , Slawomir Kadlubowski 1, Konrad Luzniak 1, Piotr Ulanski 1, Janusz M. Rosiak 1

1 Lodz University of Technology, Institute of Applied Radiation Chemistry, Wroblewskiego 15, 93-590 Lodz, Poland * [email protected]

Wound healing constitutes a very complex problem. Impaired healing is a cause of decreased comfort of living, suffering and requires large expenditures. Identification of the aethiology of chronic wound leads to application of a proper therapy. Large group of patients suffer from ischemic wounds, which do not heal due to insufficient blood supply. There are a variety of types of wound care dressings that serve many purposes depending on the wound. They can be made from a large variety of materials with markedly different performance characteristics. They are designed to help facilitate fast healing by providing the optimal healing environment and dealing with odor, leakage, maceration, pain, infection, and other problems for wounded patients [1,2]. The aim of our work was the synthesis of a new generation of hydrogel and hydrocolloid dressings containing bioactive substances supporting angiogenesis and accelerating the wound healing. The wound dressings were composed of polyvinylpyrrolidone – PVP, poly(ethylene glycol) – PEG, agar, bioactive compound and water. The irradiation was performed by an electron-beam accelerator (25 kGy, 4 µs, 50 Hz). Release kinetics of active substance from the dressings by high performance liquid chromatography – HPLC and ELISA kit were investigated. Gel swelling kinetics by the gravimetric method were examined. The equilibrium swelling degree of hydrogels and gel fraction content were determined [3]. It was observed that the amount of active substance released from hydrogel and hydrocolloid matrix into water at 25 °C reaches the level up to 90% after 6 h. Furthermore, swelling degree of hydrogel matrix in water rises with the amount of active substance and achieves the equilibrium after 160 h swelling. Gel fraction of hydrogel matrix decreases with increasing amount of bioactive substance. Moreover, irradiation of hydrocolloid dressings does not cause formation of macroscopic gel. In conclusion, hydrogel and hydrocolloid based matrix containing bioactive substances can be synthesized using EB-irradiation technique.

References [1] Fonder M.A., Lazarus G.S., Cowan D.A., Aronson-Cook B., Kohli A.R. and Mamelak A.J. Treating the chronic wound: A practical approach to the care of nonhealing wounds and wound care dressings. J. Am. Acad. Dermatol. 58 (2008), 185–206. [2] Moura L.I.F., Dias A.M.A., Carvalho E., de Sousa H.C. Recent advances on the development of wound dressings for diabetic foot ulcer treatment—A review. Acta Biomater . 9 (2013), 7093–7114. [3] Rosiak J.M.,Ulanski P., Pajewski L.A. Yoshii F., Makuuchi K. Radiation formation of hydrogels for biomedical purposes. Some remarks and comments. Radiat. Phys. Chem. 46 (1995), 161-168.

Acknowledgments This project was supported by International Atomic Energy Agency (Research Contract No. 18281/R0).

P9. EFFECT OF RADIATION GRAFTING PARAMETERS IN THE MORPHOLOGY AND MECHANICAL PROPERTIES OF FEP-BASED FILMS FOR ALKALINE ANION-EXCHANGE MEMBRANE FOR FUEL CELL APPLICATIONS

Clotide C. Pereira 1,* , Maria. C. Salvadori 2, Leonardo G. A. Silva 1, Elisabete I. Santiago 1

1 Instituto de Pesquisas Energéticas e Nucleares (IPEN - CNEN/SP), Av. Professor Lineu Prestes 2242, 05508-000 São Paulo, SP- Brazil 2 Instituto de Física da Universidade de São Paulo, Brazil * [email protected]

To understand the influence of radiation grafting parameters (gamma radiation dose, time of grafting, monomer concentration and solvent type) on the morphology and mechanical properties of poly (hexafluoropropylene-co-tetrafluoroethylene) (FEP) film, for alkaline anion-exchange membrane for fuel cell application. FEP grafted films were evaluated by PeakForce QNM (Quantitative Mechanical Properties Mapping). The radiation grafting of styrene onto 125 µm thickness poly (hexafluoropropylene-co-tetrafluoroethylene) (FEP) films was carried out by a simultaneous method using a Cobalt-60 gamma source, at doses of 40 and 60 kGy [1]. The QNM images indicated that the average roughness of grafted films was affected by the grafting conditions: lower doses and higher grafting time increased the average roughness [2]. The solvent solubility changed the roughness at low doses, while the monomer concentration did not influence the roughness. Adhesion and elastic modulus were affected by the solvent concentration and grafting time. Further tests in the alkaline anion-exchange membrane, for fuel cell applications, should be carried out for more consistent and reliable results.

References [1] Slade C. T. R., Varcoe R. J. Investigation of conductivity in FEP-based radiation-grafted alkaline anion-exchange membranes, Solid State Ionics , 176 (2005), 585 – 597. [2] Deng H., Xu Y.,Chen Q, Wei X., Zhu B. High flux positively charged nanofiltration membranes prepared by UV-initiated graft polymerization of methacrylatoethyl trimethyl ammonium chloride (DMC) onto polusulfone membranes. Journal of Membrane Science , 366 (2011), 363 – 372.

P10. IONIZING RADIATION EFFECTS MECHANICAL AND THERMAL PROPERTIES IN POLYAMIDE 6 WITH COLLOIDAL SILICON DIOXIDE (AEROSIL®)

Camila A. Amorim 1,* , Waldir P. Ferro 2, Jessica L. Moura 3, Leonardo G. A. Silva 1

1 Instituto de Pesquisas Energéticas e Nucleares – IPEN-CNEN/SP, Av. Professor Lineu Prestes, 2242 São Paulo/SP, Brazil. 2 Radici Plastics Ltda. - Rua Giuseppe Marchiori, 497 Araçariguama/SP, Brazil. 3 Rhodia Poliamida e Especialidades Ltda.- Estrada Galvão Bueno, 5505, São Bernardo do Campo/SP, Brazil. * [email protected]

To evaluate polymers development with new fillers, colloidal silicon dioxide (AEROSIL®) was used in polyamide 6 (PA 6). AEROSIL® is an amorphous substance with low density that satisfies the consumer’s demands in their applications such as fillers. For this study, it used compounds of PA 6 with three different percentage of AEROSIL®: 1 %, 3 %, and 6 %. In this sense, all the formulations were irradiated with electron beam with different doses. In addition, it was studied the effects of the ionizing radiation in mechanical properties such as tensile strength, elongation at break and impact resistance, where they were compared with non-irradiated samples. In the present work, DSC and TGA were also employed to observe the changes in thermal properties before and after irradiation. Lastly, it was determined the best formulation of AEROSIL® to be applied in compounds of polyamide 6.

P11. SYNTHESIS AND CHARACTERIZATION OF NOVEL POLYELECTROLYTE HYDROGELS OF DIFFERENT TYPES BASED ON VINYL ETHERS

Grigoriy A. Mun 1,* , Bayana B. Yermukhambetova 1, Valentina K. Yu 1, Galiya S. Irmukhametova 1, Daulet Kaldybekov 1, Asel K. Tokhtabayeva 1

1 Al-Faraby Kazakh National University, 71, al-Faraby av., 050040, Almaty, Kazakhstan * [email protected]

The novel polyelectrolyte hydrogels of anionic, cationic and amphoteric types were obtained by radiation copolymerization of functional vinyl ethers with monomers of different nature by using divinyl ether of diethylene glycol as the crosslinking agent. Cationic hydrogels were prepared by radiation copolymerization of vinyl ether of monoethanolamide (VEMEA) with vinyl ether of ethylene glycol (VEEG), hydrogels of amphoteric type were synthesized by copolymerization of VEMEA with acrylic acid (AA). Hydrogels of anionic type were prepared by copolymerization of vinyl butyl ether (VBE) with AA.

The physico-chemical behaviors of obtained hydrogels were studied upon change of pH environment and interaction with different types of linear polymers, surfactants as well as and transition metal ions. It was shown that the equilibrium degree of swelling of the polymer hydrogels ( α) in water significantly depends on the acidity of the medium, while the pH of phase transition from a swollen to a collapsed state could be manageable to regulate in a wide range by varying the composition of the copolymers.

It was determined that depending on the pH of the medium the interaction of obtained polymeric networks with linear polymers, surfactants as well as the ions might be accompanied by contraction of hydrogels or effect of their additional swelling. It was given the interpretation of the observed phenomena, discussed prospects for the practical use of the obtained hydrogels.

P12. DEVELOPMENT OF RADIATION TECHNOLOGY PRODUCTION OF THE NEW HYDROGEL MATERIALS FOR BIO-MEDICAL APPLICATION

Grigoriy A. Mun 1,3,* , Bayana B. Yermukhambetova 1,3 , Galiya S. Irmukhambetova 1,2 , Zhomart Beksultanov 3, Raikhan Rakhmetullayeva 1,3 , Ibragim E. Suleimenov 2

1 al-Farabi Kazakh National University, Almaty, Kazakhstan 2 National Engineering Academy of Republic of Kazakhstan, Almaty, Kazakhstan 3 Institute of Nuclear Physics, Almaty, Kazakhstan * [email protected]

This report presents the data obtained in recent years by our research group in the field of synthesis and characterization of water-soluble and water-swelling polymers (hydrogel) for biomedical application. In the research we use various monomers, including hydroxyl containing vinyl ethers - vinyl ether of ethyleneglycol (VEEG), vinyl ether of diethyleneglycol (VEDEG). All these monomers are produced in Kazakhstan in industrial scale. It is known that vinyl alkyl ethers are readily polymerized by cationic mechanism. Unlike vinyl alkyl ethers the functional vinyl ethers of glycols do not polymerize by cationic mechanism. This is connected with the formation of acetals or stable complexes of ammonium type in the presence of cationic polymerization catalysts. The use of radical polymerization initiators results in the obtaining of oligomers only. Thus, in reactions of radical copolymerization the vinyl ethers show very low activity. In order to study the reasons of this low activity we have used the ESR method with a spin- trap. This method allows obtaining the direct quantitative information about mechanism and kinetics of different radical processes, including radical polymerization. The obtained results allows suppose the main reason of vinyl ethers low activity in radical polymerization is their electron-donating properties or very high electron-density of their vinyl binding. The further research indicated that the method of radiation polymerization could be successfully used for preparation of water-soluble and water-swelling polymers based on these low active monomers.The radiation technology such hydrogel production has been developed. As the result of collaboration with a number of leading medical centers of Kazakhstan and Russia the possibility of wide and effective application of these hydrogel materials in different areas of medicine has been founded. For example, the technology production new inject implant material (IIM) for plastic surgery and endoscopic correction of vesico-ureteral reflux (VUR) has been developed. VUR is the most frequent form of urodynamic disorders, and this disease affects mostly children, in which case it progresses much faster and leads to serious irreversible morphofunctional changes in the kidneys and the superior urinary tracts. Unlike the hydrogel implant material used today in soft tissue, the rheological properties of the IIM allow to transport it into the corrected areas of the body with an endoscope or with a regular syringe (injector) and a needle in quantities sufficient for the achievement of a stable functional and cosmetic effects. The IIM has undergone a full complex of preclinical testing. It is established that IIM is completely conforms to the medical and biologic requirements for the implantation materials: it does not render any of the following: toxic, local irritative, sensibilizing, pyrogenetic, allergizing, cancerogenic or mutagenic effects; it is completely compatible with mammal tissue at long-term implantation. Clinical tests estimating safety, tolerability and efficiency of IPIM for the treatment of VUR have begun and are in the process. The results of the clinical research for a period up to six months testify for high efficiency of IIM application in infantile urology at endoscopic correction of VUR.

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P13. POLY (N-VINYL-2-PYRROLIDONE) (PVP) AND NEOMYCIN HYDROGELS AS WOUND DRESSING OBTAINED BY GAMMA IRRADIATION

Angélica Tamião Zafalon 1,* , Vinícius Juvino dos Santos 1, Ademar Benevolo Lugão 1, Duclerc Fernandes Parra 1

1 Nuclear and Energy Research Institute, IPEN-CNEN/SP, Av. Prof. Lineu Prestes, 2242, Cidade Universitária, CEP 05508-000, São Paulo – SP, Brazil * [email protected]

Poly (N-vinyl-2-pirrolidone) (PVP), poly (ethylene glycol), agar and neomycin hydrogel containing has been prepared in order to evaluate its ability to release drugs. Composite hydrogel was obtained by gamma irradiation, 25 kGy. The physical and chemical properties of the hydrogels were systemically investigated as gel fraction, swelling and in vitro cytotoxicity. The detailed structures of the hydrogels were determined by FTIR. Antimicrobial activity of the hydrogel was examined. The antibiotic drug release was determined by Liquid Chromatography-Mass Spectrometry

References [1] Gainza G., Villullas S., Pedrz J.L.P., Hernandez R.M., Igartua M. Advances in drug delivery systems (DDS) to release growth factors for wound healing and skin regeneration. Nanomed- Nanotechnol 11 (2015) 1551-1573. [2] Oertel R., Renner U., Kirch W. Determination of neomycin by LC–tandem mass spectrometry using hydrophilic interaction chromatography. J Pharm Biomed Anal 35 (2004), 633-638. [3] Kadlubowski S. Radiation-induced synthesis of nanogels based on poly(N-vinyl-2-pyrrolidone) - A review. Radiat. Phys. Chem. 102 (2014), 29–39.

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P14. DETERMINATION OF THE IMPACT OF RADIATION AGEING ON THE GLOBAL AGEING OF PE-EPDM POLYMERS IN SERVICE BY A SENSITIVITY STUDY

R. Maurin 1,* , M. Berveiller 1

1 EDF R&D France * [email protected]

EDF is engaged in the study of the aging of its facilities in order to anticipate the maintenance phases and to justify the operation duration extension of nuclear power plants (NPP) up to 60 years. The electrical cables are affected by these programs because they are present in large numbers in the NPP. The aim of this study is to understand the influence of the aging input parameters on the response of multi scale mechanistic modeling [1] for long term aging simulation (60 years in PWR conditions). A statistical approach has been used in order to do a sensitivity study.

The input parameters dispersion was modelized using a probabilistic method. 1000 simulations were run and the results were exploited using visual statistic and Sobol sensitivity indices method computed from a polynomial chaos expansion [2]. Figure 1 Partial Sobol indices for |Q| presents prime order Sobol indices and the coupling terms for the oxygen consumption Q as function of the thickness. It is representative of the global material behavior. The major effect is the temperature close to the surface, but it decreases with the depth to the benefit of irradiation and coupling effects. The dose rate effects grows up to reach ~ 40 % of the effects. The coupling effects begin with the emergence of the irradiation effect and become maximum at ~ 20% and then stabilized.

Figure 1 Partial Sobol indices for |Q| as function of the thickness ( µm) for 60 years

This study gives lot of important information about the aging modelisation in PWR conditions. It shows the probabilistic methods capability to model the oxidation profile dispersion. The study enlightens as well the complex nonlinear relationship between the aging conditions inputs.

Reference [1] Thèse Nadjet Khelidj Arts Et Métiers (2006) [2] Thèse Géraud Blatman, Université Blaise Pascal- Clermont II - Ecole doctorale sciences pour l’ingénieur de Clermont Ferrand (2009).

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P15. THE EFFECT OF PVA TYPE AND RADIATION TREATMENT ON THE PROPERTIES OF STARCH-PVA FILMS

Krystyna Cie śla 1,* , Anna Abramowska 1, Jacek Boguski 1, Joanna Drewnik 1

1 Institute of Nuclear Chemistry and Technology, Dorodna 16 str., 03-195 Warsaw, Poland * [email protected]

The interest in substitution of traditional packaging by biodegradable plastics evolves search for new materials based on natural polymers and biodegradable artificial polymers. Starch is an abundant and cheap biopolymer with a good film forming ability but forms films with rather moderate functional properties. Blending of starch with the other polymer is considered as an interesting route for improving these properties. PVA can be used for packaging purposes, and is known to be the appropriate polymer for blending with starch. The possibility of the radiation modification and the potential application for packing of the products subjected to radiation decontamination make interesting to study the effect of ionising radiation on biodegradable polymer. Our previous results have already shown that using the irradiated starch enables to obtain the films characterized by better properties as compared to these prepared basing the native starch [1-3]. Additionally, the data obtained for the starch- PVA-glycerol system characterized by various starch:PVA ratios show the increase in the compatibility of the components taking place under gamma radiation [4]. It was also discovered that irradiation enables to reduce hydrophilicity of the films with a selected composition. Our present studies concerns the effect of application of various PVA substrates and the influence of ionizing radiation on the properties of the films based on starch and PVA. Four PVAs revealing various molecular masses (in the range of 15 - 145 kDa) were selected for this purpose. The films characterized by starch:PVA ratios of 40:60 or 50:50 were prepared by solution casting and irradiated with 60 Co gamma rays (in vacuum) and with fast electrons (in air) applying an absorbed dose of 25 kGy. Mechanical properties of the films (tensile strength and elongation at break) were examined as well as wetting angle and swelling in water, in regard for evaluation of the hydrophilic/hydrophobic properties. Gel content in the samples was also determined The functional properties of the films and their sensitivity to irradiation strongly depend on the applied PVA substrate. In particular, using of PVA characterized by the high molecular mass has appeared more profitable as compared to those based on the low molecular mass PVAs.

Acknowledgments The work was sponsored in the frame of the International Atomic Energy Agency research contract No: 17493 co-funded by Polish Ministry of the Science and the Higher Education

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P16. THE EFFECT OF GAMMA-RADIATION ON BIODEGRADABILITY OF SYNTHETIC PHB STRUCTURAL FOAMS PP/HMSPP BASED

Elizabeth C. L. Cardoso 1,* , Sandra R. Scagliusi 1,* and Ademar B. Lugão 1

1 Center for Chemical and Environmental Technology (CQMA), Nuclear and Energy Research Institute – Av. Professor Lineu Prestes 2242, Cidade Universitária, CEP 05508- 000, S.Paulo, Brazil * [email protected] ; [email protected]

This research was carried out to evaluate how gamma-radiation affected PP/HMSPP structural foams filled with biodegradable synthetic polyester PHB, in terms of thermal properties, biodegradability and infrared spectrum. Polymers are used in various applications and in different industrial areas providing enormous quantities of wastes in environment, contributing with 20 to 30% of total volume of solid residues. Besides, shortage of plastics resins obtained from oil and natural gas is addressing research and development toward alternative materials; environmental concerning in litter reduction is being directed to renewable polymers for manufacturing of polymeric foams. Biodegradable polymers, a new generation of polymers produced from various natural resources, environmentally safe and friendly, can contribute for pollution reduction. Poly[( R)-3-hydroxybutyrate] (PHB), one of the typical natural bio-polyesters produced by many microorganisms as an intracellular carbon and energy storage material was chosen to be blended with PP/HMSPP and further inducing biodegradation. High density structural foams are specially used in civil construction, in replacement of metals, woods and concrete, but contribute for environmental pollution, due to components nature; the incorporation of PHB in PP/HMSPP polymeric matrix was studied, after gamma radiation applied within zero, 50, 100, 150, 200 and 500 kGy doses. Soil burial test pointed toward a partial biodegradation of irradiated PHB-PP/HMSPP foams. Thermal analyses involving TG/DTG techniques were accomplished to study behavior changes. Infrared spectrum of foams using FTIR detected resulting bands after 12 months soil burial foams previously irradiated.

Fig. 1: Thermal behavior of PP/HMSPP – PHB composites, prior to gamma-radiation.

References [1] Pieter Spitael and Christopher W.Macosko, (2004) Polymer Engineering and Science , 44, 11, 2090 – 2100. [2] Güven, O. (2005), IAEA-CN-115-68 , pp.67 – 68. [3] Bhattacharya, A (2000). Radiation and Industrial Polymers – Prog. Polym. Sci., 25 , 371-401. [4] Miriam L. C. Machado et al, (2010) Polímeros: Ciência e Tecnologia, 20 , 1, 65-71.

