Viscosity B-coefficients and activation free energy of viscous flow for hexanedioic acid in aqueous polyvinylpyrrolidone solution

Viscosity and density data for the ternary solution of hexanedioic acid + polyvinylpyrrolidone (PVP k30)+ water at temperatures 298.15, 303.15, 308.15 and 313.15 K have been measured. On the basis of the Eyring and Feakins equation, the viscosity B-coefficients and the activation parameters for viscous flow of the solution have been evaluated. The effect of temperature and PVP concentration on these parameters has been discussed. With the increase in PVP concentration, the activation free energy of diffusion for hexanedioic acid is decreased. This is an indication that the diffusion ability of hexanedoic acid is improved by the addition of PVP into solution. (c) 2005 Elsevier B.V. All rights reserved.