Preparation and characterization of PLA/PBAT blends toughened by poly(lactic acid-r-malic acid) copolymer

PLA and PBAT blending is of great significance as biodegradable polymers with good properties. However, they are immiscible and form phase separation morphology in their blend; toughening is critical for the blend to obtain better mechanical properties. Copolymer of malic acid and l -lactide (PMLA) with long-chain branched topology is blended with PLA and PBAT, as to enhance the interfacial interactions for a toughened biodegradable polymer blend. The mechanical and thermal properties are investigated of the resultant blend. Together with SEM and positron annihilation lifetime spectroscopy analysis, the results show that PMLA is an efficient toughening agent for PLA and PBAT blend. The elongation at break increases more than sixfold and the impact strength increases 87.5% than neat PLA and PBAT blend with 8-to-2 weight fraction ratio. At the same time, the resultant blend still keeps fully biodegradable and shows promoted potential for broader application. Graphical Abstract