ULTRAFILTRATION MEMBRANES PREPARED BY STYRENE-GRAFTED POLYVINYLPYRROLIDONE

The suitability of a new grafted copolymer for preparing ultrafiltrati on membranes was studied. The copolymer was obtained by radiochemical grafting of styrene onto polyvinylpyrrolidone. The membranes were prep ared by the phase-inversion technique from N-methyl-2-pyrrolidone solu tions. Influence of grafting degree and solutions concentration on the ultrafiltration performances were studied. It was demonstrated that f or polystyrene grafting values close to 85% w/w and a copolymer soluti on concentration of 15% w/v, the membranes have a high permeate flux ( more than 100 L . m-2 . h-1) and a good separation factor (more than 9 5%) for aqueous dextran solutions. The mechanical resistance of the me mbranes was evaluated and their microscopic structure was examined by SEM.