Blends of butyl and bromobutyl rubbers and polystyrene-polyisobutylene-polystyrene (PS-PIB-PS) block copolymers with improved processability and physical properties

摘要

An investigation of the effects of polystyrene-polyisobutylene linear triblock and three-arm star block thermoplastic elastomers on the processability and properties of butyl and bromobutyl rubbers was undertaken. All properties improved, with the exception of bromobutyl adhesion, which remained acceptable. The green strength of raw polymer blends improved by 30-80% and 5-20% improvement was seen on the carbon black compounds. Die swell was reduced by as much as 60% for compounds containing a triarm-star block. Tear strength doubled and air permeability decreased (by about) 20-40%. Fatigue life improved dramatically (20-fold on 300% crack growth and 80-fold on 600% crack growth). The cured blends can be viewed as interpenetrating networks of the chemically crosslinked rubber and the physically crosslinked thermoplastic elastomers.