Data on sorption and transport of water in polyvinyl alcohol films, modified by thermal
treatment above Tg, or by chemical crosslinking with glutaraldehyde at different crosslinking
degrees, are presented. Equilibrium swelling is constrained by both treatments, except
for low degrees of crosslinking where the said reduction is counterbalanced by the partial
loss of crystallinity. Analysis of the resulting water uptake kinetics indicates that viscous
relaxation effects are, at least partly, responsible for the observed non-Fickian kinetic
behavior. Thermodynamic diffusion coefficients of water, DW, and relaxation frequencies
of the swelling polymer, bW, are determined by application of a theoretical model accounting
for relaxation-dependent sorption kinetics in glassy polymers. The results indicate that
the effect of both heat-treatment and chemical crosslinking is more intense on the macromolecular
relaxation process than on the diffusion coefficient of water. Comparison of the
release kinetics of a model drug from as-prepared, non-crosslinked and from crosslinked
matrices indicate that the retardation of macromolecular relaxations process induced by
crosslinking results in a more uniform release rate
Data on sorption and transport of water in polyvinyl alcohol films, modified by thermal
treatment above Tg, or by chemical crosslinking with glutaraldehyde at different crosslinking
degrees, are presented. Equilibrium swelling is constrained by both treatments, except
for low degrees of crosslinking where the said reduction is counterbalanced by the partial
loss of crystallinity. Analysis of the resulting water uptake kinetics indicates that viscous
relaxation effects are, at least partly, responsible for the observed non-Fickian kinetic
behavior. Thermodynamic diffusion coefficients of water, DW, and relaxation frequencies
of the swelling polymer, bW, are determined by application of a theoretical model accounting
for relaxation-dependent sorption kinetics in glassy polymers. The results indicate that
the effect of both heat-treatment and chemical crosslinking is more intense on the macromolecular
relaxation process than on the diffusion coefficient of water. Comparison of the
release kinetics of a model drug from as-prepared, non-crosslinked and from crosslinked
matrices indicate that the retardation of macromolecular relaxations process induced by
crosslinking results in a more uniform release rate
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