STUDIES ON IMPACT MODIFICATION OF POLYSTYRENE (PS) BY ETHYLENE PROPYLENE DIENE (EPDM) RUBBER AND ITS GRAFT-COPOLYMERS .2. PS EPDM-G-(STYRENE-CO-METHYLMETHACRYLATE) BLENDS

The toughness of a polymer blend is one of the major factors deciding its practical application. An impact modified polystyrene (PS) is usually a multiphase system consisting of the thermoplastics and an elastomeric component. The heterogeneous character of such a system and the interfacial adhesion between the components determine its impact strength. The graft copolymer of ethlene–propylene–diene (5‐ethylidene‐2‐norbornene) rubber with styrene and methylmethacrylate is synthesized, characterized, and blended with polystyrene to improve its impact strength. It is observed that there is improvement in impact strength with the subsequent decrease of tensile strength. The improved impact strength has been discussed in terms of morphology, compatibility, and interfacial adhesion of graft copolymers with PS matrix. Copyright © 1990 John Wiley & Sons, Inc.