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P17. POLYMERS DEGRADATION UNDER RADIOLYSIS: ADAPTATIONS OF DEVICES FOR IRRADIATING SAMPLES DEDICATED TO ANALYTICAL METHODS PERSPECTIVES

J-L. Roujou 1,* , V. Dauvois 1, M. Ferry 1, D. Durand 1, M. Cornaton 1, S. Esnouf 1, D. Lebeau 1, S. Legand 1, Y. Ngono-Ravache 2, J-M. Ramillon 2

1 Den-Service d’Etude du Comportement des Radionucléides (SECR), CEA, Université Paris-Saclay, F-91191, Gif-sur-Yvette, France. 2 CIMAP – CEA-CNRS-ENSI, Université de Caen, BP5133, F-14070 Caen cedex 5, France. * [email protected]

The degradation of polymers under irradiation leads, to gas emission, and, to chemical modifications of the polymer backbone. The determination of reliable radiation chemical yields of these modifications requires the management of many different parameters, such as irradiation nature, dose, dose rate, temperature, surrounding atmosphere…For determining those chemical yields the use of analytical devices creates other constraints to deal with, such as detection limits, or samples transfers to the “detector”.

In the LRMO laboratory, studies are realized in the context of the nuclear safety, to evaluate risks of degradation under radiolysis of the organic materials in the nuclear wastes during conditioning, transport, storage and final disposal in French deep underground repository. In these conditions, different emitters are encountered, as well as very high doses. Depending on the researched parameter, the realization of specific irradiation devices can be required with controlled atmospheres and temperatures. Some devices can be batches closed vessels, or adapted multi-dose rate profiler inside the vessel with displacement of sample, or dynamic vessels for solutions, within the objective to determine radiation chemical yields under non usual conditions (very high doses up to several MGy, high temperature, under acidic atmosphere…). The various glass vessels devices, as well as the specific environment inside the vessels, for analytical methods, and for dose deposition will be presented.

Moreover, many analytical tools are available, as a function of the modification in material that has to be evaluated. High resolution gas mass spectrometry, allowing differentiation between CO and N 2 can be used for gas radiation chemical yields determination. In the case of the polymer backbone modification or for organic molecules release studies, mass spectrometers with different sources or coupled analytical techniques such as GC-MS or LC- MS can be employed. The direct measurements on irradiated polymers using FTIR methods and ATG-DSC.

This poster will present some experimental devices commonly used for irradiations in the laboratory and the connection towards analytical tools uses.

105

P18. RADIATION SYNTHESIS OF HYDROGELS OF DEXTRAN METHACRYLATE

Kamila Szafulera 1, Radoslaw A. Wach 1, *, Piotr Ulanski 1, Janusz M. Rosiak 1

1 Lodz University of Technology, Institute of Applied Radiation Chemistry, Chemistry Department Wroblewskiego 15, 93-590 Lodz, Poland * [email protected]

Dextran is a bacterially derived polysaccharide, mainly composed of linear α-1,6 linked D- glucopyranose residuals with a low percentages of α-1,2, α-1,3 or α-1,4 linked side chains [1]. Biomaterials based on this natural polymer are widely used for biomedical applications due to dextran’s well-documented biocompatibility and biodegradability in physiological environment, as well as relatively low cost and possibility of modifications [1,2]. The active hydroxyl groups present in the structure of dextran can be replaced by different functional groups yielding derivatives with specific characteristics which can be chemically engineered to obtain various microstructured scaffolds including spheres, fibers or hydrogel for biomedical applications [1]. Hydrogels are a three-dimensional (3D) crosslinked polymeric networks enabled to absorb high amount of water and/or biological fluids. Chemically crosslinked dextran-based hydrogels are widely investigated in recent years due to their potential applications in soft tissue engineering and as a wound dressing. [1,2]. The aim of the study was to synthesize dextran methacrylate (Dex-MA) with different degrees of substitution (DS) and further attempt of hydrogels formulation by means of irradiation of its aqueous solutions. The modification of dextran (100 kDa) through the addition of glycidyl methacrylate (GMA) was adapted from the methodology described by van Dijk-Wolthuis [3]. Crosslinking of Dex-MA with degree of substitution (DS) of 0.2, 0.4, 1, 1.2 and 1.5 was carried out in water solution using electron beam. Solutions in different concentration s, such as: 5, 10, 30 and 50 g/L were irradiated in wide range of doses up to 50 kGy. Obtained hydrogels were characterized based on calculations of gel fraction (GF) and equilibrium degree of swelling (EDS). It was observed that yield of crosslinking process is strongly dependent on the DS of methacrylated dextran, as well as on the concentration of irradiated solution. For lower DS, higher concentration of Dex-MA is required to form chemically crosslinked gels. Yet, the gel fraction appears even at low doses of below 1 kGy. Irradiation of water solution of methacrylated dextran allowed to obtain hydrogels in absence of additives such as monomers, a catalyst and crosslinked agents, thus application of ionizing radiation seems to be an interesting alternative to classical chemical method for obtaining hydrogels of this natural polymer, especially for biomedical applications, when chemical purity is the critical factor. Moreover, when applying sufficient dose, typically 25 kGy simultaneous sterilization takes place, yielding a sterile product.

References [1] Sun G., Mao J.J., Engineering dextran-based scaffolds for drug delivery and tissue repair, Nanomedicine 7 (2012), 1771. [2] Sun G., Shen Y-I., Kusuma S., Fox-Talbot K., Steenbergen Ch.J., Punctional neovascularization of biodegradable dextran hydrogels with multiple angiogenic growth factors, Biomaterials 32 (2011), 95. [3] van Dijk-Wolthuis W., Franssen O., Talsma H, van Steenbergen M.J., Kettense-van den Bosch J.J., Hennink W.E., Synthesis, characterization, and polymerization of glycidyl methacrylate derivatized dextran, Macromolecules , 28 (1995), 6317.

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P19. LOADING AND RELEASE OF CIPROFLOXACIN FROM PLASMA POLYMERIZED ACRYLIC ACID COATINGS

Tania Tapia-Esquivel 1, Brenda Segura-Bailon 1, and Juan-Carlos Ruiz 1,*

1 División de Ciencias Básicas e Ingeniería, Universidad Autónoma Metropolitana Iztapalapa, Av. San Rafael Atlixco No. 186, 09340 Mexico City, Mexico * [email protected]

Plasma-assisted modification- and deposition-processes have been used for creating bioactive polymer surfaces in biomedical and cell-culture applications [1]. Poly acrylic acid grafted onto polypropylene (PP-g-PAAc) loaded with ciprofloxacin has proved its effectiveness against methicillin-resistant Staphylococcus aureus (MRSA) biofilm [2]. The union of theses previous knowledge (surface modification with plasma polymers and interaction between drugs and -COOH groups present in the polymer) was presented by García-Fernandez et al. [3]. In the mentioned paper, low-pressure plasma-polymerized ethylene film coatings rich in bonded oxygen groups (L-PPE:O) were deposited on poly(ethylene terephthalate; PET) in order to act as hosts for antimicrobial drugs.

The present work describes the use of plasma polymerized acrylic acid (pp-AAc) coatings for loading and release of ciprofloxacin, in order to inhibit the growth of bacteria biofilm formation. pp-AAc films were deposited using different input powers in a RF plasma reactor in vacuum, and stability studies of pp-AAc deposits in aqueous media (PBS and water) were performed. The films were characterized by XPS (X-ray Photoelectron Spectroscopy), FTIR (Fourier transform infrared spectroscopy), and profilometry. Chemical derivatization studies with TFAA (triflouroaceticanhydride) and TFE (Trifluoroethanol) were carried out for quantification of –OH and –COOH groups, respectively. Optimal conditions will be discussed for getting stable pp-AAc films upon immersion in media. Also, the capacity of stable pp- AAc films for loading and release of ciprofloxacin will be presented; and the use for inhibiting bacteria growth microbiological studies with bacteria will be shown.

References [1] R. Förch, A. N. Chifen, A. Bousquet, H. L. Khor, M. Jungblut, L.-Q. Chu, Z. Zhang, I. Osey- Mensah, E.-K. Sinner, W. Knoll (2007); Chem. Vap. Deposit. 13, 280. [2]. J.-C. Ruiz, C. Alvarez-Lorenzo, P. Taboada, G. Burillo, E. Bucio, K. De Prijck, H. J. Nelis, T. Coenye, A. Concheiro (2008), European Journal of Pharmaceutics and Biopharmaceutics 70, 467– 477. [3] M. J. Garcia-Fernandez, L. Martinez-Calvo, J.-C. Ruiz, M. R. Wertheimer, A. Concheiro, C. Alvarez-Lorenzo (2012), Plasma Process. Polym. , 9, 540–549.

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P20. REMOVAL OF CD(II) IONS FROM AQUEOUS MEDIA USING POROUS CELLULOSIC ADSORBENT

Murat Barsbay 1,* , Pınar Akka ş Kavaklı 1, Serhad Tilki 1, Cengiz Kavaklı 1, Olgun Güven 1

1 Department of Chemistry, Hacettepe University, 06800 Beytepe, Ankara, Turkey * [email protected]

As the industrial activities increasing rapidly all over the world, contamination of water sources with toxic metal ions is being a more serious global concern. Concentration, separation, and removal of these ions have become increasingly attractive areas of research and have led to new technological developments [1].

Cellulose, a very abundant natural polymer, is known to have larger specific surface area than many other common natural polymers; thus posses many potential applications as adsorbent. However, the molecular structure of cellulose limits its usage in adsorption studies without proper modifications [2].The synthesis of cellulosic graft copolymers by introduction of grafts of synthetic polymers that impart specific properties is one of the most efficient ways for modifying the physical and chemical properties of cellulose. In the present study, a series of glycidyl methacrylate (GMA) grafted samples with graft levels varying over a wide range of values (3% - 70%) have been prepared based on a cellulose filter paper (Whatman No. 1) using γ-irradiation. The range in graft level was achieved by varying the γ-irradiation dose and monomer concentration. Then, iminodiacetic acid (IDA) was immobilized to cellulose samples via covalent attachment through the GMA units (Figure 1). The synthesized samples have been characterized by ATR-FTIR, X-ray photoelectron spectroscopy, thermal analysis and scanning electron microscopy.

Figure 1. Schematic representation of the activation process of cellulose paper: i) Radiation-induced grafting of GMA to cellulose, ii) Immobilization of IDA to cellulose through the epoxy rings of PGMA

The synthesized IDA immobilized cellulosic copolymers were then used for the removal of Cd (II) ions from aqueous solutions. The IDA immobilized adsorbents were found to be effective for the removal of Cd (II) ions. The adsorption kinetics was investigated at various pH and ion concentration values and in existence of competitive ions. It has been seen that the synthesized cellulosic materials may be used in polluted water systems for the removal of Cd (II) metal ions over a wide range of pH.

References [1] Akka şKavaklı P., Güven O., Removal of Concentrated Heavy Metal Ions from Aqueous Solutions Using Polymers with Enriched Amidoxime Groups, J. Appl. Polym.Sci. 93 (2004), 1705- 1710. [2] O'Sullivan, A. C., The structure slowly unravels, Cellulose 4 (1997), 173-207.

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P21. COMPARISON OF GAMMA RADIATION EFFECTS ON NATURAL CORN AND POTATO STARCHES AND MODIFIED CASSAVA STARCH

Bruna S. Teixeira 1, Patricia Y. I. Takinami 1, Nelida L. del Mastro 1, *

1 Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), Av. Professor Lineu Prestes 2242, 05508-000 São Paulo, SP, Brazil * [email protected]

There is increasing demand worldwide for starch as production of starch using products continues to grow. Starches from different botanical origin have different biosynthetic mechanisms and may exhibit distinct molecular structure and characteristics as well as diversity in granule shape, size, composition, and other constituents. Corn starch represents over 75% of the world's starch market. Potato starch is a very refined starch, containing minimal protein or fat. Cassava (or manioc) starch production in Latin America is located mainly in Southern Brazil. The production process for making starch from cassava is simple because cassava is a purer starch source than potato or cereals. Although native starches can be used as gelling agents in many gelling products depending on their source and availability, in many industrial utilizations physical and chemically modified starches are commonly used. The objective of this work was to evaluate the effect of gamma radiation on physicochemical starches properties of natural potato and corn starches and to compare with a typical Brazilian product, cassava starch modified through fermentation, and also to prepare composite hydrocolloid films based on them. Starches were irradiated with 60 Co in doses of 0 - 15 kGy, dose rate about 1 kGy/h. The viscosity of all starches aqueous preparations decreased as a function of radiation dose; maximum rupture force of the films, on the other hand, was affected differently for each starch. Color analysis showed that doses of 15 kGy promoted a slight rise in the parameter b* (yellow color) while the parameter L was not significantly affected. The results obtained also showed that the granule morphology and X-ray diffraction pattern remained almost unchanged by irradiation. Biochemical changes due to irradiation were detected using the vibrational spectroscopic technique Fourier transform infrared spectroscopy (FTIR). Significant differences were found in granule size distribution mainly for corn and manioc starch but the radiation did not cause significant changes in the thermal properties.

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P22. ECOLOGIC PARTICLEBOARD BASED ON HDPE/EVA BLEND REINFORCED WITH CORNCOB FIBER AND ZINC OXIDE NANOPARTICLE TREATED BY ELECTRON-BEAM RADIATION

Fabiana Lainetti 1,* , Rene R. Oliveira 1, Rita C. L. B. Rodrigues 2, Esperidiana A. B. Moura 1

1 Center for Chemical and Environmental Technology (CQMA), Nuclear and Energy Research Institute – Sao Paulo, SP., Brazil. 2 Escola de Engenharia de Lorena, Departamento de Biotecnologia. Universidade de Sao Paulo, Lorena, SP, Brazil. * [email protected]

Agricultural residues such as sugarcane bagasse, soy husk, rice husk, cornstalks, and corncob represent a potentially valuable source of fiber that could be used as a reinforcement in polymer for several applications. Corncob, a sub products of corn agroindustry, is generated in large quantities in Brazil. The traditional use of this residue in Brazil includes bedding for animals and livestock feeding. However, a large amount of corn sub products is unutilized, is burning or left in the field. An alternative use for corncob would be to produce particleboard panels in association with a polymer material. Thereby, this composite can be a cheap alternative to construction and a possible way to decrease the amount of waste from landfill. The objective of this work is to study the potential use of corncob as fiber reinforcements for thermoplastics as an alternative to wood fibers. In this work, HDPE/EVA blend reinforced with corncob fiber (20 wt. %) and zinc oxide nanoparticles (1 wt. %) was prepared by melt- mixing processing, using a twin screw extruder machine, with 16 mm and L/D = 25 rate. The temperature profile was 160/ 160/ 165/ 170/ 175/ 180 ºC. Screw speed was 60 rpm. The extrudates were cooled down for a better dimensional stability, pelletized, dried again at 60 ± 2 ºC for 4 h and fed into injection molding machine and specimens test samples were obtained. Part of samples were irradiated at 100 and 200 kGy using an electron beam accelerator, at room temperature in presence of air. The irradiated and non-irradiated samples were characterized by mechanical tests, XRD, TG, DSC, FE-SEM analysis and the correlation between properties was discussed. In addition, the sol–gel analysis were carried out in the non-irradiated and irradiated samples in order to evaluate the degree of cross-linking in the HDPE/EVA blend as a result of electron-beam irradiation. The non-irradiated HDPE/EVA blend dissolved completely in the xylene. On the other hand, the irradiated HDPE/EVA lost only small part of its original weight dissolved in the organic solvent. Consequently, these results indicate that a large part of the material was cross-linked and insoluble in hot xylene. The mechanical test results of the irradiated samples showed superior mechanical performance than non-irradiated sample and better interface adhesion between corncob fiber and polymer matrix. These results confirm that the addition of corncob fiber and zinc oxide nanoparticle improved the original characteristics of HDPE/EVA blend and led to the obtaining of ecologic particleboard and interior design for application in home construction for low-income people.

References [1] Mangesh V. Madurwar, Rahul V. Ralegaonkar, Sachin A. Mandavgane Application of agro-waste for sustainable construction materials: A review. Construction and Building Materials, 2013, v. 38, p. 872-878. [2] Panthapulakkal, S.; Sain, M. Agro-residue reinforced high-density polyethylene composites: fiber characterization and analysis of composite properties. Composites: Part A, 2007, v. 38, p. 1445-1454.

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P23. PREPARATION AND CHARACTERIZATION OF EVA/CLAY/TIO 2 FLEXIBLE FILM MODIFIED BY ELECTRON BEAM RADIATION

M. V. de S. Seixas 1,2,* , José A. Santos 1, Vijay K. Rangari 3, Francisco Valenzuela-Díaz 2, Helio Wiebeck 2, Esperidiana A. B. Moura 1

1 Center for Chemical and Environmental Technology (CQMA), Nuclear and Energy Research Institute – Sao Paulo, SP., Brazil 2 Metallurgical and Materials Engineering Department, Polytechnic School, University of Sao Paulo Sao Paulo, SP, Brazil 3 Department of Materials Science and Engineering, Tuskegee University, Tuskegee, AL, USA * [email protected]

Since the advent of the food can in the 19 th century, protection, hygiene, product quality and convenience have been major drivers of food technology and packaging innovation. In recent years, there has been a rising demand for packaging that offers both ease of use and high quality food to consumers with busy lifestyles. The objective of this study is to prepare and caracterize EVA/Clay flexible film for application as food packaging materials. EVA with 1 wt. % of TiO 2 and 1-3 wt. % of green Brazilian Clay, from Cubati, Pb, Brazil were prepared by melt extrusion, using a twin screw extruder machine and blown extrusion process. Part of EVA/CLAY/TiO 2 flexible film were irradiated at radiation dose range 100-250 kGy using a 1.5 MeV electronbeam accelerator, at room temperature in presence of air. The irradiated and non-irradiated specimens tests samples were submitted to mechanical tests, XRD, UV-VIS, DSC, TG and FE-SEM analysis. The results showed significant changes on mechanical and thermal properties of EVA/CLAY/TiO 2 flexible film due to nanoparticle addition and electron-beam irradiation. These results showed that it is possible to get interesting property gains in EVA flexible films by using nanoparticle and electron-beam radiation treatments.

Table I – Mechanical and Thermal Properties of EVA/CLAY/TiO2 flexible film Flexible films Tensile strength Elongation at Melting temperature Melting enthalpy at break (MPa) break (%) (Tm, °C) (DHm, J.g -1) EVA flexible films EVA flexible films irradiated

EVA/CLAY (1%)/TiO 2 flexible films

EVA/CLAY (1%)/TiO 2 flexible films irradiated

(a) 1= EVA/CLAY/TiO 2 flexible film; (b) Vapor transmission rate; (c) Oxygen transmission rate; (d) iPLA (5 wt. %) electron-beam irradiated at 150 kGy; (e) 0 % Relative Humidity; (f) 90 % Relative Humidity; (g) 90 % Relative Humidit.; (g) 2= PBAT/PLA/CaCO 3; thickness: 60 µm

111

P24. MECHANICAL, THERMAL AND BARRIER PROPERTIES OF EVOH/GRAPHENE OXIDE FLEXIBLE FILMS TREATED BY ELECTRON BEAM RADIATION

Julyana G. Santana 1,* , Angel Ortiz 1, Meshude Akbulut 2, Vijay K. Rangari 3, Francisco Valenzuela-Díaz 4, Olgun Güven 2, Esperidiana A. B. Moura 1

1 Center for Chemical and Environmental Technology (CQMA), Nuclear and Energy Research Institute – Sao Paulo, SP., Brazil 2 Hacettepe University, Department of Chemistry, Polymer Chemistry Division, Beytepe, Ankara, Turkey 3 Department of Materials Science and Engineering, Tuskegee University, Tuskegee, AL, USA 4 Metallurgical and Materials Engineering Department, Polytechnic School, University of Sao Paulo Sao Paulo, SP, Brazil * [email protected]

Ethylene vinyl alcohol (EVOH) copolymers are semicrystalline random copolymers of ethylene and vinyl alcohol that are widely used in the food packaging industry owing to their excellent chemical resistance, high transparency as well as excellent gas barrier properties to oxygen, organic solvents, and food aromas. However, EVOH is very sensitive to moisture and its gas barrier ability deteriorates in high relative humidity conditions. This study presents the preparation of EVOH/Graphene oxide films by twin-screw extrusion and blown film extrusion processing. The preparation of EVOH/Graphene oxide (EVOH/GO) films was carried out in two steps: EVOH with Graphene oxide powder (0-0.5 wt. %) was fed into a co-rotating twin- screw extruder, then the EVOH/GO nanocomposite was transformed into thin films using an extrusion blown film, single screw machine with 25 mm diameter and specimens test samples were obtained. Part of EVOH/GO flexible films were submitted to electron-beam irradiation at 150 and 200 kGy, using a 1.5 MeV electron beam accelerator, at room temperature in presence of air. The irradiated and non-irradiated samples were characterized by mechanical tests, XRD, TG, DSC, FE-SEM and TEM analysis and the correlation between properties was discussed. In addition, the oxygen permeability tests were performed at 23 °C, 0 % and 90 % relative humidity using an OX-TRAN (MOCON Inc.). The free volume hole radius of both crystalline (0.201 nm) and amorphous parts (0.258 nm) of EVOH only and EVOH-GO samples were measured by Positron Annihilation Life-Time Spectroscopy. According to the results of the optical transparency measured, the EVOH/GO retaining good transparency films for all graphene oxide percentage added. The EVOH matrix with 0.1-0.4 wt. % graphene oxide content presented better oxygen barrier properties at 0 % relative humidity when compared with neat EVOH flexible films. After irradiation treatment, both, mechanical and oxygen barrier properties were drastically improved. Upon introduction of GO into EVOH matrix a reduction in the free volume hole radius in both parts have been observed indicating the formation of a more compact structure in EVOH/GO nanocomposites. Formation of hydrogen bonding between OH groups of EVOH and polar groups on graphene is assumed to be responsible for the reduction in free volume.

