蒙脱土/二氧化钛/聚酰亚胺纳米杂化薄膜低温力学及热稳定性能研究

利用插层法和溶胶-凝胶法制备了不同含量的蒙脱土/ 二氧化钛/ 聚酰亚胺(MMT/ TiO₂ / PI) 纳米杂化薄膜。采用傅立叶红外光谱、紫外可见光谱、扫描电镜和热重分析等对该体系的分子结构、断口形貌和热性能进行了表征, 同时研究了聚酰亚胺杂化薄膜低温(77 K) 力学性能。结果表明, 纳米粒子与基体结合情况良好, 热分解温度Td有所上升。TiO₂ / PI 杂化薄膜低温拉伸强度随TiO₂ 质量分数增加而有所下降; 而MMT/ TiO₂ / PI 杂化薄膜拉伸强度随TiO₂质量分数增加而增加并在TiO₂质量分数为2 %时达到最大值, 说明TiO₂ 与MMT 超混杂产生了协同效应。另外, 弹性模量随无机颗粒含量的增加而提高, 但断裂伸长率则下降。 

Cryogenic mechanical properties and thermal stabil ity of polyimidehybrid f ilms f illed with MMT-TiO2 nano-particles

MMT/ TiO2 / PI hybrid films with various nano-filler content s were successfully prepared via in-situintercalation and sol-gel process. The molecule st ructure , fracture morphology and thermal properties were investigated by FTIR , UV-Vis , SEM and TGA , respectively. The mechanical properties at cryogenic temperature (77 K)were studied as a function of TiO2 mass f raction. The result s show that the MMT and TiO2 particles are welldispersed in the polyimide mat rix. Td of hybrid films is higher than that of the pure PI film. At 77 K, the tensilest rength of TiO2 / PI hybrid film decreases with the increase of TiO2 mass f raction while that of MMT/ TiO2 / PIhybrid film increases with the increase of TiO2 mass f raction and reaches the maximum when the TiO2 mass f ractionis 2 %. The elastic modulus increases with the increase of TiO2 mass f raction but the elongation decreases with theincrease of TiO2 mass f raction.