Development of Biodegradable Talc‐Filled PBAT / PLA and PBSA / PBAT Binary Blend Films: Effects of Multilayer Architecture and Uniaxial Orientation on Performance

ABSTRACT This study aims to develop polybutylene adipate‐co‐terephthalate (PBAT) based binary blend composite films with either polylactic acid (PLA) or polybutylene succinate‐co‐adipate (PBSA) and achieve performance comparable to commercially available biodegradable packaging films (ecovio F23B1). PBAT‐PLA and PBSA‐PBAT films were produced in both single‐layer and tri‐layer configurations, with talc as a reinforcing filler, followed by uniaxial stretching. The unstretched PBAT‐PLA films exhibited higher tensile modulus and strength than the PBSA–PBAT films. Moreover, multilayer films showed better performance compared to monolayer films for PBAT‐PLA films. Stretching enhanced the mechanical properties of both PBAT‐PLA and PBSA‐PBAT films. The greatest improvement was noticed for tri‐layer PBAT‐PLA with 18% talc film at stretch ratio of 4, showing a maximum increase of ~197% in tensile strength and ~221% in Young's modulus relative to the unstretched film. This was due to strain‐induced crystallization and orientation of polymer chains in the direction of stretching. For the same reason, PBAT‐PLA films showed maximum improvements up to ~20% and ~38% in water vapor and oxygen barrier properties, respectively. Additionally, multilayer films showed better UV barrier performance than monolayer films for all film groups, and after stretching to the maximum stretch ratio, light transmittance fell below 10% for all samples.