Brominated isobutylene isoprene rubber

BIIR Brominated isobutylene-isoprene rubber (bromobulyl rubber)... 

ACRONYMS PIB, HR (isobutylene isoprene rubber), ClIIR (chlorinated HR), BrIIR (brominated IIR) ... 

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... 

Halobutyl rubber (HIIR) is used primarily in tire innerliner and white sidewalls. These elastomers are best for tire air retention owing to lower air permeability as well as aging and fatigue resistance. The chlorinated (CIIR) and brominated (BUR) versions of isobutylene isoprene rubber (HR) can be blended with other elastomers to improve adhesion between HIIR compounds and those based on general purpose elastomers, and improve vulcanization kinetics [16]. 

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

Butyl rubber, brominated. See Isobutylene/isoprene copolymer, brominated Butyl rubber, chlorinated. See Isobutylene/isoprene copolymer, chlorinated Butyl salicylate... 

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

Butyl and Halobutyl Rubber. Butyl mbber is made by the polymerization of isobutylene a small amount of isoprene is added to provide sites for curing. It is designated HR because of these monomers. Halogenation of butyl mbber with bromine or chlorine increases the reaction rate for vulcanization and laminates or blends of halobutyl are feasible for production of mbber goods. It is estimated that of the - 100 million kg of butyl (UR) and halobutyl (HIIR) mbber in North America, over 90% is used in tire apphcations. The halogenated polymer is used in the innerliner of tubeless tires. Butyl mbber is used to make innertubes and curing bladders. The two major suppHers of butyl and halobutyl polymers in North America are Exxon and Bayer (see ELASTOLffiRS,SYNTHETIC-BUTYLrubber). 

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. 

Halogenated Butyl Rubber. Halogenation at the isoprene site ia butyl mbber proceeds by a halonium ion mechanism leading to a double-bond shift and formation of an exomethylene alkyl haUde. Both chlorinated and brominated mbber show the predominate stmcture (1) (>80%), by nmr, as described eadier (33,34). Halogenation of the unsaturation has no apparent effect on the isobutylene backbone chains. Cross-linked samples do not crystallize on extension due to the chain irregularities introduced by the halogenated isoprene units. 

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. 

Butyl rubber is exclusively made by a solution polymerization process. Hence, nanoparticles can only be introduced as a dispersion with the butyl polymer before the solvent is removed, with the monomer, or in a standard compounding protocol. Butyl rubber is prepared from isobutylene. There are no double bonds available for cure after polymerization. A small amount of isoprene is added to the polymerization process to provide for the double bonds necessary for cure. Bromination of the polymer is also done to provide cross-linking sites. 

Thin films of blended deuterated polystyrene (dPS) and poly(vinyl methyl ether) (PVME) were imaged as a fimction of the dPS PVME ratio. Near the critical composition of 35% dPS, an imdulating, spinodal-like structure was observed, whereas for compositions away from the critical mixture ratio, regular mounds or holes (< dPS < < crit and < dPS > (pent, respectively) were present. These variations were assigned to surface tension effects (120). Blends of PBD, SBR, isobutylene-brominated p-methylstyrene, PP, PE, natural rubber, and isoprene-styrene-isoprene block rubbers were imaged (Fig. 18). Stiff, styrenic phases and rubbery core-shell phases were evident as the authors utilized force-modulated afm to determine detailed microstructure of blends, including those with fillers such as carbon-black and silica (121). 

Method of synthesis the manufacture of the bromobutyl rubber is a two step process the polymerization of isobutylene and isoprene to produce butyl rubber, followed by bromination to form bromobutyl rubber a slurry of fine particles of butyl rubber dispersed in methyl chloride is formed in the reactor after Lewis acid initiation bromine is added to the butyl solution in highly agitated reaction vessels ... 

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