| Abstract
| - Thermally induced molecular graft copolymerization of the zwitterionic monomer, N,N‘-dimethyl(methylmethacryloyl ethyl)ammonium propanesulfonate (DMAPS), with the ozone-preactivated poly(vinylene fluoride) (PVDF) was carried out in a mixed solvent of N-methyl-2-pyrrolidone (NMP) and dimethylsulfoxide (DMSO). The chemical composition of the resulting PVDF with grafted DMAPS polymer (PDMAPS)side chains, or the PDMAPS-g-PVDF copolymers, was analyzed by elemental analysis. An increase in the[DMAPS]/[-CH2CF2-] molar feed ratio used for graft polymerization gave rise to an increase in the graftconcentration of the DMAPS polymer in the copolymer. Microfiltration (MF) membranes were preparedfrom the DMSO solutions of the copolymers by phase inversion in aqueous media of different ionic strengthand temperature. The surface composition and morphology of the MF membranes were investigated byX-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), respectively. The meanpore size of the membrane decreased with the increase in graft concentration of the PDMAPS-g-PVDFcopolymer. However, it increased with an increase in the ionic strength of the casting bath. Due to theanti-polyelectrolyte effect, the permeability of aqueous solutions through the PDMAPS-g-PVDF MFmembranes exhibited a dependence on electrolyte concentration. The flow rate was observed to decreaseas the electrolyte concentration of the permeate was increased.
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