Extrusion Processing for Manufacture of Low-Density, Fine-Celled Polypropylene Foams ~aniE. Naguib A thesis submittd in conformity with the requirements for the Degree of Doctor of Philosophy Department of Mechanical and lndustrial Engineering university OF Toronto @Copyrightby B. E. Naguib 2001 National Library Bibliothèque nationale 1*1 .,,da du Canada Acquisitions and Acquisitions et Bibliographie Services senrices bibliographiques 395 WeU'iglon Street 395. nie Wellington Ollawa ON K1A ON4 ûttawa ON K1A ON4 Canada Canada The author has granted a non- L'auteur a accordé une licence non exclusive licence allowing the exclusive permettant à la National Library of Canada to Bibliothèque nationale du Canada de reproduce, loan, distribute or seii reproduire, prêter, distribuer ou copies of this thesis in microfom, vendre des copies de cette thèse sous paper or elecironic formats. la forme de microfiche/f'ilm, de reproduction sur papier ou sur format électronique. The author retains ownership of the L'auteur conserve ta propriété du copyright in this thesis. Neither the droit d'auteur qui protège cette thèse. thesis nor substantiai extracts fiom it Ni la thèse ni des exûaits substantiels may be printed or otherwise de celle-ci ne doivent être imprimes reproduced without the author's ou autrement reproduits sans son pemksion. autorisation. Extrusion Processing for Manufacture of Low-Density, Fine-Celled Polypropylene Foam Hani E. Naguib Degree of DacCor of Philosophy, 2001 Department of Mechanical and Industrial Engineering University of Toronto A continuous extrusion process for the manufacture of low-density, fine-celled poiypropylene foams is presented. Due to its outstanding Functiond characteristics and low materiai cost, polypropylene foarns have been considered as a substitute for other thennoplastic foams in industriai appIications. However, only limited research has been conducted on the production of polypropylene foarns because of the weak melt strength, and no research has been conducted to investigate the mechanisms that govern the expandabiiity of poIypropylene foams. This thesis presents the effective scrategies for increasing the volume expansion ratio as welI as the mechanisms goveming the foam density of polypropylene foams. The basic strategies taken in this study for the promotion of a large volume expansion ratio of polypropylene foams are: (a) to use a branched materiai For preventing ceIl coalescence; (b) to use a long-chah blowing agent with low diffusivity; (c) to lower the melt temperature for decreasing gas Ioss during expansion; and (d) to optirnize the processing conditions in the die for avoiding premature crysrdlization. The effects of processing and materiais parameters on the foam morphoiogies of poIypropyIene materiais were thoroughly studied using a single-screw tandem foam extrusion system. A careFuI analysis of extended experimentd resuIts obtained at various processing conditions indicates that the final votume expansion ratio of the extruded polypropylene foams blown with butane is governed either by Ioss of blowing agent or by crystdlization of the polyrner matrix. By tailoring the processing conditions in the die, ultra low-density, fine-celied polypropylene foarns with very high expansion ratio up to 90-fold were successfuIly produced from the branched poiypropyiene resins. Fundamental snidies have also been conducted to investisate the effect of various processing and materials parameters on the thermodynamic, thermal and meit fracture behaviors of polypropyIene melts with foaming additives that influence the ceIl morphology of poiypropylene foams. ln memory of my Aunt Aida, who passed away during my Ph.0. program. 1 know you still hear me and pray for me. 1 thank you for al1 the pars you took care of me, for your love, support and encouragement. 1 could not make it without you. You will aiways be in my heart and my thoughts In memory of my Mother who was and still is my inspiration in my life 70 my great Father to whom 1 owe al1 that 1 am and al1 that 1 am going to ber and al1 that 1 can ever hope to be Acknowledgments 1 would like to start by giving thanks to the beneficent and mercifuI God, my Lord and Savior Jesus Christ, for he has covered me, supported me, preserved me, accepted me ont0 him, had compassion on me, sustained me, and brought me to this hour. 1 would like to express my sincere gratitude to my supervisor Professor Chu1 B. Park for providing guidance and encouragement throughout my iesearch. I will never forget the support he gave at my most difficult times. 