Abstract
Thermosetting epoxy resins containing polyaromatic backbones such as naphthalene and dihydroanthracene showed low coefficients of thermal expansion (CTE) and high glass transition temperatures. 4,4′-Diaminodiphenyl sulfone (DDS)-cured polyaromatic epoxy resin showed a CTE of 49.8 ppm/K with a Tg of 235°C. These values are 15.3 ppm/K lower and 19°C higher than those of DDS-cured bisphenol A type epoxy resin (DGEBA), and 22.0 ppm/K lower and 77°C higher than those of cresol novolac(CN)-cured DGEBA. There is a correlation between density and CTE of the cured resins, some contribution of the π-π stacking effect for polyaromatic backbones of epoxy resins and the stereostructure of DDS to decrease in CTE was indicated. Moreover, boron trifluoride monoethylamine complex (BTMEA) was found to be effective as a curing accelerator for DDS-cured epoxy resins.
