摘要
利用2,2′-双(3,4-二羧基苯基)六氟丙烷二酐(6FDA)与2,2′-双(3-氨基-4-羟基苯基)六氟丙烷(APAF)和4,4′-二氨基-2,2′-双三氟甲基联苯(TFMB)共聚合,并采用化学环化工艺合成了共聚结构的聚酰亚胺(n(APAF)∶n(TFMB)=5∶5),并经不同温度的热处理得到一系列热重排聚合物薄膜(TR)。研究了热重排过程中薄膜结构的变化及其对气体分离透过性能及力学性能的影响。结果表明,未热重排的聚酰亚胺前驱体能溶于N-甲基-吡咯烷酮(NMP)、N,N-二甲基乙酰胺(DMAc)和N,N-二甲基甲酰胺(DMF)等有机溶剂,具有较好的成膜性;聚合物主链中酰亚胺环与邻羟基经350~450℃热重排反应可形成刚性噁唑环。随着热处理温度的升高,气体渗透性能从7.2mol/(m2·s·Pa)增大到36.7 mol/(m2·s·Pa),分离系数略有降低。同时,热重排反应赋予聚合物薄膜优异的热稳定性和力学性能,TR400-2在氮气氛围中5%的热失重温度为491℃,10%的热失重温度为519℃,薄膜的断裂强度为85~136 MPa,断裂伸长率为3.0%~9.0%。以上结果表明基于热重排反应制备的聚酰亚胺膜材料在气体分离领域有着极大的应用前景。
Recently,thermally rearranged(TR)poly(benzoxazole-co-imide)have been paid a lot attention due to their outstanding gas separation performance.Herein,the copolymers 6FDA-APAF/TFMB(molar ratio of n(APAF)∶n(TFMB)=5∶5)containing hydroxyl were synthesized by chemical imidization and they were thermally rearranged at different temperatures.The 4,4′-(hexafluoroisopropylidene)diphthalicanhydride(6FDA)was used as dianhydride monomer,and 2,2′-bis(3-Amino-4-hydroxyl-phenyl)hexafluoropropane(APAF)and 4,4′-diamino-2,2′-trifluoromethyl biphenyl(TFMB)were used as diamine monomers.Their physical properties and gas permeation behaviors were investigated.The polyimide precursor has a fairly good solubility in most of the solvents such as NMP,DMAc and DMF,that ensures good film processing.The results show that benzoxazole ring is formed successfully after thermally rearranged at 350-450℃.In nitrogen,the TR400-2 has 5%weight loss at temperature of 491℃and 10%weight loss at temperature of 519℃.All films'breaking strength and elongation at break are in the range of 85-136 MPa and 3.0%-9.0%,respectively.The gas permeability for CO 2 increases from 7.2 to 36.7 mol/(m 2·s·Pa)and the CO 2/CH 4 selectivity decreases a little with increasing the treating temperature.The thermally rearranged films exhibit good thermal stability and mechanical property.In general,the results show that the permeability and separation selectivity of thermally rearranged(TR)poly(benzoxazole-co-imide)have been enhanced obviously,which proves that thermally rearranged membranes have a great application prospect in the field of gas separation.
作者
江雪薇
董杰
赵昕
张清华
JIANG Xuewei;DONG Jie;ZHAO Xin;ZHANG Qinghua(State Key Laboratory for Modification of Chemical Fibers and Polymer Materials,College of Materials Science and Engineering,Donghua University,Shanghai 201620,China)
出处
《功能材料》
EI
CAS
CSCD
北大核心
2018年第4期4024-4031,共8页
Journal of Functional Materials
基金
国家自然科学基金资助项目(21774091)
关键词
热重排
聚酰亚胺膜
气体分离
渗透性
thermally rearranged polymer
polyimide membrane
gas separation
permeability
