Preparation of Poly(vinylidene fluoride) Hollow Fiber Membrane via Thermally Induced Phase Separation

摘要

Recently, a few studies have been reported on preparation of Poly(vinylidene fluoride) (PVDF) microporous membrane via thermally induced phase separation (TIPS) method1,. The well-documented advantage of TIPS method is the ease of control compared to conventional casting process. The hollow fiber membranes have shown high potential for the commercial applications in reverse osmosis (RO), ultrafiltration (UF) and microfiltration (MF), since the productivity and the efficiency of the separation process can be largely improved due to the large surface area per unit volume of the fiber module3. The formation of polypropylene, polyethylene and poly(ethylene-co-vinyl alcohol) hollow fiber membranes via TIPS have been studied4-6. Also, PVDF hollow fiber membranes for microfiltration were successfully prepared by PVDF/γ-butyrolactone system using modified TIPS process by Cha et al. In their study, a solvent (dimethylacetamide) for PVDF was added in cooling bath and the dense top layer of hollow fiber was suppressed. In this study, PVDF hollow fiber membranes were prepared along with diluent mixtures (dibutyl phthalate (DBP)/di(2-ethylhexyl) phthalate (DEHP)) and with bore liquid (Liquid paraffin (LP)) via the TIPS process. The objective of this study is to demonstrate the effect of the interaction between diluent and polymer on the structure of membrane. The effect of hollow membrane structure on the performance of membrane was also discussed.