References [1] Mokwena, K.K.; Tang, J. Critical Reviews in Food Science and Nutrition, 2012, v. 52, p.640–650 [2] Cui, Y.; Kundalwal, S.I.; Kumar, S. Carbon 2016, v. 98, p.313-333. [3] Kim, S.W.; Choi, H.M. Polymers, 2015, v. 27, issue 6, p.694–704.

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P25. EFFECTS OF BIO-CACO 3 NANOPARTICLES AND GRAPHENE NANOSHEETS ON PROPERTIES OF PBAT/PLA FLEXIBLE FILMS TREATED BY IONIZING RADIATION

Pedro R. S. Reis 1,* , Elizabeth C. L. Cardoso 1, Felipe R. Lourenço 1, Angel V. Ortiz 1, Vijay K. Rangari 2, Esperidiana A. B. Moura 1

1 Center for Chemical and Environmental Technology (CQMA), Nuclear and Energy Research Institute – Sao Paulo, SP., Brazil. 2 Department of Materials Science and Engineering, Tuskegee University, Tuskegee, AL, USA. * [email protected]

Currently, flexible plastic packaging is widely used instead of rigid and semi-rigid plastic packaging. Flexible packaging is in general not recyclable, practically non-degradable, consequently not selectively collected and representing a serious global environmental problem. Therefore, the development of biodegradable flexible packaging can be an important alternative to minimize the quantities of plastic waste material disposed of to landfill throughout the world. The target of this study was to develop flexible film composites based on PBAT/PLA blends reinforced with bio-CaCO 3 nanoparticle (30 wt. %) and graphene nanoosheets (0.1-0.2 wt. %). Composite films were prepared using a twin-screw extruder machine and blown extrusion process and treated by gamma radiation at radiation dose up to 25 kGy. The composite films were characterized by mechanical tests, XRD, MVTR, OTR, TG, DSC, FE-SEM and TEM analysis. In addition, the microbiologic tests in order to evaluate the efficiency of ionizing radiation treatment on reduction of the original level of contamination of the composite films were also carried out. The results showed that the incorporation of bio-CaCO 3 nanoparticle and graphene oxide nanoosheets in PBAT/PLA Blend drastically improved the mechanical and oxygen barrier properties of PBAT/PLA flexible film. The gain in tensile strength at break due to bio-CaCO 3 addition was of about 60 %, when compared with PBAT/PLA blend film. Some tests results of PBAT/PLA reinforced with bio-CaCO 3 are presented in Table I. In addition, the incorporation of only 0.1 wt. % of graphene nanoosheets improved the mechanical properties of PBAT/PLA/Bio-CaCO 3 flexible film and led to an important gain of the oxygen barrier.

Table I – Results of CaCO 3 micro addition on penetration resistance, surface tension, tensile properties, vapor transmission rate (MVTR) and oxygen transmission rate (OTR) of PBAT/PLA blend. Tensile MVTR (b) Penetration Penetration Surface Elongation OTR (c) Flexible strength (g/m 2.day) resistance Distance tension at break (cc/m 2.day) Films at break (23°C; 85 (N) (mm) (mN/m) (%) (23 ° C) (MPa) % RH) 7.6 ± 1117 (e) 1 (a) 3.0 8.2 51.0 210 ± 12 142 0.4 1207 (f) 11.9 ± 962 (e) 2 (g) 5.0 7.4 51.3 199.9 ± 13 123 0.6 1107 (f)

(a) 1=PBAT/PLA thickness: 60 µm; (b) Vapor transmission rate; (c) Oxygen transmission rate; (d) iPLA (5 wt. %) electron-beam irradiated at 150 kGy; (e) 0 % Relative Humidity; (f) 90 % Relative Humidity; (g) 90 % Relative Humidit.; (g) 2=PBAT/PLA/CaCO 3; thickness: 60 µm

References [1] Raheem, D. Emir. J. Food Agric. 2013; v. 25, issue 3, p.177-188 [2] Yoo, B., Shin, H., Yoon, H. and Park, H. J. Appl. Polym. Sci., 2014, v 131, 39628

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P26. DETERMINATION OF ARRHENIUS COEFFICIENTS OF N- VINYLPYRROLIDONE POLYMERIZATION IN AQUEOUS SOLUTION BY PULSED ELECTRON POLYMERIZATION - SIZE EXCLUSION CHROMATOGRAPHY (PEP-SEC)

Piotr Sawicki 1,* , Sławomir Kadłubowski 1, Piotr Ula ński 1

1 Institute of Applied Radiation Chemistry, Lodz University of Technology, Lodz, Poland * [email protected]

Considering the emerging need for well-defined polymeric materials, detailed knowledge on polymerization reactions mechanisms and kinetics becomes crucial for research and industry all over the world. Two most important kinetic parameters – propagation ( kp ) and termination (kt ) rate coefficients – for long time were accessible only as the kp /kt 0.5 ratio.

Currently the preferable and IUPAC-encouraged method for dealing with this issue is so called Pulsed Laser Polymerization – Size Exclusion Chromatography (PLP–SEC) providing independently kp values. Despite many advantages, this method has also its limitations, most of all studied system has to be homogenous and non-turbid, which is not always possible to achieve. After the pioneer work of Van Herk and coworkers [1] a new approach was proposed: to substitute laser light with electron beam.

It has been already demonstrated, that the radiation-based procedure with a proposed name Pulsed Electron (Beam) Polymerization – Size Exclusion Chromatography (PEP–SEC) meets the requirements for reliable determination of propagation rate coefficients. [2]

Currently reported results of electron pulse polymerization of N-vinylpirrolidone in aqueous solutions at different concentrations and temperatures allow to determine the Arrhenius coefficient of this reaction. Presented data further confirm the usability and accuracy of the proposed method.

References [1] Van Herk, et al. Macromolecules 1996 , 29 (3), 1027–1030. [2] Bartoszek, et al. ACS Macro Lett. 2014 , 639–642.

114

P27. A STUDY ON RADICAL DECAYS AND RADIATION-INDUCED GRAFTING OF IRRADIATED POLYETHYLENE NONWOVEN FABRIC AT VARIOUS STORAGE CONDITIONS

Seiichi Saiki 1,* , Keiko Okaya 2, Noriaki Seko 1, Hisaaki Kudo 2

1 Quantum Beam Science Research Directorate, National Institutes for Quantum and Radiological Science and Technology, Japan 2 School of Engineering, The University of Tokyo, Japan * [email protected]

Radiation-induced graft polymerization has been applied as one kind of polymer modification methods for many fields such as a metal adsorbent, a deodorant, surface modification and so on. A pre-irradiation method of radiation-induced graft polymerization has been often adopted for industrial manufacture, which separates into “irradiation process” and “graft polymerization process”. After irradiation process, an irradiated trunk polymer should be preserved under appropriate conditions to keep the amount of radicals. To control degree of grafting and reduce manufacturing costs, this “storage process” should be optimized. In this study, focusing on polyethylene nonwoven fabric as a model of a trunk polymer, an amount of radicals was measured by ESR method in response to storage time and temperature, and compared with the result of grafting experiments to show the guideline of irradiated sample preservation for radiation-induced graft polymerization. In the experiments, a few pieces of nonwoven fabric cut into 3 mm × 3 cm for ESR measurements and 2 cm square for grafting experiments, were irradiated by an electron beam in polyethylene bags purged by nitrogen gas. ESR measurements were conducted after keeping at a given time and temperature. Grafting experiments were conducted at 333 K for 2 h in o/w emulsion prepared by homogenizing glycidyl methacrylate, water and Tween 20 as a surfactant. As a result, the amount of radicals and degree of grafting decreased with higher storage temperature and longer storage time, and the one-to-one relation between the amount of radicals and degree of grafting could be observed. Details of relationship between degree of grafting and the amount of radicals including dose dependency will be discussed in this presentation.

115

P28. MOLECULAR DYNAMICS SIMULATION OF POLYMER-LIKE THIN FILMS IRRADIATED BY FAST IONS: A COMPARISON BETWEEN FENE AND LENNARD-JONES POTENTIALS

N. W. Lima 1, R. Gonzalez 2, L.I. Gutierrers 1, R. Thomaz 1, S. Muller 1, R. M. Papaléo 1,* , E. M. Bringa 3

1 Faculdade de Física, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil. 2 Departamento de Física, Facultad de Ciencias, Universidade de Chile, Santiago, Chile. 3 Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Mendoza, Argentina. *[email protected]

In this work, surface effects of individual heavy ion impacting thin polymer-like films were investigated, using molecular dynamics simulation (MDS) and a FENE potential to describe the molecular chains. Macromolecules were constructed from 1000 particles, where each particle represents a monomer with a mass of 100 u.The perturbation introduced by the ions in the lattice was modeled assuming the initial excitation energy is converted into an effective temperature in the cylindrical ion track, as in a thermal spike. In order to define a thin film, the particles were artificially labeled as belonging to the film or the substrate according to their initial depth within the sample, and the track was heated only within the film thickness h (varied from 2-60 nm).The effect of a decreasing thickness on cratering and sputtering was evaluated. The results were compared to experimental data of thin polymer films bombarded by MeV-GeV ions and to simulations performed with the Lennard-Jones potential. While several qualitative results observed in the experiments [1] were also seen in the simulations, irrespective of the potential used, there are important differences observed on FENE films. Craters, sputtering yields and flow of molten material are substantially reduced in FENE simulations. Craters could not be identified in ultrathin FENE layers with thicknesses h around 2 nm and crater depth saturates for h>20 nm. Overall, there is a better agreement between MDS and experiments for the FENE potential.

References [1] R. M. Papaléo et al, Confinement Effects of Ion Tracks in Ultrathin Polymer Films. Phys. Rev. Lett. 114, 118302 (2015).

116

P29. THE EFFECT OF ELECTRON BEAM RADIATION ON MECHANICAL AND PHYSICO-CHEMICAL PROPERTIES OF P(TMC-CO-LA)

A. Adamus 1,* , R.A. Wach 1, P. Ulanski 1, J.M. Rosiak 1

1 Institute of Applied Radiation Chemistry, Lodz University of Technology, Wroblewskiego 15, 93-590 Lodz, Poland * [email protected]

Poly(L-lactide) (PLLA) is known to be the most desirable biocompatible and biodegradable semicrystalline polymer. Because of these characteristics, PLLA is widely studied in detail for biomedical applications, particularly those that demand good mechanical properties for surgical sutures and devices for internal bone fixation [1]. Furthermore, PLLA homopolymer is found to exhibit too hard and too brittle characters as widely usable biodegradable materials and in the pure form, without additives, it cannot be effectively modified or sterilized using ionizing radiation, because it degrades readily while irradiated, leading subsequently to a polymer of lower molecular weight. Therefore, physical properties must be improved by copolymerizations of lactide with other monomers in order to generate more flexible materials. Poly(trimethylene carbonate) (PTMC) is an interesting candidate to introduce modifications to rigid PLA. PTMC of aliphatic carbonate is also biodegradable and it can be sterilized by electron beam irradiation. PTMC undergoes cross-linking initiated by radiation, which results in an increase in the molecular weight. At room temperature, it is a rubbery and flexible material [2]. In this work influence of ionizing radiation on diblock copolymers poly(lactide-co- trimethylene carbonate) have been studied. P(LA-b-TMC) with 30 and 50 mol% TMC were synthesized by ring opening polymerization. Copolymers films were prepared via compression moulding, vacuum sealed and irradiated with 25 and 100 kGy. Changes in mechanical properties were performed. In addition, the structures of the films were explored using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The thermal properties, contact angle and thermal stability of the copolymers films have also been examined. Combination of the two components of different properties, such as that is trimethylene carbonate and lactide copolymer, results in a material more flexible than pure PLA, but with much improved mechanical properties as compared to PTMC. The mechanical properties also showed higher tensile strength and elongation with increasing dose for copolymer containing equimolar content TMC and LA. Our results show that ionizing radiation of copolymers causes that P(TMC-co-LLA) elastomers have shown great potential for various biomaterials applications. Therefore, by introducing PTMC into PLA through copolymerization, the synthesis of poly(lactic acid)-co- poly(trimethylene carbonate) becomes an important way to improve the sensitivity to radiation of PLA.

Acknowledgements This work has been financed by National Science Centre, Poland grant 2012/05/N/ST5/01869.

References [1] H. Yasuda, K. Yamamoto, Y. Nakayama, C. Tsutsumi, P. Lecomte, R. Jerome, S. McCarthy, D. Kaplan, React. Funct. Polym., 61 (2004) 277. [2] T. Matsuda, I.K. Kwon, S. Kidoaki, Biomacromolecules 5 (2004) 295–305.

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P30. THE ROLE OF HYDROGELS IN THE RADICAL PRODUCTION OF FRICKE GELS IRRADIATED AT LOW TEMPERATURE

S. Lazzaroni 1,2 , G.M. Liosi 3,* , R. Marconi 1, G. D’Agostino 2, M. Mariani 3, A. Buttafava 1, D. Dondi 1

1 Department of Chemistry, University of Pavia, via Taramelli 12, 27100 Pavia, Italy. 2 Istituto Nazionale di Ricerca Metrologica (INRIM), via Taramelli 12, 27100 Pavia, Italy. 3 Energy Department, Politecnico di Milano, via Lambruschini 4, 20156 Milano, Italy. * [email protected]

Hydrogels are frequently exploited as matrix to be used in radiotherapy pre-treatment 3D dosimetry. For this purpose, a dosimetric solution is added to the matrix to evaluate the spatial distribution of the absorbed dose. Usually, the active dosimeter is a Fricke derived solution in which a complexant (e.g. xylenol orange) is added to enhance the visual response and to preserve the spatial dose distribution [1]. It is well known that Fricke gel dosimeters have a sensitivity that is higher with respect to the standard Fricke solution. In this work, we focused our attention on the role of the polymer (hydrogel) used as matrix. In particular, a natural polymer (gelatin from porcine skin) and an artificial polymer (PVA) were investigated. The reaction mechanism was studied by EPR spectroscopy, that allows to detect and identify the radical species and iron concentration. To better comprehend the reaction mechanism, the gels were irradiated at liquid nitrogen temperature and then heated inside the EPR cavity. Different radical species were detected and identified at different temperatures. The initial species were ·OH radicals that undergo several reactions leading to the formation of peroxyl radicals. The oxidation of iron occurs at temperatures higher than 220K, where the peroxyl radicals decompose (figure 1). Polymers play an important role for the radical formation even at low concentration (in the range 3-10% w/w). In fact, radical species stemming from carbon backbone of hydrogels are clearly identifiable and their concentration is higher with respect to that deriving from direct radiolysis. In conclusion, it can be hypothesized that unstable radicals produced by the bound water radiolysis induce a damage on the polymer giving more stable and thus less reactive species.

Figure1. Concentration of organic radicals (left) and iron III (right) in a.u. as detected by EPR spectroscopy

References [1] T Olding et al., " Effective Management of FXG Gel Dosimetry ", Journal of Physics: Conference Series 250 (2010), 6th International Conference on 3D Radiation Dosimetry (IC3DDose), doi:10.1088/1742-6596/250/1/012028

118

P31. CHITOSAN-CONTAINING HYDROGEL DRESSINGS PREPARED BY RADIATION TECHNIQUE

Wiktoria Mozalewska 1, Renata Czechowska-Biskup 1, Alicja K. Olejnik 1,* , Radoslaw A. Wach 1, Janusz M. Rosiak 1

1 Institute of Applied Radiation Chemistry, Faculty of Chemistry, Lodz University of Technology Wroblewskiego 15, 93-590 Lodz, Poland * [email protected]

Manufacturing of hydrogel wound dressings with antimicrobial compound of chitosan by means of radiation crosslinking was the aim of present study. The approach included several steps. Firstly, radiation-induced degradation of chitosan to preselected molecular weight was accomplished [1], since it is known that biological activity of chitosan is controlled by its molecular weight [2]. The changes of commercially available chitosan (Heppe Medical Chitosan GmbH, Germany) molecular weight were followed by viscometric method. Secondly the chitosan samples of weight-average molecular weights in range 20-500 kDa were dissolved in aqueous lactic acid (LA) solution at various concentrations and different amounts of the solution were added to the regular composition of polymers used for the classical hydrogel wound dressing [3]. Alternatively, solid chitosan was dispersed in the initial reaction mixture in the amount up to 0.5% (w/v). Irradiation of the solidified reaction mixture by electron beam with the doses from a few kGys to 30 kGy resulted in obtaining permanent hydrogels comprising chitosan. The effect of lactic acid on solidification temperature of the initial mixture, governed by agar – the ingredient responsible for formation of physical gel before irradiation in order to maintain desired shape, was examined by rheometry. The polymeric mixture underwent solidification at lower temperature with the increase in LA concentration. Variation in crosslinking of poly(N- vinylpyrrolidone) – the main component of hydrogel dressings– was determined as a function of lactic acid concentration. The gel fraction and the equilibrium degree of swelling (EDS) resulted from sol-gel analysis [4].Gel fraction was somewhat decreasing in the presence of LA, whereas the EDS increased. Microbiological assessment of the chitosan-containing hydrogel dressings introduced to initial reaction mixture either in lactic acid solution and in a solid state (dispersion) was evaluated. Antimicrobial activity of both types of hydrogels was demonstrated against Escherichia coli strain. Therefore, incorporation of chitosan in the classical hydrogel dressing manufactured by radiation technique provides added value to the well-known product.

References [1] Ula ński P., Rosiak J.M., Struszczyk H., Wojtasz-Paj ąk A. Method of lowering molecular weight of chitosan. (2006) Polish Patent no 193744. [2] Jung B.O., Chung S.J., Lee G.W. Effects of molecular weight of chitosan on its antimicrobial activity. J. Chitin Chitosan. 7 (2002), 231-236. [3]Rosiak J.M., Ula ński P., Pajewski L.A., Yoshii F., MakuuchiK.Radiation formation of hydrogels for biomedical purposes. Some remarks and comments.Radiat. Phys. Chem . 46(1995), 161-168. [4] Rosiak J.M. Gel/sol analysis of irradiated polymers. Radiat. Phys. Chem . 51(1) (1998), 13-17.

119

P32. SYNTHESIS OF CELLULOSE DERIVATIVE BASED SUPERABSORBENT HYDROGELS

Erzsébet Takács 1,3 , Tamás Fekete 1,2,* , Judit Borsa 3, László Wojnárovits 1

Superabsorbents are three-dimensional polymer networks capable of absorbing large amounts of water: e.g. gels with carboxyl, hydroxyl or other hydrophilic functional groups. Due to their unique properties related to the very high water uptake and responsive behavior, they have a wide variety of potential applications, e.g. in agriculture, tissue engineering and sensors.

