不同固化剂复配的低温固化环氧树脂体系性能

The resin system of a special solid rocket motor composite case is limited to cure at 55 ℃.The common low-temperature cured epoxy resin systems can satisfy the requirement of curing temperature, however, the corresponding heat-resistance and mechanical properties are inferior, which cannot meet the performance requirement as the resin matrix of composites.Therefore, three curing agents amino-terminated polyoxypropylene(MA223), polyamide(PA651), isophorone diamine(IPDA), were mixed with medium-temperature curing agent diaminodiphenylmethane(DDM), separately.The effects on the curing process, heat-resistance and mechanical properties of TDE-85 resin system were studied.The results show that the resin system with the mixed low-temperature and medium-temperature curing agents at proper ratio can be fully cured at 55 ℃.The glass-transition temperatures of the three resin systems, which are above 90 ℃, are higher than the common low-temperature curing system due to the introduction of DDM with rigid benzene ring.The tensile, flexural and compression properties of TDE-85/MA223/DDM are preferable, and mechanical properties of TDE-85/PA651/DDM are medium.However, the tensile and flexural properties of TDE-85/IPDA/DDM are inferior because of the lack of flexible chains in its molecular structure.In consideration of comprehensive performance, the combination of the flexible molecular chain of MA223 and the rigid benzene ring of aromatic amine DDM endows the resin system with good heat resistance, mechanical properties and the ability of being cured at low temperature.Therefore, curing agent MA223 can be preferably used as the low-temperature curing agent of the resin system of a special solid rocket motor composite case.