POLYISOBUTYLENE-BASED RUBBERS: PAST, PRESENT, FUTURE

This paper will discuss polyisobutylene-based rubbers. Halobutyl rubbers, brominated or chlorinated copolymers of isobutylene and isoprene are the most important representative of this group. Its unique combination of properties such as low permeability and high damping makes these rubbers irreplaceable. Specialty grades such as crosslinked butyl, butyl-based thermoplastic vulcanizates, star-branched butyl and the brominated copolymer of isobutylene and para-methylstyrene will also be discussed. Recently a randomly branched peroxide-curable butyl rubber was designed. The newest representatives, thermoplastic rubbers based on block copolymers of polyisobutylene and polystyrene or its derivatives, have been shown to be biocompatible. The linear triblock poly(styrene-b-isobutylene-b-styrene) SIBS is used in clinical practice as the drug eluting coating on coronary stents. The randomly branched version reinforced with carbon black, silica and nanoclay opened a new chapter in polyisobutylene-based “biorubbers”. With new applications such as heart valve and breast implant under development, these rubbers have a bright future.