Sustainable development of multifunctional epoxy composites reinforced with jujube seed particles

Abstract

Abstract This study investigates the multi-functional performance of epoxy composites reinforced with Indian wild jujube ( Ziziphus mauritiana ) seed particles as a sustainable and low-cost reinforcement. Composites were fabricated by hand layup with particle concentrations of 4, 8, 12, 16, and 20 wt% in an LY-556 epoxy matrix cured with HY-951 at room temperature. Mechanical, tribological, water absorption, and thermal properties were evaluated, and scanning electron microscopy was used to relate performance to morphology and interfacial behaviour. Particle size analysis showed a bimodal distribution with an average hydrodynamic diameter of 1099 nm and a polydispersity index of 0.969. The composite with 12 wt% particles showed the highest tensile strength of 43.5 MPa, which is a 14.5% improvement over pure epoxy at 38.0 MPa. The maximum flexural strength of 148.7 MPa was obtained at 8 wt% with a 7.5% improvement. Water absorption increased with filler content under both conditions, while saltwater absorption remained lower due to ion-retarded diffusion. Erosion resistance improved for all composites, with the lowest erosion rate of 1.59 mg/min at 20 wt% compared to 1.74 mg/min for pure epoxy. The lowest wear rate of 7.560 × 10⁻⁶ mm³/(Nm) was observed at 4 wt%, after which wear increased with filler content. Thermal analysis showed slower degradation and higher char residue above 450 °C with increasing particle content. This study provides one of the first comprehensive evaluations of epoxy composites reinforced solely with jujube seed particles across mechanical, tribological, and thermal domains. The utilisation of agricultural jujube seed waste as reinforcement supports circular economy principles and contributes to SDG 9 (Industry, Innovation and Infrastructure), SDG 12 (Responsible Consumption and Production), and SDG 13 (Climate Action). Furthermore, the valorisation of agricultural waste into engineering reinforcements promotes resource efficiency and supports the development of sustainable composite materials for advanced engineering applications.

The authors' abstract, as published at the source. Discover Sustainability, 2026 · DOI ↗