Sunflower-oil biodiesel-oligoesters/polylactide blends: Plasticizing effect and ageing

Polylactide (PLA) is an attractive and widely used polymer which has received much attention in the last decade since it is biodegradable and produced from renewable resources. The polymer is of interest in the production of packaging films. However, plasticization of PLA is required in order to obtain soft films. In this work, PLA was blended with a new renewable oligomer obtained from biodiesel. The crystallization behavior and the mechanical properties of the blends were investigated for contents up to 20wt% of plasticizer. The plasticizing effect was characterized by a decrease on the glass transition temperature due to an increase in PLA chain mobility, which induced crystallization on heating. Thermal stability was not significantly affected, and mechanical properties showed an increase in ductility with the plasticizer content. Good compatibility was observed between the plasticizer and PLA, making this material suitable for biodegradable film manufacture. The addition of the plasticizer did not induce Tg increase with aging. However, a significant increment of crystallinity was observed after one year of storage at room temperature for the blend containing 20% of the plasticizer. (C) 2014 Elsevier Ltd. All rights reserved.