Most of the practically applied superabsorbents (acrylate-based gels being the most widely used) are non-biodegradable. Therefore, producing gels with high water uptake using renewable and biodegradable materials is of great practical importance. Such renewable source is cellulose, the most abundant renewable material on earth, which can also be easily functionalized due to its hydroxyl groups.

Hydrogels with high water uptake were prepared by ionizing radiation induced crosslinking in aqueous solutions of four cellulose derivatives (carboxymethylcellulose sodium salt – CMC-Na, methylcellulose – MC, hydroxyethylcellulose – HEC and hydroxypropylcellulose – HPC). The gel fraction increased with absorbed dose, while water uptake decreased. At high polymer concentrations lower gel fractions were found due to the lower polymer chain mobility and inhomogeneity at low water content. The swelling rate gradually slowed down after 4-5 hours. CMC and HEC gels reached equilibrium after 24 hours, while HPC and MC gels required longer immersion times. Gels showed second-order swelling kinetics in water. The mechanism of the water diffusion proved to be anomalous. In pure water, CMC gels showed the highest, while HPC and MC gels the lowest water uptake. The derivatives had different sensitivities to ionic strength in the swelling solution. The salt type also proved to be a significant factor at uniform ionic strength. Thus different cellulose derivative based gels may be preferred at various applications depending on the environment.

120

P33. RADIATION FORMATION OF NANOGELS BASED ON POLY(ACRYLIC ACID) FOR APPLICATIONS IN RADIATION THERAPY

M. Matusiak 1,* , S. Kadlubowski 1, P. Ulanski 1

1 Institute of Applied Radiation Chemistry, Faculty of Chemistry, Lodz University of Technology, Wroblewskiego 15, 93-590 Lodz, Poland * [email protected]

Nanogel is a two-component system of a diameter in the range of tens of nanometers, consisting of an intramolecularly crosslinked polymer chain and solvent, typically water, filling the space between segments of the macromolecule [1]. One of the methods used for synthesizing nanogels is linking the segments of a single macromolecule by ionizing radiation, using intramolecular recombination of radiation-generated polymer radicals. The huge advantage of this technique is absence of monomers, catalyst or crosslinking agents etc. It means that the only substrates are polymer molecules and water. This method is an interesting alternative way of synthesizing polymeric carriers for biomedical applications [2-5].

The aim of the study is radiation synthesis and characterization the poly(acrylic acid) nanogels. The physico-chemical properties were described by determination of weight- average molecular weight, hydrodynamic radius, radius of gyration and the second virial coefficient. In addition, the influence of the polymer concentration and the dose of ionizing radiation on these parameters was analyzed. Adjusting the PAA concentration and dose of radiation, one can control the molecular weight and dimensions of nanogels [4]. Radiation- synthesized PAA nanogels, after functionalization, will be tested as as carriers for delivering radionuclides to the tumor cells.

References [1] Ulanski P., Rosiak J.M. Polymeric Nano/Microgels; in „Encyclopedia of Nanoscience and Nanotechnology” (ed. H.S. Nalwa). American Scientific Publishers, Stevenson Ranch, CA. Vol. VIII (2004), 845-871. [2] Ulanski P., Janik I., Rosiak J.M. Radiation formation of polymeric nanogels. Radiat. Phys. Chem. 52 (1998), 289–294. [3] Kadlubowski S. Radiation-induced synthesis of nanogels based on poly(N-vinyl-2-pyrrolidone) - a review. Radiat. Phys. Chem. 102 (2014), 29-39. [4] An J.-C., Weaver A., Kim B., Barkatt A., Poster D., Vreeland W.N., Silverman J., Al-Sheikhly M.. Radiation-induced synthesis of poly(vinylpyrrolidone) nanogel. Polymer 52 (2011), 5746-5755. [5] Dispenza C., Sabatino M.A., Grimaldi N., Bulone D., Bondi M.L., Casaletto M.P., Rigogliuso S., Adamo G., Ghersi G. Minimalism in Radiation Synthesis of Biomedical Functional Nanogels. Biomacromolecules 13 (2012), 1805-1817. [6] Kadlubowski S., Grobelny J., Olejniczak W., Cichomski M., Ulanski P. Pulses of Fast Electrons as a Tool To Synthesize Poly(acrylic acid) Nanogels. Intramolecular Cross-Linking of Linear Polymer Chains in Additive-Free Aqueous Solution. Macromolecules 36 (2003), 2484-2492.

This work has been supported by the International Atomic Energy Agency in the framework of the Coordinated Research Project F22064 (Research Contract No. 18354/R0).

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P34. RADIATION AND SONOCHEMICAL FORMULATION OF GOLD NANOPARTICLES

Renata Czechowska-Biskup 1,* , Bo żena Rokita 1, Piotr Sawicki 1, Piotr Komorowski 2, Piotr Ula ński 1, Janusz M. Rosiak 1

1 Institute of Applied Radiation Chemistry, Faculty of Chemistry, Lodz University of Technology Wroblewskiego 15, 93-590 Lodz, Poland 2 BioNanoPark Laboratories, Lodz Regional Science and Technology Park Ltd., Poland Dubois 114/116, 93-465 Lodz, Poland * [email protected]

The objective of this work was optimization of radiation synthesis of gold nanoparticles stabilized by poly(acrylic acid) – PAA.Gold nanoparticles (AuNPs) in recent years have been the subject of intensive research in photodynamic therapy, medical diagnostics and active transport of drugs, especially in cancer treatment [1]. Number of methods have been used to synthesize of AuNPs, mainly involving reduction of gold salt by various reducing chemical agents such as sodium borohydride or sodium citrate. However in these methods, impurities are difficult to remove after synthesis and can influence the purity of particles. Physicochemical methods such as radiation and sonochemical synthesis of gold nanoparticles (partially similar mechanisms of reduction action) can be classified as environment-friendly methods, the absence of chemical reducing agents in the solution does not produce undesirable compounds [2,3]. Due to the high surface energy of gold nanoparticles and their tendency to aggregate during the synthesis to prevent coalescence process, polymers are used as compounds which act as a coating of individual nanoparticles and cause their stabilization. Synthesis involved reduction of metal ions by reactive species generated by radiolysis or sonolysis of water in the aqueous solution of metal salt. Nanoparticles were characterized by UV-Vis spectroscopy, dynamic light scattering (size, polydispersity), ζ potential measurements and transmission electron microscopy. The study involved testing the influence of molar ratio of gold precursor – chloroauric acid to PAA and pH on the stabilizing effect, as well as optimization of key parameters of the procedure. Our results show that both irradiation and sonication methods can be efficiently used to synthesize gold nanoparticles. The obtained nanoparticles consist of a nucleus of gold nanoparticle surrounded by layer of polymer. From the position of the maximum of absorption bands in the visible light (wavelength approx. 520 nm) and an intense red/purple color dispersions, as well as other measurements, we estimate the size of AuNPs as15-50 nm. The final aim of this study is to elaborate radiation-based and sonochemical methods of synthesizing metal nanoparticles containing radioisotopes for targeted radiotherapy.

This work has been supported in part by the International Atomic Energy Agency (IAEA), Research Contract No: 18354/R0

References [1] Louis C. Pluchery O.Gold nanoparticles for physics, chemistry and biology. Imperial College Press, London (2012). [2] Spotheim-Maurizot M., Mostafavi M., Douki T., Rigny P.Radiation chemistry. From basics to applications in material and life sciences, EDP Sciences, Les Ulis (2008). [3] Sakai T., Enomoto H., Sakai H., Abe M. Hydrogen-assisted fabrication of spherical gold nanoparticles through sonochemical reduction of tetrachloride gold(III) ions in water. Ultrason. Sonochem. 21 (2014), 946–950.

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P35. POLY(ACRYLIC ACID) GRAFTED PET TRACK-ETCHED MEMBRANES AS NANOSCALE TEMPLATE FOR GAMMA- RADIATION SYNTHESIS OF SILVER AND GOLD NANOPARTICLES

Ilya Korolkov 1,2 , Olgun Güven 3,* , Anastassiya Mashentseva 1,2

1 Institute of Nuclear Physic Republic of Kazakhstan, 050032, Ibragimov str., 1, Almaty, Kazakhstan 2 L.N. Gumilyov Eurasian National University, Munaitpassov av., 5, 010008 Astana, Kazakhstan 3 Department of Chemistry, Hacettepe University, 06800 Beytepe, Ankara, Turkey * [email protected]

Track-etched membranes based on poly(ethylene terephthalate) (PET TeMs) are polymer thin films with controlled pore diameter and pore number per unit area. They were produced by irradiation of 12 µm thick PET films with 84 Kr 15+ using Cyclotron DC-60 and subsequently chemically etched in sodium hydroxide solution. PET membrane surface is semi-hydrophilic with low chemical activity. To enhance chemical activity and expand the application of PET membranes, functionalization of surface and nanosized pores with different functional monomers have been performed in our previous works [1-3]. In this study PET TeMs were grafted with acrylic acid and using e-beam source. Acrylic acid was chosen as the monomer for the membrane modification due to its high complexing ability with heavy metal ions. Silver and gold ions were successfully immobilized on the surface and inside the pores of PET TeMs with average 400 nm pore diameter. Au 3+ and Ag + ions chelating with -COOH groups of grafted poly(acrylic acid) on PET TeMs surface that prevent the formation of agglomerates during reduction of ions to metallic nanoparticles. The gamma irradiation was performed in a 60 Co γ-source with doses in the range of 50-200 kGy in aqueous alcohol solutions. Metal nanoparticles inside PET TeMs channels were elucidated by XRD, SEM, EDX and FTIR analysis.

References [1] Korolkov I., Mashentseva A., Niyazova D., Güven O., Barsbay M., Zdorovets M., Polym. Degrad. Stab. 107 (2014), 150-157. [2] Korolkov I., Mashentseva A., Güven O., Zdorovets M., Nucl. Instr.And Meth. B 365 (2015), 651- 655. [3] Korolkov I., Mashentseva A., Güven O. Nucl.Instr.And Meth. B365 (2015), 419-423.

123

P36. USE OF EXPERIMENTAL IRRADIATIORS FOR PRODUCTS SPECIFICATION VALIDATIONS

Hervé Michel 1,* , Chris Johnson 2, Brian McEvoy 3

1 Synergy Health Däniken AG, now part of STERIS Applied Sterilization Technologies, Hogenweidstrasse 6, CH-4658 Däniken, Switzerland 2 STERIS Applied Sterilization Technologies, 2500 Commerce Drive, Libertyville, IL 60048, USA 3 Synergy Health Ireland Ltd., now part of STERIS Applied Sterilization Technologies, IDA Business & Technology Park, Tullamore, Ireland * [email protected]

With the continuing advancements in the Healthcare industry, Industrial Sterilization providers such as STERIS Applied Sterilization Technologies (AST) face the ever increasing challenge of providing high-precision, multi-variable data for its clients. While Batch design irradiators and research loops provide more flexibility over continuous type irradiators; design-of-experiment (DOE) multiple variable effects are difficult to assess in these systems. In order to meet the needs of our customers and moreover the prescriptive requirements of the relevant internationally recognized standards, STERISAST operates a number of globally positioned, dedicated, high-precision research facilities including Gamma Experimental radiation facilities at Marcoule (FR), Swindon (UK), Radeberg (DE) and Libertyville (US).

The experimental facilities facilitate the accurate and precise delivery of dose in well-defined conditions with national laboratory Standard grade alanine dosimetry. With the ability to define processing parameters, Experimental irradiators may be programmed to mimic the operating conditions of most gamma industrial irradiators with regard to dose rate, temperature, density-challenge corrections through reference ratio establishment to deliver accurate precise doses which is often the case for sterilization dose setting validation, and/or maximum dose validation studies.

Such capabilities allow our Customers to assess their products using dedicated research facilities whilst replicating the conditions experienced during validation phase at the assigned industrial irradiator and as well as unique variables which might impact product functionality. The use of such dedicated radiation facilities allow studies to be carried out ‘off-line’ from the industrial process and moreover facilitates detailed assessment of Customer product outcomes.

The purpose of this presentation is to present the STERIS AST irradiator capacity and capability in terms of dose rate, temperature and dose uniformity and also the qualification results.

124

P37. REMOVAL OF URANYL IONS FROM WATER BY SODIUM ALGINATE-ACRYLAMIDE SEMI-INTERPENETRATING NETWORKS

Sinem Demir 1, Murat Torun 1,* , Dilek Şolpan 1

1 Hacettepe University, Department of Chemistry, 06800 Beytepe/Aankara, Turkey * [email protected]

In recent years, heavy metals are among the most important contaminants in water sources and are becoming a severe public health problem. Adsorption has been shown to be an effective and economically feasible alternative method for removal of heavy metals [1–3]. Recently, specific sorbents such as polymers or copolymers have been proposed, consisting of a functional group which interacts specifically with the metal ions. Many types of adsorbents have been tested for the removal of metal ions. Due to the worldwide interest in the extraction of uranium from sea water, there have been many studies on this subject. Uranyl ions can reach natural waters by several ways and there maybe some adverse effects on living organisms that used up these natural water sources. Some adsorbents are developed to remove uranyl ions from water as well as regaining [4]. There are some researches on uranyl compounds to remove from water other than adsorption which are precipitation, liquid extraction and filtration [5,6]. In order to increase the metal ion uptake capacity by hydrogels, (Sodium Alginate/Acrylamide) semi penetrating networks (NaAlg/AAm)IPN were prepared and tested for uranyl uptake with the purpose of removing these pollutants from the aqueous environment. (NaAlg/AAm)IPN was used after synthesis in Co-60 gamma source after irradiation for a 10 kGy with a dose rate of 0.03 kGy/h. Thermal and spectroscopic analysis were performed for synthesized hydrogels that used for uranyl adsorption. Adsorption isotherms for uranyl nitrate and uranyl acetate were determined as S type in Giles classification system [7]. High swelling values for hydrogels were observed at definite pH values. Some diffusion parameters were determined and compared. The diffusion of both water and uranyl ions to IPN was observed as non Fickian type.

References [1] Reed,B.E, Nonavinakere,S.K. Sep. Sci. Technol ., 27 (14), 1985–2000, 1992. [2] Goto,A, Moropka,A.S. Fukamachi,M. Kusakabe,K. Sep. Sci. Technol ., 28 (13–14), 2229–2235, 1993. [3] Reed,B.E, Matsumoto,M.R. Sep. Sci. Technol ., 28 (13–14): 2179 – 2195, 1993. [4] Şolpan D., Torun M. Journal of Applied Polymer Science 114, 543-550, 2009. [5] Maheswari M.A., Subramanian M.S., React Func Polym., 51, 101-107, 2002. [6] Jian V.K., Sait S.S., Shrivastav P., Agrawal Y.K. Sep Sci Technol., 33 , 1803-1811, 1998. [7] Giles C.H., Macewan T.H., Nakhwa S.N. Smith D. J. Chem. Soc. , 74, 3973-3993, 1960.

125

P38. PREPARATION OF ION EXCHANGE ADSORBENT BY RADIATION-INDUCED GRAFTING OF 4-VINYL PYRIDINE ONTO CELLULOSE MICROSPHERE FOR CR(VI) REMOVAL

Hui-Ling Ma 1,3, *, Youwei Zhang 2,3 , Jing Peng 3, Jiuqiang Li 3, Liancai Wang 1, Xinmiao Zeng 1, Maolin Zhai 3

1 Beijing Key Laboratory of Radiation Advanced Materials, Beijing Research Center for Radiation Application, Beijing 100015, China 2 Aviation Key Laboratory of Science and Technology on Stealth Materials, Beijing Institute of Aeronautical Materials, Beijing 100095, China 3 Department of Applied Chemistry and the Key Laboratory of Polymer Chemistry and Physics of the Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China * [email protected]

4-vinyl pyridine (4VP) was grafted onto cellulose microsphere (CM) by radiation-induced grafting technique. The effects of graft polymerization conditions such as total absorbed dose, dose rate, solvent mixture ratio and monomer concentration on the grafting yield were studied to obtain a suitable grafting yield for the proposed application as anion exchange adsorbent. The Fourier transform infrared and X-ray photoelectron spectroscopy results of the graft- modified polymer confirmed poly(4-vinyl pyridine) grafting onto the surface of cellulose microsphere. The 4VP-grafted cellulose microsphere was subsequently protonation for the removal of Cr(VI) ions. The parameters that might influence Cr(VI) ions adsorption capacity such as adsorption time, the feed of adsorbent, the Cr(VI) concentration and the pH were discussed. The equilibrium adsorption could be achieved within 30 min and the adsorption capacity reached a maximum Cr(VI) uptake (78.6 mg/g) as the pH was 2.74. Equilibrium data were explained with the help of Langmuir equation. The obtained results illustrate that the prepared microspheres acquire a promising potential in the practical field of water treatment.

126

P39. PREPARATION OF IMMUNOGLOBULIN ADSORBENTS BY RADIATION-INDUCED GRAFTING OF CELLULOSE FIBERS

Gabriela Torchio 1, M. Laura Carbajal 1 and Mariano Grasselli 1,*

Purification of biopharmaceuticals is generally more cost intensive than corresponding fermentation processes in the biotech industry, and can account for up to 80% of production costs. Affinity chromatography with Protein A is one of the most important and expensive step, industrially used for monoclonal antibody production. Novel process integration and intensification methods, based on the utilization of non- traditional chromatographic processes, or extractive methods, are highly required in order to reduce these costs. The application of aqueous two phase systems, expanded bead adsorptions, convective flow systems, and fiber-based adsorbents have been recently discussed to tackle bottlenecks [1]. Adsorbents fibers, prepared by radiation-induced and chemical grafting of cellulose fibers, have shown high capacity at higher flow rates for separation and purification of proteins [2]. In addition, the natural arrangement of cellulose into fibers allows the development of nonwoven structures, which could be useful for adsorptive process of non-clarified biological samples. In this work are studied the preparation of modified cellulose fibers containing an Avimer [3], a similar Protein A ligand. This Avimer contain a Cysteine amino acid (with a thiol moiety) in the N-terminal tag of the protein, which can link to the epoxy group of glycidyl methacrylate (GMA) by a ‘click’ reaction. Radiation-induced graft polymerization has been used to prepare a composite material of poly(GMA)/cellulose fiber. Cellulose fibers have been previously treated with NaOH solution to improve their swelling. GMA 3 % in water/ethanol solution (1/1 v/v) was used for preparation of grafted fibers by simultaneous method, using a 60 Co irradiation source (10 kGy at 1 kGy/h), yielding 20 % of grafting. Grafted fibers were modified with a thiol containing Green Fluorescent Protein, to follow the immobilization process by fluorescent methods. The optimized reaction for protein immobilization involves a pre-incubation of grafted fibers with DMSO followed by incubation with the Avimer solution in citrate buffer at pH 8.4 with EDTA 1 mM at 5 °C during 72 h. The binding capacity of Avimer-fibers for immunoglobulins was 14.2 ± 1.3 mg/g and in dynamic conditions falls to 7.3 mg/g. This work demonstrated the preparation of advance affinity chromatography materials by radiation-induced modification of cellulose fibers.

References [1] D'Souza, R.N., et al . Emerging technologies for the integration and intensification of downstream bioprocesses. Pharm. Bioproc. 1, (2013), 423-440. [2] Singh, N.K., et al. Preparation and characterization of grafted cellulosic fibers and their applications in protein purification. Sep. Purif. Technol. 143, (2015), 177-183. [3] Kangwa, M., et al., High-level fed-batch fermentative expression of an engineered Staphylococcal protein A based ligand in E. coli: purification and characterization. AMB Exp. 5, (2015), 1-10.

