Synergistic Toughening in Rubber Modified Blends

摘要

Particle size and particle adhesion are two factors involved in the rubber toughening of glassy polymers. The role of each has been examined in the toughening of polystyrene (PS), styrene acrylonitrile (SAN) copolymers and poly(methyl methacrylate) (PMMA). An SBS block copolymer and an emulsion rubber particle with a PMMA grafted shell were compared as modifiers for these polymers and subsequently used in combination. The emulsion particles toughened PMMA and SANs (14.7 ans 25.0% AN) with which its PMMA shell was miscible. It did not toughen PS or a SAN(6.3% AN) with which its PMMA shell was immiscible. Emulsion particle size as well as adhesion were responsible for its poor performance in the latter case. When used in combination for the matrix SAN(25% AN by weight), a synergistic toughening effect well beyond that of either additive alone was observed.