In this study, acrylonitrile ( AN) and hydroxyl ethyl methacrylate ( HEMA) were grafted onto poly( vinyl alcohol) (PVA) using cerium (IV) ammonium nitrate as initiator at 30 degrees C. The graft copolymer was characterized using the Fourier transform infrared spectroscopy ( FTIR) and elemental analysis. The grafted PVA membranes (PVA-g-AN/HEMA) were prepared by a casting method, and used in the separation of acetic acid-water mixtures by pervaporation. The effects of the membrane thickness, operating temperature, and feed composition on the permeation rate and separation factor for acetic acid-water mixtures were studied. Depending on the membrane thickness, the temperature and feed composition PVA-g-AN/HEMA membranes gave separation factors 2.26-14.60 and permeation rates of 0.18-2.07 kg/m(2)h. It was also determined that grafted membranes gave lower permeation rates and greater separation factors than PVA membranes. Diffusion coefficients of acetic acid-water mixtures were calculated from permeation rate values. The Arrhenius activation parameters were calculated for the 20 wt.% acetic acid content in the feed using the permeation rate and the diffusion data obtained at between 25-50 degrees C.