Rubber isobutylene, isoprene polymer

Butyl rubber is produced at very low temperature (below — 90°C) to control the rapid exotherm, and to provide high molecular weight. The process consists of charging isobutylene along with isoprene (2-4%) with an inert diluent such as methyl chloride to a reactor to which a Friedel-Crafts catalyst is added. The polymerization is very rapid, and the polymer forms in a crumb or slurry in the diluent. Heat is removed via the reactor jacket. The slurry is steam-stripped to remove all volatiles. The catalyst is neutralized, and antioxidants are added to the slurry prior to drying.53 The halogenated derivatives are produced by the direct addition of the halogen to a solution of the isobutylene-isoprene polymer. 

Butadiene, 2-methyl-, polymer with 2-methyl-1-propene Butyl rubber Isobutylene/isoprene co-polymer Kalar 5214 Kalat 5263 Kalene 800 2-Methyl-1,3butadiene polymer with 2-methyl-1-propene Poly(isobutylene-co-isoprene). Cross-linked butyl composition produces nonsagging butyl-based sealants, e.g., automotive windshield tape, hot melt sealant as base for butyl mastics Viscosity (Mooney, ML 1- 8,100°) = 42-52. Hardman. 

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... 

Until the mid-1950s the only polyolefins (polyalkenes) of commercial importance were polyethylene, polyisobutylene and isobutylene-isoprene copolymers (butyl rubber). Attempts to produce polymers from other olefins had, at best, resulted only in the preparation of low molecular weight material of no apparent commercial value. 

Several polymers based on 1,3-dienes are used as elastomers. These include styrene-1,3-butadiene (SBR), styrene-1,3-butadiene terpolymer with an unsaturated carboxylic acid (carboxylated SBR), acrylonitrile-1,3-butadiene (NBR or nitrile rubber) (Secs. 6-8a, 6-8e), isobutylene-isoprene (butyl rubber) (Sec. 5-2i-l), and block copolymers of isoprene or... 

Synonyms 1,3-Butadiene-2-methyl polymer with 2-methyl-l-propene Butyl rubber HR Isobutylene/isoprene copolymers 3-Methyl-1,3-butadiene polymer with 2-methyl-1 -propene Poly (isobutylene-co-isoprene) Definition Copolymer of isobutylene and isoprene monomers Formuia (CsHs C4H8),... 

Polysar EPM 306 Polysar EPM405 Polysar EPMXF 004. See EPM rubber Polysar SI 018 Polysar SS 260. See Styrene/butadiene polymer Poiysar XL 30102 Polysar XL 40302 Polysar XL 68102. See Isobutylene/isoprene copolymer Polyset 2015. See Polyethylene, high-density Polysilicic acid. See Silica, hydrated Polysilicone. See Silicone elastomer Polysilicone-1... 

Butyl Rubber (HR). This polymer is produced by cationic copolymerization of isobutylene mixed with minor amounts of isoprene. Its molecules are 97 to 99.5 mole percent derived from isobutylene, the rest being derived from isoprene. Its structure can be represented as follows ... 

OSO4 staining - when there is at least 5% unsaturation in the polymers being investigated, e.g. NR/EPDM, bromo isobutylene isoprene rubber/ neoprene (BIIR/neoprene). 

There are many other industrial examples such as acrylic fibers made from polyacrylonitrile (with 7% vinyl acetate). The monomer is fairly water soluble at about 5% and the polymerization occurs in the aqueous phase. However, the polymer is insoluble in water. The primary particles precipitate and agglomerate, forming larger particles that are stabilized by ionic initiator end groups. Butyl rubber (isobutylene+ < 5% isoprene) is produced by cationic polymerization with aluminum trichloride catalyst in methyl chloride at about -100 °C. The polymer precipitates as fine polymer particles from the reaction medium. 

Standard or unmodified grades of butyl rubber are linear, amorphous, gel-free copolymers of isobutylene and isoprene. Individual grades differ from each other in functionality, the level of unsaturation varying with the ratio of isoprene to isobutylene, raw polymer viscosity (a function of molecular... 

Butyl mbber, a copolymer of isobutjiene with 0.5—2.5% isoprene to make vulcanization possible, is the most important commercial polymer made by cationic polymerization (see Elastomers, synthetic-butyl rubber). The polymerization is initiated by water in conjunction with AlCl and carried out at low temperature (—90 to —100° C) to prevent chain transfer that limits the molecular weight (1). Another important commercial appHcation of cationic polymerization is the manufacture of polybutenes, low molecular weight copolymers of isobutylene and a smaller amount of other butenes (1) used in adhesives, sealants, lubricants, viscosity improvers, etc. 

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. 

Butyl rubber (BR) and polyisobutylene (PIB) are widely used in adhesives as primary elastomeric binders and as tackifiers and modifiers. The main difference between these polymers is that butyl is a copolymer of isobutylene with a minor amount of isoprene (which introduces unsaturation due to carbon-carbon double bonds), while polyisobutylene is a homopolymer. 

Cationic polymerizations work better when the monomers possess an electron-donating group that stabilizes the intermediate carbocation. For example, isobutylene produces a stable carbocation, and usually copolymerizes with a small amount of isoprene using cationic initiators. The product polymer is a synthetic rubber widely used for tire inner tubes ... 

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