Preparation of PVDF hollow fiber membrane via thermally induced phase separation (TIPS)

The porous poly (vinylidene fluoride) PVDF hollow fiber membranes were successfully prepared from a ternary system including PVDF, solvent and nonsolvent via thermally induced phase separation (TIPS) process. Glycerol triacetate as solvent and glycerol and PEG200 as nonsolvents were used in this study. The effects of nonsolvent type and nonsolvent concentration on polymer/solvent/nonsolvent phase diagram were studied and based on these results, hollow fiber membranes are fabricated. The effects of nonsolvent type, air gap distance and water bath temperature on morphology, permeation, solute rejection and strength of fabricated membranes were studied. Although the strength of the hollow fiber membrane containing glycerol was a little lower than other membranes, water permeability of this membrane is higher than the other membranes. Using shorter air gap distance, higher bath temperature and higher glycerol concentration were effective to obtain higher water ermeability.

Keywords:

PVDF , hollow fiber membrane , liquid-liquid phase separation , crystallization , membrane characterization