Brominated isobutylene-isoprene copolymer

Brominated butyl rubber Brominated isobutylene/isoprene copolymer. See Isobutylene/isoprene copolymer, brominated Brominated neopentyl glycol diglycidyl ether CAS 31452-80-9... 

Synonyms BIIR Brominated butyl rubber Brominated isobutylene/isoprene copolymer Bromobutyl rubber 1,3-Butadiene, 2-methyl-, polymer with 2-methyl-1-propene, brominated Butyl rubber, brominated Isobutylene, isoprene polymer, brominated Definition Elastomer vulcanized by sulfur systems vulcanizate offers low gas permeability, good weather/ozone resist., better chem./heat resist, than butyl rubber... 

Isobutylene/isoprene copolymer Isobutylene/isoprene copolymer, brominated Isobutylene/isoprene copolymer, chlorinated D-Mannitol 2,2 -Methylenebis 6-(1-methylcyclohexyl)-p-cresol Natural rubber Oleyl alcohol... 

Bromobutyl rubber. See Isobutylene/isoprene copolymer, brominated... 

Butadiene, 2-methyl-, polymer with 2-methyl-1-propene, brominated. See Isobutylene/isoprene copolymer, brominated... 

EPM rubber Fluorosilicone elastomer rubber, pharmaceutical closures Isobutylene/isoprene copolymer, brominated rubber, pharmaceutical stoppers Isobutylene/isoprene copolymer, chlorinated rubber, profiles EPM rubber... 

Butyl rubber and other isobutylene polymers of technological importance iaclude various homopolymers and isobutylene copolymers containing unsaturation achieved by copolymerization with isoprene. Bromination or chlorination of the unsaturated site is practiced commercially, and other modifications are beiag iavestigated. 

Standard butyl rubber, which is a copolymer of isobutylene with about 2% of isoprene vulcanises in the same manner as natural rubber but, as it only contains a small proportion of polyisoprene, the cross-link percentage is much reduced. It is therefore not possible to make ebonite from a butyl rubber. The same vulcanisation chemistry, with some modifications, applies to ethylene-propylene terpolymers and brominated butyl rubber. 

Butyl rubber consists mostly of isobutylene (95-98%) and about 2-5% isoprene units. 1 The isoprene unit is halogenated by either chlorine or bromine to obtain the corresponding halobutyl rubbers. Despite the superior elastomeric properties of halobutyl, the elastomer can easily undergo dehydrohalogenation leading to crosslinfang, and the isoprene unsaturation is subject to ozone cracking. To remedy these problems and to improve the halobutyl properties, a new class of elastomer poly(isobutylene-co-p-methylstyrene) [poly (IB-PMS)] was developed. Unlike butyl rubber, it contains no double bonds and therefore cannot be crosslinked unless otherwise functionalized. The chemical structures of butyl rubber and poly (IB-PMS) copolymers are shown below. 

Isobutylene has been of interest since the early days of synthetic polymer research when Friedel Crafts catalysts were used to prepare elastic materials. Isobutylene polymers of commercial importance include homopolymers and copolymers containing small amounts of isoprene or p-methylstyrene. Currently, chlorinated and brominated derivatives of butyl(poly[isobutylene-co-isoprene]) have the highest sales volume. 

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