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P40. THE EFFECT OF GAMMA IRRADIATION ON THE PROPERTIES OF POLY(3-HYDROXYBUTYRATE-CO-3- HYDROXYVALERATE)/POLY( Ε-CAPROLACTONE) BLENDS

Yang Liu 1,* , Bolong Li 1, Hongyan Yu 1, Liancai Wang 1, Xinmiao Zeng 1, Baohua Guo 2

1 Beijing Research Center for Radiation Application, Beijing key laboratory of radiation advanced materials, Beijing 100015, China 2 Institute of Polymer Science & Engineering, Department of Chemical Engineering, Tsinghua Univesity, Beijing 100084, China * [email protected]

In this work, blends of poly(3-hydroxybutyrate-co -3-hydroxyvalerate) (PHBV) and poly( ε- caprolactone) (PCL) were prepared by solvent casting method with mass ratio of 1:1, the blends were irradiated by 60 Co-γ rays. The influence of irradiation on blends structure, mechanical property, thermal property and biocompatibility were investigated at different irradiation doses, 25, 50, 70 and 100 kGy. For the PHBV/PCL blends being processed under 100 kGy irradiation, a significant reduction of Mw was noted, decreasing from 90 kDa to 30 kDa. The mechanical properties of the blends decrease with the increase in irradiation dose. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) results show that the melting temperature decreases after irradiation compared to the non-irradiated specimen, while the irradiated specimen shows a higher decomposition temperature. The biocompatibility of PHBV/PCL blends were investigated by thiazolyl blue tetrazolium bromide (MTT) test, the irradiated specimens have higher relative growth rate (RGR) with increase of irradiation dose. At the dose of 100 kGy, the value of RGR increased from 69.85% of non-irradiated specimen to 88.12%, indicating that γ-ray could potentially improve the biocompatibility of PHBV/PCL blends.

Figure 1. GPC curves of PHBV/PCL blends: Figure 2. Thermal degradation curves of the various (a) 0 kGy; (b) after irradiation at a dose of 25 kGy; PHBV/PCL blends: (a) 0 kGy; (b) after irradiation at a (c) after irradiation at a dose of 100 kGy. dose of 25 kGy; (c) after irradiation at a dose of 100 kGy.

References [1] Hermida, E. B. et al. Macromol Symp. (2008), 263, 102-113. [2] Wessler, K., Nishida, M. H., da Silva, J., Pezzin, A. P. T. & Pezzin, S. H. Macromol Symp. (2006), 245, 161-165. [3] Chiono, V. et al. J Biomed Mater Res A 85A (2008) 938-953.

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P41. PREPARATION OF CHITOSAN/POLYVINYLPYRROLIDONE MATRICES BY GAMMA IRRADIATION: CHARACTERIZATION AND PRELIMINARY CELL RESPONSE STUDIES

Maria Helena Casimiro 1,* , Susana R. Gomes 1, Gabriela Rodrigues 2, João Paulo Leal 1,3 , Luís M. Ferreira 1

1 Centro de Ciências e Tecnologias Nucleares (C 2TN), Instituto Superior Técnico, Universidade de Lisboa, EN 10 (km 139.7), 2695-066 Bobadela, LRS, Portugal. 2 Centro de Ecologia, Evolução e Alterações Ambientais (cE3c), Faculdade de Ciências da Universidade de Lisboa, 1749-016 Campo Grande, Lisboa, Portugal. 3 Centro de Química e Bioquímica (CQB), Faculdade de Ciências da Universidade de Lisboa, 1749-016 Campo Grande, Lisboa, Portugal. * [email protected]

Several studies have shown that chitosan possesses several characteristics favorable for promoting dermal regeneration and accelerated wound healing [1-2]. In this work we wish to report the work that we have done on the development and characterization of biocompatible and biodegradable chitosan based matrices to be used as skin scaffolds. Poly(vinylpyrrrolidone) (PVP) was used as copolymer and a two steps methodology of freeze- drying and gamma irradiation from a 60 Co source was used to obtain the porous matrices.

The influence of copolymer concentration, synthesis procedure and absorbed dose on matrices’ physical, chemical and structural properties was evaluated. The in vitro cellular viability and proliferation of human Caucasian fetal foreskin fibroblast cell line was analyzed as a measure of matrices’ biocompatibility and ability to assist skin regeneration.

Results show that, over the studied range values, γ-radiation dose, copolymer concentration and synthesis procedure can be used to tailor the matrices’ morphology in terms of porosity and surface roughness. Early results from biological assays show that cells adhered to the surface of all matrices which did not present cytotoxicity. These features show that the matrices in study may be a potential suitable scaffold for tissue regeneration.

Acknowledgements This work was financially supported by the International Atomic Energy Agency (IAEA) under the Research Contract No. 18202/R2.

References [1] T. Dai, M. Tanaka, Y.-Y. Huang, M.R. Hamblin. Chitosan preparations for wounds and burns: antimicrobial and wound-healing effects. Expert. Rev. Anti. Infect. Ther. 9 (2011), 857-879. [2] M.H. Casimiro, M.H. Gil, J.P. Leal. Suitability of gamma irradiated chitosan based membranes as matrix in drug release system. Int. J. Pharm. 395 (2010), 142-146.

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P42. CONSTRUCTION OF MULTI-PURPOSE IRRADIATION FACILITY AT KACST

Bumsoo Han 1,* , Turki S Alkhuraiji 2, Won-Gu Kang 1, Chang M. Kang 1, Alaa A. Alwatban 3

1 EB Tech Co., Ltd., Daejeon, Republic of Korea. 2 King AbdulAziz City for Science & Technology (KACST), Kingdom of Saudi Arabia. 3 HGBD Arabia engineering consultants Co.), Kingdom of Saudi Arabia. * [email protected]

The King AbdulAziz City for Science & Technology (KACST) in the Kingdom of Saudi Arabia plans to build a 10 MeV, 1.5mA electron linear accelerator and 0.7 MeV, 30 mA mobile electron accelerator for the purpose of performing research on the irradiation of agricultural products and industrial materials and for environmental applications. The accelerator will be supplied by EB Tech Co., Ltd. (EB TECH), Korea (rep. of) and the design and construction of the irradiation research center building will be conducted in cooperation with KACST, EB TECH and HGBD Arabia engineering consultants Co. (HGBD). The linear electron accelerator is a standing wave accelerating type with a working frequency of 2856MHz. The power source generates 5MW of microwave pulses using the klystron while the mobile electron accelerator is coreless transformer type accelerator mounted on the trailer. Shielding calculations were performed by MCNP and the results show that the calculated doses at all detector locations meet the recommendation of International Commission on Radiological Protection (ICRP) dose limit of 50 mSv/yr. The irradiation research center building has the concrete shield structure for linear accelerator and shelter for mobile accelerator together with research laboratories and workshop. Stainless steel conveyor for composites, cable handling equipment (pay-off, take-up and capstan) and other material handling system will also be installed for each individual research and proto- production.

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P43. SYNTHESIS OF HYDROGELS BASED ON DMAPMA-CO-IA BY GAMMA RADIATION FOR THE RETENTION OF HEAVY IONS

José Apango 1, Alejandra Ortega 1,*

1 Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, México * [email protected]

Hydrogels are crosslinked hydrophilic polymers that can swell in aqueous medium due to their functional groups and they have been used in environmental applications because their excellent absorbent properties [1]. In recent years, the use of hydrogels with specific functional groups for the removal metals ions from water has increased since they have many advantages such as easy preparation methods, high efficiency of adsorption and, in many cases, reusability with simple chemical or physical changes in the environment [2]. In the literature, we can find that the use of materials containing carboxyl, sulphate, phosphate, amine and amide groups in their structures favor the metal-hydrogel complex [3]. Although hydrogels can be obtained by chemical methods, it is easier obtain them by ionizing radiation (UV, gamma or electron-beam) because the polymerization and crosslinking process is simultaneous, and the process can be carried out at room temperature [3,4].

In this work, new hydrogels based on N-(3-dimethylamine)-propyl methacrylamide (DMAPMA) and itaconic acid (IA) were synthesized by gamma radiation. The optimal synthesis conditions were obtained and the materials were characterized by IR, DSC and TGA; the swelling behavior was also studied. Furthermore, the hydrogels capacity to remove chromates (Cr 2+ ) and mercury (Hg 2+ ) ions from aqueous solutions was evaluated, and the preliminary results are presented.

Figure 1. Chemical structure of synthesized hydrogel

References [1] Ozgur Ozay. Synthesis and swelling behavior of novel pH responsive hydrogels for environmental applications. Polym.-Plast. Technol. Eng. 53 (2014), 130-140. [2] M. Zendehdel, A. Barati, H. Alikhani. Removal of heavy metals from aqueous solution by poly(acrylamide-co-acrylic acid) modified with porous materials. Polym. Bull. 67 (2011), 343-360. [3] R. González-Gómez, A. Ortega, L.M. Lazo, G. Burillo. Retention of heavy metal ions on comb- type hydrogels based on acrylic acid and 4-vinylpyridine, synthesized by gamma radiation. Radiat. Phys. Chem. 102 (2014), 117-123. [4] E. Ramírez, G. Burillo, C. Barrera-Díaz, G. Roa, B. Bilyeu. Use of pH-sensitive polymer hydrogels in lead removal from aqueous solution. J. Hazard. Mater. 192 (2011), 432-439.

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P44. RADIATION EFFECTS IN THE PVDF/GRAPHENE OXIDE NANOCOMPOSITES

Juliana V. Pereira 1, Adriana S. M. Batista 2, Jefferson P. Nascimento 3, Clascídia A. Furtado 3, Luiz O. Faria3,*

Exposure to ionizing radiation has been found to induce changes in poly(vinylidene fluoride) (PVDF) homopolymers. The high dose gamma irradiation process induces the formation of C=C and C=O bonds and the decreasing of its melting latent heat (LM) and, consequently, of its crystalline order [1]. We have investigated the possibility of preparing nanocomposites of PVDF with graphene oxide (GO) through the radio-induction of molecular bonds between the polymeric material and the carbon nanostructures. This investigation aimed to produce nanocomposites with new properties related to the PVDF beta-crystalline phase such as high piezoelectricity and relaxor ferroelectric behavior. The loss of PVDF crystalline fraction associated to the decrease of LM has been characterized by DSC technique [1]. In this work, PVDF nanocomposites with 1.88% of graphene oxide were irradiated with gamma doses ranging from 100 to 1000 kGy. The formation of radio-induced FTIR absorption peaks is not observed for PVDF-OG samples, since it is not possible to see any significant new peaks between 1500-2000 cm -1 (Figure 1a). However, we note in Figure 1 b) that LM increases for increasing doses. The results indicate that the crystalline fraction of the irradiated PVDF-OG nanocomposites is higher than the pristine polymer, with the appearing of multiple peaks in the DSC thermograms. In this work we discuss how the gamma radiation interacts with the nanocomposite crystalline structure.

Figure 1a. FTIR spectra for PVDF /OG samples irradiated with doses between 100-950 kGy and b. 2nd heating cycle thermograms for PVDF/OG samples exposed of gamma radiation.

References [1] A. S. M. Batista, M. R. Gual, C. Pereira, L. O. Faria. Thermal analysis for study of the gamma radiation effects in poly(vinylidene fluoride). Radiation Physics and Chemistry , 345-348.

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P45. P(VDF-TRFE) / NANOSIZED BI 2O3 POLYMER-COMPOSITES FOR X-RAY SHIELDING

Fontainha C. C. P. 1, Neto A. T. B. 2, Faria L. O. 2,*

1 Depto. de Engenharia Nuclear - UFMG, Av. Antônio Carlos 6627, 31270-970 Belo Horizonte, MG, Brazil 2 Centro de Desenvolvimento da Tecnologia Nuclear, Av. Antônio Carlos 6627, C.P. 941, 30270-901, Belo Horizonte, MG, Brazil * [email protected]

The design of efficient, lightweight, cost-effective, and flexible materials that provide radiation shielding to patients has drew the attention of several researchers along the world. Recently, nanocomposites made of P(VDF-TrFE) copolymers and ZrO 2 nanoparticles encapsulated by methacrylic acid (MMA) has been proposed for application as protective shielding in interventional radiology procedures [1]. In this work we have used similar methodologies in order to produce nanocomposites made of P(VDF-TrFE) copolymers and bismuth oxides (Bi 2O3) nanoparticles. We have prepared P(VDF-TrFE)/ Bi 2O3 composites with Bi 2O3 nano particles encapsulated with MMA and with microparticulated Bi 2O3. The samples were exposed to 100 mGy of X-rays ISO radiation qualities N40, N70 and N100 with mean energies of 33, 54 and 83 keV, respectively. The attenuation factors were determined by using XR-QA2 radiochromic films. In Figure 1 we show the attenuation factors for both composites, P(VDF-TrFE)/ Bi 2O3 nano and micro, and also for pristine P(VDF-TrFE) copolymer. These results were normalized for samples 100 µm thick. The better attenuation behavior was observed for the nanocomposites prepared with Bi 2O3 nanoparticles, presenting attenuation higher than 28% for N70 and N100 radiation qualities. We attribute the performance of the nanocomposite to the good compatibility between P(VDF-TrFE) copolymers and MMA that provides a very good distribution of the bismuth oxide nanoparticles into the polymeric matrix. These results demonstrates that P(VDF-TrFE)/ Bi 2O3 nanocomposites are good candidates for application as protective shielding devices in interventional radiology procedures .

Fig. 1 – Attenuation factor for P(VDF-TrFE)/Bi 2O3 nanocomposites (red), microcomposites (blue) and pristine P(VDF-TrFE) (magenta) samples 100 µm thick.

References [1] C.C.P. Fontainha, A.T.B. Neto, A.P. Santos, L.O. Faria, P(VDF-TrFE)/ZrO2 Polymer-Composites for X-ray Shielding. Mat. Research 2016 - DOI: http://dx.doi.org/10.1590/1980-5373-MR-2015- 0576.

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P46. TRUTHS AND MYTHS ABOUT AGING AND FADING OF PADC RADON DETECTORS

Jaroslaw M. Wasikiewicz 1,*

1 Public Health England, Centre for Radiation, Chemical and Environmental Hazards, Chilton, Didcot, OX11 0RQ, UK * [email protected]

Poly-allyl diglycol carbonate (PADC) has a long history of application in both alpha and neutron dosimetry [1-2]. A wide range of environmental effects on its radon (Rn-222) detection sensitivity are generally known and acknowledged [3]. However in operational services the sensitivity and accuracy of dosemeter reading is a key factor and must be monitored regularly in order to correctly estimate the dose from radon exposure. Moreover, knowledge of such effects can offer a solid background in providing guidance for detector placement in order to obtain uninfluenced and accurate results.

Some of the pre- and post- radiation environmental effects are among the major contributors to detector sensitivity. The former, often referred to as “aging” or “storing“, is the post- production time for which PADC is kept under certain conditions before it is used as a detector material. The latter, defined as “fading”, is the time between material exposure and etching process completion.

This study presents the results from a comprehensive investigation of environmental factors on both aging and fading effects on PADC radon detection sensitivity and nuclear tracks formation. Atmosphere of ambient air or nitrogen, elevated and decreased temperatures, submerging in basic and acidic solutions and finally irradiation with UV and gamma rays were environmental conditions used to assess changes in detector response.

Results of up to 12 months investigation of environmental effects on nuclear track formation in PADC material shows that in both cases of aging and fading sensitivity to radon for up to six months remains unaffected when stored properly under nitrogen atmosphere. However when stored under other environmental conditions the response to alpha particles was significantly affected. The details are discussed in this study.

References [1] Gilvin, P.J., Bartlett, D.T., Steele, J.D. The NRPB PADC neutron personal dosimetry service. Radiat. Prot. Dosim. 20 (1987), 99-102. [2] Bartlett, D.T., Gilvin, P.J., Still, R., Dixon, D.W., Miles, J.C.H. The NRPB radon personal dosimetry service. J. Radiol. Prot. 8 (1988), 19-24. [3] Barlett D.T. Aging of and environmental effects on PADC (CR-39). Radiat. Prot. Dosim. 20 (1987), 71-75.

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P47. FABRICATION OF THERMO-RESPONSIVE MEMBRANE FOR MEDICAL DEVICES BY RADIATION GRAFTING

Yumi Yamahara 1,* , Toru Hinata 1, Naotsugu Nagasawa 2, Akihiro Oshima 3, Masakazu Washio 1

1 Waseda Research Institute for Science and Engineering, Waseda University, Japan 2 QuBS, National Institutes for Quantum and Radiological Science and Technology 3 Graduate School of Engineering, Osaka University, Japan * [email protected]

Introduction Recently, poly (N-isoproplyacrylamide) (PNIPAAm) which is thermo-responsive polymer is studied for application of medical devices [1]. PNIPAAm changes wettability and chain length at 32 oC, lower critical solution temperature (LCST), reversibly. To use radiation grafting method, the characteristic of thermo-responsivity of PNIPPAm can be added to base materials at will. So fabrication of thermo-responsive membrane by radiation grafting would be useful for developing switching devices, such as drug delivery system (DDS) nano biodevices and culture dishes for regenerative medicine. In this study, thermo-responsive membranes were fabricated using radiation grafting method and their characteristics were evaluated.

Experimental Poly (ethylene-co -tetrafluoroethylene) (ETFE) membranes (50 µm, NeoFlon®, DAIKIN INDUSTRY) was irradiated by electron beam (1 mA, 200 kV) uging EB accelarator (Curetron®, NHV Corp.) under N 2 atomsphere and at 24 °C. Then, irradiated ETFE was grafted with 40 wt% NIPAAm solution (solvent: 2-propanol). Grafted yield was calculated from the mass change of before and after. FT-IR and NMR spectroscopy to confirm the grafting of NIPPAm. The contact angle measurement to research thermo-responsivity of obtained membranes were performed. HeLa cells were cultured on the obtained membranes to examine its adhensinvess by temperature.

Results & Discussion Grafting yield was increased with increasing of reaction periods. 10.9 % PNIPAAm grafted membrane which was fabricated by EB grafting method was evaluated. From FT-IR and NMR spectroscopy, signals derived from PNIPAAm was emerged in each spectrum of grafted membrane. It is confirmed that PNIPAAm was grafted on ETFE. Although the contact angle of non-grafted ETFE was not changed by various temperatures, the contract angle of obtained membrane was changed from 76 ° at 20 °C to 83 ° at 40 °C. Thus, thermo-responsivity was appeared by PNIPAAm grafting onto ETFE. From culturing HeLa cells, they had a tendency of adhering at 35 °C and detaching at 20 °C. it was derived from thermo-responsivity of the membranes.

Conclusion PNIPAAm grafted ETFE was fabricated by EB grafting method. From FT-IR and NMR spectroscopy, it was conformed that PNIPAAm was grafted onto ETFE. The thermo- responsivity was appeared by PNIPAAm grafting onto ETFE by contact angle measurement and cellular adhesiveness. Through them, the prospect of fabricating thermo-responsive membrane for medical devices could be gotten.

References [1] Giancarlo M., Laura G. Macromol. Rapid Commun. 25 (2004), 559–564.

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P48. CALIBRATION OF RADIATION SURVEY METERS USING THE BRAKING RAYS OF AN ELECTRON BEAM

Arnaud Chapon 1,*

1 CERAP, Conseil et Etude en Radioprotection, Cherbourg-Octeville, France. * [email protected]

CERAP has developed an innovative method to calibrate radiation survey meters (fig. 1) through large ranges of energy and dose-rate [1]. It consists in using the braking rays produced by an electron beam as calibration source instead of a high activity radioactive source [2]. The production rate and reliability of the process are much better than the standard method. It is also safer for workers and for environment, and the shape of the calibration X-spectrum is fairly representative of the typical one experienced in nuclear power plants, as shown on figure 2.

Figure 1. Some examples of Figure 2. Spectra of calibration Figure 3. HVEE Singletron radiation survey meters sources and typical gamma accelerator – electron beam up to spectrum found on nuclear 3,5 MeV and 1 mA power plants

Braking rays are generated by interaction of an electron beam in a W target. The beam is delivered by a HVEE Singletron accelerator [3] which allows to produce mono-kinetic electrons with an energy set to a value between 200 keV and 3.5 MeV. Another strong challenge comes from the large range of dose rate through which we have to calibrate radiation survey meters: it goes from few 0.1 µSv/h to about 100 Sv/h. It is allowed by the wide range of currents, from 10 pA to 1 mA!

To summarize, we will have a HVEE Singletron accelerator (fig. 3) which will produce mono- kinetic electrons with an energy range going from 200 keV to 3.5 MeV and a current from 10 pA to 1 mA and a removable target allowing to irradiate setups either with electrons or X- rays. Furthermore, as the setup will not be full time used, it will be available for many other applications and research in domains of irradiation of polymers, electronics, composite materials...

