PHYSICOCHEMICAL STUDIES OF CHITOSAN-POLY(VINYL ALCOHOL) BLENDS PLASTICIZED WITH SORBITOL AND SUCROSE

The physical properties of chitosan/PVA/plasticizer blends, prepared b y casting, were investigated. It was found that the thermal properties (melting point, heat of fusion) for PVA showed a decrease proportiona l to the plasticizers' content. The percentage elongation and CO2 and water vapour permeability of chitosan/PVA blends were found to increas e with an increase in plasticizer content. However, high plasticizer c ontents caused a substantial decrease in both tensile strength and mod ulus. The semi-empirical models, applied for calculating the mechanica l properties and the CO2 permeability, were in satisfactory agreement with the experimental values, apart from a certain variation, which sh ould be probably attributed to differences in molecular weight, percen tage crystallinity and percentage of hydrolyzed or deacetylated materi al (PVA and chitosan, respectively). (C) 1997 Published by Elsevier Sc ience Ltd. All rights reserved.