耐高温可溶性聚酰亚胺树脂及其复合材料

制备了2种耐高温可溶型聚酰亚胺树脂(PI-1, PI-2)及其复合材料, 系统研究了树脂的工艺性, 纯树脂固化物的热性能及其复合材料的界面形貌、 介电性能和力学性能. 研究结果表明, 树脂低聚物在极性非质子溶剂中具有良好的溶解性, 且熔体黏度较低, 表明其具有优异的加工性能. 两种树脂固化物在空气中的5%热失重温度均高于550 ℃, PI-1树脂的玻璃化转变温度(T_g)为430 ℃, PI-2树脂的T_g为380 ℃. 石英纤维/PI-1和石英纤维/PI-2复合材料具有较低的介电常数和介电损耗. 碳纤维/PI-1复合材料在420 ℃下的弯曲强度保持率可达62%, 层间剪切强度保持率可达48%, 具有较优异的高温力学性能. 采用普通模压工艺制备了厚度高达45 mm的复合材料制件, 进一步证明这2种树脂具有优异的工艺性.

High Temperature Resistant and Soluble Polyimide Resins and Their Composites

Two soluble imide oligomers and their composites were prepared， and their processability， the interfacial morphology， and thermal， dielectric and mechanical properties were systematically investigated. The results revealed that the oligomers possessed excellent processability， evidenced by their good solubility in aprotic solvents and low melt viscosities. The 5% mass loss temperatures of the cured resins were higher than 550 ℃. The temperature of glass transition（T_g） values of cured PI-1 and PI-2 were 430 and 380 ℃， respectively. The quartz fiber reinforced composites displayed relatively low dielectric constant and dielectric loss at a frequency of 1─3 GHz. Carbon fiber/PI-1 composite retained 62% of its original flexural strength and 48% of its original inter-laminar shear strength at 420 ℃， indicative of their excellent mechanical properties at eleva-ted temperatures. Composites with a thickness higher than 45 mm were fabricated through compress-molding， which further demonstrates the excellent processability of the resins.