Graphene-alumina hybrid nanoparticle effects on the thermomechanical behavior of jute fiber/epoxy nanocomposites

This study investigates the synergistic reinforcement effects of graphene (GNP) and aluminum oxide (Al₂O₃) hybrid nanoparticles on the thermo-mechanical behavior of sustainable jute fiber/epoxy composites to identify the optimal nanoparticle loading that balances strength and thermal stability. Jute/epoxy laminates containing 35 wt% jute and 10 wt% Al₂O₃ were fabricated via compression molding with varying GNP contents (0, 0.5, 1.0, and 1.5 wt%). The composites were characterized through tensile, flexural, impact, and hardness testing (ASTM standards), along with thermogravimetric (TGA/DTG/DTA), Fourier-transform infrared (FTIR), and scanning electron microscopy (SEM) analyses to evaluate thermal stability, interfacial bonding, and fracture morphology. The composite with 0.5 wt% GNP exhibits the best mechanical performance, with a tensile modulus of 1.74 GPa, tensile strength of 39.95 MPa, flexural modulus of 10.21 GPa, flexural strength of 126.23 MPa, impact strength of 22.57 kJ/m², and hardness of 95.5 Shore D, showing up to 60 % and 35 % improvements in stiffness and strength compared to the GNP-free system. Thermal stability improves consistently with higher GNP loading, with the 1.5 wt% GNP composite showing the highest decomposition onset (∼350°C) and 30 % residual mass at 600°C. FTIR and SEM analyses confirm effective interfacial bonding, homogeneous nanoparticle dispersion, and distinct fracture mechanisms linked to GNP agglomeration. Overall, a hybrid formulation containing 0.5 wt% GNP and 10 wt% Al₂O₃ provides an optimal combination of mechanical enhancement and thermal resistance, demonstrating the potential of these eco-friendly composites for high-performance applications in automotive, marine, and aerospace structures.