Plasticizers styrene butadiene rubber

Styrene is manufactured by alkylating benzene with ethene followed by dehydrogenation, or from petroleum reformate coproduction with propylene oxide. Styrene is used almost exclusively for the manufacture of polymers, of which the most important are polystyrene, ABS plastics and styrene-butadiene rubber. U.S. production 1980 3 megatonnes. 

Other polymers used in the PSA industry include synthetic polyisoprenes and polybutadienes, styrene-butadiene rubbers, butadiene-acrylonitrile rubbers, polychloroprenes, and some polyisobutylenes. With the exception of pure polyisobutylenes, these polymer backbones retain some unsaturation, which makes them susceptible to oxidation and UV degradation. The rubbers require compounding with tackifiers and, if desired, plasticizers or oils to make them tacky. To improve performance and to make them more processible, diene-based polymers are typically compounded with additional stabilizers, chemical crosslinkers, and solvents for coating. Emulsion polymerized styrene butadiene rubbers (SBRs) are a common basis for PSA formulation [121]. The tackified SBR PSAs show improved cohesive strength as the Mooney viscosity and percent bound styrene in the rubber increases. The peel performance typically is best with 24—40% bound styrene in the rubber. To increase adhesion to polar surfaces, carboxylated SBRs have been used for PSA formulation. Blends of SBR and natural rubber are commonly used to improve long-term stability of the adhesives. 

Plastics, such as PE, PP, polystyrene (PS), polyester, and nylon, etc., and elastomers such as natural rubber, EPDM, butyl rubber, NR, and styrene butadiene rubber (SBR), etc., are usually used as blend components in making thermoplastic elastomers. Such blends have certain advantages over the other type of TPEs. The desired properties are achieved by suitable elasto-mers/plastic selection and their proportion in the blend. 

Polystyrene (PS) The volume of expanded polystyrene produced probably exceeds the volume production of all other plastics (excluding the polyurethanes) put together. At least half the weight of polystyrene produced is in the form of high impact polystyrene (HIPS)—a complex blend containing styrene-butadiene rubber or polybutadiene. 

In a block copolymer, a long segment made from one monomer is followed by a segment formed from the other monomer. One example is the block copolymer formed from styrene and butadiene. Pure polystyrene is a transparent, brittle material that is easily broken polybutadiene is a synthetic rubber that is very resilient, but soft and opaque. A block copolymer of the two monomers produces high-impact polystyrene, a material that is a durable, strong, yet transparent plastic. A different formulation of the two polymers produces styrene-butadiene rubber (SBR), which is used mainly for automobile tires and running shoes, but also in chewing gum. 

S. Bandyopadhyay, S.L. Agrawal, P. Sajith, N. Mandal, S. Dasgupta, R. Mukhopadhyay, A.S. Deuri, and S.C. Ameta, Research on the application of recycled waste RFL (Resorcinol-Formaldehyde-Latex) dip solid in Styrene Butadiene Rubber based compounds. Progress in Rubber, Plastics and Recycling Technology, 23(1), 21, 2007. 

Uses. Plastics and synthetic rubber are the major uses for styrene. They account for the exponential growth from a few million pounds per year in 1938 to more than 8 billion pounds today. The numerous plastics include polystyrene, styrenated polyesters, acrylonitrile-butadiene-styrene (ABS), styrene-acrylonitrile (SAN), and styrene-butadiene (SB). Styrene-butadiene rubber (SBR) was a landmark chemical achievement when it was comrner-cialized during World War II. The styrene derivatives are found everywhere—in food-grade film, coys, construction pipe, foam, boats, latex paints, tires, luggage, and furniture. 

In Table 8.4 we see that most butadiene is polymerized either by itself or with styrene or acrylonitrile. The most important synthetic elastomer is styrene-butadiene rubber (SBR). SBR, along with polybutadiene, has its biggest market in automobile tires. Specialty elastomers are polychloroprene and nitrile rubber, and an important plastic is acrylonitrile/butadiene/styrene (ABS) terpolymer. Butadiene is made into adiponitrile, which is converted into hexamethylenediamine (HMDA), on of the monomers for nylon. 

Butadiene is used primarily in the production of synthetic rubbers, including styrene-butadiene rubber (SBR), polybutadiene nibber (BR), styrene-butadiene latex (SBL), chloroprene rubber (CR) and nitrile rubber (NR). Important plastics containing butadiene as a monomeric component are shock-resistant polystyrene, a two-phase system consisting of polystyrene and polybutadiene ABS polymers consisting of acrylonitrile, butadiene and styrene and a copolymer of methyl methacrylate, butadiene and styrene (MBS), which is used as a modifier for poly(vinyl chloride). It is also used as an intermediate in the production of chloroprene, adiponitrile and other basic petrochemicals. The worldwide use pattern for butadiene in 1981 was as follows (%) SBR + SBL, 56 BR, 22 CR, 6 NR, 4 ABS, 4 hexamethylenediamine, 4 other, 4. The use pattern for butadiene in the United States in 1995 was (%) SBR, 31 BR, 24 SBL, 13 CR, 4 ABS, 5 NR, 2 adiponitrile, 12 and other, 9 (Anon., 1996b). 

