Development of granite waste nanoparticle-reinforced Montrichardia linifera /epoxy hybrid composites: a step towards sustainable materials for lightweight applications

The development of sustainable natural fibre-reinforced polymer composites using industrial waste-derived fillers has gained increasing attention for advanced engineering applications. This study reports the fabrication and characterization of novel hybrid epoxy composites reinforced with woven Montrichardia linifera fibres (MLF) and granite waste nanoparticles using the hand lay-up technique. Five composite formulations were prepared by varying the granite waste nanoparticle content from 1 to 5 wt.% while maintaining a constant fibre content. The influence of filler loading on the mechanical, thermal, morphological, and antibacterial properties of the composites was systematically evaluated. Among the investigated formulations, the composite containing 3 wt.% granite waste nanoparticles exhibited the optimum performance, achieving a tensile strength of 80.39 MPa, flexural strength of 84.29 MPa, impact strength of 14.97 kJ m−2, and Shore D hardness of 51. Thermal characterization revealed a thermal conductivity of 3.65 W m−1 K−1, a coefficient of linear thermal expansion of 4.82 × 10−6 °C−1, a heat deflection temperature of 141 °C, and a decomposition temperature of 425 °C, indicating good thermal stability. SEM analysis demonstrated uniform nanoparticle dispersion and strong fibre–matrix interfacial bonding at the optimum filler loading, whereas higher filler contents resulted in particle agglomeration, interfacial debonding, and void formation, leading to reduced mechanical performance. Antibacterial testing against Pseudomonas aeruginosa confirmed moderate antibacterial activity.