PS–PMMA Block copolymer system as compatibilizer for PS–PVC blends

Abstract

Abstract We are studying the use of PS–PMMA block copolymer systems to improve the mechanical properties of immiscible PS–PVC blends. For a particular PS–PMMA block copolymer system, we found that effective compatibilization occurs at compatibilizer levels of 1–5 wt % in a 50/50 PS–PVC blend. In the samples, storage and stress relaxation moduli were at least midway between those of pure PS and PVC. On the other hand, the equivalent uncompatibilized blend exhibited storage and stress relaxation moduli that are much lower than those of the soft PVC component. Stress relaxation moduli of pure PS remained fairly constant with time, while a 25% drop was observed for pure PVC after 120 sec. Also after 120 s, stress relaxation moduli for the uncompatibilized blend exhibited a 20% drop, while a less than 10% drop was observed for the compatibilized PS–PVC blends.