Surface Modification of Porous Polypropylene Membrane by Plasma-Initiated RAFT Graft Polymerization of Hydroxyethyl Methacrylate

A reversible addition-fragment chain transfer(RAFT) graft polymerization initiated by plasma, with hydroxyethyl methacrylate (HEMA) as the monomer, was used to modify the surface of porous polypropylene (PP) membrane for hydrophilicity improvement. After an investigation of the graft polymerization kinetic, the surface chemistry, the surface morphology and the porous structure of modified membranes were evaluated by FT-IR, SEM, mercury intrusion and water flux measurement. Results showed that the polymerization rate of the plasma-initiated RAFT graft polymerization was dramatically lowered relative to that without RAFT agent. The grafting amounts on modified surfaces exhibited a linear increase with the increasing of polymerization time, and simultaneously the pore sizes and the water fluxes of the modified membranes would be consecutively decreased.