CHARACTERIZATION OF ULTRAFILTRATION MEMBRANES .1. WATER AND ORGANIC-SOLVENT PERMEABILITIES

The hydraulic permeabilities of several commercial ultrafiltration membranes with respect to water and organic solvents have been measured in the absence of solutes. Darcy's law was used to describe the convective transport of water and organic solvents through the ultrafilters. The permeability coefficient defined by this law could be used to characterize the membrane behaviour towards one class of solvent. Comparative studies of organic-solvent permeabilities for two important commercial membranes, Rhône-Poulenc IRIS 3038 and 3042, are reported. The irreversible structure modification exhibited by the IRIS 3038, after annealing in dioxane, hydrocarbons, or mixtures of polar solvents, is discussed. The solvating ability of these solvents allowed an increase in the mobility of the polymer chains and a rearrangement to a more stable configuration occurred. On the contrary, the IRIS 3042 was initially in a stable state and annealing in organic solvents had no effect on its water permeability. © 1979.