Paper number 1058

MECHANISM OF THERMAL SPIKING-ENHANCED MOISTURE ABSORPTION BY CYANATE ESTER CURED EPOXY RESIN MATRICES

Sunil K. Karad and Frank R. Jones

Maharashtra Institute of Technology, Paud road, Pune 411038, India
Department of Engineering Materials, University of Sheffield, Mappin street, Sheffield S1 3JD, UK

Summary

The moisture absorption of blends of cyanate ester resin with epoxy resin, has been studied under constant hygrothermal condition and with a series of thermal spikes, in an attempt to understand the so-called enhanced moisture absorption phenomenon. Various resin blends of differing composition were studied, so that the effect of resin structure on moisture absorption could be assessed. It was found that intermittently applied thermal spikes can cause enhanced moisture absorption by cyanate ester and blends with epoxy resin in humid environment. The equilibrium moisture concentration was found to increase with the concentration of cyanate ester in the blend. The results of the desorption study on both control and spiked specimens showed that some of the water molecules remain entrained in the resin, probably as a result of hydrolysis of the polymer matrix. The glass transition temperature was reduced by absorbed moisture.

Keywords

cyanate ester, moisture absorption, thermal spiking, glass transition temperature.