Viscoelastic Properties of Heterophase Blends of Homopolymers and Block Copolymers

摘要

Stress relaxation and dynamic mechanical measurements were carried out for two types of heterophase polyblends. One is obtained by blending homopolymers of butadiene and styrene (high impact polystyrene of HIPS); the other by blending homopolymer of butadiene with a triblock copolymer of styrene-butadiene-styrene (SBS/B). It was found that for HIPS, time temperature superposition is difficult, and the shift factors cannot be adequately interpreted by a reasonable model. For SBS/B it is impossible to carry out superposition. Possible mechanisms giving rise to the new transition are discussed. (Author)