2026 Volume 47 Issue 2 Pages 96-105
We found that the reaction of 4,4’-diglycidyloxydiphenyl ether with 4,4’-dihydroxydiphenyl ether produced a crystalline cured polymer. The crystalline cured polymer had excellent heat resistance corresponding to Tm, which is higher than Tg, and also showed excellent properties such as low thermal expansion, low moisture absorption and high thermal conductivity due to the improved packing of molecular chains by crystallization. By applying 4,4’-dihydroxybiphenyl as a curing agent to improve heat resistance, Tm was improved by 59.8 °C to 245.6 °C. A crystalline cured polymer was similarly obtained from 4,4’-diglycidyloxybenzophenone, and Tm increased to 230.9 °C. Furthermore, with the aim of introducing a cross-linked structure to improve heat resistance, we examined the application of 4,4’-diaminodiphenylsulfone (DDS) as a curing agent. By using 50 wt% DDS as a curing agent, it was possible to maintain crystallinity while increasing the Tg by 51.3 °C to 169.0 °C. The evaluation of the crystalline cured polymers as a molding material revealed that the thermal conductivity of molded product filled with 94 wt% alumina was 6.9 W/m･K, which was approximately twice that of molded product made from conventional bisphenol F-type epoxy resin.
