A study of sorption/desorption profiles and diffusion anomalies of organic haloalkanes into a polymeric blend of ethylene-propylene random copolymer and isotactic polypropylene

Experimental values for sorption, desorption, resorption and redesorption processes for a polymeric blend of ethylene-propylene random copolymer and isotactic polypropylene were obtained at 25, 40, 55 and 70 degrees C with haloalkanes using a gravimetric method. Diffusion coefficients exhibited a dependence on the type and nature of solvent molecules. In view of an increase in diffusivity with temperature, Arrhenius relation was used to estimate the energy of activation for diffusion. These results showed a dependence on polymer-solvent interactions. A numerical method based on the finite difference method was used to calculate liquid concentration profiles into polymer membranes and these results were compared with those obtained from analytical solutions of Fick's equation. (C) 1996 Elsevier Science Ltd.