DOCSLIB.ORG

Expandable Thermoplastic Polymer Beads and Process for Their Production

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Expandable Thermoplastic Polymer Beads and Process for Their Production Europaisches Patentamt O 017 086 0») European Patent Office (1Î) Publication number: Office européen des brevets Bl (12 EUROPEAN PATENT SPECIFICATION (45) Date of publication of patent spécification: 24.08.83 ® Int. ci.3: C08J 9/20, B32B 27/08, B32 B 27/30, B 32 B 27/32 @ Application number: 80101440.8 (22) Date offiling: 19.03.80 (54) Expandable thermoplastic polymer beads and process for their production. (§) Priority: 19.03.79 JP 32680/79 (73) Proprietor: KANEGAFUCHI KAGAKU KOGYO KABUSHIKI KAISHA 2-4 Nakanoshima 3-chome @ Date of publication of application: Kita-ku Osaka-shi (JP) 15.10.80 Bulletin 80/21 @ Inventor: Senda, Kenichi (45) Publication of the grant of the patent: 17-8095, 1-Ban, Miyanoue 24.08.83 Bulletin 83/34 Akashi-shi Hyogo-ken (JP) Inventor: Nishida, Tatehiko 269-14, Tai Aboshi-ku @ Design ated Contracting States: Himeji-shi Hyogo-ken (JP) BE DE FR GB Inventor: Nakagawa, Masao 442-21, Sone-cho Takasago-shi Hyogo-ken (JP) (56) Références cited: DE - A - 1 694 094 DE-A-2 755 005 (74) Représentative: Vossius-Vossius-Tauchner- DE-B-2525173 Heunemann-Rauh Patentanwalte US - A - 3 743 61 1 P.O.Box 860767 Siebertstrasse 4 D-8000 Munchen 86 (DE)' Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shaH not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1 ) European patent convention). Courier Press, Leamington Spa, England. The present invention relates to expandable small particles having a large surface area. thermoplastic polymer beads which hardly lose Therefore, easy evaporation of the foaming any of a foaming agent absorbed within their agent takes place in the beads according to expandable form and maintain satisfactory elas- US-A-3 743 611. ticity and rigidity; the novel polymer beads are Under these circumstances, the present useful for the production of foamed shaped inventors have investigated ways to eliminate articles, wherein the polymer beads are pre- the foregoing drawbacks in these types of liminarily foamed (prefoamed) with heat and the products by improving their foaming agent prefoamed beads are then packed into a retention capacity. As a result, the present suitable metal mould to give a product of the inventors have created the expandable thermo- desired shape upon further heating. The pre- plastic polymer beads of the invention, which sent invention further concerns the production can readily be prefoamed by the manufacturers of expandable thermoplastic polymer beads of foamed articles and which additionally have having a core composed of vinyl polymer grains satisfactory elasticity and strength, as well as and a skin of an olefin polymer covering the excellent mouldability. The invention was finally grains. made complete by the discovery that the ideal Up to the present day a few types of expand- product can be obtained if grains of a vinyl poly- able polymer beads have already been pro- mer are covered or coated with a polyolefin duced on a commercial scale by adding a resin (olefin polymer), thereby causing the styrene-based monomer to a polyethylene- coated vinyl polymer to retain a foaming agent based resin in an aqueous medium, polymeriz- and imparting the necessary elasticity through ing these together and then impregnating the the polyolefin outer layer (skin). This invention, product with a foaming agent. These modified therefore, relates to novel expandable thermo- beads certainly give expanded articles (popcorn plastic polymer beads consisting of composite plastics) superior in elasticity to comparable beads having a core and a skin and containing a conventional foamed polystyrene and show a foaming agent; the core being composed of a relatively high degree of expansion compared to polymer formed from one or more vinyl mono- the conventional foamed polyolefins. In other mers; the skin being composed of an olefin words, by comparison with pure polyethylene polymer containing some or all of said vinyl resin expandable polymer beads of these types monomers; and the foaming agent being a gas can easily absorb a foaming agent and give rise or a liquid at ordinary temperature and pres- to a relatively highly expanded pre-foam. How- sure and having a boiling point lower than the ever, being prone to lose foaming agent, the softening point of the core material. beads must first be pre-foamed within a short The vinyl polymer used in this invention time after absorbing foaming agent and then denotes a polymer composed chiefly of styrene dispatched to the manufacturers of foamed and/or methyl methacrylate units. These poly- articles. mers are superior in their capacity for retaining Thermofoamable