内凝固浴组成对聚氯乙烯中空纤维膜结构和性能的影响

EFFECT OF INTERNAL COAGULANT BATH COMPOSITION ON THE STRUCTURE AND PERFORMANCE OF PVC HOLLOW FIBER MEMBRANES

利用非溶剂致相法纺丝制备聚氯乙烯(PVC)中空纤维膜,考察了内凝固浴中分别添加溶剂N,N-二甲基甲酰胺(DMF)、NaCl和CaCl2对膜结构和性能的影响。结果表明,膜内表面孔结构随内凝固浴中DMF含量的提高,逐渐由致密的蜂窝状变成稀疏的海绵状;膜的水通量先上升后下降、力学性能提高;质量分数6%的DMF内凝固浴的膜性能最优,水通量和力学性能相对于纯水内凝固浴都有很大的提高,制成滤芯时产水量最大。内凝固浴中添加NaCl和CaCl2使中空纤维膜的力学性能提高,但水通量下降。相比而言,内凝固浴中添加溶剂对膜的性能改善效果优于内凝固浴中添加盐。

PVC hollow fiber membrances were prepared through nonsolvent-inducedphase process. The effect of N,N-dirnethyl fonnamide （DMF）, sodium chloride, calcium chloride inthe internal coagulant bath on the structure and performance of the membranes were investigated. The results show that the structure of inner membrane surface varied from compact honeycomb to looser sponge when the DMF mass fraction increasing. The water flux increased and then decreased, the mechanical properties increase. The optimum performance of membrances was DMF （mass fraction 6%） in the internal coagulant bath, the water flux and the mechanical properties were better than pure water. The production of water is largest through filter element verificated. When sodium chloride or calcium chloride was added to the internal coagulant bath, the mechanical properties increase, but the water flux decrease. Comparatively, the solvent is better than salt in the internal coagulant bath to improving the comprehensive properties of the membranes.