Evaluation of the effect of the incorporation of poly(lactic acid) and maleic anhydride in the thermoshrinkage of films from thermoplastic starch

Abstract

AbstractStudies on the property of shape memory in thermoplastic starch (TPS) have shown good results, making such starch a suitable candidate for use in shrink packaging. It is however necessary to evaluate blending it with other bioplastics that would improve its properties while maintaining heat shrinkage. This article thus shows the evaluation of the incorporation of different concentrations of polylactic acid (PLA) and maleic anhydride (MA) as coupling agent and their effect on shrinkage and the changes in structure of the films obtained by blown film extrusion. In most of the blends, the incorporation of PLA and MA was found to favor film shrinkage, obtaining values of up to 55% due to the fact that the interaction between TPS and PLA increased with the incorporation of MA. This was corroborated by the % of MA grafted, thermogravimetric analysis (TGA), rheological and structural tests. This allowed generating a greater molecular orientation of the films, thereby obtaining greater shrinkage. It was determined that the incorporation of PLA and % MA grafted generated good shrinkage results due to the physical and chemical crosslinking achieved in the processing of the blends in the presence of MA, enhancing their application as packaging.