thermoplastic beads a foaming agent, as well as in their foamability consisting of an aliphatic olefin polymer, a and further advantageous physical properties. foaming agent and an organic material for The vinyl polymer which constitutes the core of enhancing preservation of the foaming agent the expandable thermoplastic polymer beads within said beads are described in US-A- consists of a polymer or polymers made from 3743611. The said organic material may be monomers and containing from 60 to 100% by another thermoplastic resin having an affinity to weight of styrene and/or methyl methacrylate said foaming agent, a solvent for the resin and from 0 to 40% by weight of monomers above room temperature or a copolymerizable other than styrene and/or methyl methacrylate, vinyl monomer and mixtures thereof. such as acrylonitrile vinyl acetate or mixtures The thermoplastic beads according to US- thereof. When the content of styrene and/or A-3 743 611 1 contain the aliphatic olefin methyl methacrylate is less than 60% by polymer as basic component. The organic weight, the resulting polymer does not have a material for enhancing preservation of the sufficient foaming agent retention capacity or foaming agent (which may be a vinyl polymer) is the physical properties required in the expanded simply mixed with the olefin polymer without moulding. any specific form or distribution of one compo- The olefin polymer used in this invention is nent or the other. However, since the olefin preferably polyethylene, an ethylene-vinyl polymer (e.g. polyethylene) is little compatible acetate copolymer, an ethylene-methyl meth- with the vinyl polymer (e.g. polystyrene), phase acrylate copolymer, an ethylene-vinylchloride separation occurs easily in the microstructure. copolymer, 1,2-polybutadiene or similar; these The vinyl polymer which is to serve as foaming may be used either singly or in combination agent preserving medium is not comprised in with each other. the beads according to US-A-3 743 611 in The vinyl monomer contained in the olefin the form of one large grain but in the form of polymer, i.e. in the skin of the expandable thermoplastic polymer beads of this invention, used. By the use of the vinyl monomers other is limited to those vinyl monomers which can be than the primary one (styrene), however, the absorbed into the olefin polymer. Once it has stability of the suspension mixture will be been absorbed into the olefin polymer, the vinyl improved; moreover, inasmuch as these vinyl monomer serves not only to lower the melt monomers are well grafted on or blended with viscosity of the olefin polymer to make the coat- the vinyl polymer (polystyrene), they can help to ing of the vinyl polymer easy but also improve control the mechanical properties of the core the strength of the skin when properly incor- polymer. porated. The vinyl monomer content in the The grains of the core polymer used have a olefin polymer is 5 to 50% by weight, and pre- size of 300 to 5000 micron (p) in the case of ferably 10 to 30% by weight. When the vinyl polystyrene. This particle size can also be used monomer content is less than 5% by weight, the in the case of the other polymers. effect and functioning are inferior; conversely, Given that the symbol A is the weight of when the content is more than 50% by weight, grains of the vinyl polymer, B the weight of the the skin formed from the polyolefin becomes powdered olefin polymer, and C the weight of too hard and brittle. one or a mixture of more than one type of vinyl The vinyl polymer formed from the monomer monomer, the weight ratio of (A+B) to C is in absorbed into the polyolefin is preferably the range of from 90:10 to 30:70. When the composed chiefly of polystyrene; however, a ratio of (A+B):C is greater than 90:10, the poly- small amount of polymethyl methacrylate poly- olefin coat on the vinyl polymer becomes inade- acrylonitrile, polyvinyl acetate or similar may be quate. Conversely, when the ratio is smaller mixed with the polystyrene. than 30:70, the suspension of the solution It is necessary that the weight ratio of the mixture becomes unstable. Moreover, the core to the skin be in the range of from 95:5 to proportion of A to B must be so determined that 30:70. When the weight ratio of core to skin the proportion of the core to the skin lies in the exceeds 95:5, the polyolefin can no longer be range of from 95:5 to 30:70 in weight. expected to have the desired effect. In view of the fact that the exact distribution By contrast, when the weight ratio is below of the vinyl monomers (their weight is C) 30:70, the foaming capacity to produce satis- between the vinyl polymer (its weight is A) and factory expansion becomes too low to allow the olefin polymer (its weight is B) cannot be practical application of the beads.
