一种含三氟甲基取代不对称芳香二胺及其可溶性透明聚醚酰亚胺的合成与表征

Soluble and Optically Transparent Poly(ether imide) Based on a Novel Aromatic Unsymmetrical Trifluoromethylated Diamine

以2,6-二甲基苯酚和4-硝基苯甲酰氯为起始原料,经三步有机反应设计合成了一种含氟不对称芳香二胺:(4'-(4"-胺基-2"-三氟甲基苯氧基)-3',5'-二甲基苯)-(4-胺基苯)甲酮(3);并由该二胺单体和二苯醚四酸二酐经一步法缩聚制备了一种新型含氟聚醚酰亚胺,其特性粘度为0.68dL/g.该聚醚酰亚胺表现出优良的溶解性能和光学性能:室温下不仅可以溶于N-甲基-2-吡咯烷酮、N,N-二甲基乙酰胺、N,N-二甲基甲酰胺等强极性溶剂中,还能溶于低沸点的氯仿、四氢呋喃、二氯甲烷等溶剂中;由该聚合物溶液所制的薄膜无色透明,截断波长在352,400nm后具有高的透明性.此外该聚醚酰亚胺还表现出良好的热性能和机械性能:玻璃化转变温度在288℃,氮气中起始分解温度在508℃;该聚合物薄膜的拉伸强度为91MPa,断裂伸长率在10%～15%,起始模量为1.7GPa.

A novel aromatic unsymmetrical fluorinated diamine monomer, （4＇-（4＂-amino-2＂-trifluoro- methylphenoxy）-3＇,5＇-dimethylphenyl）（4-aminophenyl）methanone （3）, was successfully synthesized in three steps using 2,6-dimethylphenol and 4-nitrobenzoyl chloride as starting material, which was then employed to prepare a fluorinated poly（ether imide） with commercial aromatic dianhydride, 4,4＇-oxydiphthalic anhydride. The inherent viscosity of the resulting polyimide was 0.68 dL/g, and it exhibited an excellent solubility and optical property. It was readily soluble not only in some strong polar solvents such as N-methyl-2- pyrrolidone, N,N-dimethylacetamide, and N,N-dimethylformamide, but also had a good solubility in some low-boiling-point solvents such as chloroform, tetrahydrofuran, and dichloromethane. The polyimide film showed high optical transparency and colorless, with a UV-vis absorption edge at 352 nm. Furthermore, the polyimide also showed good thermal and mechanical properties. Onset decomposition temperature （To） of the polyimide was at 508 ℃ under nitrogen atmosphere, and its glass-transition temperature （Tg） was at 288 ℃. The polyimide film had strengths at break at 91 MPa, elongations to break of 10%-15%, and initial moduli at 1.7 GPa.