Enhancing filtration flux and antifouling performance of PVDF membrane constructed from semi-interpenetrating network and block copolymers

Abstract

Organic fouling causes the filtration property and serve life decrease of the PVDF membrane and is the challenge for filtration applications. Therefore, it is an urgency desire to construct a PVDF membrane with good filtration and antifouling for researchers. To this end, a based PVDF and poly(N-isopropyl acrylamide)(PNIPA) semi-interpenetrating network polymer was synthesized and used as membrane matrix for preparing semi-interpenetrating network/block copolymers blend membrane. The membrane composition, structure and performance were systematically characterized and investigated by FTIR spectrum, XPS, SEM, contact angle instrument and the other experimental techniques etc. Results indicate that the prepared membrane contains PVDF, PNIPA and block copolymer poly(ethylene oxide)-b-poly(propylene oxide)-b- poly(ethylene oxide) (F127) components, shows a porous cross section comprising a thin top surface layer with small pores, a finger-shape lower layer and a sponge-shape pore bottom layer. When the membrane are used for the filtration of bovine serum albumin(BSA) in aqueous solution at 25 ℃, the rejection can exceed 95.0% at a high flux of 307 L/(m2·h·bar). Simply raising filtration temperature to 60 °C, the flux can reach 606 L/(m2·h·bar) while the rejection barely changes, significantly improving the filtration ability of the membrane. Furthermore, the flux can recover above 93% of the original value after a BSA filtration and a subsequent water washing. Undoubtedly, the prepared membrane displays great potential for filtering BSA aqueous solution and the reason can be ascribed to the synergy between PNIPA and F127 of the membrane.