Journal of Membrane Science, 50 (1990) 225-241 Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands 225 INTERACTIONS OF ORGANIC HALIDES WITH A POLYURETHANE ELASTOMER U. SHANTHAMURTHY AITHAL, TEJRAJ M. AMINABHAVI* Department of Chemistry, Karnatak University, Dharwad 580 003 (India) PATRICK E. CASSIDY* Department of Chemistry, Southwest Texas State University, San Marcos, TX 78666 (U.S.A.) (Received April 12,1989; accepted in revised form October 20,1989) Summary Interactions of halogen-substituted organic penetrants have been studied with a polyurethane membrane over the temperature interval of 25-60°C. Transport parameters such as diffusivity, solubility, and permeability have been measured. A temperature dependence of these quantities has been used to predict activation parameters for the transport mechanism. Equilibrium sorption data were used to estimate the entropy and Gibbs energy for the sorption process by using the Van’t Hoff relationship. Furthermore, a phenomenological treatment has been suggested to esti- mate the classical Flory-Huggins interaction parameter for polyurethane-solvent pairs. These data were used to calculate the molar mass between crosslinks of the polyurethane network. For all the penetrants, the transport mechanism was found to be anomalous. Introduction zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA The wide range of physical and morphological characteristics that can be obtained by changing the chemical composition and processing history of po- lyurethane elastomers has generated a great deal of interest in understanding their structure-property relationships, the ultimate goal being to tailor these materials to meet specific applications. The unique properties of polyurethane elastomers are attributed to a microphase separated structure consisting of hard and soft segment domains [ 11. Aromatic polyurethanes, in view of their low water uptake [2] and excellent resistance to chemical attack by organic solvents [ 3-71, find wide applications in solid rocket motors [ 81, adhesives [ 91, sealants, and as potting compounds [lo]. As a part of our continuing efforts to investigate the transport characteris- tics of a segmented polyurethane, we now present the results of an investiga- *Authors for correspondence. 0376-7388/90/$03.50 0 1990 Elsevier Science Publishers B.V.