Evaluation of solubility and diffusion coefficients in polymer film-vapor systems by sorption experiments

Sorption experiments are commonly used to determine the equilibrium and kinetics of mass-transfer processes of vapors in polymeric materials. Electrogravimetry is recognized as a powerful technique. A discussion of the standard theoretical approach to determine solubility and diffusion coefficients is presented. The reduced mathematical expression commonly used for calculations of D values is discussed. A consistency test to check for common deviations caused by the experimental complexity is discussed and resolved. The sorption of hexanol and ethyl caproate into a metallocene polyethylene and an ionomer was measured by electrogravimetry. Transport was characterized through the solubility and the diffusion coefficients. The formalism presented was used in these experiments and is commented upon. (C) 1999 Elsevier Science B.V. All rights reserved.