Performance comparison of polyester composites reinforced with hybrid fibers and biomass fillers: Mechanical, impact, and flammability aspects

Hybrid composites are increasingly studied for their environmental benefits and enhanced mechanical performance. This study investigates polyester composites reinforced with combinations of glass fiber (GF), pineapple fiber (PF) and basalt fiber (BF), including a variant using carrot peel-derived polyester resin (GF-PR). Composites were fabricated via hand lay-up and tested for tensile, flexural, impact, and hardness properties. GF-BF composites showed superior mechanical performance, attributed to basalt fiber’s ability to enhance fracture toughness, crack-bridging, and elongation at break. GB1 (3 vol.% pectin) exhibited the highest tensile strength (298.05 MPa), impact strength (9.5 J) and flexural strength (331.08 MPa). GB2 (5 vol.% pectin) recorded the highest hardness (85.2 Shore-D), drop impact resistance (52.3 J), and deflection (4.7 mm), indicating balanced durability and toughness. In flammability tests, GP2 showed the lowest flame propagation rate (12.70 mm/min), marking it as the most fire-resistant. SEM analysis revealed effective fiber-matrix bonding and typical failure patterns. Overall, BF-GFspecimens exhibited excellent flame-retardant and strength properties, suitable for wind turbine blades, construction, and automotive applications.