Lightweight eco-friendly polymer composites reinforced with banana and orange peel natural agro-waste particulate fillers: Processing, characterisation, and structural performance evaluation

This study investigates the development of hybrid agro-waste–filled polymer composites for potential use in eco-friendly friction materials. Banana peel and orange-peel powders were incorporated as secondary bio-fillers in an epoxy-based composite system containing carbon powder and Al₂O₃ as thermally stable constituents. Composites were fabricated using a controlled hand layup and compression-molding route, and the compositions were varied to evaluate their influence on mechanical and tribological performance. The developed materials were characterized through compressive strength, flexural behavior, pin-on-disc wear testing (ASTM G99), thermogravimetric and differential thermal analysis (TGA/DTA), and water and oil absorption measurements. Among the investigated formulations, the hybrid composition containing 7 wt% banana peel, 8 wt% orange peel, and 5 wt% Al₂O₃ exhibited the best overall performance, showing improved compressive load-bearing capacity (24.4 MPa) and reduced specific wear rate compared with other compositions under identical test conditions. TGA results indicated a primary degradation peak near 370 °C, consistent with lignocellulosic filler decomposition, while the presence of carbon and alumina contributed to char formation and stabilization during sliding. Water and oil absorption remained within acceptable limits for non-structural friction composites. The results demonstrate that agro-waste fillers can function as sustainable secondary constituents in hybrid friction composites for moderate-duty applications. This work provides a preliminary assessment of banana–orange peel–reinforced epoxy composites and establishes a basis for further optimization and full brake-pad qualification testing.