Load more

Recommended publications
  • Pd Nanoparticles-Loaded Vinyl Polymer Gels: Preparation, Structure and Catalysis
    catalysts Article Pd Nanoparticles-Loaded Vinyl Polymer Gels: Preparation, Structure and Catalysis Elsayed Elbayoumy 1,2 , Yuting Wang 1, Jamil Rahman 1,3, Claudio Trombini 3, Masayoshi Bando 1, Zhiyi Song 1, Mostafa A. Diab 2, Farid S. Mohamed 2, Naofumi Naga 4 and Tamaki Nakano 1,5,* 1 Institute for Catalysis and Graduate School of Chemical Sciences and Engineering, Hokkaido University, N21 W10, Kita-ku, Sapporo 001-0021, Japan; [email protected] (E.E.); [email protected] (Y.W.); [email protected] (J.R.); [email protected] (M.B.); [email protected] (Z.S.) 2 Department of Chemistry, Faculty of Science, Damietta University, New Damietta 34517, Egypt; [email protected] (M.A.D.); [email protected] (F.S.M.) 3 Dipartimento di Chimica “G. Ciamician”, Università degli Studi di Bologna, via Selmi 2, 40126 Bologna, Italy; [email protected] 4 Department of Applied Chemistry, Shibaura Institute of Technology, College of Engineering, 3-7-5 Toyosu, Koto-ku, Tokyo 135-8548, Japan; [email protected] 5 Integrated Research Consortium on Chemical Sciences (IRCCS), Institute for Catalysis, Hokkaido University, N21 W10, Kita-ku, Sapporo 001-0021, Japan * Correspondence: [email protected]; Tel.: +81-11-706-9155 Abstract: Four vinyl polymer gels (VPGs) were synthesized by free radical polymerization of divinyl- benzene, ethane-1,2-diyl dimethacrylate, and copolymerization of divinylbenzene with styrene, and ethane-1,2-diyl dimethacrylate with methyl methacrylate, as supports for palladium nanoparticles. VPGs obtained from divinylbenzene and from divinylbenzene with styrene had spherical shapes while those obtained from ethane-1,2-diyl dimethacrylate and from ethane-1,2-diyl dimethacry- late with methyl methacrylate did not have any specific shapes.
    [Show full text]
  • United States Patent Office Patented Jan
    3,019,208 United States Patent Office Patented Jan. 30, 1962 2 3,019,208 has of itself properties which were obtained by copoly METHOD OF MAKING GRAFT COPOLYMERS OF merizing comonomers with vinyl chloride. Certain spe WNYEL CHORDE AND POLYACRYLATE cial properties are obtained by using various copoly Robert J. Reid, Canal Fulton, and Chris E. Best, Franklin merizable monoethylenically unsaturated comonomers Township, Summit County, Ohio, assignors to The with the vinyl chloride, and in producing the graft co Firestone Tire & Rubber Company, Akron, Ohio, a polymer up to 10 or 15 percent of such comonomers corporation of Ohio may be used, such as for example vinyl acetate, vinylidene No Drawing. Filled Jan. 18, 1954, Ser. No. 404,806 chloride, trichlorethylene, etc. The term “vinyl chlo 6 Claims. (C. 260-45.5) ride resin' will be used herein generally to include poly 0. vinylchloride and copolymers of vinyl chloride with This invention relates to the production of graft co small amounts of comonomers which are often employed polymers by grafting a vinyl resin (composed of either in making copolymers with vinyl chloride. vinyl chloride or a mixture of vinyl chloride and a The graft copolymerization process is carried out in comonomer) onto an acrylate polymer. The polyacryl latex. Vinyl chloride with or without a small amount of ate is first polymerized in an emulsion, and then without 5 other suitable monomer is added to a previously pre Separation of the polyacrylate from the emulsion the pared latex of polyacrylate. Additional catalyst and vinyl resin is polymerized onto it. emulsifying agent, such as soap, etc., may be added but Acrylate polymer and vinyl polymer or copolymer are are not required.
