Twin-screw extrusion optimization and study of morphological, thermal, mechanical and fracture properties of sustainable Poly(lactic acid) (PLA) and Poly(butylene sebacate) (PBSe) blends

The pursuit of sustainability in material science forces the utilization of bio-based and/or biodegradable alternatives to fossil-based plastics. With growing attention in recent years, particularly in applications like packaging and agriculture, biodegradable and bio-based polymers offer potential solutions to mitigate environmental concerns associated with plastic disposal. In this context, Poly(butylene sebacate) (PBSe), a commercially available biobased and biodegradable aliphatic polyester derived from sebacic acid and 1,4-butandiol, presents a promising innovation due to its flexibility, availability in the market and compatibility with poly(lactic acid) (PLA). Up to day few works investigated the addition of PBSe to PLA, for this reason the present work focuses on comprehensively characterizing PLA/PBSe blends (with different PBSe amounts from 10 up to 40 wt%). The blends have been produced through extrusion compounding after a careful Design of Experiment for optimizing process parameters to efficiently improve mixing and energy consumption. Thermal, mechanical, and morphological properties were evaluated, combined with micromechanical analysis employing dilatometric tests. Additionally, an elasto-plastic fracture mechanics protocol was applied to quantify toughness and energy absorption capabilities, demonstrating the potential of PLA/PBSe blends in sustainable material applications. In this work also emerged the great capacity of PBSe in acting as toughener for PLA especially when is present in low amount.