Abstract

The quest for materials combining high thermal stability with environmental sustainability is intensifying in modern engineering. Synthetic fibres, while effective, often undermine sustainability goals due to their adverse environmental impact. This study explores the potential of Borassus flabellifer fruit shell (husk), typically discarded as agricultural waste in Bangladesh, as a bio-fibre alternative for thermal insulation applications. This work investigates the morphological, chemical, and thermal properties of the husk following alkali treatments with 5% sodium hydroxide (NaOH) of varying durations. The findings demonstrate that alkali treatment significantly enhances the thermal properties of Borassus husk, with observed increases in char content from 25% to 32% and Integral decomposition process temperature (IDPT) ranging from 905 to 1048 °C, which is around 12-30% higher than its untreated fibre, indicating enhanced thermal stability. Additionally, these treatments resulted in a reduction in specific heat capacity (Cp), which may be corresponded with an increase in integral process decomposition heat (IPDH). Scanning electron microscopy (SEM) analysis revealed that treated husks exhibit a rougher and cleaner surface, likely enhancing their adhesion properties in composite preparation. Fourier Transform Infrared Spectroscopy (FTIR) analysis supported these findings, showing reduced hemicellulose peaks, which align with lower moisture absorption as confirmed by thermogravimetric analysis (TGA). The optimum results were particularly observed in samples treated for 0.25 hour and 0.75 hour, indicating that Borassus husk treated with alkali for short durations could be an effective material for advanced engineering applications, which would promote eco-friendly, energy-efficient, and sustainable development.