耦合相转化技术制备聚偏氟乙烯中空纤维膜及微结构调控

Preparation of polyvinylidene fluoride hollow fiber membranes and microstructure control by coupling phase transformation

为考察热致相分离(TIPS)降温过程中非溶剂致相转化(NIPS)的作用及水溶性非稀释剂对中空纤维膜微结构的影响,以聚偏氟乙烯(PVDF)为原料,加入不同比例水溶性非稀释剂聚乙二醇(PEG400),利用TIPS与NIPS的耦合来制备中空纤维膜。利用热台偏光显微镜和差示扫描量热仪对铸膜液的成膜过程进行分析,通过扫描电子显微镜对膜微结构进行表征,并对中空纤维膜进行性能测试。结果表明:当稀释剂/PEG400质量比为10/9时,NIPS对膜微结构有较强的致孔作用,膜外表面出现了大量微孔,水通量达到最大值352L/(m^2·h),碳素墨水截留率接近100%,断裂应力为6.6MPa。

To investigate the effect of NIPS during TIPS cooling and the effect of water-soluble non-diluent on hollow fiber membrane microstructure, hollow fiber membranes were prepared by the coupling of thermally induced phase separation (TIPS) with non-solvent induced phase transformation(NIPS) with polyvinylidene fluoride(PVDF) as raw material and addition polyethylene glycol(PEG400), a water-soluble non-diluent of different proportions. The membrane forming mechanism of the dope solution was analyzed by means of thermal platform polarizing microscope and differential scanning calorimeter. The microstructure of hollow fiber membrane was characterized by scanning electron microscope, and the properties of hollow fiber membrane were tested. The results show that when the mass ratio of diluent/PEG400 is 10/9, NIPS has a strong pore-forming effect on the membrane microstructure, a large number of micropores appear on the outer surface of the membrane, the maximum water flux of membrane is 352 L/(m^2·h), the rejection rate of membrane to carbon ink is close to the 100%, and the breaking strength of membrane is 6.6 MPa.