Sorption and diffusion of a number of chlorinated alkanes through a diol chain extended polyurethane (PU) membranes have been investigated at 25, 40 and 60degreesC, based on an immersion weight gain method. From the sorption result, the diffusion (D) and permeation (P) coefficients of halogenated hydrocarbon penetrants have been calculated. Molecular transport data depends on membrane-solvent interactions, size of the penetrants, temperature and also morphology of the chain extended PUs. The temperature dependence of the transport coefficient has been used to estimate the activation parameters for the process of diffusion (E-D) and permeation (E-p) from the Arrhenius plots. Furthermore, the sorption results have been interpreted interms of the thermodynamic parameters such as enthalpy and entropy. (C) 2003 Elsevier Science B.V. All rights reserved.