1 would Iike also to thank my Ph. D. thesis committee: Prof. Steve Bdke from Department of Chemical Engineering, Prof Shaker Meguid, Prof Beno Benhabib €rom the department of Mechanical and Industrial Engineering. Special thanks to Prof. O. A, Aziz, Prof. M. Al Gammal, Prof. A. AbdeI Messih and Mr. Albert Mickail for their guidance throughout my career and the time and effort spent. My gratitude is extended to the Department of Mechanical and Industnal Engineering at the University of Toronto for providing the University of Toronto Open Fellowships, the Ontario Graduate Scholarship, as well as, the NSERC Postdoctoral fellowship. Also, i would like to thank Boredis AG. Company, in Austria for their funding and support in this project. I would also like to thank my colleagues in the Microcellular Plastics Manuhcturing Laboratory for their help and Friendship over the pst four years. They include Simon Park, Dmitry Ladin, Dr. Valentina Padareva, Anthony Yeung, Amir Behravesh, Ghaus Rizvi, Esther Richards, Patrick Lee, Linda Lin, Remon Pop-iiiev, Deepak Fernandes, Dr. Chris Song, Dr. Sang Mae Lee, Dr. Yuejian Liu, Minhee Lee, Xiang Xu, Donglei KU, Wanlin Chen, Chris Ozolins, Anjan, Xioyang Guan, Rehan Khan, Gumjan Guo, and Haiou Zhang. Especially, sincere gratitude poes to Simon and Dmitry who shared common thoughts. 1 would like to thank al1 the undergraduate students that worked with me Erin Youn, Young fi, David Allas, Suzan Oh, Won Park, Carri Li, Joyce Lam, Fames Koo, Brandon Lee, Michael Lee, Ibrahim Abu Eisha, and others. Also, 1 wish to acknowledge the professiond technical support from Mike Smith, Len Rooseman, Jeff Sansome and Dave Eisdaile in the Machine TooI Laboratory, from Wendy and Amanda in the generai office, from Mary Rose, Teresa, Dan and Sheila in the purchasing department, and from Oscar in the computer support. A special thanks to Esther Richards for proof reading my thesis and for Dimtry Ladin, Mohammed Attia, DongIei Xu, Linda Lin, Ghaus Rizvi, Xiang Xu, WanIin chen and Lianne Ing for the time they spent for helping me at the final stage of the thesis. iv 1 would like to thank my family al1 over the world; from Egypt: 1 would like to thank my wife for her continuous efforts to provide me with her love and support, my great father, my beloved brother Rami, his wife Mary and Daniel, to my beloved cousins: Sarni, Nagi and their families, Shadi, and to a11 my aunts and uncles especidly Aunt Mary, Uncle Soria] and Uncle Atef for their continuous support and encouragement. My family in Canada: my God father Uncle Esmat, to my beloved cousins: Tarek, Kim, Mark, Magdy, Samer, Rosemary, Chris and Sally. A special thanks to my parents in Canada Uncle Said and Aunt Mona for their continuous care and love. My family in the States: my God mother Nadia for her continuous love and support, my uncles and riunts: Osiris, Nela, Menes, Madelaine, Kamilia, and my cousins: Mona. Marc, Sergio, Franco, and their families, Gehan and James. 1 would like to thank father Reuiss, father Georgeos, father Makari from St. Georges Church in Toronto, father Amonios and father Messaeil form St. Mark church in Toronto. A special thanks to the youth group in my church, who supported me with their prayers and provide me with more love to rny Lord Jesus Christ. 1 also would like to thank many friends ihab and Lydia, Essam and Marianne, Adel and Sally, Bassem and Dalia, Sameh and Gehan, Roger and Mira, Jules and Mary, Joseph Armanios, Talaat and Mona, Nagui and Dalia, Dimitry Saad, and Alfred Mobayad. Finally, 1 would like to praise my Lord with David the prophet and king by saying II O LORD. yorr have searched me and you knoiv me. YOUknoiv ivhen C sir and ivhen I rise; You perceive my rfroirgl~tsfrom afar. Yori discent my going otrr and my king down: Yoir are faniriliur ivith al1 niy ivays. Before a word 13 on Iny tongrle You know ir cumplrrely. O LORD. Yori hem me in--bellinriund before: Yori have laid yoiir hand iipon me. Such knoivledge is too wondefil fur me. tao loftyfor me to airain. Where can I go fiom pur Spirit? Wliere can Iflreji-om yuurpresence? IfIp up to the heavens. You are there; iff make tny bed in the depths You are there. IfI rise on the wings of the daivn, iflsettle on rhe fur side of the sea, even tlrere your hand ivill giride me. your nghr hand will hold me fast. IfI say, "Siirely the darkness will hide me and the light become nighr urotitrd me," even the darkness will nor br dark ro Yoti; the nigfrt will shine like the duy, for darkness is as tighr to You. For You creared my inmost being: You knit me togerher in my mother's womb. I praire You because I am fearfitlly and ivonderfulfymade; Your ivorks are rvonderfuf. I knorv rharfiill ivefi. My frame ivas not hiddenfrorn Yori when 1 was made in the secret place. When I ivas ivoven together in the depths of the earrh. Your qves saw my rinformed body. Al1 the duys ordainecifor me iuere wiftenin Your book before one of rhem came to be. Hoiv precioiw to me are Your rhorighrs, O God! Hoiv vast fs the strm of them! Were 1 to cortnr them.