A DETAILED STUDY OF THE VISCOELASTIC NATURE OF VAPOR SORPTION AND TRANSPORT IN A CELLULOSIC POLYMER .2. SORPTION AND LONGITUDINAL SWELLING KINETIC CORRELATIONS

Longitudinal swelling kinetics of cellulose acetate films sorbing acet one vapor at 30 degrees C were studied under various conditions and co rrelated with the corresponding sorption kinetic measurements reported in Part I. The results were analyzed in the light of (1) previous the oretical studies of simple viscoelastic polymer-penetrant model system s and (2) mechanical stress-strain data on the cellulose acetate-aceto ne system, which are also reported here. The conclusions drawn from th is analysis confirm and/or amplify (particularly as regards the effect of longitudinal differential swelling stresses) our previous interpre tations based on sorption kinetic analysis, concerning the physical na ture and causes of various features of the non-Fickian kinetic behavio r of cellulosic polymer-micromolecular penetrant systems. History-depe ndent long-term aging effects were also observed and investigated. (C) 1995 John Wiley & Sons, Inc.