Abstract
Poly(vinylidene fluoride) (PVDF) hollow fiber membrane was prepared from PVDF/diethyl phthalate system via thermally induced phase separation (TIPS). The diethyl phthalate was used as bore liquid to make a lumen of the hollow fiber for the purpose of prevention of the diluent evaporation and the larger pores formation at the inner surface of the hollow fiber. The melting temperature greatly affected the membrane structure. When the melting temperature was 180°C, spherulite structure due to the polymer crystallization was obtained, while the inter-connected structure (lacy structure) was formed at 150°C. The formation mechanism of the membrane structure was discussed based on the DSC data. The spherulite structure showed the higher water permeability with the lower mechanical strength. On the other hand, the inter-connected structure showed the fairly high strength. The effect of the addition of clay on the membrane performance was also investigated. The addition of clay was useful to form inter-connected structure.
