Sustainable hybrid composites reinforced with fish scale biofillers: Mechanical, thermal, and environmental assessment

This study explores hybrid composites of polyester resin reinforced with jute, glass fiber, and 5–20 % fish scale powder (FSP), fabricated by hand lay-up, and evaluates their mechanical, thermal, and environmental performance. The composites were characterized using Fourier-transform infrared spectroscopy (FTIR), bulk density, water absorption, soil degradation, tensile, hardness, impact, flexural, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), flammability, and scanning electron microscopy (SEM) tests. The 10 % FSP composite showed optimal mechanical properties (tensile: 51.28 MPa, flexural: 48.23 MPa, impact: 13.01 kJ/m²), along with improved biodegradability, thermal stability (23 % residue), and flame retardancy (delayed ignition, reduced burning rate). Despite enhanced water absorption, the 10 % FSP composite balanced mechanical robustness with eco-friendly attributes, offering potential for application in sustainable interior automotive components, non-load-bearing panels, and biodegradable consumer products. This work underscores the viability of fish scale-derived bio-fillers in improving sustainability and multi functionality in hybrid composites. Future work may explore the incorporation of different composition of FSP, hybrid configurations, or surface modifications to further enhance the overall performance of sustainable composites. • Fish scale powder is an effective biofiller for composites. • Incorporation of fish scale powder contributed to biodegradability. • Fish scale powder enhances thermal stability and flame retardancy. • At optimal resin to bio-filler mixture provided the best performance.