Analysis of Thermal Insulation Characteristics in Epoxy Composites Reinforced with Hybrid Materials: Calabash and Rice Husk Ash

This research investigates the thermal insulation properties of epoxy composites reinforced with hybrid natural materials, specifically calabash and rice husk ash (RHA). Addressing the increasing demand for sustainable, cost-effective, and energy-efficient materials in the construction and automotive industries, we employed a systematic approach involving material characterization, composite fabrication, and thermal performance evaluation via differential scanning calorimetry (DSC). Composites were prepared using varying proportions of calabash and RHA as fillers in an epoxy matrix. Key metrics were analysed, including thermal conductivity, thermal resistance, specific heat capacity, and mechanical properties (Shore D hardness and density). The optimal composite formulation—comprising 20% calabash fiber, 20% RHA, and 60% epoxy resin—demonstrated exceptional thermal performance, achieving a thermal conductivity of 0.284805 W/m·K and thermal diffusivity of 0.131303 m²/s, meeting industrial insulation benchmarks. Comparative analysis with conventional materials, such as fiberglass and polyurethane composites, highlighted the superior thermal performance of the hybrid epoxy composite. This work illustrates the potential of integrating agricultural by-products into advanced materials for sustainable thermal insulation applications.