Thermoplastic starch/PVAl compounds: preparation, processing, and properties

As a renewable and native polymeric material, thermoplastic starch is gaining increased acceptance because of resource and environment concerns. This study reports the formulation design of native starch/polyvinyl alcohol (PVAl) compounds; the preparation technology to make them available for thermoplastic processing; and their rheological, mechanical, and degradation properties. Among various plasticizers investigated, a mixture of glycerin and water (50/50 wt %) is found to be the best one for the compounds in terms of rheological behavior, mechanical properties, and environmental stability. The mechanical properties do not increase with the PVAl content to an expected extent, mainly due to the poor interface adhesion between the fibrous PVAl structure and the starch matrix.