    [Show full text]
  • Arxiv:1805.10147V1 [Cond-Mat.Soft] 25 May 2018
    Polymorphism of syndiotactic polystyrene crystals from multiscale simulations Chan Liu,1 Kurt Kremer,1 and Tristan Bereau1, a) Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany (Dated: 4 May 2019) Syndiotactic polystyrene (sPS) exhibits complex polymorphic behavior upon crystallization. Computational modeling of polymer crystallization has remained a challenging task because the relevant processes are slow on the molecular time scale. We report herein a detailed characterization of sPS-crystal polymorphism by means of coarse-grained (CG) and atomistic (AA) modeling. The CG model, parametrized in the melt, shows remarkable transferability properties in the crystalline phase. Not only is the transition temperature in good agreement with atomistic simulations, it stabilizes the main α and β polymorphs, observed experimentally. We compare in detail the propensity of polymorphs at the CG and AA level and discuss finite-size as well as box-geometry effects. All in all, we demontrate the appeal of CG modeling to efficiently characterize polymer-crystal polymorphism at large scale. I. INTRODUCTION bead B The crystallization of molecular assemblies often in- volves the stabilization of a variety of distinct conform- ers, denoted polymorphism.1 The impact of polymorphs, may it be thermodynamic, structural, or physiological, makes their understanding and prediction essential for (a) a broad area of research, from hard condensed mat- bead A ter to organic materials. The computational modeling of crystalline materials has rapidly developed in recent years, from crystallization2,3 to predicting polymorphs and their relative stability4{7. These developments are remarkable given the complexity of the system: from the (b) (c) (d) molecular architecture to sampling challenges at low tem- peratures to the significant timescales involved.
    [Show full text]
  • AN F V O N (M Ny // | VN 5C N I Ya 5 Loool \ - H F N O V\ | // T VV I M 5OO W - 1
    July 16, 1968 G. H. POTTER ETA 3,393,174 HOT MELT ADHESIVE COMPOSITION Filed Sept. 17, 1965 LAP SHEAR AND PEEL STRENGTH WS. PER CENT MgO INETHYLENE/WINYLACETATE (72.28) - -T M 2OOOH- |- - / N 2O O tap SAAAA S7APAWG7A/ I A. AEA/ 57 AAWG7A/ 5OO |- H ea | 5 / | V AN f V o N (m Ny // | VN 5C N I Ya 5 loool \ - H f N O V\ | // t VV I M 5OO w - 1. - - |- 5 -----1 : \/ O O 2O 3O 4O so 68 % BY WT. MgO NVENTORS GEOAPGA. A1 AO77 Ap CA1ADA M/A/7M/OAP7Ay VA By6.waufMA7HAW L. ZV77 ATTORNEY 3,393,174 United States Patent Office Patented July 16, 1968 1. 2 3,393,74 The a-olefin content of the olefin polymers is at least HOT MELT ADHESIVE COMPOSITION 60% of the total copolymer. Where vinyl esters are utilized George H. Potter, St. Albans, and Clyde J. Whitworth, as comonomers with a-olefins they constitute at least Jr., Charleston, W. Va., and Nathan L. Zutty, West 10% by weight of the total copolymer and preferably field, N.J., assignors to Union Carbide Corporation, a about 18% to 40% by weight. Where acrylic acids or corporation of New York alkyl esters are utilized as the comonomers with ox-olefins Filed Sept. 17, 1965, Ser. No. 488,086 they are preferably present in an amount constituting at 8 Claims. (CI. 260-41) least about 5% by weight and preferably about 10% to 30% by weight of the total copolymer. ABSTRACT OF THE DISCLOSURE 10 Among the fillers that are useful in these hot melt The lap shear and peel strengths of the vinyl polymers, adhesive compositions can be mentioned zinc oxide, such as, polyvinyl acetate, ethylene/vinyl acetate copoly barium oxide, magnesium oxide, calcium oxide, lead mers, ethylene/acrylic acid copolymers and ethylene/ethyl Oxide (PbO4), ferric oxide, carbon black, hydrated silica, acrylate copolymers were enhanced by blending these hydrated magnesium aluminum silicate and the like.
