Assessment of Bismaleimide-modified Cyanate Ester as Matrix Resin for Elevated Service Temperature Carbon Composite Applications

Bisphenol A-based cyanate ester resin (BADCy) was modified with different amounts of bismaleimide (BMI) to improve the thermomechanical properties of the parent resin. The DSC investigation of the curing of mixtures of BADCy and BMI suggested that they cured in one single step and addition of BMI shifted the cure initiation and peak curing temperatures of BADCy to higher temperatures. The addition of BMI delayed the gelation times of BADCy. The BMI modification of BADCy did not seem to affect the high T _g of BADCy but a marginal increase in water absorption was seen. Flexural strength of carbon composites with BADCy increased considerably upon modification with BMI. The elevated temperature testing of carbon composites made with BMI-modified BADCy suggest that they retain their advantageous mechanical properties quite well even at 120 C.