RUBBER-TOUGHENED LINEAR AND STAR-SHAPED POLY(D,L-LACTIDE-CO-GLYCOLIDE) - SYNTHESIS, PROPERTIES AND IN-VITRO DEGRADATION

Blends of D,L-lactide/glycolide copolymers were synthesized and their properties and in vitro degradation behaviour were evaluated as a func tion of chain architecture and blend composition. Tensile and impact p roperties of the blends are hardly influenced by matrix composition an d chain architecture, but predominantly vary with the amount of rubber . In vitro degradation showed that hydrolytic degradation is enhanced by the incorporation of glycolide into the poly(D,L-lactide) matrix. S urprisingly, blends based on 6-arm star-shaped poly(D,L-lactide-co-gly colide) retain their mechanical properties for a longer period than bl ends with linear matrices of comparable composition. Physical aging of the linear copolymers is more severe and faster than that of star-sha ped copolymers. (C) 1997 Elsevier Science Ltd.