    [Show full text]
  • Characterization of High Molecular Weight Poly(Vinyl Chloride) – Lithium Tetraborate Electrolyte Plasticized by Propylene Carbonate
    9 Characterization of High Molecular Weight Poly(vinyl chloride) – Lithium Tetraborate Electrolyte Plasticized by Propylene Carbonate Ramesh T. Subramaniam1,*, Liew Chiam-Wen1, Lau Pui Yee2 and Ezra Morris2 1Centre for Ionics University Malaya, Department of Physics, Faculty of Science, University of Malaya, Kuala Lumpur 2Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Kuala Lumpur Malaysia 1. Introduction An electrolyte is a substance consisting of free ions and acts as a medium channel for transferring the charges between a pair of electrodes. Sometimes, they are also referred as “lytes” which is derived from the Greek word, “lytos”, which means “it may be dissolved”. Electrolyte is comprised of positively charged species which is called as cation and negatively charged species, anion. The properties of an electrolyte can be exploited via electrolysis process: separation of chemically bonded element or compounds by applying the electrical current. In the early stage, liquid electrolytes have been discovered and investigated. Liquid electrolyte is a substance that conducts the electricity in an aqueous solution by migrating both cations and anions to the opposite electrodes through an electrically conducting path as a useful electric current. However, it faces problem of leakage of hazardous liquids or gases. Other drawbacks are formation of lithium dendrite, electrolytic degradation of electrolyte and uses of flammable organic solvent (Ramesh et al., 2011a). Apart from that, it exhibits poor long–term stability due to the evaporation of the liquid phase in the cells (Yang et al., 2008). Therefore, solid polymer electrolytes (SPEs) were synthesized to prevail over the limitations of conventional liquid electrolytes. 1.1 Solid polymer electrolytes The development on SPEs was initiated by the pioneering work of Wright et al.
    [Show full text]
  • Lecture1541230922.Pdf
    MODULE-1 Introduction: -The macromolecules are divided between biological and non-biological materials. The biological polymers form the very foundation of life and intelligence, and provide much of the food on which man exists. The non-biological polymers are primarily the synthetic materials used for plastics, fibers and elastomers but a few naturally occurring polymers such as rubber wool and cellulose are included in this class. Today these substances are truly indispensable to mankind because these are essential to his clothing,shelter, transportation, communication as well as the conveniences of modern living. Polymer Biological Non- biological Proteins, starch, wool plastics, fibers easterners Note: Polymer is not said to be as macromolecule, because polymer is composedof repeating units whereas the macromolecules may not be composed of repeating units. Definition: A polymer is a large molecule built up by the repetition of small, simple chemical units known as repeating units which are held together by chemical covalent bonds. These repeating units are called monomer Polymer – ---- poly + meres Many parts In some cases, the repetition is linear but in other cases the chains are branched on interconnected to form three dimensional networks. The repeating units of the polymer are usually equivalent on nearly equivalent to the monomer on the starting material from which the polymer is formed. A higher polymer is one in which the number of repeating units is in excess of about 1000 Degree of polymerization (DP): - The no of repeating units or monomer units in the chain of a polymer is called degree of polymerization (DP) . The molecular weight of an addition polymer is the product of the molecular weight of the repeating unit and the degree of polymerization (DP).
    [Show full text]
  • Line Width of Nuclear Magnetic Resonance High Resolution Spectra of Vinyl Polymers
    VoI. I, No. I, Junuary-Februury I968 NhlR SPECTRA OF VINYL POLYMERS 93 are nine distinct branching possibilities (A, B, or C constants would be required for complete description branching from A,, B, or C), as many as nine additional of the system. kinetic constants would be required to specify the B. Two major simplifications were made in the system, not considering whatever constants are neces- derivation of eq 15-20. The first was that the effect of sary to describe the branching mechanism. penultimate and ante-penultimate units was negligible, 2. Nearest Neighbor Effects. In the model, the sta- the second assumed constant feed ratios of monomers bility of any link was assumed to be independent of the (fi). If the first assumption is invalid, alternate treat- presence and type of neighboring links. If, however, ments are available.18 If the second is invalid (as, for the effect of a given linkage extends beyond this linkage, example, in a batch or semibatch process), then eq then additional (constants are necessary. For a ter- 15-20 may be integrated numerically to give appropriate polymer, in the case of an A-A linkage, for example, values ofJi. the following scission constants need to be included: (18) E. Merz, T. Alfrey, and G. Goldfinger, J. Polymer Sci., 1, ka~~a,kaaab, k,,,,, kbaab, kbaac, k,,,,. A total of 36 75 (1946). Line Width of Nuclear Magnetic Resonance High Resolution Spectra of Vinyl Polymers A. L. Segre Centro Nazionale di Chiniica delle Macromolerole del C.N.R., Sezione I .Milan, Italy. Receiced Nofiember 21, 1967 ABSTRACT: The line widths of high resolution nmr spectra of vinyl polymers were studied with particular refer- ence to isotactic polypropylene.
