Acrylonitrile copolymers: Synthesis, characterization, and formation of ultrafiltration membranes

A variety of poly(acrylonitrile-co-acrylamide) polymers of different compos itions were synthesized by free radical copolymerization. Thin films were c ast from polymer solutions, and coagulated into ultrafiltration membranes. The effect of preparative parameters on membrane gel structure was investig ated. For nonsupported membranes, concentrated polymer solutions produce fi ne pore membranes with a lower flux; extending the drying time causes a dim inution in membrane thickness, swelling index, and fluxes; the membrane thi ckness, swelling index, and permeate flux all increased with increasing coa gulation bath temperature. For supported membranes, dilute polymer casting solutions, small casting gate opening, and added polyvinylpyrrolidone to th e casting solution all increased the permeate flux. The membranes containin g acrylamide were more hydrophilic, and had a smaller dispersion force comp onent of the surface free energy than those prepared from the polyacrylonit rile homopolymer. (C) 1999 John Wiley & Sons, Inc.