FRACTURE MECHANISMS IN RIGID CORE-SHELL PARTICLE MODIFIED HIGH-PERFORMANCE EPOXIES

The fracture mechanisms of a high performance epoxy system modified wi th two types of preformed rigid core-shell particles (RC-SP) were inve stigated. The use of the preformed RCSP enables the control of the dis persion of the toughener phase in the epoxy, which, in turn, allows th e mechanical properties of the modified epoxy to be optimized. The tou ghening effect via the RCSP modification is found to be as good as tha t via the core-shell rubber modification. The moduli and T-g of these RCSP-modified epoxies are virtually unaltered via the RCSP modificatio n, when compared with the neat epoxy resin equivalent The toughening m echanisms in these toughened systems appear to be predominantly crack deflection, crack bifurcation, and microcracking. Approaches for effec tive toughening of high performance polymers via rigid polymers are di scussed.