Hydrophilic Modification Of Pvdf Membrane And Preparation Of Tubular Composite Membrane

Poly(vinylidene fluoride)(PVDF) is one of the most outstanding materials for microporous membranes. But the hydrophobic nature of PVDF makes it susceptible to be contaminated by proteins, humic acid, and oils. Hydrophilic modification is an efficient strategy to improve the performance of membrane. In this work, amphiphilic terpolymer and ionic liquid modified nano-SiO2were synthesized and used as additives in the preparation of PVDF membranes. The fabrication of tubular PVDF composite membranes was simply discussed.Firstly, glass transition temperature (Tg) tunable terpolymer poly(methyl methacrylate-co-butyl acrylate) with poly(ethylene glycol) side chains (P(MMA-co-BA)-g-PEO) was synthesized by free radical polymerization. The composition, molecular weight and Tg of terpolymers were characterized by1H NMR, GPC, and DSC, respectively. Then PVDF/terpolymer blend membranes with different terpolymer amount were prepared by NIPS. Filtration tests indicated that the terpolymer improved hydrophilicity and anti-fouling properties of PVDF membrane.Secondly, PVDF/IL-SiO2hybrid membranes with ionic liquid modified nano-SiO2were prepared. Streaming potential measurement indicated that hybrid membrane is positively charged. The addition of IL-SiO2resulted in obvious improvement in both water flux and rejection ability of the hybrid membrane.Lastly, PVDF tubular composite membrane was prepared by coating method. The results indicated that tubular support pore size and coating times determine the resulting property of tubular membranes. The effects of transmembrane pressure and flow rate on membrane process were also investigated.