Segmented network structures for the separation of water/ethanol mixtures by pervaporation

Abstract

α,ω-Acrylate terminated poly(1,3-dioxolane) (polyDXL), was used as a hydrophilic cross-linker of hydrophobic poly(methyl methacrylate) (polyMMA) chains for the synthesis of amphiphilic AB-block copolymer networks. The application of these segmented networks as membranes for dehydration of water/ethanol mixtures by the pervaporation technique was investigated. Because the cross-links inhibit to a great extent phase separation between the components of these materials, as revealed by dynamic mechanical thermal analysis, an optimal control of the membrane characteristics could be achieved by variation of the hydrophilicity–hydrophobicity balance and the cross-link density. The combination of desorption experiments, determination of swelling degrees and calculation of deviation coefficients (ε) allowed us to demonstrate in these membranes the existence of a so-called coupling effect. It was shown that polyDXL plays a predominant role in the specific interactions between the membrane and the solvents, which cause the preferential water transport in all the membranes over the whole composition range of the feed mixture. © 1998 SCI.