References [1] Vérification de l’étalonnage de radiamètres au moyen d’un accélérateur d’électrons , A. Chapon, J.-M. Bordy, SFRP (2015). [2] Reference radiation fields for radiation protection – Definitions and fundamental concepts, ISO 29661. [3] Singletron accelerator systems, High Voltage Engineering.

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P49. FORMATION OF NANOWIRES VIA SOLID STATE POLYMERIZATION/CROSSLINKING REACTIONS OF ORGANIC MATERIALS INDUCED BY SWIFT HEAVY ION IRRADIATION

Akifumi Horio 1, Tsuneaki Sakurai 1,* and Shu Seki 1,*

1 Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Kyotodaigaku-katsura, Nishikyo-ku, Kyoto 615-8510, Japan. * [email protected], [email protected]

High energy charged particles passing through condensed media release their kinetic energy into a limited nm-sized cylindrical area along their trajectories, which gives corresponding insoluble nanowires with a uniform diameter and length via crosslinking reactions when we use polymeric materials as the target [1] ( Figure 1 ). In this study, we have newly fabricated nanowires from small molecules without long covalent chains, triphenylamines. The nanowires are visualized clearly by atomic force microscopy (AFM) ( Figure 2 (a) ), suggesting that highly efficient polymerization reactions of materials took place upon particle irradiation. As in the sharp contrast, polystyrene derivatives also gave nanowires using present method (Figure 2 (b) ), indicating that swift heavy ion irradiation induces crosslinking reactions of solid-state polystyrenes. The radiation induced reactions can be assessed that halogenated benzene rings have higher reaction efficiencies reflected by the larger diameter of the nanowires produced from halogenated polystyrene derivatives than those from non- halogenated ones. We considered that this is due to the dissociative electron attachment reactions upon particle irradiation facilitating the higher yield of neutral radical in an ion track, and hence the effective crosslinking reactions. The present method offers a better understanding of basic intra-track interactions via swift heavy ion irradiation to organic media, unveiling the present method as a universal tool for nanostructuring of a variety of organic materials from organic small molecules to polymers.

Figure 2. AFM images (scale bar, 500 nm) of (a) triphenylamine and (b) polystyrene derivatives after irradiation and development of their thin films on silicon substrates. The irradiation was carried out using 490 MeV 192 Os 30+ particles at Figure 1. Schematic illustration of nanowire fabrication the fluence of 1.0 × 10 9cm -2. The films were developed with processes by high energy single particle irradiation. cyclohexane for triphenylamines and toluene for polystyrenes.

References [1] S. Seki et al. Formation of nanowires along ion trajectories in Si backbone polymers Adv. Mater. 13 (2001), 1663-1665.

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P50. PREPARATION OF WELL-DEFINED ERYTROMYCINE IMPRINTED NON-WOVEN FABRICS VIA GAMMA IRRADIATION INDUCED GRAFTING

Meshude Akbulut Söylemez 1,* , Murat Barsbay 1, Olgun Güven 1

1 Hacettepe University, Department of Chemistry, Beytepe, 06800 Ankara, Turkey * [email protected]

Erythromycin is a broad spectrum antibiotic which was discovered more than sixty years ago. It is a good alternative for β-lactams as it causes less allergic reactions. It is possible to use erythromycin for treatment of upper and lower respiratory tract, genitals, skin, and soft tissue infections [1]. Recently, it has been shown that common and improper usage of erythromycin may cause a potential threat for human health. Erythromycin is often used in trace amount for treatments in human and animals. It is therefore necessary to develop novel materials for detection of this compound. Molecularly imprinted polymers (MIPs) are tailor-made materials with high specific selectivity for a certain template molecule in trace amount. This method includes polymerization/crosslinking of functional monomers and crosslinking agent around a template molecule. Removal of template molecule creates specific binding sites for template molecule in the network in terms of functionality, size and shape [2].

In this study a novel method was used to synthesize well-defined molecularly imprinted polymers (MIPs) using RAFT polymerization, one of the most prominent of controlled radical polymerization (CRP) techniques. This method involves surface modification of a porous support material such as PE/PP nonwoven fabric. Methacrylic acid (MAA) was grafted onto PE/PP nonwoven fabrics under γ-irradiation. 2-phenyl-2-propyl benzodithioate was employed as the chain transfer agent (CTA), i.e. RAFT agent. Ethylene glycol dimethacrylate (EGDMA) was used as crosslinker in dimethyl formamide (DMF). MAA/erythromycin ratios of 2/1, 4/1, 6/1 were used for the synthesis of MIPs. Non-imprinted polymers (NIPs) were also synthesized in the absence of erythromycin. The synthesized MIPs were characterized by ATR-FTIR, XPS and SEM analysis. It was seen that RAFT polymerization could be successfully utilized in conjunction with radiation-induced grafting technique for the preparation of well-defined MIPs. The MIPs synthesized by RAFT method presented a better binding capacity compared to those prepared by conventional method where no RAFT agent was employed.

References [1] Xu Z-Q, Flavin MT, Eiznhamer DA. Macrolides and ketolides. In: Dougherty TJ, Pucci MJ, editors. Antibiotic Discovery and Development. New York: Springer; 2012. p. 181–228. [2] Rañada Ma.L., Akbulut M., Abad L., Güven O. Molecularly imprinted poly(N-vinyl imidazole) based polymers grafted onto nonwoven fabrics for recognition/removal of phloretic acid. Radiat. Phys. Chem. 94 (2014), 93–97.

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P51. TEMPLATE EFFECT ON THE SIZE AND SIZE DISTRIBUTION OF FREE VOLUME HOLES IN THE MOLECULARLY IMPRINTED NETWORKS SYNTHESIZED VIA GAMMA IRRADIATION

Meshude Akbulut Söylemez 1,* , Olgun Güven 1

1 Hacettepe University, Department of Chemistry, Beytepe, 06800 Ankara, Turkey * [email protected]

Molecular imprinting is a useful method providing the creation of recognition sites in polymeric matrices for various molecules called template. In this method a template molecule and functional monomer(s) form a pre-polymerization complex. This complex is then polymerized in the presence of a crosslinker. Upon removal of template molecule cavities that can recognize template molecule in terms of shape, functionality and size are produced. The size of these cavities may be responsible for selective rebinding of template molecule [1]. Positron annihilation lifetime spectroscopy (PALS) is one of the most useful methods to analyze the size and size distribution of the free volume holes in polymers [2]. In this study, the effect of template molecule was investigated on the formation of free volume holes in MIPs designed for atrazine. MIPs were synthesized by grafting onto PE/PP non-woven fabrics (MIP1) and in situ -membrane preparation (MIP2) via gamma irradiation. Methacrylic acid was used as functional monomer while ethylene glycol dimethacrylate was employed as crosslinking agent in DMF medium for both procedures. Control polymers (NIP1 and NIP2) were synthesized by the same procedures in the absence of template molecule. PALS analysis proved that presence of template molecule brings homogenity to the size distribution of free volume holes in the MIP matrices for MIP1 and MIP2. As seen in Fig. 1, two different peaks for annihilation of o-Ps for NIP1(c,d) and those of PE/PP substrate(m,n) are replaced by one sharper and narrower peak for MIP1 (c’). This is a direct proof showing the presence of atrazine bringing uniformity to the size and size distribution of free volume holes in MIP matrices. The same effect was observed for MIP2.

Figure 1. Lifetime distributions of free positrons (k,a,a'), para-positronium (p-Ps) (l, b, b') and ortho- positronium (o-Ps) in crystalline (m, c) and amorphous (n, d) regions of (a) PE/PP non-woven fabric, (b) control polymer grafted non-woven fabric (NIP1), (c) atrazine imprinted polymer grafted non-woven fabric (MIP1) according to MELT analysis of PALS results.

References [1] Rañada Ma.L., Akbulut M., Abad L., Güven O. Molecularly imprinted poly(N-vinyl imidazole) based polymers grafted onto nonwoven fabrics for recognition/removal of phloretic acid. Radiat. Phys. Chem. 94 (2014), 93–97. [2] Djourelov N., Ate ş Z., Güven O., Misheva M., Suzuki T., Positron annihilation lifetime spectroscopy of molecularly imprinted hydroxyethyl methacrylate based polymers. Polymer 48 (2007), 2692-2699.

139

P52. EVALUATION OF ELECTRON BEAM ENERGY SPREAD VARIATION AND ITS INFLUENCE ON RADIATION PROCESSING

Z. Zimek 1,* , V.M. Lazurik 2, V.T. Lazurik 2, G. Popov 2

1 Institute of Nuclear Chemistry and Technology, 16 Dorodna str., 03-195, Warsaw, Poland 2 V.N. KarasinKharkiv National University, 4 Svobody Sq., 61022, Kharkiv, Ukraine * [email protected]

Electron beam energy spread variation may have some influence on technical and economical parameters of bulk polymer devices radiation processing. High energy electron accelerators powered by magnetron type of RF source are frequently use in radiation sterilization process. Those devices can be characterized by relatively high instability of electron energy and electron energy spread. The variation of electron energy spread was investigated with application of computational method for determination of EB energy on the base of two- parametric fitting depth dose distribution curve [1]. Method can effectively evaluate electron energy spread value from the experimental data related to depth dose distribution measured by the use of aluminum wedge with a continuous strip of dosimetric film. The basic model parameters are as follow: E 0 - energy of mono-energetic and mono-directional electron source, X0 - the thickness of the aluminum layer, located in front of irradiated object, E p – the most probable energy establish by practical range R p measurements with aluminum wedge application. The difference between E 0 and E p values corresponds to the energy losses in accelerator output window, air between window and irradiated material surface and initial energy spread of electron beam. The electron beam energy losses because of window and air presence are constant for certain electron energy level and specific geometry of irradiation. Those energy losses can be estimated on the base of existing literature data base. Therefore the initial electron beam energy spread and its variation can be evaluated by processing the depth dose distribution data connected to Rp measurements according to two-parametric fitting method. Long and short term electron energy instabilities and energy spread variation were investigated for radiation sterilization facility equipped with high energy electron accelerator powered by magnetron RF source. The influence of electron energy spread on depth dose distribution and practical range R p were investigated with the use of computer simulation based on the Monte Carlo method (Mode-RTL computer program). Wider energy spread for certain initial electron energy level corresponds to shorter penetration range. Degree of energy spread variation and its influence on electron penetration range were establish by processing experimental data obtained during practical range Rp measurements with aluminum wedge application.

References [1] V.M. Lazurik, V.T. Lazurik, G. Popov, Z. Zimek, Two-parametric model of electron beam in computational dosimetry for radiation processing, Radiation Physics and Chemistry , (in press, available online from 9 December 2015)

Acknowledgement The work was performed in the frame of the project “The development of innovative advanced therapy medical product (biological dressing of the human race) in the treatment of Epidermolysis Bullosa and other chronic wounds”, The National Centre for Research and Development (Poland)

140

P53. ACRYLIC POLYMER GRAFTED ONTO POLYPROPYLENE SUTURES FOR ANTIMICROBIAL MATERIALS

Felipe López-Saucedo 1,* and Emilio Bucio 1

Radiation processing has many advantages over other conventional methods. When using radiation for material processing, no catalysts or additives are needed in order to initiate the reaction. Grafting techniques normally include the pre-irradiation, as well as the mutual or the simultaneous method. Materials which exhibit changes in response to external stimuli such as pH, electric current, and temperature have been defined as “intelligent materials”; which are required for advanced applications such as drug delivery systems. N-isopropylacrylamide (NIPAAm), N-vinylimidazole (NVIM), and 2-hydroxyethylmethacrylate (HEMA) were separately grafted onto polypropylene sutures (PP) by means of pre-irradiation and/or direct method using a 60 Co γ-source, with the purpose of obtaining antimicrobial materials. The effects of pre-irradiation dose as well as monomer concentration, solvent, reaction temperature and reaction time on the grafting efficiency were investigated. Typical conditions for achieving maximum grafting yield were observed for different conditions. The location of the graft polymerization was examined by different methods including infrared spectra (FTIR- ATR), thermal decomposition by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and swelling. Preliminary studies provide large differences of yield rates in the graft of PP-g-HEMA, with oxidative pre-irradiation. Low and not quantitative grafting percentages were obtained using water as solvent (0-15%). Due to results were not the best with water, the solvent was changed to ethanol/ water 3:1 mixture, and the grafting increases up to 75.6%. A second series of experiments was achieved by the method of oxidative pre- irradiation (40 kGy), with the monomer NIPAAm (1.7 M), onto PP, with toluene as solvent, the graft PP-g-NIPAAm reported a yield of 114.3%. The effect of the solvent is notorious and toluene is the most suitable, due to their hydrophobic properties as the polymer matrix. Posterior experiments for grafting HEMA and NIPAAm monomers in a single step to synthesize of PP-g-HEMA/ NIPAAm with high yields of 222.1 and 522.6%, in molar ratios of NIPAAm-HEMA 1:1 and 2:1 respectively. Which portends a profitable production of materials with potential biomedical applications.

References [1] García-Vargas M., González-Chomón C., Magariños B., Concheiro A., Alvarez-Lorenzo C., Bucio E. Acrylic polymer-grafted polypropylene sutures for covalent immobilization or reversible adsorption of vancomycin. Int J Pharm . 461 (2014), 286–295. [2] Saxena S., Ray A.R., Kapil A., Pavon-Djavid G., Letourneur D., Gupta B., Meddahi-Pelle A. Development of a new polypropylene-based suture: plasma grafting, surface treatment, characterization, and biocompatibility studies. Macromol Biosci. 11 (2011) 373–382.

Acknowledgements . The authors thank to DGAPA-UNAM Grant IN200714 for supported.

141

P54. SYNTHESIS AND CHARACTERIZATION OF POLYMERIC FILMS RICH IN PRIMARY AMINES FOR CELL CULTURES, BY GAMMA RADIATION

Mitzi P. Pérez-Calixto 1,* & Guillermina Burillo 1

1 Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Circuito exterior, Ciudad Universitaria, México D.F. 04510, México * [email protected]

Development of biomaterials have been increased, due the necessity to find bio-inert materials able to present a specific cellular response. Biomaterials are very important for tissue engineering. They can be used as bridges to regenerate damaged tissue growth, as well as support for immobilized biomolecules (drugs, fungicides, enzymes, etc.). Polymer surface modification can be carry out by incorporating functional groups on polymeric materials for the appropriate cell adhesion. It is well known that hydrophobic polymeric surfaces cannot add cells, however, hydrophilic surfaces, mainly rich in nitrogen, facilitate the adherence. The amine functional groups (-NH 2) are one of the most important for cells and protein adhesion.

Nowadays, the modification can be carried out by physical or chemical methods. One of this methods is plasma surface modification [1,2], even though is the more common, the systems synthesized are partly soluble in water, besides the formation of a great amount of free radicals [3], which generate the incorporation of oxygen when is in contact with the air.To overcome this problem, the modified films were synthesized by gamma radiation in two step method. In this work, radiation grafting of acryloyl chloride onto polypropylene (PP) has been applied to insert carboxyl functionalities on PP; and then, the radiation grafted films were reacted with some diamines. Amine concentration was determined and after a period of time, the effect of aging on the amine functional groups was determined by derivatization with 4-trifluoromethyl benzaldehyde (TFAA), and subsequently characterized by XPS ( N/N/C ratios), ATR-FTIR and contact angle.

Acknowledgements The authors thanks to M. Cruz, and A. Ortega for technical support and DGAPA UNAM Grant IN200116 for financial support.

References [1] Bullett, N A., Bullett, D.P., Truica-Marasescu, F E., Lerouge, S., Mwale, F., Wertheimer, M R. (2004). Polymer surface micropattering by plasma and VUV-photochemical modification for controlled cell culture; Applied Surface Science 235 395-405. [2] Shard, A.G., Whittle, J D., Beck, A.J., Brookes, P N., Bullett, N.A., Talib, R.A., Mistry, A., Barton, D., Mc Arthur, L.(2004). Examination of unsaturation in plasma of allylamine and propylamine; J. Phys. Chem B; 108, 12472-12480. [3] Ruiz, J.C., Georges-Robillard A., Thérèsy Ch., Lerouge S., Wertheimer M. R. (2010) Fabrication and Characterization of amine roch organic thin films: focus in stability. Plasma Process. Poly 7. DOI 10.1002

142

P55. DEVELOPMENT OF THERMO-RESPONSIVE HYDROGELS MEMBRANES: N-ISOPROPYL ACRYLAMIDE AND N-VINYL CAPROLACTAM BY IONIZING RADIATION FOR BIOMEDICAL APPLICATION

López-Barriguete J.E. 1,* and Bucio E. 1

1 Departamento de Química de Radiaciones y Radioquímica, Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Circuito exterior, Ciudad Universitaria, Ciudad de México 04510, México * [email protected]

Four different systems of co-polymers hydrogels with diverse temperature responses has been prepared to elaborate membranes for biomedical application. The two thermo-responsive polymers are N-isopropyl acrylamide (NIPAAm) and N-vinyl caprolactam (NVCL), both have a low critical solution temperature (LCST) close to the human body temperature. The use of gamma radiation technique allows to testing different doses ranging from 25 to 150 kGy. The LCST of each system was measured by calorimetric process. Differential scanning calorimetry (DSC), technique allows to obtain the temperature critical point, which indicates the phase transition from hydrophilic stage to hydrophobic stage. Hence, were modified by adding a hydrophilic monomer to increase or displace the critical point. Acrylic acid (AAc), methacrylic acid (MAAc), dimethyl acrylamide (DMAAm) and hydroxyethyl methacrylate (HEMA) are the hydrophilic monomers. An essential point to design the composition of polymers is the monomers relation. The systems selected can be tuneable to use in diverse application like drug delivery, wound relief or biosensors. All the samples were characterized by Fourier Transform Infra Red spectroscopy (FTIR), DSC and X-Ray Diffraction (XRD). FTIR spectroscopy confirmed the cross-linking of the membranes. The temperature ranging correspond from 0 to 80 ºC by 1 ºC min -1 sampling, thus obtain the LCST. XDR technique will show us the amorphous structure by different radiation doses.

Figure 1. DSC thermograms of poly(NVCL-co-DMAAm) 50:50. LCST is indicated

Acknowledgements The authors thank to DGAPA-UNAM Grant IN200714 for supported.

143

P56. RADIATION RESISTANCE ASSESSMENT OF EPDM FORMULATION FOR ELECTRICAL INSULATION

Sandra R. Scagliusi 1,* , Elizabeth C. L. Cardoso 1, Traian Zaharescu 2, Ademar B. Lugão 1

1 Instituto de Pesquisas Energéticas e Nucleares, IPEN - CNEN/SP., Av. Professor Lineu Prestes 2242 05508-000 São Paulo, SP., Brazil 2 INCDIE ICPE CA, 313 Splaiul Unirii, Bucharest 030138, Romania * [email protected]

Polymeric materials applications for electrical insulation manufacturing are based in their favorable properties related to high stability [1]. The use of EPDM (terpolymer ethylene propylene diene monomer) elastomer in electrical insulation is fostered due to its excellent resistance to bad weather, ozone and chemical agents besides presenting good flexibility at room temperature as well as in low ones [2]. Gamma-radiation effect in EPDM rubber depends on various factors as: absorbed doses, doses rate, exposure environment, material chemical structures, among others [3, 4]. The present study is focused on the evaluation of radiation resistance of EPDM compounds used in electrical insulation. The assessment of radiation effects in these compounds was based in results obtained from Chemiluminiscence, DSC and FTIR essays, accomplished in non-irradiated and irradiated samples at 25, 50, 75, 100 and 200 kGy doses. Non-isothermal Chemiluminiscence spectra (Fig. 1) illustrates small variations existing between oxidation forces, suggesting the competition between crosslinking and degradation. Results obtained proved the effective EPDM structural resistance against radiations, pointing toward use of EPDM compounds in electrical applications.

