DIENE COPOLYMER

Table B.3 Synthesis and Features of Hydrogenated Diene-Diene Copolymers...

The cross-sectional area per chain in the hexagonal lattice of irradiated PE varies between 20.6 and 22.0 A. It is, thus, always greater than the cross-sectional area in the rotator phase in paraffins (19.5-20.0 A ), but on average somewhat smaller than that in constrained PE fibers above 7, /, (21.4-22.7 A ). An ethylene-propylene diene copolymer with approximately 64%, 32%, and 4% by weight of each component, respectively, was found to contain hexagonal crystals with a cross-sectional area per chain of 20.3 A". 

Ethylene-propylene-diene-copolymer good good good... 

We have considerable latitude when it comes to choosing the chemical composition of rubber toughened polystyrene. Suitable unsaturated rubbers include styrene-butadiene copolymers, cis 1,4 polybutadiene, and ethylene-propylene-diene copolymers. Acrylonitrile-butadiene-styrene is a more complex type of block copolymer. It is made by swelling polybutadiene with styrene and acrylonitrile, then initiating copolymerization. This typically takes place in an emulsion polymerization process. 

In particular, the increase of tacticity and the possibility of achieving the synthesis of "all cis" diene copolymers of high molecular weight allows the possibilities of broadening the range of products attainable in conventional, solution polybutadiene plants,... 

Stereochemical analysis of H and C NMR has been accomplished for the polymers of butadiene, isoprene, and other dienes, for polymers containing heteroatoms in the main chain, and for vinyl and diene copolymers lack of space precludes discussion of these interesting studies (11, 118). 

I. Blends of Resins with Diene Copolymer Elastomers... 

In addition, borane-containing POs can be prepared by copolymerization of olefin with borane monomers or by hydroboration of polyolefins including unsaturated groups, such as olefin-divinylbenzene copolymer and olefin-diene copolymers. Many kinds of graft copolymers, such as poly-elhylene-gra/f-poly( vinyl alcohol), PE-g-PMMA, polypropylcnc-gra/f-poly-(maleicanhydride-co-styrene), polypropylene-gra/f-poly(methacrylic acid), polypropylene-gra/f-poly(vinyl alcohol), polypropylene-gra/f-polycaprolac-tone (PP-g-PCL), polypropylcnc-gra/f-poly(methyl methacrylate) (PP-g-PMMA), poly( ethylene-co-propylene)-gra/f-poly(methyl methacrylate) (EPR-g-PMMA), and poly(ethylene-co-propylene)-gra/f-poly(maleic anhydride-costyrene), have been synthesized by such a method resulting in controllable composition and molecular microstructures [63-66]. 

Structure and Composition of Diene Copolymers. One finds that most of the reported copolymerization studies on butadiene or isoprene involve styrene as comonomer. In part this is due to the early interest in styrene-butadiene synthetic rubbers. The free radical produced copolymers (GRS, usually about 20—25% styrene units) contain about 20% of its butadiene fraction in the 1,2 form. The ratio of 1,2 to 1,4 units is little affected by polymerization variables such as temperature, conversion and styrene content (39). Butadiene and styrene copolymers contain 50 to 60% 1,2-diene units when prepared by sodium catalysts at 50° (39). This behaviour is once more significantly different when lithium is used in place of sodium as can be seen in Table 3. 

Hadjichristidis N, Iatrou H et al (1993) Morphology and miscibility of miktoarm styrene-diene copolymers and terpolymers. Macromolecules 26 5812-5815... 

Copolymers of ethylene with a-olefins, such as the short-chain branched LLDPE (linear low-density polyethylene) impact materials or the EPD (ethylene-propylene-diene copolymer) rubbers represent major percentages of the total polyolefin production, due to their desirable mechanical properties. Solid-state MgCl2-supported Ziegler-Natta catalysts however, have unfavourable reactivity... 

Table 23.4 Order-disorder transition temperatures of hydrogenated poly(styrene-block-diene) copolymers...

As the functionality of the (acrylic ester-diene) copolymers l8,19> is higher than two, the disproportionation mechanism is unimportant and may be neglected. That means that in the diazo-initiated polymerization, termination mostly takes place by recombination. 

Hydrogenated Styrene-Diene Copolymers and Radial Isoprene Chemistry... 

Manufacture Styrene-diene copolymers are produced by anionic solution polymerization, typically using i-butyl lithium in cyclohexane at 60-120°C. The system may also be promoted by small amounts of an amine such as tetramethylethylene diamine or an ether, such as tetrahydrofuran. Polymerization solids are in the range of 20-25%. 

Eckert, R.J.A. and Covey, D.F. (1988) Developments in the field of hydrogenated diene copolymers as viscosity index improvers. Lubr. Sci. 1 (1) 65-80. 

Composition (type of polymeric components). The base polymer (which is to be modified) may be an amorphous polymer [e.g., polystyrene (PS), styrene-acrylonitrile copolymer, polycarbonate, or poly(vinyl chloride)], a semicrystalline polymer [e.g., polyamide (PA) or polypropylene (PP)], or a thermoset resin (e.g., epoxy resin). The modifier may be a rubber-like elastomer (e.g., polybutadiene, ethylene-vinyl acetate copolymer, ethylene-propylene copolymer, or ethylene-propylene-diene copolymer), a core-shell modifier, or another polymer. Even smaller amounts of a compatibilizer, such as a copolymer, are sometimes added as a third component to control the morphology. 

Soluble copolymers of styrene were considered as candidates for hydrogenation to impact PVCH materials. Anionic diene copolymers with styrene were chosen for study because the structure of polydiene portions could be controlled to give flexible rubbery segments on hydro-... 

Hauser et al. [1993] claim that articles for medical and other uses made from a polymer alloy of a clear styrenic acrylate, a ductile styrene-diene polymer, and a rubbery block styrene-diene copolymer may be sterihzed by gamma irradiation, without significant increase in its yellowness index or significant deterioration of the alloy s mechanical properties (Table 11.9). There are many applications, e.g., urine sample botdes, items in space probes, and cosmetic containers, that are made from transparent plastics and need to be radiation-sterihzed. However, many clear plastics do develop color on irradiation, and their mechanical properties tend to deteriorate, particularly on irradiation in air. Hauser et al. 

The photodegradable resin comprises a styrene-diene copolymer containing 0.1—10% by weight of butadiene or isoprene and >0.001% by weight of > 1 of the transition-metal salts together with a brominated aliphatic hydrocarbon... 

Ethylene-propylene-diene copolymers magnesium compounds VOCI3, VCI4, alkylaluminum... 

New diene copolymers can be expected. Butadiene-acrylic acid and butadiene-methylvinylp3mdine copolymers have been reported. One of the former copolymers, compounded with zinc oxide, formed a vulcanizate with a tensile strength of over 8,000 psi, the highest on record. The latter copol3rmer has been quaternized with active halogen compounds to form a new type of elastomeric material. ... 

High density polyethylene (HOPE) Linear low density polyethylene (LLDPE) Isotactic polypropylene (iPP) Syndiotactic polypropylene (sPP) tram-1,4-Polyisoprene Syndiotactic polystyrene (sPS) Cyclooleflns Ethylene-propylene copolymers Styrene-ethylene copolymers cw -1,4-polybutadiene rrarw -1,4-Poly isoprene Random ethylene-a-olefin copolymers Ethylene-propylene rubber (EPR) Ethylene-propylene-diene copolymers (EPDM)... 

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