Physico-chemical studies of chitosan-poly(vinyl alcohol) blends plasticized with sorbitol and sucrose

The physical properties of chitosan/PVA/plasticizer blends, prepared by casting, were investigated. It was found that the thermal properties (melting point, heat of fusion) for PVA showed a decrease proportional to the plasticizers' content. The percentage elongation and CO2 and water vapour permeability of chitosan/PVA blends were found to increase with an increase in plasticizer content. However, high plasticizer contents caused a substantial decrease in both tensile strength and modulus. The semi-empirical models, applied for calculating the mechanical properties and the CO2 permeability, were in satisfactory agreement with the experimental values, apart from a certain variation, which should be probably attributed to differences in molecular weight, percentage crystallinity and percentage of hydrolyzed or deacetylated material (PVA and chitosan, respectively). (C) 1997 Published by Elsevier Science Ltd. All rights reserved.