Preparation and characterization of biodegradable and compostable PLA/TPS/ESO compositions

In this study, biodegradable and compostable compositions, derived from totally natural feedstock/raw materials, namely polylactide (PLA), potato thermoplastic starch (TPS) and plant glycerin have been made by melt extrusion with epoxydized soybean oil (ESO) as reactive modifier in order to improve PLAs ductility and reduce the products cost without compromising biodegradation. The obtained PLA/mTPS(0,5ES0)[75/25] and PLA/mTPS(2ESO)[75/25] compositions provides satisfactory.mechanical properties comparable to native PLA. Addition of 25% TPS and 0,5-2% ESO to PLA, improved impact strength from 13,70 kJ/m2 to 16,69 kJ/m2 70 kJ/m2 to 16,69 kJ/m2 compared to neat PLA and increase elongation at break from 2,6% to 8,8%. The addition of ESO into PLA/TPS composition enhanced water resistance and improved impact strength to over 16 kJ/m2 for PLA/TPS(2%ESO)[75/25] composition. The thermal, rheological and morphology of fractured surface were also studied. Finally, biodegradability and compostability of prepared samples was specified by stimulated composting process (according to PN-EN 14806:2010 standard). Possibility of replacing up to 25% of PLA by TPS and ESO, allows to reduces the costs of the product as well as maintain quite similar properties and ability to composting relative to native PLA.