DIFFUSION AND SORPTION OF ORGANIC LIQUIDS THROUGH POLYMER MEMBRANES .10. POLYURETHANE, NITRILE-BUTADIENE RUBBER AND EPICHLOROHYDRIN VERSUS ALIPHATIC-ALCOHOLS (C1-C5)

Diffusion and sorption of eight aliphatic alcohols - namely methanol, ethanol, 1-propanol, 2-propanol, t-butanol, 2-methyl-1-propanol, 1-pentanol and 3-methyl-1-butanol - into three engineering polymer membranes has been studied in the temperature range 25-60-degrees-C to investigate the kinetics of the transport mechanism. The results have been analysed in terms of the Fickian diffusion equation. The anomalous transport behaviour of rubber-alcohol systems is attributed to a leaching out of the polymer systems during solvent immersion. The dependence of transport coefficients and activation parameters, as obtained from a temperature dependence of these coefficients, have been discussed in terms of the polymer-solvent interactions and their effect on the size, shape and type of penetrant molecules. Furthermore, the transport results have been interpreted in terms of enthalpy and entropy contributions. Dependence of the transport parameter on penetrant concentration has also been investigated.