Comparative experimental analysis on an eco-friendly sodium carbonate- and alkali treated butea parviflora fibers for green composites: Unveiling of mechanical, microstructural morphological, chemical, thermal, and acoustical properties

Natural fiber-based materials are gaining importance due to their light weight, renewability, and adequate strength, making them attractive alternatives to synthetic fibers. In this study, Butea parviflora (BP) fibers were treated with alkali (KOH) and eco-friendly sodium carbonate (Na 2 CO 3 ) to enhance performance. The treated fibers were characterized for density, crystallinity, spectroscopic, morphological, tensile, and thermal properties. KOH-treated fibers showed lower density (1.34 g/cc) and higher crystallinity (84%) compared to Na 2 CO 3 -treated fibers (1.41 g/cc; 71%). SEM images confirmed increased surface roughness, favoring better matrix adhesion. Improved tensile strength and modulus were observed for alkali-treated fibers, while thermal analysis revealed stability up to ∼230 °C. Thermal conductivity was found to be ∼0.020-0.021 W/mK. Epoxy composites reinforced with BP fibers demonstrated enhanced mechanical and sound absorption behavior. This work highlights the potential of BP fibers as sustainable reinforcements, though research gaps remain in long-term durability, moisture resistance, and large-scale processing. Future studies should address these aspects to expand industrial applications in automotive, construction, and acoustic materials.