High toughness poly(lactic acid) (PLA) formulations obtained by ternary blends with poly(3-hydroxybutyrate) (PHB) and flexible polyesters from succinic acid

This work reports the development of poly(lactic acid) (PLA) formulations with improved toughness by ternary blends with poly(3-hydroxybutyrate) (PHB) and two different flexible polyesters derived from succinic acid, namely poly(butylene succinate) (PBS) and a copolymer, poly(butylene succinate-co-adipate) (PBSA). The main aim of this work is to increase the low intrinsic toughness of PLA without compromising the thermal properties by manufacturing ternary blends using epoxidized vegetable oils as compatibilizer agents. The ternary blends were manufactured by reactive extrusion in a co-rotating extruder and were subjected to mechanical, thermal, thermos-mechanical and morphology characterization. The obtained results confirm that these two succinic acid-derived polymers, i.e., PBS and PBSA, positively contribute to increase ductile properties in ternary blends with PLA and PHB with a subsequent improvement on impact toughness. In addition, both epoxidized vegetable oils, ELO and ESBO, are responsible for somewhat compatibilization between all three polyesters in blends which gives improved ductile properties with regard to uncompatibilized ternary blends. In addition, the temperature range in which these materials can be used is broader than ternary blends with other flexible polyester such as poly(e-caprolactone), as both PBS and PBSA melt at about 100 °C. These PLA-based materials with improved impact properties offer interesting applications in the packaging industry.