THEORETICAL ESTIMATIONS OF DIFFUSION-COEFFICIENTS

A model calculating the diffusion coefficients of liquids in polymeric membranes from the diffusion coefficients at zero concentration was developed. This model is based on Fujita's volume theory and considers crystallinity in the polymer and is tested by using available data in the literature, i.e., n‐hexane–polyethylene and benzene–polyethylene systems. The calculated diffusion coefficients were simulated by calculating the pure liquid permeabilities in a pervaporation system. When comparing the predicted pure liquid permeabilities with the experimental values, these calculated values were found to be in fairly good agreement. Copyright © 1990 John Wiley & Sons, Inc.