Elastomers styrenics

Elastomers. Elastomers are polymers or copolymers of hydrocarbons (see Elastomers, synthetic Rubber, natural). Natural mbber is essentially polyisoprene, whereas the most common synthetic mbber is a styrene—butadiene copolymer. Moreover, nearly all synthetic mbber is reinforced with carbon black, itself produced by partial oxidation of heavy hydrocarbons. Table 10 gives U.S. elastomer production for 1991. The two most important elastomers, styrene—butadiene mbber (qv) and polybutadiene mbber, are used primarily in automobile tires. 

Thermoplastic elastomers are often multiphase compositions in which the phases are intimately dispersed. In many cases, the phases are chemically bonded by block or graft copolymerization. In others, a fine dispersion is apparentiy sufficient. In these multiphase systems, at least one phase consists of a material that is hard at room temperature but becomes fluid upon heating. Another phase consists of a softer material that is mbberlike at RT. A simple stmcture is an A—B—A block copolymer, where A is a hard phase and B an elastomer, eg, poly(styrene- -elastomer- -styrene). 

An interesting observation arose with the thermoplastic elastomer styrene/ butadiene (S/B) tri-block copolymer (Kraton ). These are made by anionic... 

Uses Synthetic rubbers and elastomers (styrene-butadiene, polybutadiene, neoprene) organic synthesis (Diels-Alder reactions) latex paints resins chemical intermediate. 

To form a random polymer the two monomers must react with themselves at a rate comparable to that at which they react with each other. In random polymers they need not be present in equal amounts either. The most important synthetic elastomer, styrene-butadiene rubber (SBR), is a copolymer of approximately 6 mol of butadiene to 1 mol of styrene. The... 

Manufacturing (NAICS 326), Rubber Products (NAICS 3262) totals 35.3 billion, of which Tires (NAICS 32621) makes up 15.4 billion, showing the dominance of the automobile tire market in this sector of the chemical industry. The top polymer production summary in Table 1.16 gives a numerical list of important synthetic elastomers. Styrene-butadiene rubber (SBR) dominates the list at 1.93 billion lb for U.S. production. All other synthetic elastomers are much smaller. While elastomers had a slight increase in production from 1980-1990, only 0.5% annually, SBR was down 2.3% per year. From 1990-2000 it was up 1.0% per year. The fastest growing elastomer is ethylene-propylene, up 5.2% annually for 1990-2000. Table 18.1 gives a breakdown in percent production of synthetic elastomers and consumption of natural rubber in the U.S. 

Of the 17 billion lb of butadiene consumed in 1999, almost two thirds went into the production of elastomers (styrene-butadiene latex rubber (SBR), polybutadiene, nitrile, and polychloroprene). Adiponitrile, ABS resins, styrene-butadiene latex, styrene block copolymers, and other smaller polymer uses accounted for the remainder. The largest single use was for styrene-butadiene copolymers (SBR and latex). Most of it was made by an emulsion process using a free-radical initiator and a styrene-butadiene ratio of about 1 3. More detailed description of the rubber and polymer used can be found in Chapters 16 and 15. 

Ethanox 376 is a stabilizer that provides heat stability by preventing thermo-oxidative degradation during processing and service life. It provides compatibility with resins and extraction resistance. It can be applied in polyolefins, such as polyethylene, polypropylene, polybutene-1 and other polymers such as engineering plastics, styrenes, polyurethanes, saturated and unsaturated elastomers, styrenics, rubber modified styrenics, segmented block copolymers, and PVC. 

This is an example of the preparation of ABA-type thermoplastic elastomer. Styrene is polymerized first since styryl initiation of isoprene is faster than the reverse reaction. The reaction is carried out in a nonpolar solvent with Li" " as the counterion to enable predominantly cis-l,4-polyisoprene to be formed in the second growth stage. The living polystyrene-6/ocfc-polyisoprene AB di-block copolymer resulting from the second stage is then coupled by a double nucleophilic displacement of Cl ions from a stoichiometric equivalent of dichloromethane to give a polystyrene-61ock-polyisoprene-/)/ock-polystyrene triblock copolymer. 

Silicone rubbers Stereo regular elastomers Styrene-butadiene rubbers (50 percent or less styrene content)... 

Elastomers styrene-butadiene rubbers and latexes, thermoplastic rubbers, nitrile rubber, ethylene-propylene rubber, polychloroprene rubber. 

