低临界共溶温度PES体系制备微孔膜的研究

Study on Preparation of Microporous Membrane via PES Low Critical Solution Temperature System

以聚醚砜(PES)/N,N-二甲基乙酰胺(DMAc)/一缩二乙二醇(DEG)低临界共溶温度(LCST)体系为铸膜液,利用低临界共溶温度(LCST)的热致相分离(LCST-TIPS,简称RTIPS)法制备了PES微孔膜。通过透光实验测试RTIPS过程的LCST,以扫描电镜、渗透和力学实验表征膜的形态和性能。研究了非溶剂/溶剂(DEG:DMAc)质量比和成膜水浴温度对PES膜结构和性能的影响。实验结果表明,随DEG:DMAc质量比增加,相分离温度降低;利用RTIPS技术抑制了膜断面指状孔的出现,形成表面有明显微孔和断面对称的双连续膜结构;DEG:DMAc质量比0.8:1,成膜水浴温度60℃,膜纯水通量和平均孔径最大;通过RTIPS机理所成膜综合力学性能优于非溶剂致相分离(NIPS)法所制备的膜。

Microporous polyethersulfone（PES） membranes were successfully prepared by thermally induced phase separation method in which the employed membrane-forming system features a low critical solution temperature（LCST-TIPS,i.e.RTIPS） and consists of PES,N,N-dimethylacetamide（DMAc） and diethylene glycol（DEG）.Light transmittance was performed to survey the LCST during the RTIPS process.The morphology and performance of the prepared PES membranes were respectively characterized with scanning electron microscopy,permeation and mechanical experiments.The effects of the mass ratios of nonsolvent/solvent（DEG：DMAc） and water bath temperature on membrane structure and properties were investigated.The results show that the phase separation temperature decreases with increasing mass ratio of DEG：DMAc.Using the RTIPS process,the membrane structure changes from a finger-like pores structure to a bicontinuous structure along its cross-section,and a porous surface was also observed.With the mass ratio of DEG：DMAc of 0.8：1 and the water bath temperature of 60℃,the membrane has the maximum mean pore size and pure water flux.Moreover,the mechanical properties of membranes prepared via the RTIPS are better than those of the membranes prepared by nonsolvent induced phase separation（NIPS） method.