Effect of additives on the morphology and properties of poly(vinylidene fluoride) blend hollow fiber membrane prepared by the thermally induced phase separation method

The effects of poly(vinylpyrrolidone ) (PVP) and poly(methyl methacrylate) (PMMA) additives on poly(vinylidene fluoride) (PVDF) hollow fiber membranes fabricated via the thermally induced phase separation process were studied. The addition of PVP showed a significant effect on the membrane structure, while addition of PMMA had little effect. In the PVDF/PVP blend membrane, the growth of spherulites was effectively inhibited due to the low compatibility between PVDF and PVP. An asymmetric structure consisting of a dense skin layer near the outer surface and a spherulite structure inside the membrane was obtained in this blend membrane. Measurements of tensile strength and water contact angle were also carried out. In contrast to the addition of PMMA, the addition of PVP significantly improved the maximum stress, elongation and hydrophilicity of membranes. Filtration experiments with BSA solution showed that PVDF/PVP membranes had much better fouling resistance than PVDF/PMMA and plain PVDF membranes.