Abstract
Mutual diffusion coefficients for ketones (acetone, methyl ethyl ketone and methyl propyl ketone) in poly(n-hexyl methacrylate) were measured at 313.15, 323.15 and 333.15K by using a sorption apparatus with a quartz spring. The mass-average molecular weight and the glass transition temperature of poly(n-hexyl methacrylate) used in this study were 4×105 and 268.15K, respectively. Solvents were reagent-grade purchased from Wako Chemical Co. Ltd. and were used without further purification. It is found that the mutual diffusion coefficients obtained increase with increasing the temperature and the concentration of solvent, and decrease with increasing the molecular weight of solvent.In addition, the binary mutual diffusion coefficients were correlated by the modified free volume theory. The four parameters of pure polymer and solvent among the eight parameters required in the theory were estimated by applying a method proposed by Iwai et al. The Flory parameters was determined by a least squares method , by using solubility data measured by the same apparatus. The remaining binary three characteristic parameters were determined by fitting the theory to the experimental mutual diffusion coefficient data by use of a nonlinear regression analysis . The correlated results are in good agreement with the experimental data. The modified free volume theory is found to be successful in correlating the mutual diffusion coefficients for ketones in poly(n-hexyl methacrylate).
