Effets des agents interfaciaux copolymères tribloc sur le comportement en rupture et en écoulement du mélange de polystyrène/caoutchouc-éthylène-propylène

Abstract

In a previous study two triblock copolymers of styrene/ethylene - butylene/styrene (SEBS), of different molecular weights, were used to compatibilize a blend of 80 volume % of polystyrene (PS) and 20 volume % of ethylene - propylene rubber (EPA). The aim of this work is to foster the understanding of the effects of the two triblock copolymers on fracture and yielding behavior of the blends over a large range of loading rates and temperatures. For this purpose, the blends of different concentrations of these two triblock copolymers were studied at various test conditions. The focus is put on the time - temperature dependence of fracture performance and yielding behavior of these blends. The addition of the triblock copolymer, known as an interfacial modifier, allows the brittle PS/EPR blend to become more ductile. The time-temperature dependence of the brittle-ductile transition in fracture performance of the blends is controlled by an energy activation process and can be predicted by the Arrhenius equation."--Résumé abrégé par UMI