Figure 1. Non-isothermal chemiluminescence spectra recorded on the EPDM based sample

References [1] M. Zanin (1992) Propriedades elétricas do elastômero EPDM para aplicação em isolação elétrica. Available: http://www.teses.usp.br/teses/disponiveis/54/54132/tde-16102014-173028/. [2] S. Okabe, N. Hayakawa, H. Murase, H. Hama, and H. Okubo (2006), Common insulating properties in insulating materials,” IEEE TDEI ,v. 13 , p. 327-335. [3] A. Rivaton, S. Cambon, J.L. Gardette (2006) Radiochemical ageing of ethylene–propylene–diene elastomers. Evaluation of some anti-oxidants. Polym. Degrad. Stab., v. 91 , p. 136-143. [4] T. Zaharescu, M. Marinescu, E. M. Lungulescu, S. R. Scagliusi, A. B. Lugão, (2015) Characterization of ethylene-propylene-diene terpolymer based electrical insulation, 9th International Symposium on Advanced Topics in Electrical Engineering (ATEE) , Bucharest, p. 476-479.

144

P57. POLYETHYLENE AS A BENCHMARK FOR ADVANCED FIRST PRINCIPLES CALCULATIONS OF OPTICAL PROPERTIES OF POLYMERS

Guido Roma 1,* , Davina Moodelly 1, Layla Martin-Samos 2, Fabien Bruneval 1

1 DEN-Service de Recherches de Métallurgie Physique, CEA, Université Paris-Saclay, F- 91191, Gif-sur-Yvette, France. 2 Materials Research Laboratory, University of Nova Gorica, SI-5000 Nova Gorica, Slovenia. * [email protected]

Radiation damage in polymers can be initiated by a variety of mechanisms, according to the type of projectile. When dealing with insulating polymers, electronic excitations play a crucial triggering role. We consider here polyethylene (PE) for two reasons: first, it is a reasonably simple insulating model polymer; second, it is an important component of many cable insulators employed in a nuclear environment. The formation and trapping of excitons in PE has been already discussed one decade ago [1] using Density Functional Theory. In the meanwhile, however, important progress has been made in methods that give a more accurate description of the electronic structure, like many body perturbation approach based on the GW approximation and the Bethe-Salpeter equation (BSE), accounting for excitonic effects, or Time Dependent Density Functional Theory (TDDFT). The latter was recently used as a powerful tool to interpret reflectivity measurements on ancient paper [2]. Here we use the GW-BSE approach to study the optical absorption spectrum of three model system: crystalline PE, an isolated –CH 2– infinite chain, and a few small alcane molecules. We use a plane wave formalism using Quantum-Espresso and the SaX code [3] for quasi-particule calculations. We discuss convergence issues and some structural effects, which can be strong on the quasi- particle band structure, but tend to reduce on the excitonic spectra. For some specific cases we make comparisons to TDDFT results and/or a localized basis set approach recently implemented [4]. We will also present some results concerning the optical signature of carbonyle and carboxyle defects in the PE chain.

References [1] D. Ceresoli et al., Trapping of excitons at chemical defects in polyethylene. J. Chem. Phys. 121 (2004), 6478-6484. [2] A. Mosca-Conte et al., Visual degradation in Leonardo da Vinci's iconic self-portrait: A nanoscale study. Appl. Phys. Lett. 104 (2014), 224101. [3] L. Martin-Samos and G. Bussi, SaX: An open source package for electronic-structure and optical- properties calculations in the GW approximation. Comp. Phys. Commun. 180 (2009), 1416-1425. [4] F. Bruneval, S. M. Hamed and J. B. Neaton, A systematic benchmark of the ab initio Bethe-Salpeter equation approach for low-lying optical excitations of small organic molecules. J. Chem. Phys. 142 (2015), 224101.

145

P58. CHARACTERIZATION OF RADIOLYTIC AGEING OF EVA/EPDM POLYMER BY ATR-FTIR SPECTROSCOPY AND PRINCIPAL COMPONENT ANALYSIS

A. Levet 1, J. Colombani 1,* , L. Duponchel 2

1 IRSN/PSN-RES/SEREX/L2EC, CEN Cadarache, BP3, 13115 St Paul lez Durance, France 2 LASIR CNRS UMR 8516, Université Lille 1, 59655 Villeneuve d’Ascq Cedex, France * [email protected]

The ageing of structure materials and components of Nuclear Power Plants (NPP) is a topic of interest particularly within the scope of extending the life time operation of the French NPP. The Instrumentation and Control (I&C) cables, situated in the reactor building and considered as difficult to be replaced, are key elements for nuclear safety: they have to support normal operation and accidental conditions. The electrical functionality of these I&C cables being strongly dependant on the ageing of their insulating materials, the study of radiolytic ageing of these polymeric materials is therefore of major concern from a nuclear safety point of view. The present study is dedicated to the characterization of radiolytic ageing of Halogen Free (HF) insulating materials of I&C cables. This material is mainly composed of two polymers: Ethylene Vinyl Acetate (EVA), Ethylene Propylene Diene Monomer (EPDM), and of a mineral filler: Alumina trihydrate (Al(OH) 3). The feasibility of using the ATR-FTIR spectroscopy coupled with Principal Component Analysis (PCA) is investigated for studying the effect of the dose (from 7 to 70 kGy) and of the dose rate (11 to 1000 Gy.h -1) on the accelerated ageing processes of the insulating material. PCA represents spectra as points located in a 2D-space; study of its results allows determination of characteristic bands which can’t be seen directly on spectra. Results of PCA show a space structuration according to the integrated dose. Figure 1 represents chart set by the first two components PC1 and PC2. Principal component 1 allows structuration according to the dose: high dose for negative scores and low dose for positive scores. Analyses of PC1 loading allow the identification of peaks explaining this structuration. Studies are underway to determine the chemical functions which correspond to these peaks. Then, it will be possible to connect the increase and decrease of the peaks with the degradation mechanisms of EVA and EPDM [1].

Figure 1. PCA scatter plot of FTIR spectra of insulating materials (color: dose (kGy))

References [1] Rivaton A., Cambon S., Gardette J.-L. Radiochemical ageing of EPDM elastomers. 3. Mechanism of radiooxidation. Nucl. Instr. And Meth. B 227 (2005), 357-368.

146

P59. EFFECT OF RADIATION ON MECHANICAL PROPERTIES OF FKM RUBBER BEFORE AND AFTER VULCANIZATION

Heloísa Augusto Zen 1,* , Ademar Benévolo Lugão 1

1 Instituto de Pesquisas Energéticas e Nucleares (IPEN-CNEN/SP), Brazil * [email protected]

In this work was studied the effect of radiation process on mechanical properties of FKM rubber, before and after vulcanization. The elastomer used was a fluorinated type, with 70% of fluor in its composition. The compound of fluoroelastomer (FKM) was based on Viton® by DuPont which is an elastomer that has low fuel permeation allowing be used as sealant and especially as o-ring product. The effect of radiation process in rubber can induce an increase in crosslinking density. The FKM was submitted to gamma radiation at 5, 10 and 20 kGy. The vulcanization was carried out at 195°C in a thermopress and thin films were obtained. The characterization techniques used were mechanical tests (stress – strain) to evaluated elongation and tension at break, rheometric properties to analyze maximum and minimum torques, and degree of swelling. By elongation at break was possible to observe an increase in crosslinking density when the vulcanization was carried out after the irradiation process, on the other hand the degradation process was verified when FKM was submitted to radiation process after the vulcanization.

147

P60. VULCANIZATION OF CIS-1,4-POLYBUTADIENE RUBBER (CPBR)/ NATURE RUBBER (NR) BY 60 CO GAMMA RADIATION

Wenzhao Wang 1,* , Yang Jiao 1,* , Yongjun Lu 1, Ancheng Ren 1, Jiangwei Liu 1, Xinmiao Zeng 1, Liancai Wang 1, Yanxia Zhang 1, Yueying Guo 1

1 Beijing Research Center for Radiation Application, Beijing Key Laboratory of Radiation Advanced Materials 1., China * [email protected]; * [email protected]

Abstract: In this study, the cPBR/NR blends with sulfur and the other additives were prepared using a two-roll mill. And then the cPBR/NR blends were vulcanized by 60 Co irradiation with different doses from 50 to 250 kGy. The γ-irradiated cPBR/NR blends were dealt with two different processes: without aging and with aging. And crosslink density of both un-aged and aged cPBR/NR blends was calculated. The results showed that the crosslink density of both of them increased with the radiation dose increase and there was new crosslinking reaction during the aging process from the data of the crosslink density of un-aged and aged ones. After then, physic- mechanical properties of the un-aged and aged ones were studied and the properties of mechanical were discussed in the following sections.

Results:

Qv Mc Sample Without aging With aging Without aging With aging 50 11.89 5.88 29146 8788 100 9.05 5.11 18307 6922 150 7.27 4.27 12618 5118 200 5.23 3.32 7206 3347 250 5.03 3.58 6747 3808 Table 1. Effects of radiation dose on the volume swelling and the molecular weight between crosslinks of cPBR/NR blends [1] .

Figure 1. Tensile strength of cPBR/NR systems with different radiation doses.

References [1] Tariq Y., Sara K., Muhammad S., Rohama, G. Radiation crosslinking of styrene-butadiene rubber containing waste tire rubber and polyfunctional monomers.Radiat.Phys. Chem. 106 (2015), 343-347.

148

P61. GRAFTING OF N-VINYLCAPROLACTAM AND 2- HYDROXYETHYL METHACRYLATE ONTO POLYPROPYLENE FILMS FOR BIOMEDICAL APLICATIONS

Geovanni González-Hernández 1,* and Emilio Bucio 1

The grafting of 2-hydroxyethyl methacrylate (HEMA) and N-vinylcaprolactam (NVCL) onto polypropylene films (PP), using γ-radiation was made at different conditions of dose, reaction temperature and monomer concentration, in order to study the optimum conditions. On the first grafting, only one of the monomers was used to study the kinetics of the polymerization depending on the variables already mentioned. Different grafting methods for NVCL were analyzed to choose the best technique and use it in all the future tests. Preirradiation oxidative method (POM): PP films were weighted, placed into glass ampoules and exposed to 60 Co γ- source in the presence of air at environmental temperature at different doses (10-70 kGy) in order to promote the formation of peroxides and hydroperoxides. Then, in the preirradiated ampoules, a solution of HEMA or NVCL was introduced at different concentrations (10- 50 vol. %, 8mL). If the solution was of HEMA, the ampoules were filled with argon to remove air and were sealed. In case of NVCL, the ampoules were degassed by a freeze-thaw process and sealed. Both types of ampoules were heated at different temperatures (45-70 °C) during 6 h in the case of HEMAS´s solution and 24h for NVCL´s ampoules. With the objective of removing the residual monomer and homopolymer that could be formed during the reaction, the films were soaked into acetone during 6 h and in ethanol during 18 h, and dried under vacuum over night. Direct irradiation method (DIM): PP films were weighted and collocated in glass ampoules with a solution of NVCL (20-60%, 8mL) in heptane. The ampoules were degassed by a freeze-thaw process, sealed and then irradiated at different doses (50-150 kGy). The grafted PP films were washed with acetone during 24 h and dried under vacuum over night. With the results of these proves, it was decided to make the grafting of both monomers by one and two steps method using preirradiation oxidative method. In the grafting by two step method, the grafting order was changed to analyze its effect in the chemical properties of the copolymer. The grafting was made with the same procedure described above. The grafting by one step method was made by directed irradiation method using a solution of HEMA/NVCL (50:50 vol. %) on toluene, and filled. The ampoule was irradiated at different doses (50-90 kGy). Chemical structure of PP before and after grafting will be characterized using infrared spectroscopy (FTIR-ATR), thermal analysis (DSC and TGA), contact angle and swelling.

References [1] Valencia-Mora, R.A., et al., Grafting of thermo-sensitive N-vinylcaprolactam onto silicone rubber through the direct method. Radiat. Phys. Chem. In Press (2015). [2] Morales-Wiemer, E.A., et al., Radiation grafting of N, N´-dimethylacrylamide and 2- hydroxythylmethacrylate onto polypropylene films by one step method. Radiat. Phys. Chem. 84, 166- 169 (2013).

Acknowledgements . The authors thank to DGAPA-UNAM Grant IN200714 for support.

149

P62. PREPARATION OF NANOGELS BY RADIATION-INDUCED CROSS-LINKING OF INTERPOLYMER COMPLEXES OF POLY(ACRYLIC ACID) WITH POLY(VINYL PYRROLIDONE) AND POLY(VINYL IMIDAZOLE) IN AQUEOUS MEDIUM AND THEIR CHARACTERIZATION

Mohammadreza Ghaffarlou 1,* , Olgun Güven 1

1 Hacettepe University, Department of Chemistry, 06800, Ankara, Turkey * [email protected]

Nanogels are nanosized hydrogel particles that combine the properties of both hydrogels and nanomaterials. Like hydrogels, they show high water content, tunable chemical and physical structures, good mechanical properties, and biocompatibility. The nanoscale mainly provides a large surface area for bioconjugation, long time of circulation in blood, and tunable size from nanometers to micrometers with the possibility of being actively or passively targeted to the desired site of action, e.g., tumor sites. The sum of these properties plus the presence of an interior network for the encapsulation of biomolecules makes nanogels ideal candidates for their application in nanomedicine [1]. The size and functionality of nanogels are two important properties to be controlled for specific drug deliver applications. Functionality can be introduced by chemical modification of alredy formed nanogels or by using polymers carrying specific functionalities [2].

In this study we followed a new approch to make nanogels multifunctional by using interpolymer complexes (IPC) as the precursors. Dilute aqueous solutions of poly(acrylic acid) PAA, poly(N-vinyl pyrrolidone) PVP, and poly(N-vinyl imidazole) PVIm of different molecular weights and concentrations were prepared and their interpolymer complexes were formed by mixing respective solutions. The coil size of the interpolymer complexes at different conditions (polymer molecular weight, concentration, mixing ratios, pH and temperature) were measured using Dynamic Light Scattering (DLS) technique. Once the coil sizes and stabilities have been established, solutions of interpolymer complexes were irradiated by gamma rays to form corresponding nanogels. The size of the nanogels were found to be smaller than the size of the precursor IPC coil sizes due to formation of intra-chain crosslinks. At relatively low doses of 5-15 kGy, IPC nanogels with 30-200 nm radia were obtained. Thus a facile and simple way of preparing multifunctional nanogels with double amphiphilic properties carrying polyacidic or polybasic structures has been developed.

References [1] Molina M., Asadian-Birjand M., Balach MJ., Bergueiro J., Miceliac E and Calderon M. Stimuli- responsive nanogel composites and their application in nanomedicine. Chem. Soc. Rev. 44 (2015) 6161-6186, [2] Kabanov AV., Vinogradov SV. Nanogels as pharmaceutical carriers: Finite networks of infinite capabilities Angew. Chem. Intern. Ed. 48 (2009), 5418–5429.

150

P63. EVALUATION OF MAGAT POLYMER GEL WITH CBCT

P. Sathiyaraj 1,* , E.J.J. Samuel 2

1 BKL Walawalkar Hospital, Department of Radiotherapy and Medical Physics Dervan, Maharashtra-India1. 2 VIT University-Photonics, Nuclear and Medical Physics division Vellore-India * [email protected]

Aim The possibility of the CBCT for evaluation of the Gel was reported but it is necessary to compare the results with standard CT for polymer gel dosimeter. The aim of this study is compare the linearity, temporal stability, sensitivity of post irradiation and relative dose measurement of MAGAT gel with CBCT and standard CT.

Material and Methods MAGAT gel was prepared by methacrylic acid (MAA), gelatin, Tetrakis hydroxyl phosphonium chloride (THPC) and water. MAA act as monomer, gelatin act as dose holder, THPC used for removing the oxygen from water. After preparation gel solution was kept at 4ºC for convert from liquid phase to gel phase. Using Linear accelerator (LINAC) gels were irradiated and kept in fridge for whole night to allow the complete polymerization. Next day it was read by CBCT and standard CT. CBCT is part of the LINAC and easy to access in the busy environment hospitals. Dose was extracted by knowing of the CT-Number and linearity, temporal stability, Post irradiation sensitivity & PDD analysis was performed.

Results All studied parameters from standard CT were comparable with CBCT. Figures-1&2 show the linearity and temporal stability of MAGAT and with CBCT and CT

Fig1- Linearity of MAGAT Fig2- Temporal stability of MAGAT

Conclusion Though the CBCT used as one of the gel readout tool, it is necessary to make sure the performance of the CBCT is comparable with standard CT. This study concludes that CBCT which is attached with LINAC have the capability to read the polymer gel and potentially we can use it in Radiotherapy application.

Reference [1] Da-Chuan Cheng, Mu-Bai Chung et all. MAGAT Gel Dosimetry Validation in RapidArcTM Treatment Using Cone-beam CT, Journal of Medical and Biological Engineering, 2012-33(5): 486- 490

151

P64. RADIATION-INDUCED CROSSLINKING OF POLYAMIDE11 IN PRESENCE OF TRIALLYL ISOCYANULATE

Takanori Tago 1,2 , Naotsugu Nagasawa 2, Hisaaki Kudo 1,* , Mitsumasa Taguchi 2

1 Graduate School of Engineering, the University of Tokyo, Japan 2 National Institutes for Quantum and Radiological Science and Technology, Japan * [email protected]

Recently, biomass-derived plastics (bioplastics) are expanded as environment-friendly materials for a sustainable society. Poly (L-lactic acid) (PLA) derived from corn starch is a hard and transparent bioplastic and now widespread with a potential to replace the conventional petroleum-derived plastics. However, the PLA has the less thermal stability above around 60 °C and impact resistance at room temperature than the conventional plastics. It has already reported that PLA is one of radiation-degradable polymers but crosslinked by irradiating with crosslinking agent to improve the thermal property. Applications, however, are limited, because the impact resistance is nearly un-improved. In this study, to improve the above-mentioned two properties of PLA, we investigated a combination method of blending of PLA with polyamide11 (PA11) having high impact resistance, which is produced from castor oil, and then crosslinking with crosslinking agent by irradiation. As the crosslinker, triallyl iso-cyanurate (abbreviated as TAIC) was selected [1].

Films of 0.5 mm in thickness, of PLA/PA11 blends with TAIC 3.0 phr (parts per hundred resin) were prepared by using a mixer at 210 °C for 10 min and hot-pressing at 210 °C for 5 min. The cross-linking structures were formed by irradiation of 2 MeV electron beam in the degassed atmosphere to 5 - 100 kGy. The gel contents was determined by weighing insoluble parts of the cross-linked films after immersion in mixed solvent of chloroform and formic acid for 48 h at room temperature.

The gel contents of the PLA/PA11 blends increased with absorbed dose and increase of the mixed ratio of PA11, and the gel fraction showed about 80 % at the dose of 100 kGy. The blends with high gel contents (higher than 80 %) demonstrated very little deformation above the melting temperature (around 185 °C) of PA11 by the thermo- mechanical analysis. The impact value of the cross-linked PLA/PA11 (50/50 wt%) blends irradiated to 100 kGy indicated 4.9 kJ/m 2 by the Charpy impact test. It showed the higher impact resistance by about 2.5 times than the original PLA. Therefore, the applications of bio-plastics will be expanded by the combination method of blending and radiation-induced cross-linking.

References [1] Naotsugu Nagasawa, Ayako Kaneda, Shinichi Kanazawa, Toshiaki Yagi, Hiroshi Mitomo, Fumio Yoshii, Masao Tamada, “Application of poly(lactic acid) modified by radiation crosslinking”, Nucl. Instrum. Methods Phys. Res., Sect. B, 236 (2005), 611-616.

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P65. HOW MUCH IONIZING RADIATION MAY INDUCE NEGATIVE EFFECTS ON RESISTENCE PROPERTIES OF DOUBLE PACKAGING FOR MEDICAL PRODUCTS PROTECTION?

