PERVAPORATION SEPARATION OF BINARY ORGANIC-AQUEOUS LIQUID-MIXTURES USING CROSS-LINKED PVA MEMBRANES .1. CHARACTERIZATION OF THE REACTION BETWEEN PVA AND PAA

For the purposes of the water-selective membrane material development for pervaporation separation, poly(vinyl alcohol) (PVA) was crosslinked with a low molecular weight of poly(acrylic acid) (PAA). The crosslinking reactions between PVA and PAA were characterized through IR spectroscopy, differential scanning calorimetry (DSC), and tensile tests when varying the reaction conditions, that is, time, temperature, amounts of crosslinking agents, PAA. It was found that the crosslinking reaction was fast: in other words, that the reaction mainly occurred at the initial step of each reaction condition. The best reaction conditions for preparing the crosslinked PVA membranes were found to be: reaction time not over 1 h, reaction temperature in the range of 150-180-degrees-C. PAA contents of 15-20 wt % were found satisfactory with respect to the application areas. (C) 1993 John Wiley & Sons, Inc.