Swelling equilibrium and sorption kinetics of polyvinyl acetate film

Abstract

The absorption and diffusion kinetics of solvent molecules into polyvinyl acetate film has been studied at different temperatures (13, 25 and 37 oC). The maximum swelling quotient was found to be dependent on the solvent and the temperature of absorption. The initial slope method was utilized to determine the diffusion mode, which was found to deviate from Fick’s law and hence described as anomalous. The gravimetric absorption, data were analysed based on Crank’s model. The early time sorption kinetic data were obtained to investigate the diffusion mechanism of the solvent in the PVA molecule. It was observed that the maximum swelling quotients for the solvents increase in the order, n-hexane < Carbontetrachloride < Water. The absorption and the diffusion characteristics of the solvents in the PVA film were evaluated and the variation properties discussed in terms of the nature of the solvent, temperature, interaction constants between the polymer chains and the molecular mass of the polymer. Our report shows that absorption of these solvents could not cause the dissolution of the PVA film at these temperatures.