第一外凝胶剂对PVDF-PFSA中空纤维共混膜结构的影响

Effect of the First External Coagulants on Morphologies of PVDF-PFSA Hollow Fiber Blend Membranes

以聚偏氟乙烯(PVDF)与全氟磺酸(PFSA)为共混材料,采用双外凝胶剂法制备了PVDF-PFSA中空纤维共混膜,考察了第一外凝胶剂中乙醇浓度及长度对膜结构的影响。实验结果表明,乙醇的质量分数从30%增加到90%,膜断面指状孔与海绵状结构中网络状部分逐渐减少,外皮层逐渐消失,纯水通量明显上升,牛血清截留率下降;乙醇水溶液质量分数为70%时,膜断面均为海绵状结构,牛血清截留率低,在8.0%左右基本保持不变;随第一外凝胶剂长度增加(5cm～25cm),纯水通量增加,断面海绵状结构中网络状部分逐渐减少,呈现趋于圆整的颗粒状结构。

Polyvinylidene fluoride （PVDF）-perfluorosulfonic acid （PFSA） hollow fber blend membranes were prepared using the dual-coagulant method. Effect of the first external coagulant on morphologies of membranes was investigated. Finger-like voids and outer layer gradually disappeared,pure water permeation flux （PWP） increased and BSA retention （R） decreased with the increment of ethanol concentration. While ethanol aqueous solution mass fraction was 70%,finger-like voids were absent,outer layer and network structures gradually disappeared,PWP increased and R was about 8.0% and almost kept unchanged with the increment of the length of first external coagulant from 5 cm to 25 cm.