Monolayer and multilayer biodegradable biocomposite blown films: Effect of poly (3-hydroxybutyrate-co-3-hydroxyvalerate) and talc on mechanical and barrier properties

This study explores the blending of poly(butylene succinate-co-adipate) (PBSA) with poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and talc to assess their effects on film processability, mechanical properties, and gas barrier performance in blown films. PHBV was incorporated into the PBSA matrix to boost stiffness and reduce oxygen and water vapor permeability. Extensional viscosity measurements were used to correlate rheological behavior with processability. Incorporation of 15 wt% PHBV notably improved the modulus and barrier performance of PBSA films without significantly compromising their deformability, although strain hardening behavior decreased, leading to processing instability. Incorporation of reactive peroxide developed a strain hardening behavior in biocomposites based on ternary biopolymer blends, as confirmed by extensional viscosity data. The addition of talc further enhanced stiffness and barrier properties but resulted in a decreased elongation at break. Trilayer films demonstrated improved processability compared to monolayer films, evidenced by increased film width during production. Notably, trilayer films containing talc in both the core and outer layers achieved an optimal balance of mechanical strength, gas barrier performance, and flexibility.