聚酰亚胺渗透汽化膜用于有机溶剂脱水的改性研究进展

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.