聚酰胺酸合成工艺与聚酰亚胺膜制备及表征

聚酰亚胺是一类新型高性能的聚合物材料,是由聚酰胺酸脱水环化而成,因此高分子量的聚酰胺酸是获得高性能PI的前提。探讨了聚酰胺酸合成过程中的影响因素,得出了合成高分子量的聚酰胺酸的最佳工艺条件为:均苯四羧酸二酐与4,4' 二氨基二苯醚摩尔比为1.015～1.020∶1,反应温度20℃,反应时间为3h,聚酰胺酸在N 甲基 2 吡咯烷酮中的特性粘度为0.62dL/g左右。采用热转化法将聚酰胺酸脱水环化制备成均苯型聚酰亚胺膜,通过差示扫描量热法、红外光谱等进行了表征,其玻璃化转变温度为365～385℃,拉伸强度达192.4MPa,表明得到的聚酰亚胺膜具有优良的机械性能。

Study on process for synthesis of polyamic acid and preparation and characterization of polyimide membrane

Polyimide is a new kind of polymer material with high performance. Polyimide is made from polyamic acid by cyclodehydration, so polyamic acid with high molecular weight is essential to get polyimide with high performance. The effects on process for synthesis of polyamic acid has been investigated. The optimal reaction condition in order to get high molecular weight of polyamic acid were obtained: the mole ratio of pyromellitic acid dianhydride to 4,4'-diaminodiphenylether is about 1.015～1.020∶1,the reaction temperature is 20℃,the reaction time is about 3 h, and the intrinsic viscosity of polyamic acid in NMP was measured to be 0.62 dL/g. By using the method of thermal conversion, the polyimide membrane has been successfully prepared. Polyimide membrane is characterizd by IR, DSC, the glass transition and the tensile strength of the polyimide membrane are determined to be 365～385℃ and 192.4 MPa respectively. The test results showed that polyimid has good mechanical properties.