Two novel aromatic diamines 3,5-diaminobenzophenone (PDA) and 4-(trifluoromethyl) phenyl 3,5-diaminobenzoate (FPDA) were mixed separately with 4, 4'-diaminodiphenyl ether (ODA) and 3,5-diaminebenzoic acid (DABA) with different ratios, and then copolymerized separately with 4, 4'-oxydiphthalic anhydride (ODPA), 3,3' ,4,4'-benzophenonetetracarboxylic dianhydride (BTDA) and 4,4'-(hexafluoroisopropylidene) diphthalic anhydride (6FDA) to give poly(amic acid)s, which were converted into cross-linked polyimides (Pis) with ethylene glycol (EG) by thermal imidization. The structures of these series of Pis were characterized by FT-IR, NMR and GPC. The effect of side-chain content on the thermal stability was investigated by DSC and TGA. The effects of the fluorine group on the properties and separation performance of side-chain polyimides were investigated. The membranes of polyimide obtained were employed in pervaporation separation of benzene/cyclohexane mixtures. The two side-chain polyimide membranes containing 6FDA have an optimal separation efficiency in terms of both flux and separation factor. The cross-linked 6FDA-FPDA/ODA/DABA (1 : 7 : 2) membranes show the most promising separation performance with a flux of 9. 84 kg · μm · m-2 · h-1 and separation factor of 6. 1 for benzene/cyclo-hexane (50/50, mass ratio) at 50℃.%针对苯/环己烷混合物体系的特点,采用两种新型侧链二胺3,5-二氨基苯甲酸苯酯(PDA)和3,5-二氨基苯甲酸-4-三氟甲基苯酯(FPDA),制备了一系列由不同二酐与二胺单体如4,4'-二氨基二苯醚(ODA)和3,5-二氨基苯甲酸(DABA)聚合而成的用于渗透汽化分离苯/环己烷的聚酰亚胺膜,对其结构和各项性质进行了表征,并对膜材料的微观结构与宏观分离性能之间的关系进行了较为深入的研究.随着侧链二胺的引入,聚酰亚胺膜的分离效率随之持续增大,分离能力得以改善.渗透汽化实验结果表明,以6FDA为二酐单体的两类聚酰亚胺膜具有较优异的分离性能.乙二醇交联的6FDA-FPDA/ODA/DABA(1∶7∶2)膜综合渗透汽化分离性能最优.在50℃时,对于含苯50％(质量)的苯/环己烷混合物,其渗透通量为9.84 kg· μm·m-2·h-1,分离因子达6.1.
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