Polyacrylamide-grafted-sodium alginate copolymers were prepared by persulfate-induced radical polymerization by using polymer-to-monomer ratios of 2:1 and 1:1. Polymers were characterized by Fourier transform infrared spectroscopy, differential thermal analysis, and viscosity. Membranes were prepared from the polymers, crosslinked with glutaraldehyde, and used in the pervaporation separation of water + isopropanol mixtures at 30 degreesC. Equilibrium swelling experiments were performed for mixtures containing 10 to 80 mass % of water in the feed. Both the grafted copolymer membranes were ruptured while separating 10 mass % of water in the feed mixture. However, beyond 20 mass % of water in the feed mixture, flux increased with increasing grafting ratio, while selectivity decreased. Pervaporation separation experiments were carried out at 30, 40, and 50 degreesC for 20 mass % of water in the feed mixture. By increasing the temperature, flux increased, whereas selectivity decreased. Arrhenius activation parameters for pervaporation and diffusion decreased with increasing grafting ratio of the membranes. (C) 2004 Wiley Periodicals, Inc.