Thermal and mechanical characteristics of natural fiber-reinforced composites using bio-binder as sustainable insulation materials

To reduce deforestation and promote the utilization of agro-industrial by-products this study fabricated a completely bio-derived composite using date trunk fibers and non-edible okra as sustainable feedstock. Composites with 0-50 wt. percentage okra content were produced using compression molding and tested to assess mechanical strength, thermal insulation, and sound absorption. Rising okra proportion improved interfacial bonding and minimized porosity, leading to increased compressive strength (up to 28 MPa) and elastic modulus (0.49 GPa). Thermal conductivity numbers were observed in the range between 0.051and 0.067 W/m.K at room temperature, confirming suitability for insulation applications. The fabricated composites demonstrated high thermal stability with 11% mass loss at 270°C, and achieving a maximum acoustic absorption coefficient (0.9). The specific heat capacity values were found between 1.35 × 10³ and 2.38 × 10³ J/kg·K, and corresponding thermal diffusivity between 0.0307 and 0.0651 mm²/s, reflecting effective heat storage. These results validate the use of date palm and okra by-products as feedstock for bio-based composites fabrication via a simple method without depending on any toxic ingredients, pretreatment, and sophisticated processing. These results confirm that valorizing date palm trunk fibers and okra residues into bio-based composites, and acoustically efficient materials for construction use in arid climates.