Cryogenic microcracking of rubber toughened composites

This study investigated the influence of carboxyl‐terminated butadiene acrylonitrile (CTBN) liquid rubbers on the microcracking response of polymeric composite materials to cryogenic cycling. Matrices of carbon fiber/epoxy prepregs were modified with different concentrations of two CTBN liquid rubbers. The glass transition temperature and the interlaminar shear strength of the laminate systems were depressed as a result of the presence of CTBN in the epoxy phase. An increase in total rubber concentration with the continuous phase was found to decrease and in some cases eliminate microcracking in laminates exposed to cryogenic cycling.