|
内容記述 |
The γ-ray resistance of epoxy network polymers was evaluated. Bisphenol A diglycidyl ether (DGEBA) was used as an epoxy oligomer, and 4,4’-diaminodiphenylmethane (DDM), hexahydrophthalic anhydride (HHPA), and phenolic novolac (PN) were used as curing agents. The thermally crosslinked polymers were irradiated with 0?10 MGy of γ-rays. The crosslink density as well as the glass-transition temperature (Tg) for the DDM-cured and PN-cured DGEBA resins decreased upon γ-ray irradiation; however, the elastic modulus at room temperature and the density of the resins increased. By contrast, the Tg for the HHPA-cured DGEBA resin increased slightly and the crosslink density decreased markedly when the specimen was irradiated with γ-rays. Among the three cured systems, the HHPA-cured DGEBA resin exhibited the greatest amount of gas generation during irradiation. Infrared absorption spectra revealed a decrease in the number of ester bonds and an increase in the number of aliphatic and aromatic ether bonds, suggesting that new crosslinking occurred concurrently with chain scission. Overall, among the three cured systems, the PN-cured DGEBA resin was the most stable in terms of chemical structure and physical properties under γ-ray irradiation. |
