Hydrophilic modification of polyvinylidene fluoride membrane by blending amphiphilic copolymer via thermally induced phase separation

Abstract

A new amphiphilic copolymer TD‐A is melt‐blended with polyvinylidene fluoride to fabricate hollow fiber membranes in order to improve the hydrophilicity and anti‐fouling property. Membrane samples with different blending ratios are prepared via thermally induced phase separation method. An optimum blending ratio of TD‐A (10 wt%) is determined by a series of characterizations to evaluate the effects of TD‐A contents on membrane properties. The hydrophilicity of the blended membrane samples increases with the increasing blending ratio, but excessive content of TD‐A in blended membranes can lead to structural defects and reduction of mechanical properties. TD‐A blended hollow fiber membrane with optimum blending ratio shows excellent bi‐continuous structure and high water flux. Membrane fouling is remarkably reduced due to the incorporation of TD‐A by static absorption and cyclic filtration tests of bovine serum albumin. Moreover, constant surface chemical compositions and stable flux during long‐term chemical cleaning demonstrate the hydrophilic stability of the blended membrane.