PERVAPORATION OF WATER-ETHANOL MIXTURES THROUGH PLASMA GRAFT-POLYMERIZATION OF POLAR MONOMER ONTO CROSS-LINKED POLYURETHANE MEMBRANE

To improve the pervaporation performance, the plasma post-graft polyme rization of 2,3-epoxypropylmethacrylate (EPMA) onto the crosslinking p olyurethane (CPU) membrane, EPMA-g-CPU, was synthesized in this study. The crosslinking between soft-soft hydroxyl-terminated polybutadiene (HTPB) segments were prepared by the introduction of benzoyl peroxide to the HTPB-based PU membrane. The effect of plasma treatment time and plasma supply power on the grafting yield was discussed. The optimum plasma treatment conditions were 10 W supply power and 120 s treatment time. The surface properties of the EPMA-g-CPU membrane were characte rized by Fourier transform infrared spectroscopy, electron spectroscop y for chemical analysis, and a contact angle meter. A separation facto r of 97 and a 240 g m(-2) h(-1) permeation rate through the EPMA-g-CPU membrane with a 4.81 mg/cm(2) grafting yield for a 90 wt % feed ethan ol concentration were obtained. Compared with ungrafted CPU membrane, the EPMA-g-CPU membrane effectively improved the pervaporation perform ances. (C) 1998 John Wiley & Sons, Inc.