Sustainable epoxy composites from hemp/pineapple/glass fibers for lightweight automobile panels.

The rapid industrial revolution has led to increased use of synthetic materials in various automotive panel applications, resulting in environmental concerns due to their non-biodegradability. To address these issues, natural fiber composites have been explored as sustainable alternatives; however, their mechanical performance often falls short compared to synthetic counterparts. In the present study, hybrid natural/synthetic fiber composites were developed using pineapple and hemp mat fabrics with intermediate glass fiber mats to enhance performance characteristics. The composites were fabricated using the vacuum infusion technique with varied stacking sequences of hemp and pineapple fibers, hybridized with glass fiber mats for improved mechanical strength and durability. Comprehensive mechanical, thermal, viscoelastic, and low-velocity impact analyses were conducted to evaluate the composites' performance. Fracture morphology was examined using scanning electron microscopy. Mechanical results revealed that the pure hemp composite with intermediate glass layers exhibited the highest tensile and flexural strengths, at 58.24 MPa and 98.35 MPa, respectively. Viscoelastic analysis indicated that the pure pineapple fiber composite demonstrated the highest storage modulus of 2875.51 MPa, consistent with the observed flexural modulus trend. However, this configuration also exhibited a higher thermal expansion, with a coefficient of thermal expansion of 215.66 ppm/°C, attributed to the fiber-matrix interfacial bonding and chemical composition. A low-velocity impact analysis showed that hybrid composites with varied stacking sequences offered superior impact resistance. Overall, the results confirm that the properties of these hybrid composites can be tailored based on specific application requirements, making them promising candidates for lightweight, high-performance automotive panel applications.