PVDF–TiO2 composite hollow fiber ultrafiltration membranes prepared by TiO2 sol–gel method and blending method

Organic–inorganic polyvinylidene fluoride (PVDF)–titanium dioxide (TiO2) composite hollow fiber ultrafiltration (UF) membranes were prepared by TiO2 sol–gel method and blending method, respectively. The membranes were characterized in terms of microstructure, hydrophilicity, permeation performance, thermal stability, and mechanical strength. The experimental results indicated that PVDF–TiO2 composite UF membranes exhibited significant differences in surface properties and intrinsic properties because of the addition of inorganic particles. The TiO2 particles improved the membrane strength and thermal stability of PVDF–TiO2 composite UF membranes. In particular, hydrophilicity and permeability increased dramatically with the increase of TiO2, whereas the retention property of UF membranes was nearly unchanged. However, high TiO2 concentration induced the aggregation of particles, resulting in the decline of hydrophilicity and permeability. Compared with PVDF–TiO2 composite hollow fiber UF membranes prepared by TiO2 blending method, PVDF–TiO2 composite hollow fiber UF membranes prepared by TiO2 sol–gel method formed a dispersed inorganic network, and the stronger interaction between inorganic network and polymeric chains led to TiO2 particles being uniformly dispersed in UF membranes. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009