Occupational exposure to 1,3-butadiene occurs in the production of monomeric 1,3-butadiene and of 1,3-butadiene-based polymers and 1,3-butadiene-derived products. The mean full-shift, time-weighted average exposure levels measured for workers in these industries have usually been below 10 ppm [22 mg/m- ], although that level may be exceeded during some short-term activities. Recent data from monomer extraction and styrene-butadiene rubber plants showed lower average concentrations (< 5 ppm [< 11 mg/m ]). 1,3-Butadiene is not usually found at detectable levels in workplace air during manufacture of finished rubber and plastic products. 

Meinhardt, T.J., Young, R.J. Hartle, R.W. (1978) Epidemiologic investigations of styrene-butadiene rubber production and reinforced plastics. Scand. J. Work Environ. Health, 4 (Suppl. 2), 240-246... 

BUTADIENE. [CAS 106-90-0]. CHrCH C CH3, 1,3-butadiene (methyl-allene), formula weight 54.09. bp —4.41cC, sp gr 0.6272, insoluble in H2 O. soluble in alcohol and edier in all proportions, Butadiene is a very reactive compound, arising from its conjugated double-bond structure. Most butadiene production goes into die manufacture of polymers, notably SBR (styrene-butadiene rubber) and ABS (acryloiiitrile-buladiene-slyrene) plastics. Several organic syntheses, such as Diels-Alder reaction, commence with the double-bond system provided by this compound. 

STYRENE. Styrene, CgH5CH=CH2, is the simplest and by far the most important member of a series of aromatic monomers. Also known commercially as styrene monomer (SM). styrene is produced in large quantities for polymerization. It is a versatile monomer extensively used for the manufacture of plastics, including crystalline polystyrene, rubber-modified impact polystyrene, expandable polystyrene, acrylonitrile-butadiene-styrene copolymer (ABS), styrene-acrylonitrile resins (SAN), styrene-butadiene latex, styrene-butadiene rubber (SBR). and unsaturated polyester resins. See also Acrylonitrile Polymers. 

Plasticizers. These materials are added to reduce the hardness of the compound and can reduce the viscosity of the uncured compound to facilitate processes such as mixing and extruding. The most common materials are petroleum-based oils, esters, and fatty acids. Critical properties of these materials are their compatibility with the rubber and their viscosity. Failure to obtain sufficient compatibility will cause the plasticizer to diffuse out of the compound. The oils are classified as aromatic, naphthenic, or paraffinic according to their components. Aromatic oils will be more compatible with styrene-butadiene rubber than paraffinic oils, whereas the inverse will be true for butyl rubber. The aromatic oils are dark colored and thus cannot be used where color is critical, as in the white sidewall of a tire. The naphthenic and paraffinic oils can be colorless and are referred to as nonstaining. 

Rubbers are plasticized with petroleum oils, before vulcanization, to improve processability and adhesion of rubber layers to each other and to reduce the cost and increase the softness of the final product. Large quantities of these oil-extended rubbers are used in tire compounds and related products. The oil content is frequently about 50 wt% of the styrene-butadiene rubber. The chemical composition of the extender oil is important. Saturated hydrocarbons have limited compatibility with most rubbers and may sweat-out. Aromatic oils are more compatible and unsaturated straight chain and cyclic compounds are intermediate in solvent power. 

Several copolymers are commercially important and used in a wide range of consumer products. For example, the copolymer of vinyl chloride and vinylidene chloride forms Saran, the film used in the well-known plastic food wrap. Copolymerization of 1,3-butadiene and styrene forms styrene-butadiene rubber (SBR), the polymer used almost exclusively in automobile tires. 

NOTE Ibtals for plastics are for those products listed and exclude some small-volume plastics. Synthetic rubber data include Canada. Dry-weight basis unless otherwise specified Density 0.940 and below " Data include Canada from 2001 Density above 0.940 Data include Canada from 1995 Data include Canada from 2000 Data include Canada from 1994 Includes styrene-butadiene copolymers and othm styrene-based polymers Unmodified Includes butyl styrene-butadiene rubber latex, nitrile latex, polyisoprene, and miscellaneous others. SOURCES American Plastics Council, International Institute of Synthetic Rubber Producers. 

Butadiene is used as a chemical intermediate and as a polymer component in the synthetic rubber industry, the latter accounting for 75% of the butadiene produced. Styrene-butadiene rubber, polybutadiene rubber, adiponitrile, styrene-butadiene latex, acrylonitrile-butadiene-styrene resins, and nitrile rubber are used in the manufacture of tires, nylon products, plastic bottles and food wraps, molded rubber goods, latex adhesives, carpet backing and pads, shoe soles, and medical devices. 

Used as a secondary accelerator with antioxidant, antiozonant, and stabilizing function in synthetic rubber and high polymer materials in the plastics and rubber industries. Mainly used in styrene-butadiene rubber (SBR), chloroprene rubber (CR), epichlorohydrin, and chlorosulfonated polyethylene rubber. Promotes heat-resistance of chlorosulfonated polyethylene rubber, EPDM and CSM and sunshine resistance of CR. 

Elastomers include natural rubber (polyisoprene), synthetic polyisoprene, styrene-butadiene rubbers, butyl rubber (isobutylene-isoprene), polybutadiene, ethylene-propylene-diene (EPDM), neoprene (polychloroprene), acrylonitrile-butadiene rubbers, polysulfide rubbers, polyurethane rubbers, crosslinked polyethylene rubber and polynorbomene rubbers. Typically in elastomer mixing the elastomer is mixed with other additives such as carbon black, fillers, oils/plasticizers and accelerators/antioxidants. 

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