Influence of PVA Concentration on the Properties of Lontar Palm Leaf‐Sugarcane Bagasse Hybrid Biocomposite Films

Natural fiber‐reinforced bioplastics represent a viable strategy for valorizing agricultural waste; however, the combined reinforcement of lontar palm ( Borassus flabellifer ) leaf and sugarcane bagasse fibers in a polyvinyl alcohol (PVA) matrix remains underexplored. This study investigates the effects of varying PVA concentrations (15, 30, and 45 wt%) on the physical, mechanical, thermal, and interfacial properties of hybrid biocomposite films. Extracted cellulose fibers served as structural reinforcement. Tensile strength increased with higher PVA loading, peaking at 1.79 MPa at 45 wt% PVA, while elongation reached an optimal 43.36% at 30 wt.% PVA. Physical characterization revealed a maximum swelling of 70.3% at 45 wt.% PVA, whereas water solubility decreased from 63.54% at 15 wt.% PVA to a minimum of 55.30% at 45 wt.% PVA. The 45 wt.% formulation also exhibited superior structural and thermal stability, showing the lowest soil‐burial degradation (36.80%) and minimal heat‐induced weight loss (8.99% at 120°C). Spectroscopic analyses confirmed robust interfacial bonding via hydrogen linkages (3500–3200 cm − 1 ) and prominent C─O/C─O─C vibrations (1200–1000 cm − 1 ) between the cellulose fillers and polymer chains. Overall, balancing PVA concentration with hybrid fiber reinforcement is critical to tailoring mechanical strength, water affinity, and degradation resistance in biodegradable films