逆向热致相分离法(RTIPS)制备PES/DMAc/DEG体系微孔膜及其性能表征

Preparation and Characterization of PES/DMAc/DEG System Microporous Membrane by Reverse Thermal-Induced Phase Separation(RTIPS)

以PES/DMAc/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PES微孔膜。探究影响PES微孔膜理化性能及其结构的2个主要因素:凝胶浴温度、非溶剂(DEG)/溶剂(DMAc)的质量比。运用扫描电镜(SEM)﹑纯水通量﹑BSA截留率和机械强度表征微孔膜的结构和性能。试验结果表明:随DEG∶DMAc质量比增加,PES/DMAc/DEG体系的相分离温度降低;SEM结果显示,RTIPS法制备的PES微孔膜表面有明显的微孔,断面呈现双连续海绵状结构;当DEG∶DMAc质量比为0.9∶1、凝胶浴温度为80℃时,PES/DMAc/DEG体系制得的PES膜的渗透性能和机械性能最优:纯水通量为1 230 L/(m^2·h),断裂强度为1.95 MPa。PES/DMAc/DEG体系制得的最优性能的PES平板膜MSWDEG-2-80的应用结果显示,其对膜进水中的UV254具有较好的去除效果,且膜出水浊度稳定,为(0.23±0.01) NTU。

Microporous PES membranes were successfully prepared by reverse thermally induced phase separation(RTIPS)method,which featured a membrane-forming system of low critical solution temperature(LCST-TIPS),and consisted of PES,DMAc and DEG.Effects of the gel bath temperature and mass ratios of nonsolvent(DEG)/solvent(DMAc)on microporous membrane properties and structure were investigated.Scanning electron microscopes(SEM),pure water flux,BSA rejection ratio and mechanical properties were used to characterize the structure and properties of membranes.The results showed that phase separation temperature decreased with increasing mass ratio of DEG/DMAc.SEM results showed that the surface of microporous membrane prepared by RTIPS method had obvious micropores top-surface,and its cross-sections were bi-continuous spongy structure.With 0.9/1 of DEG/DMAc and water bath temperature of 80℃,PES membrane permeability and mechanical properties were optimal,membrane pure water flux was 1230 L/(m2·h),and breaking strength was 1.95 MPa.The application results of superior PES flat sheet membrane MSWDEG-2-80 fabricated from PES/DMAc/DEG system showed that MSWDEG-2-80 possessed excellent removal ratio on the inflow’UV254,besides,the membrane outflow indicated stable turbidity of(0.23±0.01)NTU.