The role of lignin extracted from patchouli fiber waste in sustainable ternary biopolymer blends

The study investigates a ternary biopolymer blend composed of biopolymers polylactic acid (PLA), polyhydroxybutyrate-co-valerate (PHBV), and lignin extracted from patchouli fiber waste for sustainable packaging applications.A PLA: PHBV blend (70:30) was enhanced by incorporating hydrophobic lignin as a filler in varying loadings of 0, 3, 6, 9, and 12 wt%.The ternary blend was prepared using twin-screw extrusion process, pelletized, and compression-molded into specimens.Comprehensive characterization of the ternary blend included evaluations of water barrier, mechanical, functional, thermal, and morphological properties.Results demonstrated that lignin addition notably improved the compatibility between PLA and PHBV, leading to enhanced barrier performance, mechanical strength, and thermal stability.SEM morphology confirmed improved interfacial adhesion due to hydrophobic nature of lignin, which facilitated better dispersion at lower filler loadings.However, at 12 wt% lignin, property reductions were observed, attributed to lignin agglomeration and poor dispersion.Optimal performance was achieved at 9 wt% lignin loading, offering a balance of improved properties without compromising processability or structural integrity.This study highlights the potential of the PLA/PHBV/lignin ternary blend as a viable, eco-friendly material for sustainable packaging, showcasing improved functionality and environmental compatibility compared to conventional polymers.