品字形聚偏氟乙烯中空纤维膜的制备

采用溶液相转移法,通过特殊结构的纺丝喷头,制备了品字形PVDF中空纤维膜,讨论了PVDF固含量和芯液组成对品字形膜形态结构和性能的影响。结果表明,随PVDF固含量的增大,品字形膜支撑层空穴变小,膜丝外形融合程度减小,海绵体结构更致密,超滤水通量、透气系数和膜蒸馏通量相应减小,膜丝断裂强力增大;随芯液中溶剂DMAc含量的增加,品字形膜支撑层空穴变小,融合部分海绵体变致密,超滤水通量、透气系数减小,膜蒸馏通量略微提高,膜丝断裂强力增大;优化后的品字形膜的水通量较单芯膜有所降低,但断裂强力显著提高,接近单芯膜的3倍。

Preparation of triangular tri-channels PVDF membranes

Triangular tri-channels polyvinylidene fluoride(PVDF) membranes were prepared by solution induced phase separation method through special spinneret.The effects of the PVDF concentration in drop and internal coagulant composition on the morphology and properties of membranes were investigated.It was found that: large finger-like morphology became smaller,the overall level of integration decreased,sponge-like morphology became denser,UF water flux,gas permeation coefficient and VMD water flux decreased,breaking strength increased with the concentration of PVDF in drop increased from 14.5wt% to 18.2wt%.Large finger-like morphology became smaller,sponge-like morphology became denser,UF water flux and gas permeation coefficient decreased,VMD water flux increased a little,breaking strength increased with the concentration of DMAc in internal coagulant increased from 0 to 30%.The optimized triangular tri-channels PVDF membranes decreased in flux compared with one-hole membranes,however,the breaking strength increased a lot,nearly three times of one-hole membranes.