A composite membrane with a crosslinked PVA dense active layer dip coated on a polyethersulfone support membrane was prepared and evaluated with a pervaporation setup for the separation of a water-ethylene glycol mixture. The effects of preparation conditions including heat-curing temperature and time, dehydration rate, cooling rate, structure of support and crosslinking density of the crosslinked PVA active layer on the separation factor and permeate flux are discussed. Optimum results were obtained with crosslinked PVA membranes containing 3.7 wt% crosslinking agent and 0.05 wt% catalyst, giving a separation factor of 231 and a permeation rate of 383 g/(m(2) h) for a 82.5 wt% ethylene glycol aqueous solution at 80 degrees C.