Effect of take-up speed on polyvinylidene fluoride hollow fiber membrane in a thermally induced phase separation process

The porous polyvinylidene fluoride hollow fiber membranes were prepared via the thermally induced phase separation process using mixed diluent. The effects of take-up speed on the structure of membranes were investigated by scanning electron microscopy, differential scanning calorimetry, and wide-angle X-ray diffraction. The membrane properties were measured in terms of the pure water flux, porosity, and mechanical properties. The results showed that the cross-sectional structure of membrane had an obvious change and presented a uniform structure when TS increased to 72 m min-1, whereas the membrane made from TS <41 m min- presented an interconnected aggregation structure. However, the change of surface structure of all membranes was hardly observed. In addition, the strength and elongation of breakage of membrane increased obviously with the increase of TS, whereas the pure water flux and porosity changed slightly. © 2012 Wiley Periodicals, Inc.