Effect of H3PO2 on the mechanical, thermal, and electrical properties of polymers based on poly (vinyl alcohol) (PVA) and chitosan (CS)

A polymer based on poly (vinyl alcohol) (PVA) and chitosan (CS) with a weight ratio of 80:20 was prepared by solvent casting processes, and the effect of H3PO2 was investigated. Thermal analysis shows miscibility of the two polymer amorphous phases since a single T (g) was located between those of the individual components and the melting point of the crystalline phase was depressed to 189 A degrees C. It was found that the acid acts as a plasticizer for the PVA-CS blends and its T (g) is depressed significantly to 23 A degrees C as the acid concentration increases to 50%. Strain-stress tests also corroborate this effect. The DC conductivity of the blends follows an Arrhenius-type thermal activation behavior with activation energy of 0.1 eV in the 30-90 A degrees C temperature range. Moreover, the conductivity increases with increasing acid content up to a maximum value of approximately 1.4 x 10(-2) S/cm for the blend with an acid concentration of 50%.