高通量自聚微孔聚酰亚胺富氧膜的制备

Preparation of high-flux polyimide of intrinsic microporosity for oxygen enrichment membrane

开发高通量富氧膜对空气富氧和原位制氮具有重要意义.本工作以2,4,6-三甲基间苯二胺、4,4′-(六氟异亚丙基)二邻苯二甲酸酐和均苯四甲酸酐为单体,采用高温一步法制备了一种三元聚酰亚胺6FPDM.使用核磁、FTIR、TGA探究了该聚酰亚胺的化学结构和热性能.使用非溶剂诱导相分离法,通过控制铸膜液成分、添加剂、凝固浴温度、相转化时间、刮刀厚度和PMDS涂层等对膜材料的相结构、分离性能进行调控.结果表明,通过控制铸膜液成分和相转化条件(质量分数为15%无水乙醇、质量分数为1%LiNO_(3)、45℃的凝固浴和100μm的刮刀厚度)所制的相转化膜,在经过涂覆后,其氧气的通量达到了96.9 GPU,氧/氮选择性达到了4.3,在膜法富氧方面显示出了非常优异的应用前景.

A ternary copolyimide 6FPDM was prepared using 2,4,6-trimethyl M-phenylenediamine(DAM),4,4′-(hexafluoroisopropylidene)diphthalic anhydride(6FDA)and pyromellitic anhydride(PMDA)as monomers by one-step high temperature polymerization method.By using non solvent induced phase separation method(NIPS),the completion time of phase separation is controlled by controlling the casting solution composition,coagulation bath temperature,additives and membrane thickness.Then,a PMDS layer is coated on the surface of the membrane to prepare the composite membrane.The oxygen/nitrogen separation performance of the polyimide pristine membrane,asymmetric membrane and composite membrane were tested.By regulating the dope solution and phase inversion conditions(15%absolute ethanol,1%LiNO_(3),coagulation bath at 45℃,and casting knife thickness of 100μm),the resulted membrane displayed best gas permeability after coating.The oxygen flux reached 96.9 GPU,and the O_(2)/N_(2) selectivity of 4.3,which has shown great potential in membrane-based oxygen enrichment field.