Extraction and characterisation of new lignocellulosic fibre from Butea Monosperma (Palash) root for potential use as reinforcement in composites

The root of Butea monosperma (Palash), an unexplored source of lignocellulosic fiber for composite reinforcement, is the focus of the present investigation. Unlike conventional bast or leaf fibers, root-derived fibers possess distinct structural characteristics that make them promising candidates for sustainable composite applications. The fibers were extracted using a water digestion (retting) process and subsequently subjected to controlled mechanical processing using a wooden hammer. Comprehensive characterization revealed a low density of 1.23 g/cm³, a moisture content of 10.7%, and an ash content of 2.7%, indicating the lightweight nature of the fibers and their potential for energy-efficient processing. The fibers exhibited a high cellulose content (59.5%) and a crystallinity index of 60.49%, suggesting favorable mechanical efficiency. FTIR analysis showed characteristic absorption peaks at 3334.05, 2919.23, 1627.15, 1026.90, and 661.97 cm⁻¹, confirming the lignocellulosic and cellulose-rich nature of the fibers. SEM micrographs revealed a rough surface morphology, which is beneficial for fiber–matrix interfacial bonding. Thermogravimetric analysis indicated reasonable thermal stability up to 202 °C. The tensile strength and elongation at break of the fibers were measured as 188.26 MPa and 8.23%, respectively, demonstrating that the root-derived Butea monosperma fibers possess sufficient mechanical performance to serve as reinforcing materials in composite applications.