    [Show full text]
  • Mesophases in Polyethylene, Polypropylene, and Poly(1-Butene)
    Polymer 51 (2010) 4639e4662 Contents lists available at ScienceDirect Polymer journal homepage: www.elsevier.com/locate/polymer Feature Article Mesophases in polyethylene, polypropylene, and poly(1-butene) René Androsch a, Maria Laura Di Lorenzo b, Christoph Schick c, Bernhard Wunderlich d,e,*,1 a Martin-Luther-University Halle-Wittenberg, Center of Engineering Sciences, D-06099 Halle/S., Germany b Istituto di Chimica e Tecnologia dei Polimeri (CNR), c/o Comprensorio Olivetti, Via Campi Flegrei 34, 80078 Pozzuoli (NA), Italy c University of Rostock, Institute of Physics, Wismarsche Straße 43-45, D-18051 Rostock, Germany d Department of Chemistry, University of Tennessee, Knoxville, USA e Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA article info abstract Article history: This paper contains new views about the amorphous and partially ordered phases of the three polymers Received 15 April 2010 listed in the title. The discussion is based on information on structure, thermodynamic stability, and Received in revised form large-amplitude molecular motion. Polyethylene is the basic backbone of all alkene polymers, and the 14 July 2010 other two are the first members of the vinyl polymers which have stereospecifically placed alkyl side Accepted 17 July 2010 chains. Their multiphase structures consist of metastable crystals, mesophases, and surrounding rigid Available online 4 August 2010 and mobile amorphous fractions. All these phases have sizes ranging from micrometer dimensions down to nanometers. Besides the phase structures, information about the molecular coupling between the Keywords: Equilibrium phases must be considered. Depending on temperature, the polymer phases can vary from solid (rigid) to Mesophase liquid (mobile).
    [Show full text]
  • The Effects of Shear Stress on the Crystallization Kinetics of Syndiotactic Polystyrene." (1995)
    Louisiana State University LSU Digital Commons LSU Historical Dissertations and Theses Graduate School 1995 The ffecE ts of Shear Stress on the Crystallization Kinetics of Syndiotactic Polystyrene. Douglas Henry Krzystowczyk Louisiana State University and Agricultural & Mechanical College Follow this and additional works at: https://digitalcommons.lsu.edu/gradschool_disstheses Recommended Citation Krzystowczyk, Douglas Henry, "The Effects of Shear Stress on the Crystallization Kinetics of Syndiotactic Polystyrene." (1995). LSU Historical Dissertations and Theses. 5965. https://digitalcommons.lsu.edu/gradschool_disstheses/5965 This Dissertation is brought to you for free and open access by the Graduate School at LSU Digital Commons. It has been accepted for inclusion in LSU Historical Dissertations and Theses by an authorized administrator of LSU Digital Commons. For more information, please contact [email protected]. INFORMATION TO USERS This manuscript has been reproduced from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer. Hie quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely, event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note wifi indicate the deletion. Oversize materials (e.g., maps, drawings, charts) are reproduced by sectioning the original, beginning at the upper left-hand comer and continuing from left to right in equal sections with small overlaps.
