An investigation of the long-term sorption kinetics and diffusion anomalies of chloroalkanes into tetrafluoroethylene/propylene copolymer membranes at 30, 45 and 60°C

An investigation of the long-term sorption kinetics and diffusion anomalies of dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane, l,l,l-trichloroethane, 1,1,2,2-tetrachloroethane, trichloroethylene and tetrachloroethylene into the tetrafluoroethylene/propylene copolymer membranes has been carried out using gravimetric sorption technique at 30, 45 and 60 degrees C. Coefficients of diffusion and permeation have been calculated from Fick's equation. Analytical solutions of Fick's equation have been used to compute liquid concentration profiles into polymeric sheet membranes at different times. Activation parameters for diffusion and sorption have been evaluated and these results are discussed in terms of the molecular size of the liquids and the temperature. The diffusion coefficient and activation energy for diffusion do not exhibit any systematic dependence on the size of the penetrant molecules, but these are mainly influenced by the nature of chloroalkanes. (C) 1997 Elsevier Science Ltd. All rights reserved.