含三氟甲基聚酰亚胺的合成与性能研究

通过在4,4′-二氨基二苯醚(4,4-′ODA)单体中引入三氟甲基合成了一种新型二胺单体2-三氟甲基-4,4′-二氨基二苯醚(3FODA),该单体具有良好的溶解性和高的反应活性,使用3FODA替代4,4′-二氨基二苯甲烷(MDA)制备了PMR热固性聚酰亚胺树脂.树脂溶液高浓度低粘度,具有室温下良好的储存稳定性;树脂具有很好的加工性能,成型后的模压件显示了优异的热性能和耐热氧化稳定性,玻璃化转变温度在336~379℃之间;此外树脂具有较好的电性能和较低的吸水率.

SYNTHESIS AND CHARACTERIZATION OF TRIFLUROMETHYL-CONTAINING POLYIMIDES

A new fluorine-containing diamine of 2-trifluoromethyl-4,4′-diaminodiphenyl ether(3FODA) which has good solubility and high reactivity was synthesized.Two calculated molecular weight PMR polyimide resins were synthesized with 3FODA instead of methylene dianiline(MDA) in the first generation PMR polyimide KH-304 and PMR-15.The results showed that the monomer resin solution has high concentration,low viscosity and good stability under room temperature.The imidization process of the resin was investigated by TGA and FTIR,and the molding powder exhibited good processibility.The molded resins possessed high glass transition temperatures(T_g) in the range of 336～379℃ and the decomposition temperature in the range of 536～566℃.3FODA-PI-15 resin exhibited high glass transition temperatures and low decomposition temperature compared to 3FODA-PI-30 because of its low molecular weight.In addition,both 3FODA-PI15 and 3FODA-PI-30 resin showed good thermo-oxidative stability at 320℃,and 3FODA-PI-15 resin has lower weight loss because of lower content of nadic anhydride.3FODA-PI resin exhibited excellent electrical properties and low water uptake.The combined properties suggested that this kind of polyimide resins can be used as matrix resin in aviation and space industry.