Data have been published dealing with successful applications of HAS in stabilization of other polymers than PO elastomers, styrenic polymers, polyamides, polycarbonates, polyacetals, polyurethanes, linear polyesters, thermoplastic polyester elastomers, polyacrylates, epoxy resins, poly(phenylene oxide) or polysulfide [12]. In spite of their basicity, HAS may also be used for stabilization of PVC. This application includes less basic derivatives of piperidine and 1,4-dihydropyridine [12,13,145,146]. 

Commercially, the poly(styrene- -elastomer- -styrene) materials are made by anionic polymerization (7,45—47). An alkj thium initiator (RLi) first reacts with styrene [100-42-5] monomer ... 

Stabilization of SIS Thermoplastic Elastomers (Styrene Isoprene Styrene Block Copolymer)... 

TES thermoplastic elastomer-styrene torr mm mercury (mmHg)... 

Acrylonitrile-butadiene elastomers Polyacetylene Styrene-acrylonitiile Styrene-butadiene elastomers Styrene-methylmethacrylate cojxjlymer... 

S tyrene- acrylonitrile Styrene-butadiene elastomers Styrene-methylmethacrylate copolymer Sulfo-ethylene-propylene-diene monomer ionomers Syndiotactic polystyrene... 

Ki-aton G1600 SEES Perfluorinated ionomers Phenolic resins Polystyrene, head-to-head Poly(yinyl chloride), head-to-head S tyrene- acrylonitrile Styrene-butadiene elastomers Styrene-methylmethacrylate copolymer Sulfo-ethylene-propylene-diene monomer ionomers Vinylidene fluoride-hexafluoropropylene elastomers Chemigum... 

Properties Wh. powd. m.w. 638.93 dens. 1.08 kg/l m.p.101 C Uses Antioxidant, stabilizer for polyolefins, elastomers, styrenics, polyacetals, cellulosics, polyesters, PU, PVC, petroleum prods., org. substrates, food-grade polymers antioxidant in lubricants for incidental food-contact use... 

Uses Color and m.w. stabilizer, antioxidant, melt flow aid for polymer processing (polyolefins, polyesters, elastomers, styrenics, engineering thermoplastics), adhesives, coatings antioxidant, UV stabilizer for polyolefins, food-grade polymers Regulatory FDA 21CFR 178.2010 Manuf./Distrib. Aldrich http //www.sigma-aidrich.com, GE Spec. http //www.ge.com/speciaitychemicais Trade Name Synonyms AO-2 f[Ciba Spec. Chems./Plastic Addit. http //www.cibasc.com]-, Doverphos S-680 [Dover http //www.doverchem.com]-, Doverphos S-686, S-687 t[Dover... 

Acrylic elastomer Chlorotrifluoroethylene polymer EPDM rubber Ethylene/ethyl acrylate copolymer Polyvinyl chloride pPDI-PTMEG jSilicone elastomer Styrenated diphenylamine Styrene-ethylene/butylene-styrene block copolymer Tetrafluoroethylene/propylene copolymer gaskets, closure-sealing food containers Arachidyl-behenyl amide Azodicarbonamide Benzyl alcohol Butylene glycol Carbon, activated... 

Polymers Thermoplastic elastomers Styrene-butadiene-styrene (SBS), styrene-butadiene-rubber (SBR), styrene-isoprene-styrene (SIS), styrene-ethyl-butadiene-styrene (SEBS), ethyl-propyl-dien tetropolymer (EPDM), isobutene-isoprene copolymer (NR), polybutadiene (PBD),natural rubber (l),(2),(3),(4), [8]. [9], [10], [II], [13]... 

Examples of vulcanizable elastomers include natural rubber (NR), styrene butadiene rubber (SBR), butadiene rubber (BR), ethylene-propylene-diene monomer-rubber (EPDM), butyl rubber (HR), polychloroprene or neoprene (CR), epichlorohydrin rubber (ECO), polyacrylate rubber (ACM), millable polyurethane rubber, silicone rubber, and flu-oroelastomers. Examples of thermoplastic elastomers include thermoplastic polyurethane elastomers, styrenic thermoplastic elastomers, polyolefin-based thermoplastic elastomers, thermoplastic polyether-ester (copolyester) elastomers, and thermoplastic elastomers based on polyamides. 

Polypropylene, PP, was blended with 5-20 wt% elastomers [styrene-butadiene, SBR, or butadiene-acrylonitrile, NBR] to produce materials useful for blow molding of bottles, free from brittleness and stress cracking. In a later patent, EPR, BP, and PIB, with a dicarboxylic acid anhydride, were used ... 

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

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