聚氨酯/环氧树脂互穿网络硬泡的热稳定性

Thermal Stability of Rigid Polyurethane/Epoxy Resin Interpenetrating Polymer Network Foams

采用同步法合成了聚氨酯／环氧树脂互穿聚合物网络（PU／ERIPN）硬泡，通过热重分析法对其热分解过程进行了研究，计算了各分解阶段的反应动力学参数．研究表明：氮气气氛中，PU／ERIPN硬泡根据环氧树脂含量不同其热分解过程有2～3个失重阶段；随着IPN体系中环氧树脂含量增加，第一阶段的失重率减小，第二阶段的失重率增大；PU与ER质量比分别为90：10，70：30，50：50的硬泡PUE10，PUE30，PUE50在第一、二阶段总的热失重率依次为62．2％，58．0％，52．9％，均低于纯聚氨酯泡沫和纯环氧树脂的热失重率．经IPN改性后，泡沫的热稳定性显著提高，其中PUE10的热稳定性最好，说明聚氨酯和环氧树脂形成互穿网络后的协同效应使得IPN硬泡的热稳定性增强．预测IPN泡沫在300℃的氮气气氛中失重5％的热老化寿命约为8个月，表明IPN泡沫的热稳定性较好．

A series of rigid polyurethane/epoxy resin interpenetrating polymer network （PU/ER IPN） foams were prepared by a simultaneous polymerization technique. The thermal decomposition behaviors of the rigid PU/ER IPN foams were studied by thermogravimetric analysis（TGA）. The kinetic parameters of thermal degradation for the IPN foams were calculated. The data obtained by TG in presence of nitrogen show that the degradation of the IPN foams is complicated, it undergoes two or three steps, and depends on the ER contents. As the ER content increases, the mass loss in the first step decreases while in the second step increase. The total mass losses of PUE10, PUE30 and PUE50（the mass ratio of PU to ER is 90：10, 70：30, 50：50 respectively） in the first and second steps are 62.2%, 58.0%, 52.9% respectively, and each one is lower than that of pure polyurethane foam or epoxy resin. The thermal stability of PUE10 shows the best stability. The excellent thermal stability is due to the synergetic effect induced by the forced compatibility of the individual components, namely, PU and ER. The lifetime estimation indicates the maximum lifetime of PUE10 at 300 ℃ in nitrogen to be about 8 months.