INTERACTION OF SOME HIGHLY AGGRESSIVE SOLVENTS AND EFFECT OF TEMPERATURE ON THE TRANSPORT CHARACTERISTICS OF POLYURETHANE

A number of highly interacting liquids have been used as penetrants to study their transport characteristics into a commercial polyurethane membrane. The penetrant‐polyurethane interaction is strongly dependent on the nature of the interacting molecules. With tetrahydrofuran, dioxane, cyclohexanol, acetophenone, and benzyl alcohol the polymer swells greatly even at room temperature, and in such cases, sorption experiments were not carried out at higher temperatures. In a few other cases like pyridine, aniline, etc., thea polymer loses its shape and physical integrity leading to chemical degradation reactions. Some of the otherwise normally behaving liquids like n‐butanol, 1,4‐dichlorobutane, anisole, toluene, chlorobenzene, and nitrobenzene did not reach equilibrium at high temperatures (70–90°C) even after prolonged exposure, making it difficult to interpret the sorption data. The results of this study may be useful to make an overall assessment about the application of polyurethane under extreme service conditions. Furthermore, concentration‐independent diffusion coefficients have been calculated for those penetrant—polymer systems which exhibited the least amount of swelling. For highly swelling liquids, the transport mechanism deviates from the normal Fickian mode and diffusion coefficients for such systems have not been obtained. Copyright © 1990 John Wiley & Sons, Inc.