Sustainable composites based on poly(butylene adipate-co-terephthalate) and wood biocarbon: Influence of extrusion methodologies on final properties for eco-friendly flexible packaging applications

This study explores the development of sustainable composites comprising poly(butylene adipate-co-terephthalate) (PBAT) reinforced with wood biocarbon (BC) at 5 and 10 wt.% loadings. The influence of two different extrusion strategies on the structural, mechanical, and thermal properties of these bio-based composites was systematically evaluated. Composites were processed via melt extrusion followed by hot-melt film casting, aiming at flexible and eco-friendly packaging applications. Among the approaches tested, PBAT composites prepared from BC-filled powders exhibited the most promising performance, showing up to a 33% increase in Young’s modulus and a 7% enhancement in elongation at break along the machine direction compared to neat PBAT. X rays’ diffraction and differential scanning calorimetry results showed higher crystallinity, correlating with improved mechanical properties. Morphological analysis confirmed improved filler dispersion, while crystallinity increased slightly due to the limited nucleation ability of BC. These structural improvements also translated into superior barrier performance, with water and oxygen barrier enhanced by approximately 18% and 37%, respectively, due to increased crystallinity, the hydrophobic nature of BC, and the creation of a more tortuous diffusion pathway. The findings highlight the potential of optimizing filler content and processing routes to produce high-performance, sustainable PBAT-BC composites suitable for next-generation flexible packaging.