文摘
Poly(isobutylene-co-p-methylstyrene) (IB/p-MS) random copolymer is a new generation of polyisobutylene-based elastomers. The cationic copolymerization of IB with p-MS was thoroughly examined by using 2-chloro-2,4,4-trimethylpentane/ethylaluminiumsesquichloride/electron donor as initiating system. IB/p-MS random copolymers with high molecular weight were obtained at elevated temperature through the addition of ethyl acetate; the reaction proceeded in a mildly exothermic manner. Although the reactivity ratios of comonomer pairs differ by close to an order of magnitude, p-MS was uniformly distributed in the chains. IB/p-MS random copolymer can be brominated by adding molecular bromine into the copolymer solution, thereby yielding a completely saturated polymer backbone with a chemically reactive site. The types and selection of appropriate vulcanization systems for bromide-functionalized IB/p-MS random copolymers are also discussed.