    [Show full text]
  • Polymer Crystals
    Rep. Prog. Phys. 53 (1990) 549-604. Printed in the UK Polymer crystals Paul J Phillips Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996-2200, USA Abstract In the twenty years since this subject was last reviewed for this journal by Andrew Keller there has been an almost explosive growth of research in the area of crystallisation of polymers. This growth has been almost exclusively in the area of crystallisation of polymers from the molten state, whereas when Keller wrote his review most of the work was on crystallisation from solution. At that time, the research was conducted exclusively on flexible chain polymers, but during the past ten years or so rigid and semi-rigid crystallisable polymers have been synthesised and become available in large enough quantities for physical measurements to be carried out. Our level of understand- ing of such systems at this time does not warrant an extensive review, so the major concerns of this area are simply summarised. The major developments in our understanding of polymer crystals and the kinetics of their formation have been many. It is now established that adjacent re-entry folding of the molecule occurs on crystallisation from solution, but when crystallised from the melt the molecular trajectory approximates a random coil when viewed from a distance. From a closer viewpoint, it appears that adjacent re-entry folding is only one contributor and that any given molecule exits and re-enters several crystals in a manner that is determined by the crystallisation temperature. In addition, it is now accepted that the interface between the crystal and the random melt may be macroscopic in nature.
    [Show full text]
  • Molecular Parameters of Hyperbranched Polymers Made by Self-Condensing Vinyl Polymerization
    7024 Macromolecules 1997, 30, 7024-7033 Molecular Parameters of Hyperbranched Polymers Made by Self-Condensing Vinyl Polymerization. 2. Degree of Branching† Deyue Yan‡ and Axel H. E. Mu1 ller* Institut fu¨ r Physikalische Chemie, Universita¨t Mainz, D-55099 Mainz, Germany Krzysztof Matyjaszewski Department of Chemistry, Carnegie-Mellon University, Pittsburgh, Pennsylvania 15213-3890 Received December 30, 1996; Revised Manuscript Received July 30, 1997X ABSTRACT: Using a modified definition, the average degree of branching, DB, the fraction of branchpoints, FB, as well as the fractions of various structural units are calculated as a function of conversion of double bonds for hyperbranched polymers formed by self-condensing vinyl polymerization (SCVP) of monomers (or “inimers”) with the general structure AB*, where A is a vinyl group and B* is an initiating group. The results are compared to those for the polycondensation of AB2-type monomers. At full conversion, DB is somewhat smaller for SCVP (DB∞ 0.465) than for AB2 systems (DB∞ ) 0.5). ≈ There are two kinds of linear groups in SCVP whereas there is only one kind in AB2 systems. Since there are two different active centers in SCVP, i.e., initiating B* and propagating A* centers, the effect of nonequal reactivities on DB is also discussed. At a reactivity ratio of the two kinds of active centers, r ) kA/kB 2.59, a maximum value of DB∞ ) 0.5 is reached. For the limiting case r << 1, a linear polymer resembling≈ a polycondensate will be formed whereas for r >> 1 a weakly branched vinyl polymer is expected. NMR experiments allow for the determination of reactivity ratio r.
    [Show full text]
  • Acrylic Copolymer) Ternary System Peelable Sealing Decontamination Material
    polymers Article Synthesis and Preparation of (Acrylic Copolymer) Ternary System Peelable Sealing Decontamination Material Zhiyu He 1,2, Yintao Li 1, Zhiqiang Xiao 3, Huan Jiang 1, Yuanlin Zhou 1,* and Deli Luo 4,* 1 State Key Laboratory of Environment-Friendly Energy Materials, School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, China; [email protected] (Z.H.); [email protected] (Y.L.); [email protected] (H.J.) 2 Communist Youth League of Southwest University of Science and Technology, Mianyang 621010, China 3 Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621010, China; [email protected] 4 Institute of Fluid Physics, China Academy of Engineering Physics, Jiangyou 621908, China * Correspondence: [email protected] (Y.Z.); [email protected] (D.L.) Received: 16 June 2020; Accepted: 8 July 2020; Published: 14 July 2020 Abstract: Traditional methods that are used to deal with radioactive surface contamination, which are time-consuming and expensive. As one effective measure of radioactive material purification, strippable coating, which effectively coats the pollutant, and settles them on the surface of objects. However, there are some shortcomings in terms of film formation and peelability, such as a brittle coating and poor peelability. Therefore, in order to meet the treatment methods for radioactive contaminants needs, the strippable coating must have excellent sealing, corrosion resistance, weather resistance, low environmental pollution, short film formation time, and good mechanical properties; in addition, the spraying process should be simple, with moderate adhesion, and it should be capable of being quickly and completely peeled off.
    [Show full text]