Free radical grafting polymerization on PVDF membrane with acrylic acid

摘要

The grafting polymerization of acrylic acid (AA) onto PVDF microfiltration membrane was carried out. Contact angle, water flux, protein adsorption were used to characterize the grafted PVDF membrane. The results showed that acrylic acid can be grafted onto membrane surface, it is a typical grafting to process. Membranes became hydrophilic after the grafting polymerization. AFM picture showed that the porous channel of grafted membrane was separated by grafted PAA chains at high grafting degree, which means the crosslinking of grafted PAA chains occurred at high monomer concentration during the polymerization process. The water flux of grafted membrane decreased quickly with the grafting degree of membrane, and was sensitive to the pH value of water. The protein adsorption behavior of grafted membranes were investigated. All grafted PVDF membranes showed the highest adsorption amount at low pH value of solution, and the protein adsorption amount increased with the grafting degree. The reason could be the interaction between grafted PAA chains and protein, and the morphology transfer of PAA chains from coil to stretched state, and electric property as well.