Eco-Friendly Biocomposites of Eugenol Epoxy and Rice Husk Silica: Fabrication and Performance Analysis

Studying biocomposites is essential for the development of sustainable, high-performance materials that address future environmental, economic, and technical challenges. In this work, a bio-epoxy resin was synthesised from eugenol, with its chemical structure confirmed by proton nuclear magnetic resonance (¹H NMR) spectroscopy. Silica (SiO₂) was extracted from rice husk and incorporated as a reinforcing additive to fabricate fully bio-based composites with silica loadings ranging from 5 to 20 phr. The biocomposite samples, composed of the bio-epoxy resin and rice husk silica, were prepared at room temperature using an aliphatic amine curing agent. The influence of rice husk silica content on key properties of the epoxy resin, including activation energy of curing, tensile strength, impact strength, and glass transition temperature (Tg), was thoroughly investigated. The incorporation of silica led to significant enhancements in tensile and impact strengths as well as Tg, accompanied by a reduction in the curing reaction’s activation energy. Notably, the composite containing 15 phr silica demonstrated superior mechanical properties, with impact strength, tensile strength, and glass transition temperature increased by 44.46%, 52.3%, and 9.1%, respectively, compared to the pristine sample. Owing to its tunable viscosity, mechanical rigidity, and compatibility with bio-based feedstocks, this biocomposite shows promise for processing into filament or paste forms suitable for 3D printing applications.