基于2,2′-双取代BPDA基聚酰亚胺气体分离膜的性能研究  

Properties of gas separation membranes based on 2,2′-bisubstituted BPDA-based polyimides

作　　者：杨萌萌 张梦茹 陈爱民[1] YANG Mengmeng;ZHANG Mengru;CHEN Aimin(Zhejiang University of Technology,School of Chemical Engineering,Hangzhou 310014,China;Laboratory of Polymers and Composites,Ningbo Institute of Materials Technology and Engineering,Chinese Academy of Sciences,Ningbo 315201,China)

机构地区：[1]浙江工业大学,化学工程学院,杭州310014 [2]中国科学院宁波材料技术与工程研究所,高分子与复合材料实验室,宁波315201

出　　处：《膜科学与技术》2023年第2期59-67,共9页Membrane Science and Technology

基　　金：浙江省自然科学基金项目(LY19B050004)。

摘　　要：以3,3′,4,4′-联苯四甲酸二酐(BPDA)为原料制备了3种具有不同大小侧基的二酐,即2,2′-二苯基-4,4′,5,5′-联苯四羧酸苯酐(PBPDA)、2,2′-双(2″三氟甲基苯基)-4,4′,5,5′-联苯四羧酸二酐(O6FPBPDA)、3,3■,5,5■-四三氟甲基-[1,1′∶2′,1″∶2″,1■-四苯基]-4,4′,5,5′-四甲酸二酐(12FPBPDA).3种二酐与刚性扭曲的二胺,即2,6-二氨基三蝶烯(DAT)和3,9-二氨基-4,10-二甲基-6H,12H-5,11-亚甲基二苯并[b,f][1,5]二氮芳辛(TBDA2),通过一步法聚合制备了一系列自聚微孔聚酰亚胺(PIM-PI),并通过核磁、红外测试表征了聚合物结构.所得聚合物可溶于多种有机溶剂,用其制备的气体分离膜具有良好的热稳定性和机械性能,5%热失重温度为488~555℃,玻璃化转变温度为451~465℃,拉伸强度为60.5~97.7 MPa,拉伸模量为1.56~2.62 GPa.这些聚合物具有较高的气体渗透系数和中等的气体分离选择性,CO_(2)的渗透系数最高可达1008 Barrer,O_(2)的渗透系数可达200.5 Barrer,比表面积最高可达567 g/m^(2),其中O6FPBPDA-DAT的CO_(2)/CH_(4)分离性能接近1991年Robeson上限,老化后气体分离性能得到了进一步提升.上述结果表明,在BPDA的2,2′-位引入大体积侧基可以提高聚合物的自由体积分数和气体渗透系数.Three dianhydrides with different bulky 2,2′-substituents,namely 2,2′-diphenyl-4,4′,5,5′-biphenyl-tetracarboxylic phthalic anhydride(PBPDA),2,2′-bis(2″-trifluoromethylphenyl)-4,4′,5,5′-biphenyltetracarboxylic dianhydride(O6FPBPDA),and 3,3■,5,5■-tetrafluoromethyl-[1,1′:2′,1″:2″,1■-tetraphenyl]-4,4′,5,5′-tetracarboxylic dianhydride(12FPBPDA)were prepared from 3,3′,4,4′-biphenyltetracarboxylic dianhydride(BPDA).A series of intrinsically microporous polyimides were prepared from three these dianhydrides and contorted diamines,namely 2,6-diaminotriptycene(DAT),3,9-diamino-4,10-dimethyl-6H,12H-5,11-methylenedibenzo[b,f][1,5]diaza-cine(TBDA2)by one-step polycondensation in m-cresol.The structures of these polymers were characterized by ^(1)H NMR and FTIR.These polymers exhibited good solubility in a variety of organic solvents.These polymers showed good thermal and mechanical properties,with T_(g5%)of 488~555℃,T_(g) of 451~465℃,tensile strength of 60.5~97.7 MPa,and modulus of 1.56~2.62 GPa.These polymers displayed high gas permeability and moderate gas selectivity,with CO_(2)permeability being up to 1008 Barrer,O_(2) permeability being up to 200.5 Barrer,and the specific surface area being up to 567 g/m^(2).Further,the CO_(2)/CH_(4) separation performance of O6FPBPDA-DAT approached the 1991 Robeson upper bounds,and the gas separation performance had been further improved after aging.The above results indicate that the introduction of bulky substituents at the 2,2′-position of BPDA can improve the fractional free volume and gas permeability of the resulting polymers.

关 键 词：2 2′-双取代联苯二酐 大体积侧基 聚酰亚胺 气体分离性能 

分 类 号：TQ31[化学工程—高聚物工业]