Enhancement of toughness and gas barrier properties of <scp>PLA</scp>‐based films through bio‐based isosorbide dioctate: Synthesis, characterization, and application

Abstract Polylactic acid (PLA), as a bio‐based biodegradable material, has high tensile strength and modulus, but its low flexibility and poor barrier properties limit its application in packaging. In this study, Pullulan polysaccharide (Pullulan) and chain extenders (ADR4468) were selected to improve the properties of PLA‐based films. The ratio of PLA/Pullulan/ADR4468 was optimized by studying the mechanical and barrier properties of films. Then isosorbide dioctate (SDO), a kind of bio‐based plasticizer, was synthesized and added into PLA/Pullulan (4 wt%)/ADR4468 (0.8 wt%) system to study the effect of SDO content on the properties of films. A film with 15 wt% SDO showed elongation at a break of 79.7% while retaining a tensile strength of 30.6 MPa. With 20 wt% SDO, water vapor permeability and oxygen permeability of PLA/Pullulan/ADR/SDO film were reduced by 12.7% (2.95 × 10 −14 kg m/(m 2 s Pa)) and by 20.6% (1.95 × 10 −3 cm 3 m/ (m 2 d Pa)), respectively, compared with that of PLA/Pullulan/ADR films. This study fills the research gap between PLA and Pullulan blends, broadens the application scenarios of new bio‐based plasticizers, and provides a method for improving the toughness and barrier properties of PLA. The films prepared in this study have potential applications in the green‐packaging field. Highlights The synthesis and characterization of isosorbide dioctate. The modified compatibility of PLA and Pullulan by ADR 4468. The optimization of the content of PLA/Pullulan/ADR 4468 film. The improvement of toughness and barrier properties of film by SDO.