FRACTURE-BEHAVIOR OF CORE-SHELL RUBBER-MODIFIED CROSS-LINKABLE EPOXY THERMOPLASTICS

The fracture behavior of a core-shell rubber (CSR) modified crosslinka ble epoxy thermoplastic (CET) system, which exhibits high rigidity, hi gh T(g), and low crosslink density characteristics, is examined. The t oughening mechanisms in this modified CET system are found to be cavit ation of the CSR particles, followed by formation of extended shear ba nding around the advancing crack. With an addition of only 5 wt.% CSR, the modified CET possesses a greater than five-fold increase in fract ure toughness (G(IC)), as well as greatly improved fatigue crack propa gation resistance properties, with respect to those of the neat resin equivalents. The fracture mechanisms observed under static loading and under fatigue cyclic loading are compared and discussed.