Thermoplastic saturated elastomer

CLASS Chemical copolymers saturated thermoplastic elastomers... 

Styrene butadiene styrene block copolymer -a saturated thermoplastic elastomer Styrene maleic anhydride Synthetic polyisoprene Tetrafluorethylene-ethylene copolymers Thick molding compound. 

Literature estimates indicate that 10% or more of com-mereial PP is toughened by addition of 10-20% of EPR [19,148]. The major improvements are impact strength at room temperature and especially at low temperatures, environmental stress-crack resistance, and filler tolerance [18,19,108,143,148-151]. The major market is in the auto industry, while other uses include appliances, signs, sports equipment, and tool handles. At the other end of the scale, as noted earlier, addition of PP to EPR produces saturated thermoplastic elastomers. 

At high (50—100 pph) saturation levels, with a near thermoplastic elastomer, a leather-like material results that can be embossed. The paper web used ia pressure-seasitive tape is prepared by latex saturatioa ia order to give it sufficieat internal strength to release without delamiaatioa. 

Polyesters, such as microbially produced poly[(P)-3-hydroxybutyric acid] [poly(3HB)], other poly[(P)-hydroxyalkanoic acids] [poly(HA)] and related biosynthetic or chemosynthetic polyesters are a class of polymers that have potential applications as thermoplastic elastomers. In contrast to poly(ethylene) and similar polymers with saturated, non-functionalized carbon backbones, poly(HA) can be biodegraded to water, methane, and/or carbon dioxide. This review provides an overview of the microbiology, biochemistry and molecular biology of poly(HA) biodegradation. In particular, the properties of extracellular and intracellular poly(HA) hydrolyzing enzymes [poly(HA) depolymerases] are described. 

They have all the rubberiness of the ethylene/propylene (EPR) rubber matrix, and the crystalline polypropylene (PP) domains hold them together. As saturated elastomers, they have natural resistance to oxygen and ozone aging. They are the second largest class of thermoplastic elastomers, 25 percent of the total market, used mainly in mechanical rubber parts. 

Use of a chemically saturated rubber such as chlorobutyl, together with styrene as the monomer, with the rubber the predominant component by weight, results in a material similar in behavior to the thermoplastic elastomers (see Chapter 4). In all cases two glass transitions and other evidence suggested phase separation. 

Examples of the thermoplastic elastomers include polystyrene-fi/ocA -polybutadiene-h/oc -polystyrene (SBS) or the saturated center block counterpart (SEES). In the latter, the EB stands for ethylene-butylene, where a combination of 1,2 and 1,4 copolymerization of butadiene on hydrogenation presents the appearance of a random copolymer of ethylene and butylene (see Table 9.4). 

Thermoplastic elastomers that are formulated into hot-melt adhesives include polyurethane and block terpolymers, such as styrene-butadiene-styrene styrene-iso-prene-styrene and styrene-olefin-styrene, in which the olefin component is typically ethylene, propylene, and/or butylene. The saturation in the mid-segment of these terpolymers results in better UV and thermooxidative resistance than that of unsaturated butadiene and isoprene midsegments. 

Thermoplastic elastomers with unsaturated center blocks, such as polybutadiene (SBS) or polyisoprene (SIS), are much more oxidation-prone than those with saturated elastomer segments such as ethylene/butylene (SEES) or ethylene/propylene (SEPS), because the elastomer component is more oxidation-prone than the thermoplastic component. UV stabilization thus has to be adapted to the elastomer component. Eor outdoor use, stabilization is recommended either with UV stabilizers or with carbon black filler. 

Styrene-based polymers (SAN) Polyester (saturated linear PET) Polyvinylidene fluoride (PVDF) Thermoplastic elastomers (TPE)... 

Singer S.M. and Allot M.T., Thermoplastic polyurethane elastomer based on a saturated hydroxyl terminated polyol, difunctional aromatic chain extender and 1,5-naphthalene diisocyanate, US Patent 5 599 874, 1997. 

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