Thermal insulation performance of rice husk-reinforced polyester composites for sustainable building applications

This study explores the thermal insulation potential and structural viability of rice husk (RH)-reinforced polyester bio-composites for sustainable building applications. Departing from conventional RH usage in ash or powder form, RH is used here as a high-volume structural filler (75–95%) in polymer composites. Increasing RH content significantly reduces thermal conductivity (down to 0.0829 W m −1 K −1 ), density, compressive strength, and ultrasonic pulse velocity, while increasing porosity and water absorption. The composite with 75% RH (P25R75) achieved the highest mechanical performance, while samples with 85–95% RH demonstrated excellent thermal insulation properties. Regression analysis indicates a strong correlation between density and both mechanical and thermal behaviours. Despite high water absorption, the composites show promise as eco-efficient, thermally insulating, non-load-bearing building materials, especially with surface treatments in humid environments. These findings position RH as a viable, low-cost reinforcement in the development of energy-efficient building envelopes.