Effect of D-Limonene on the Stabilization of Poly (Lactic Acid)

Abstract

D-limonene is a monoterpene obtained from a variety of citrus fruit peel oil which is the most important residue in citrus industry. It is food grade and presents antioxidant properties. The use of antioxidants additives in polymers for food packaging is a common practice to reduce their potential thermo-oxidative degradation during processing and they could also prevent the food oxidation reducing the direct addition of antioxidants to the food. Among them, the great interest towards the use of renewable natural resources in the food packaging industry makes natural antioxidants candidates to stabilize biodegradable polymer formulations. In this sense, poly(lactic acid) (PLA) seems to be the most attractive biodegradable polymer for food packaging industry. Thus, the aim of this work was to study the thermal degradation of PLA films stabilized with D-limonene. Kinetic parameters were obtained by thermogravimetric analysis (TGA) in dynamic mode and the apparent activation energies (Ea) were calculated by the Friedman method. The comparison of Ea between PLA stabilized with D-limonene and non-stabilized polymer furnished information on the thermal stabilization performance. The results indicate that D-limonene shows good performance in the PLA stabilization and therefore the possibility of its use as additive intended for food packaging materials.