聚酰亚胺渗透汽化膜用于有机溶剂脱水的改性研究进展

Modified polyimide pervaporation membranes for dehydration of organic solvent

聚酰亚胺有机高分子聚合物结构内含有氢键,且具有良好的耐溶剂性、易成膜性、高力学性能等优点。聚酰亚胺膜有望在渗透汽化有机溶剂脱水领域得到广泛应用。然而,聚酰亚胺膜高分子链间作用力强,链段排列紧密,往往造成溶剂分子渗透困难、渗透通量低等问题,限制其发展。对聚酰亚胺膜开展改性研究,以提高其渗透通量,同时保持高分离因子,是近年来的主要研究方向。本文对渗透汽化膜分离技术进行了概述,介绍了其工作原理及常用分离膜种类。详细综述了近年来用于渗透脱水的聚酰亚胺膜的改性研究进展,重点评述了共混、掺杂、交联和共聚改性,并分析了四种改性方法的作用原理,对分离性能的影响及其优缺点。最后,对聚酰亚胺膜在渗透汽化分离领域未来的发展方向进行展望,指出需揭示聚酰亚胺聚合物链与溶剂分子间的作用机制,解决渗透通量与选择性之间“trade-off”的制约关系。

Polyimide contains hydrogen bonds in organic polymer structure and has good solvent resistance,easy film formation,high mechanical properties,et al.Polyimide membrane is expected to be widely used in the field of pervaporation for organic solvents.However,the strong inter-chain interaction and chain segments packing result in the low flux as the difficult water molecules penetration through the membranes based on them.Therefore,the modification is urgent to improve separation performance of polyimide membranes.In this paper,pervaporation process was summarized systematically including its mechanism and common separation membrane types.The recent research progress in modification methods of polyimide pervaporation membranes was reviewed.Four methods were discussed including blending,doping,cross-linking and copolymerization.The principles of these methods and their influence on separation performance were analyzed.The advantages and disadvantages of the modifications were also summarized.Finally,the development direction of polyimide membrane in the field of pervaporation separation was prospected.It pointed out that the interaction mechanism between polyimide polymer chain and solvent molecule needed to be revealed to solve the“trade-off”restriction between permeation flux and selectivity.