热致相分离法制备聚氯乙烯微孔膜及其结构控制与性能研究

Structure and performance of microporous PVC membranes prepared via thermally induced phase separation

选用二苯醚(DPE)为稀释剂,通过热致相分离(TIPS)法制备聚氯乙烯(PVC)微孔膜.从热力学和动力学两方面,研究聚合物浓度、冷却速率等因素对体系相分离行为和膜结构的影响.结果表明,在TIPS法制备PVC微孔膜的过程中,PVC/DPE体系发生液-液相分离,膜孔呈现典型的蜂窝状结构.聚合物浓度或冷却速率的减小,都有利于稀释剂富相液滴的生长并促进液滴尺寸的增大,进而引起膜孔径和纯水通量的增大,并导致其机械性能的减弱.

Microporous polyvinyl chloride （PVC） membranes were prepared via thermally induced phase separation （TIPS） process using diphenyl ether （DPE） as diluent. In order to understand the influences of polymer concentration and cooling rate on phase behavior and membrane structure, the thermodynamic and kinetics properties of membrane formation process were investigated by optical microscope. The resulting PVC microporous membranes presented symmetric cellular structure, which is typical results of liquidliquid phase separation. The decrease of polymer concentration and cooling rate facilitated the growth of droplet phase and increased the size of droplets. The results matched with the pore size of the obtained PVC membranes. Correspondingly, PVC membranes possessed higher water flux and worse mechanical properties when lower polymer concentration and higher cooling bath temperature were submitted to experiment.