SYNTHESIS OF ACRYLONITRILE- N -ISOPROPYLACRYLAMIDE GRAFT COPOLYMERS FOR THE PREPARATION OF THERMAL RESPONSIVE POLYACRYLONITRILE MEMBRANAES: SYNTHESIS OF ACRYLONITRILE- N -ISOPROPYLACRYLAMIDE GRAFT COPOLYMERS FOR THE PREPARATION OF THERMAL RESPONSIVE POLYACRYLONITRILE MEMBRANAES