高分子浓度对NIPS结合气体生成制备的中空纤维膜结构和性能的影响

Influence of polymer concentration on structure and performance of hollow fiber membranes prepared by NIPS cooperated with gas generation

为制备小直径中空纤维膜,将含有气体生成剂硼氢化钠的聚砜溶液通过单孔不锈钢喷丝头,直接制备中空纤维膜,研究高分子浓度对中空纤维膜结构和性能的影响.结果表明:硼氢化钠水解制氢和非溶剂致相分离(NIPS)过程之间的协同作用,有利于制备出中空结构良好和高度多孔的中空纤维膜;聚砜质量分数由15%增加到25%时,中空纤维膜致密皮层附近的指状结构和中空孔结构逐渐消失,中空纤维膜平均孔径从11.2nm增加到21.6 nm,表面有效孔隙率从6 435.1 m^(-1)减少到54.8 m^(-1),总孔隙率从84.5%减少到78.3%,中空纤维膜对刚果红的截留率从93.0%增加到97.4%.

In order to prepare hollow fiber membranes （HFMs） with small diameters, HFMs were prepared from polysulfone dimethylacetamide solution mixed with sodium borohydride as gas producing agent extrude through a stainless steel needle as single orifice spinneret. The effects of polymer concentration on the structure and performance of HFMs were investigated. The results showed that synergy between hydrogen generation from hydrolysis of sodium borohydride and nonsolvent induce phase separation（NIPS） process would benefite the fabrication of HFMs with good hollow bore structure and highly porous. As the polymer concentration increased from 15% to 25%, the finger-like structures near the dense skin surface and the hollow bore structure of HFMs disappeared gradually, the mean pore size of HFMs increased from 11.2 nm to 21.6 nm, the effective surface porosity decreased from 6 435.1 m^-1 to 54.8 m^-1, the overall porosity of HFMs decreased from 84.5% to 78.3%, and Congo red rejections increased from 93.0% to 97.4%.