Exploring the thermal conductivity of green filamentous algae natural fibre: an experimental investigation

Abstract The use of non-renewable resources in thermal insulation has significant environmental impacts. Another major problem faced by the ecosystem is the invasive growth of water weeds. Making sustainable products from waterweeds helps to prevent its overgrowth that disrupts the balance of the ecosystem. This study explores the viability of Green Filamentous Algae (GFA) as an eco-friendly thermal insulation material. GFA was collected from water bodies, cleaned, and processed into two forms: untreated (UTD) and alkali-treated (TD). Experimental investigations were conducted to evaluate the physical properties of GFA, including density, self-ignition temperature, water absorption, moisture absorption, flammability, and thermal conductivity. Results show that the untreated GFA had a density of 402.52 kg m −3 , while the treated GFA exhibited a slightly lower density of 392.32 kg m −3 . The self-ignition temperature for both untreated and treated GFA was measured between 275 °C and 280 °C. The water absorption capacity was higher in treated GFA (654.7%) compared to untreated (493.83%). Moisture absorption capacity was 15.14% for untreated GFA and 17.47% for treated GFA. Flammability tests revealed a burning rate of 20.026 mm min −1 , placing GFA in the combustibility classification 1 (CC1). Thermal conductivity values were found to be 0.308 W m −1 K −1 (UTD) and 0.273 W m −1 K −1 (TD), making treated GFA a promising candidate for sustainable insulation applications. This study demonstrates the potential of GFA as a bio-based insulation material and highlights future improvements to enhance its moisture resistance and thermal performance.