1989 Volume 38 Issue 427 Pages 367-371
The degradation behavior of high-energy electron irradiated epoxy based FRP composite laminates was studied using the Mode II interlaminar fracture toughness GIIC, measured by ENF tests. The radiation-induced degradation mechanisms were investigated with GIIC and the scanning electron micrographs of fracture surfaces.
For GFRP the significant decrease in GIIC was found. Debonding of glass fibers and epoxy matrix (or degradation of silane coupling agents) plays an important role in degradation in addition to resin degradation. Thus, the improvement of the radiation resistance of fiber-resin interfaces as well as matrix itself is of supreme importance in order to increase the radiation resistance of GFRP.
For CFRP, on the other hand, no degradation in fiber-resin interfaces was found and the slight decrease in GIIC seems to be due to the resin degradation.
The sensitivity of radiation-induced degradation was more pronounced in the Mode II Interlaminar fracture toughness than in the interlaminar shear strength, for both GFRP and CFRP. Consequently, interlaminar fracture toughness measurements were found necessary for evaluating properly the radation-induced degradation of FRP composites.
