Valorization of banana peel and pulp waste as filler in PLA/PBAT biocomposites: Interfacial enhancement via maleic anhydride compatibilization

This study investigated banana fruit waste as a filler in biodegradable biocomposites based on polylactic acid (PLA) and poly (butylene adipate-co-terephthalate) (PBAT). Two filler types, pure banana peel powder (PBP) and mixed banana biomass powder containing peel and pulp (MBP), were incorporated into a PLA/PBAT matrix, while maleic anhydride (MA) was applied as a compatibilizer to improve interfacial adhesion. Among the compatibilized formulations, 5 wt% MA provided the best overall balance of properties. At this composition, tensile strength reached 21.35 MPa for the PBP-based composite and 22.43 MPa for the MBP-based composite, while the corresponding flexural strengths were 11.67 and 10.59 MPa, and impact strengths were 2.79 and 2.32 kJ m-2, respectively. Fourier-transform infrared spectroscopy indicated interactions consistent with esterification between the filler and matrix, which was supported by improved interfacial morphology and reduced void formation. The optimized formulations were further processed into biodegradable bowl prototypes by compression molding. Evaluation of these prototypes showed compliance with 4 of 6 assessed parameters of the Indonesian National Standard for food containers (SNI 12-4260-1996). Overall, the results demonstrate the potential of banana fruit waste as a sustainable filler for PLA/PBAT-based biodegradable composites and support its further development for disposable packaging applications, although additional studies on food-contact safety and long-term performance are still needed.