| Abstract
| - Molecular modification of ozone-pretreated poly(vinylidene fluoride) (PVDF) via thermallyinduced graft copolymerization with acrylic acid (AAc) in N-methyl-2-pyrrolidone (NMP) solution wascarried out (the AAc-g-PVDF copolymer). The microstructure and composition of the AAc-g-PVDFcopolymers were characterized by FT-IR, X-ray photoelectron spectroscopy (XPS), elemental analysis,and thermogravimetric (TG) analysis. In general, the graft concentration increased with the AAc monomerconcentration used for graft copolymerization. Microfiltration (MF) membranes were prepared from theAAc-g-PVDF copolymers by the phase inversion method. The bulk and the surface compositions of themembranes were determined by elemental analysis and XPS, respectively. XPS analyses of the copolymermembranes revealed a substantial surface enrichment of the hydrophilic AAc polymer graft. The poresizes of the pristine PVDF and the AAc-g-PVDF membranes were measured using a Coulter porometer.The morphology of the membranes was studied by scanning electron microscopy (SEM). The rate ofpermeation through the AAc-g-PVDF MF membranes changed reversibly in response to pH variation ofthe aqueous solution, with the most drastic change in permeation rate occurring between pH 2 and 4.
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