Microporous polyethersulfone membranes prepared under the combined precipitation conditions with non-solvent additives
Microporous polyethersulfone membranes prepared under the combined precipitation conditions with non-solvent additives
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DOI：
10.1002/pat.982
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发表时间：
2008-04-01
影响因子：
3.4
通讯作者：
Yang, Hu
中科院分区：
文献类型：
--
作者：
Li, Jing-Feng;Xu, Zhen-Liang;Yang, Hu
以二甘醇（DegOH）为非溶剂添加剂（NSA），N，N-二甲基乙酰胺（DMAc）为溶剂（S），采用浸渍沉淀法结合气相诱导相分离（VIPS）工艺制备了聚醚砜（PES）平板膜。透光率用于跟踪浸渍过程期间以及VIPS阶段期间的沉淀速率。随着NSA的加入，铸膜液的粘度增加，导致沉淀速率变慢。虽然沉降速率降低，但瞬时分层类型得以维持。高通量膜仅在高质量比的NSA/S下获得;生产的膜在顶面上具有蜂窝状孔，在横截面上具有海绵状结构。浸渍沉淀前的VIPS过程对表面蜂窝孔的形成是重要的。随着暴露时间的增加，铸膜液表面发生液-液相分离，成核和生长导致铸膜液表面形成微孔。凝固浴温度对沉淀率也有较大影响，凝固浴温度过高主要是加速了溶剂和非溶剂的迁移。高凝固浴温度可获得具有多孔表层的高通量膜，但同时膜的机械性能减弱。版权所有（C）2007约翰威利父子有限公司
Using diethylene glycol (DegOH) as non-solvent additive (NSA) and N, N-dimethylacetamide (DMAc) as solvent (S), polyethersulfone (PES) flat sheet membranes were prepared via immersion precipitation combined with the vapor induced phase separation (VIPS) process. Light transmittance was used to follow the precipitation rate during the immersion process as well as during the VIPS stage. As the addition of the NSA, the viscosity of casting solutions increased, which led to a slow precipitation rate. Though the precipitation rate decreased, the instantaneous demixing type was maintained. High flux membranes were obtained only at a high mass ratio of NSA/S; producing membranes had cellular pores on the top surface and sponge-like structure on cross section. The VIPS process prior to immersion precipitation was important for the formation of cellular pore on the surface. With the increase in exposure time, the liquid-liquid phase separation took place on the surface of casting solution; nucleation and growth induced the formation of cellular pore on the top surface. Coagulation bath temperature also had large effect on the precipitation rate; high temperature on coagulation bath mainly accelerated the transfer of solvent and non-solvent. Higher flux membrane with a porous skin layer could be obtained at a high coagulation bath temperature, but at the same time the mechanism properties were weakened. Copyright (C) 2007 John Wiley & Sons, Ltd.