Eco-friendly coir fiber reinforced natural latex composites for improved thermal insulation and mechanical properties

Thermal insulating materials are necessary for buildings, automobiles, and industrial operations to be cool and energy-efficient. Traditional insulation materials are usually made from synthetic polymers, known to release toxic fumes and are not readily biodegradable. Sustainable green materials are progressively more significant as the need for energy preservation and environmental conservation increases. In this line, a sustainable bio-composite comprised of coir fiber (CF) and natural latex suitable for thermal insulation purposes has been developed and is presented in this study. The composites were produced with varying CF content (10%−50%) to determine the optimum fiber-to-latex ratio for improved mechanical and thermal properties. These results indicate that the mechanical properties were improved by CF incorporation, and the optimal tensile strength, elastic modulus, and maximum breaking force were recorded at 40% CF addition (Coir-Latex Composites-4). In addition, the thermal conductivity of CLC-4 was 0.04411 W/m·K, which was 22.55% lower than conventional thermal insulating materials (Poly-Ethylene foam). It also shows strong thermal stability in the thermogravimetric examination with a high residue (17.7%) at 600°C, indicating good thermal resistance. Latex helped to reduce CF hydrophilicity and water uptake with advantages at high CF contents. Fiber-matrix adhesion was confirmed by Field-Emission Scanning Electron Microscopy (FESEM), showing adequate distribution and concentration at lower fiber loadings. The mechanical properties of the material deteriorated when the CF content exceeded 40%. Therefore, the CLC composite presents an eco-friendly alternative to conventional insulation materials, having the complementary features of enhanced mechanical strength, low thermal conductivity, and biodegradability, making it a sustainable insulation for construction and energy-efficient applications.