Pervaporation Properties of Film and Composite Membranes Based on an Interpolyelectrolyte Complex of Sulfonate-Containing Aromatic Copolyamide

Film and composite membranes with a separating layer based on an interpolyelectrolyte complex of polyethylenimine and copolyamide, synthesized from isophthaloyl dichloride and two diamines, 4,4′-(2,2′-disulfonate sodium)diaminodiphenyl and 4,4′-(2,2′-disulfonate sodium)diaminodiphenylethylene, were prepared. Their mass-exchange properties in pervaporation separation of a water–isopropanol mixture were studied. The relationship between the degree of conversion in the interpolymer reaction and composition of the interpolyelectrolyte complexes, on the one hand, and membrane characteristics, on the other hand, was revealed. The interpolyelectrolyte complexes of nonstoichiometric composition, enriched in the sulfonate-containing aromatic copolyamide, show the highest performance in pervaporation separation of water–alcohol mixtures. The infl uence of the copolyamide composition on the separation characteristics of the membranes was considered. Combination of good mechanical and mass-exchange properties allows the sulfonate-containing aromatic copolyamides to be classed with promising polyanion components for interpolyelectrolyte complexes used in hydrophilic pervaporation.