Karina Meschini B. G. Porto 1,2 , Sueli Ivone Borrely 1,*

1 Instituto de Pesquisas Energéticas e Nucleares (IPEN / CNEN – SP), Av. Professor Lineu Prestes 2242, 05508-000 São Paulo, SP, Brazil 2 Instituto de Pesquisas Tecnológicas do Estado de São Paulo (IPT – SP), Av. Professor Almeida Prado, 532, 05508-901 São Paulo, SP, Brazil * [email protected]

The integrity of materials containing packaging (natural or synthetic polymers) is essential to keep the asseptic condition of commercialized products (health care products, food and pharmaceuticals). The objective of this paper was to study gamma radiation effects (25 kGy, 40 kGy and 50 kGy) on the main physical properties of surgical grade paper and multilayer films (polyester + polyethylene and polyester + polypropylene). Surgical grade paper and multilayer films are components of packaging system for radiation sterilization containing medical equipment or products. From the results we may point out that paper was more radiation sensitive samples among the studied materials and radiation effects were more pronounced for brightness, pH, tearing resistance, bursting and tensile strength. The porosity of paper was enhanced at 50 kGy. On the other hand tensile strength was the more pronounced effect for plastic films on the studied conditions. Regarding double packagings, the sealing resistance decreased with increasing dose. ABNT NBR 14990 (Brazilian standard methods) was applied for determination of studied parameters to confirm requirements for radiation sterilization suitable conditions.

153

P66. IRRADIATION INFLUENCE ON THE PROPERTIES OF HMS- POLYPROPYLENE CLAY/AGNPS COMPOUND MASTERBATCHES

W. L. Oliani 1,* , D. F. Parra 1, L. G. H. Komatsu 1, V. K. Rangari 2, N. Lincopan 3,4 and A. B. Lugão 1

1 Nuclear and Energy Research Institute, IPEN-CNEN/SP, Av. Prof. Lineu Prestes, 2242, Cidade Universitária, CEP 05508-000, São Paulo – SP, Brazil 2 Center for Advanced Materials Science and Engineering Tuskegee University, AL 36088, USA 3 Department of Microbiology, Institute of Biomedical Sciences, University of Sao Paulo, CEP 05508-000, São Paulo, Brazil 4 Department of Clinical Analysis, School of Pharmacy, University of Sao Paulo, Brazil, São Paulo, Brazil * [email protected]

HMS-Polypropylene-clay-silver nanocomposites were manufactured using twin-screw extruders. Processing conditions, namely screw speed and feed rate, are known to strongly influence the final dispersion levels attained. The polypropylene modified by gamma irradiation in acetylene at 12.5 kGy dose, also known as high-melt-strength-polypropylene (HMSPP), was mixed with montmorillonite (MMT) clay and silver nanoparticles (AgNPs) [1]. Those materials were prepared by a melt mixing masterbatch process via twin screw extrusion with a wide range of processing conditions [2]. The masterbatch were irradiated in inert atmosphere at 1.0; 3.0; 5.0; 10.0, 50.0 kGy dose and evaluated by Differential Scanning Calorimetry (DSC), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDX) and determination of antibacterial activity. The results indicate the formation of microstructures predominantly exfoliated of HMSPP nanocomposite. Further, the antibacterial properties of the hybrid polymer were investigated against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) bacteria.

Acknowledgement The authors acknowledge financial support for this work from CAPES-Process: CSF-PVE’s - 88887.115684/2016-00, CCTM/IPEN, for microscopy analysis (SEM) and multipurpose gamma irradiation facility at the CTR/IPEN.

References [1] I. O. Berenguer, W. L. Oliani , D. F. Parra, L. G. H. Komatsu, V. J. Santos, N. Lincopan, A. B. Lugao and V. K. Rangari. Fabrication of gamma-irradiated polypropylene and AgNPs nanocomposite films and their antimicrobial activity. TMS 2016– Annual Meeting Supplemental Proceedings . John Wiley & Sons, Inc., Hoboken, New Jersey-EUA, p.143-150, 2016. DOI:10.1002/9781119274896.ch18. [2] W. L. Oliani, D. F. Parra, L. F. C. P. Lima, N. Lincopan, A. B. Lugao. Development of a nanocomposite of polypropylene with biocide action from silver nanoparticles. J. Appl. Polym. Sci. , 42218(7), 2015. DOI: 10.1002/APP-42218.

154

P67. RADICAL PROCESSES INDUCED IN COLLAGEN BY RADIATION STERILIZATION

Gra żyna Przybytniak 1,* , Ewa Kornacka 1, Jarosław Sadło 1, Zbigniew Zimek 1

1 Institute of Nuclear Chemistry and Technology, Dorodna 16, 03-195 Warsaw, Poland * [email protected]

Skin allographs are valuable biomaterial which might be used as a wound dressing in the case of skin burns, trophic ulcers or tumors. Cell-free allographs preserve native porous architecture and retain the original chemical structure of the collagen matrix. In order to apply the material for biomedical purposes, sterilization is necessary as a preliminary treatment prior to further cell culture. It is generally accepted that exposure to ionizing radiation is the most certain and reliable process to eliminate pathogens in this type of materials. However, some reports in literature suggest that radiation sterilization of the collagen based materials results in their degradation followed by the deterioration of mechanical properties, increase in susceptibility to enzymatic digestion and to dissolving in neutral and acidic media. Therefore, the optimal value of dose absorbed has to be a compromise between the dose high enough to guarantee destruction of all pathogens and the dose sufficiently low to maintain acceptable biological and mechanical properties.

The adverse macroscopic consequences arisen from generated radicals result from the modification of collagen structure as well as from the development of oxidative degradation. Similar processes are created under native conditions in skin via metabolic pathways and as a result of external factors, i.e. exposure to ultraviolet radiation.

Investigation of radicals that are generated by ionizing radiation during radiation sterilization was performed by Electron Paramagnetic Resonance (EPR) spectroscopy. Collagen has a specific sequence of aminoacid residues in the chains predominantly consisting of glycine (Gly) as every third mer in repeated sequence Gly-X-Y whereas proline (Pr) and hydroxyproline (PrOH) are aminoacids representing, with high probability, X and Y, respectively. The structure of collagen fibrils is stabilized by hydrogen bonds between amino and carbonyl groups.

The EPR spectra of collagen from calf skin (Sigma-Aldrich) were analysed and compared with the signals of the most abundant residues, Gly, Pr and PrOH. Irradiation and measurements were performed under cryogenic conditions in order to stabilize primary species and to observe their conversion into the secondary radicals. Interpretation of collagen spectra recorded at various temperatures and at different microwave powers based on the results collected for aminoacid monomers making up the peptide chain. The studies were conducted in air atmosphere in order to reproduce conditions usually prevailing at the time of radiation sterilization. The oxidative degradation of collagen was estimated.

Acknowledgement The work was performed in the frame of The National Centre for Research and Development Project No. 269807, Poland, STRATEGMED2/269807/14/NCBR/2015, acronym: BIOOPA.

155

P68. COMPARATIVE STUDY OF THE POLYPROPYLENE IRRADIATED VERSUS POLYPROPYLENE WITH PRO- DEGRADANT ADDITIVE EXPOSED TO THE NATURAL AGING

Rebeca S. Grecco Romano 1,* , Washington Luiz Oliani 1, Duclerc Fernandes Parra 1, Ademar Benevolo Lugão 1

1 Nuclear and Energy Research Institute, IPEN-CNEN/SP, Av. Prof. Lineu Prestes, 2242 – Cidade Universitária – CEP 05508-000, São Paulo – SP – Brazil * [email protected]

Polypropylene (PP) is used for numerous applications in different sectors of industry due to its very good physical, chemical properties and its very low price. Consequently its use results in large amounts of waste discarded at the landfills causing serious environmental impacts. Structural changes in PP molecule are created upon exposure to ionizing radiation such as: main chain scission, crosslinking, peroxidation (in presence of air). Controlled degradation of PP can be active by exposing the polymers to well-defined parameters, such as radiation dose, antioxidants, oxygen etc. [1,2]. The aim of this study is to compare two methods of accelerated degradation: gamma irradiation of PP 20 kGy and the incorporation of commercial prodegradantd2w® (1wt.%) in PP. Dumbbell samples were manufactured by injection molding and exposed to the environment during 90 days. The samples were characterized by, Optical Microscopy (OM), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC) and Mechanical Testing. The samples PP 20 kGy, after environmental aging, showed oxidation with presence of surface cracks more intensely than the PP d2w®, presence of carbonyl groups, and a decrease of melting temperature indicating degradation.

Acknowledgement Project CAPES for supported the Project Electronuclear 012/2013, Centre of Science and Technology of Materials.

References [1 ] R.G. Romano, W. L. Oliani , D. F. Parra, A.B. Lugao. Evaluation of environmental aging of polypropylene irradiated versus pristine.TMS - Characterization of Minerals, Metals, and Materials. John Wiley & Sons, Inc., Hoboken, New Jersey-EUA, (2016) p.729-736. [2] K. Makuuchi, S. Cheng. Radiation Processing of Polymer Materials and its Industrial Applications. John Wiley & Sons, Inc., New Jersey-EUA, (2012) p.216.

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Index

A F. Bruneval P57. O34. , P53. , P55. S.S. Abramchuk O51. , O11. E. Bucio A. Abramowska O36. , P15. P61. E. Achilli O39. M. Buczkowski O36. A. Adamus O40. , P29. H.L. Bui O57. M. Adel-Hadadi O17. K.-D. Bures O5. V. Aguié-Béghin O20. , P4. G. Burillo O12. , P54. M. Akbulut Söylemez P24. , P50. , P51. A. Buttafava P30. P. Akka ş Kavaklı P20. C T.S. Alkhuraiji P42. M. Cabalka O45. O31. , O17. L.M.P. Campos O60. M. Al-Sheikhly O61. M.L. Carbajal P39. M. Allen O27. E.C.L. Cardoso P16. , P25. , P56. C. Alvarez-Lorenzo O34. E. Carretier O50. L.C. Alves O19. M. Carrillo-Solano O10. A.A. Alwatban P42. M.H. Casimiro O19. , P41. C.A. Amorim P10. O. Cavani O16. J.-C. An O31. M. Celina O42. J. Apango P43. I. Chala O26. , O59. M.F. Araújo O19. A. Chapon P48. C. Aymes-Chodur O7. E. Chatzigiannakis P3. B K. Cie śla O36. , P15. E. Balanzat O2. M.-C. Clochard O16. M. Banda O46. X. Colin O48. M. Bardet O24. J. Colombani O43. , P58. A. Barkatt O17. N. Combernoux O50. J.A.G. Barros O41. A. Concheiro O34. M. Barsbay O21. , P20. , P50. G. Consolati O58. O20. , O22. F.B. Bateman O17. X. Coqueret A.S.M. Batista P7. , P44. O64. , P4. J. Beckmann P3. M. Cornaton O53. , P17. Z. Beksultanov P12. L.T. Cumberland O17. A. Berquand O22. R. Czechowska-Biskup P31. , P34. M. Berveiller P14. D M. Bielmann O28. G. D’Agostino P30. L.C. Boaro O60. S. Dagras O6. , P2. J. Boguski P15. G.V. Danielyan O11. B. Boizot O16. A. Dannoux-Papin O55. S.I. Borrely P65. E. Dantras O6. , P2. J. Borsa O35. , P32. V. Dauvois O53. , P17. A.W. Bosman O40. M.V. de S. Seixas P23. F. Bot-Robin O43. L. de Souza Gonçalves P5. S. Bouffard O1. N. del Mastro O31. , P21. I. Boughattas O55. S. Demir P37. U. Braun P3. J. Deveaux P1. E.M. Bringa P28. T. Dietz O17. 157

O37. , O31. O49. , O30. , C. Dispenza O33. O21. , P20. P24. , O. Güven L.A. Ditta O37. P35. , P50. P51. , D. Doizi O7. P62. D. Dondi P30. H J.G. dos Santos Batista O41. B. Han P42. J. Drewnik O36. , P15. H. Hartmann O27. M.S. Driscoll O61. Y. Hénon O63. L. Duponchel P58. T. Hinata P47. D. Durand O53. , P17. A. Horio P49. E Y. Hosaka O54. S. Esnouf O7. , O53. , P17. I F G.S. Irmukhametova P11. , P12. A.N. Falcão O19. L. Islas O12. L.O. Faria P7. , P44. , P45. M. Ito O47. B. Fayolle O48. J T. Fekete O35. , P32. K. Jadwiszczak O20. V. Feldman O3. , O11. M. Jaunich P3. L.M. Ferreira O19. , P41. J.P. Jeun O13. W.P. Ferro P10. Y. Jiao P60. M. Ferry O7. , O53. , P17. C. Johnson P36. C.Y. Flores O39. M. Jonsson O37. C.C.P. Fontainha P45. V. Juvino dos Santos P13. E. Fromentin O7. K C.A. Furtado P44. O5. , P8. , P26. S. Kadłubowski K. Furtak-Wrona O20. P33. G C.M. Kang P42. E. Garcia-Caurel O16. P.H. Kang O13. L. Genovese O58. W.-G. Kang P42. M. Ghaffarlou P62. D. Kaldybekov P11. G. Giannini Artioli P5. L.R. Karam O25. K. Gillen O42. K.V. Katti O41. M. Giola O58. C. Kavaklı P20. G. Glowa O57. H.B. Kim O15. S.R. Gomes P41. Y. Kino O9. G. González-Hernández P61. D.I. Klimov O51. R. Gonzalez P47. P.H. Knag O15. D. Gorse O16. P. Komorowski P34. G. Gotzmann O57. T. Kondoh O54. M. Grasselli O39. O38. , P39. L.G.H. Komatsu P6. , P66. R.S. Grecco Romano P68. A. Kömmling P3. N. Grimald O31. M.J. Konstantinovi ć P1. V. Griseri O46. E. Kornacka P67. B. Guo P40. I. Korolkov P35. Y. Guo P60. T. Kosaka O47. A. Gusarov P1. C. Kowandy O22. L.I. Gutierres O8. , P28. P. Kozik-Ostrowka O20. M. Krzeminski O22.

158

H. Kudo O44. , P27. , P64. M.B. Mathor P5. B. Kurek P4. M. Matusiak P33. L R. Maurin P14. V. Labed O50. , O55. B. McEvoy P36. F. Lainetti P22. G. Melilli O16. D. Lairez O16. T. Mes O40. J.J.H. Lancastre O19. W. Meyer O57. J.-F. Larche O43. H. Michel O27. , P36. C. Laurent O46. G. Mizerova O44. J.A. LaVerne O52. , O61. S.F. Mohamad P4. V.M. Lazurik P52. M. Molinari O22. V.T. Lazurik P52. D. Moodelly P57. S. Lazzaroni P30. J. Morais O8. S. Le Roy O46. P. Moulin O50. P22. , P23. , P24. D. Lebeau O7. , O53. , P17. E.A.B. Moura S. Legand O7. , O53. , P17. P25. A. Levet P58. J.L. Moura P10. S. Lewandowski O6. , P2. W. Mozalewska O40. , P31. B. Li P40. S. Muller P28. J. Li P38. G.A. Mun P11. , P12. Y.M. Lim O13. A. Munari O58. N.W. Lima P28. N N. Lincopan P66. N. Nagasawa P47. , P64. G.M. Liosi P30. J.P. Nascimento P44. J. Liu P60. M. Negrin O58. Y. Liu P40. A.T.B. Neto P45. C. Longuet O59. Y. Ngono-Ravache O55. , P17. J.E. López-Barriguete P55. Y.C. Nho O13. F. López-Saucedo P53. G. Nishio O47. N. Lotti O58. F. Nizeyimana O53. P. Louette O8. O F.R. Lourenço P25. S.-H. Oh O15. Y. Lu P60. T. Oka O9. O32. , O41. O. Okamba-Diogo O53. O60. , P5. , P6. A.B. Lugão K. Okaya P27. P13. , P16. , P56. A.K. Olejnik O40. , P31. P59. , P66. , P68. W.L. Oliani P6. , P66. , P68. K. Luzniak P8. R.R. Oliveira P22. M K. Onodera O9. H.-L. Ma P38. A. Ortega O12. , P43. E. Macerata O58. A.V. Ortiz P24. , P25. Y. Maekawa O14. A. Oshima O54. , P47. J.-E. Maigret O20. B. Otazaghine O26. , O59. R. Marconi P30. T. Ovalıo ğlu O21. F.M.A. Margaça O19. P M. Mariani O58. , P30. R.M. Papaléo O8. , O56. , P28. L. Martin-Samos P57. J.S. Park O13. A. Mashentseva P35.

159

O60. , P6. , P13. S. Rouif O26. , O59. D.F. Parra P66. , P68. J.L. Roujou O53. , P17. T. Paulmier O6. , P2. J.-C. Ruiz P19. J. Paulo Leal P41. S D. Payan O6. , P2. M.A. Sabatino O37. I. Pazos O31. , O17. S. Sabharwal O62. A. Peinado O16. J. Sadło P67. J. Peng P38. S. Saiki O23. , P27. C.C. Pereira P9. Y. Saito O54. E.L.M. Pereira P7. T. Sakurai P49. J.V. Pereira P44. M.C. Salvadori P9. M.P. Pérez-Calixto P54. C. Salvan O24. J.J. Pielawski O7. E.J.J. Samuel P63. V.H. Pino-Ramos O34. J.G. Santana P24. J. J. Pireaux O8. E.I. Santiago P9. V. Pla ček O44. , O45. L.K.G. Santo O60. G. Popov P52. A.P. Santos P7. J. Portillo Casado O57. J.A. Santos P23. K.M.B.G. Porto P65. T. Šarac P1. D. Poster O31. , O17. P. Sathiyaraj P63. G.F. Prozorova O11. P. Sawicki P26. , P34. G. Przybytniak O18. , P67. S.R. Scagliusi P16. , P56. Q U. Schade P3. F. Quasso O58. L. Schrive O50. N. Quiévy P1. B. Segura-Bailon P19. R S. Seki P49. R. Rakhmetullayeva P12. T. Sekine O9. J.M. Ramillon P17. N. Seko O23. , P27. M. Ramos Gallego O40. D. Severin O8. P23. , P24. , P25. J.H. Shin O13. V.K. Rangari P66. A. Sidi O43. G. Ranoux O22. L.G.A. Silva P9. , P10. F.A.S. Ribeiro P7. M. Soccio O58. A. Rivaton O43. Y. Soeta O54. P. Reiller O7. J.Y. Sohn O13. P.R.S. Reis P25. D. Şolpan P37. A. Ren P60. R. Sonnier O26. , O59. E. Richaud O48. A. Spende O10. A.P. Rodrigues O19. I.E. Suleimenov P12. G. Rodrigues P41. S.D. Sütekin O49. R.C.L.B. Rodrigues P22. K. Szafulera P18. A. Roggero O6. , P2. T Fh. Rögner O57. T. Tago P64. B. Rokita O5. , P8. , P34. M. Taguchi P64. G. Roma P57. E. Takács O35. , P32. O5. , O29. , O40. P.Y. Takinami O31. , P21. J.M. Rosiak P8. , P18. , P29. T. Tapia-Esquivel P19. P31. , P34. G. Tataru O20.

160

B.S. Teixeira P21. M. Walo O18. G. Teyssèdre O46. C. Wang O54. R. Thomaz O8. , P28. L. Wang P38. , P40. , P60. S. Tilki P20. W. Wang P60. D. Tinoco O12. M. Washio O54. , P47. M.E. Toimil-Molares O10. J.M. Wasikiewicz P46. A.K. Tokhtabayeva P11. Y. Watanabe O47. C. Tonon O6. , P2. A.R. Whittington O38. G. Torchio P39. H. Wiebeck P23. M. Torun P37. L. Wojnárovits O35. , P32. K. Tran O24. D. Wolff P3. C. Trautmann O8. , O10. Y. Wyart O50. Z. Tsinas O17. Y U Y. Yamahara P47. O5. , O29. , P8. M. Yang O51. P. Ula ński P18. , P26. , P29. B. Yermukhambetova P11. , P12. P33. , P34. Y. Yoshida O4. , O54. N. Ulrich O10. H. Yu P40. V V.K. Yu P11. F. Valenzuela-Díaz P23. , P24. J.-M. Yun O15. K. von der Ehe P3. Z J. Vange O40. A.T. Zafalon P13. G.H.C. Varca O41. , P5. T. Zaharescu O60. , P56. S.C. Verde O19. H. Zeidler O57. J. Verdu O48. H.A. Zen P59. A. Viretto O59. X. Zeng P38. , P40. , P64. W. Vreeland O31. A.A. Zezin O51. , O11. W E.A. Zezina O51. , O11. O40. , P18. , P29. M. Zhai P38. R.A. Wach P31. Y. Zhang P38. , P66. V. Wachtendorf P3. Z. Zimek P52. , P67.

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