Rubber modification of low temperature cure cyanate ester matrices and theperformance in grass fabric composites

Low temperature cure cyanate ester resin systems were developed and modifie d with epoxy-terminated butadiene acrylonitrile rubber (ETBN) and impregnat ed into woven glass fabric. Mode I and mode II interlaminar fracture toughn ess values of the cured laminates were evaluated as a function of rubber co ncentration. Mode I fracture toughness increased to almost twice that of th e unmodified system, while mode II fracture toughness remained essentially unchanged. Composite samples were subjected to aging experiments in water a nd the absorption/desorption behavior was investigated as was the effect on thermal performance. The presence of rubber was found to reduce the rate o f matrix deterioration but also caused a substantial increase in water upta ke. It was found that although the addition of rubber to the matrices decre ased the unconditioned (dry) T-g, all specimens showed the same reduction i n T-g after equilibrium water absorption.