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 crosslinke d with a low molecular weight of poly(acrylic acid) (PAA). The crossli nking reactions between PVA and PAA were characterized through IR spec troscopy, differential scanning calorimetry (DSC), and tensile tests w hen varying the reaction conditions, that is, time, temperature, amoun ts of crosslinking agents, PAA. It was found that the crosslinking rea ction was fast: in other words, that the reaction mainly occurred at t he initial step of each reaction condition. The best reaction conditio ns for preparing the crosslinked PVA membranes were found to be: react ion time not over 1 h, reaction temperature in the range of 150-180-de grees-C. PAA contents of 15-20 wt % were found satisfactory with respe ct to the application areas. (C) 1993 John Wiley & Sons, Inc.