Isoprene polymer

Isoporphyrin cation, 4, 395 Isoprene polymers, 1, 303 Isoprothiol ane biological activity, 6, 895 as fungicide, 1, 195... 

Jagisch, F.C., Novel radial styrene-isoprene polymers for pressure sensitive adhesives. In Proceedings of the European Tape and Label Conference, Antwerp, Belgium, April 18, 1997. 

Some of the polybutadienes obtained with transition metal-based coordination catalysts have practical significance the most important is cA-1,4-polybutadiene, which exhibits excellent elastomeric properties. As regards isoprene polymers, two highly stereoregular polyisoprenes, a cA-1,4 polymer (very similar to natural rubber) and a trans- 1,4-polymer (of equal structure to that of gutta percha or balata) have been obtained with coordination catalysts. Various polymers of mixed 3,4 structure, amorphous by X-ray, were also obtained [7]. 

Natural rubber, graft copolymers of natural rubber with acrylic or methacrylic acid esters of mono-functional CiC4 alcohols butadiene and isoprene polymers polymers... 

We have seen that the double bonds in a chain of polyisoprene can exist as cis and trans stereoisomers. Synthetic polyisoprene then has the added complexity of 1,2- versus 1,4-polymerization in addition to the possible existence of different stereoisomers about the double bond. As with butadiene, different coordination catalysts produce isoprene polymers with a preponderance of 1,2- or 1,4- polymer as well as different stereochemistry. Not unexpectedly, these different polymers possess strikingly different physical properties. 

Table III. Microstructure and Molecular Weights of Butadiene and Isoprene Polymers...

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. 

Kawai and Inoue (49) recently explored the mechanical blend of poly-styrene/polyisoprene/poly(styrene-b-isoprene) polymer 1 and polymer 2 appear as both homopolymers and block components. 

In addition to vitamin E, the isoprenoids and their derivatives up to cholesterol give rise to all the fat-soluble vitamins (A,D,E,K) and to coenzyme Q (used in electron transport in the Ferris Wheel Generator). Dolichol is an isoprene polymer that participates in the transfer of oligosaccharides during glycoprotein synthesis. 

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 copolymers. See Isobutylene/isoprene copolymer Isobutylene, isoprene polymer, brominated. 

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