Application of modified vegetable oil for improvement of biodegradable materials based on thermoplastic starch and polylactic acid

Currently, it is a challenge for academia and industry to develop materials capable of replacing conventional petroleum-derived polymers. The objective of the present study was to evaluate the physicochemical and morphological properties of biodegradable materials obtained from thermoplastic yam starch (TPS), and polylactic acid (PLA) improved with the addition of epoxidized sesame oil (ESO). The blends were made by extrusion, and the films were made by compression moulding. The interaction with water, mechanical properties and structural properties were studied. As a result, the addition the ESO on the TPS / PLA polymeric matrix caused a decrease in moisture content, surface wettability and lower permeability to water vapour. Furthermore, when adding ESO at 3%, elastic modulus and the tensile strength increased approximately double and the deformation capacity for the mixtures without ESO by more than 70%. Regarding structural properties, the addition of ESO promoted the formation of a TPS / PLA interface without marked separation and smoother surfaces. The materials obtained show promising properties for the development of food packaging with low moisture content.

Keywords: Dioscorea rotundata, epoxidation, interface, physicochemical properties.