Hydrolytic degradation of highly crosslinked polyaromatic cyanate ester resins

This work presents a robust method for the study of the hydrolytic degradation of a polyaromatic cyanate ester thermoset. A detailed understanding of the kinetics of formation of phenolic degradation intermediates was determined both by fractional increase in weight and near infrared spectroscopy following exposure to controlled moisture and temperature environments. Evidence of decreased cross-linking density by chain scission degradation was also obtained based on the decrease in glass transition temperature (Tg). The effects of catalyst type and concentration on both reaction kinetics and Tg were also determined, linking hydrolysis events directly to Tg degradation. It was found that low conversion of hydrolyzable bonds can lead to significant decreases in Tg values and that the type of catalyst used significantly influences the rate of hydrolysis. The experimental techniques developed in this work were found to be a reliable and reproducible method to characterize the hydrolysis reaction, and can be extended to other cyanate ester systems.