Preparation and characterization of poly(vinylidene fluoride) flat sheet membrane with Tg tunable amphiphilic terpolymer as membrane additive

An amphiphilic terpolymer P(MMA-BA-PEOM) was synthesized by free radical polymerization and used as the macromolecular additive in the preparation of PVDF blend membranes. The glass transition temperature (T g ) of terpolymers was controlled with a wide range from −   6 to 40   °C by adjusting the feed ratio of rigid monomer MMA to soft monomer BA . The increase of static contact angle of copolymer with PBA content indicated that softer chain can facilitate the hydrophobic parts of the additive segregation to the surface of a polymer film at the solid–air interface. The observation of morphology of the extracted PVDF blend membrane verified that P(MMA-BA-PEOM) could facilitate the surface segregation. Filtration experiment showed that PVDF membrane modified by terpolymer P(MMA-BA-PEOM) has a higher pure water flux (365   L   m −   2   h −   1 ) and relative flux recovery (71%) than that modified by bipolymer P(MMA-co-POEM).