A revised version of a recently proposed free‐volume theory of polymer‐solvent diffusion is introduced and evaluated using experimental diffusivity data collected over wide temperature and concentration ranges. The theory accurately predicts the large temperature and concentration variations typically observed for polymer‐solvent diffusion coefficients.

SynopsisNew diffusivity data are presented for solvent diffusion in poly(viny1 acetate), poly(methy1 methacrylate), and polystyrene. These data are used to test the predictive and correlative capabilities of a recently proposed free-volume theory of diffusion. Comparisons of data and theory showed that the proposed theory provided an accurate description of diffusion in concentrated polymer solutions.