Characterization of Raw and Alkaline-Treated Novel Lignocellulosic Fibers from Mimusops elengi Leaves for Potential Composite Reinforcements

In this study, a novel plant-based fiber was extracted from the leaves of Mimusops elengi, an abundant agro-waste resource, using a straightforward mechanical crushing technique. The extracted fibers demonstrated significant potential as reinforcement materials in polymer composites. Both raw and alkali-treated fibers were thoroughly characterized to evaluate their physical, chemical, thermal, and mechanical properties. Chemical composition analysis revealed a notable increase in cellulose content from 45.44% in raw fibers to 54.92% in alkali-treated fibers, accompanied by a reduction in hemicellulose and lignin content. The crystallinity index improved from 61% to 64%, indicating enhanced structural order. ATR-FTIR spectroscopy confirmed the effective removal of hemicellulose and other surface impurities following alkali treatment. Thermogravimetric analysis (TGA) demonstrated improved thermal stability, with maximum degradation temperatures increasing from 357°C (raw fibers) to 365°C (treated fibers). Mechanical testing showed a slight enhancement in tensile strength, rising from 425 MPa to 435 MPa. Microscopy analysis revealed increased surface roughness in the treated fibers, suggesting improved fiber–matrix interfacial bonding in composite applications. Compared to other natural fibers, Mimusops elengi fibers exhibited competitive physical and mechanical properties, positioning them as promising candidates for eco-friendly and sustainable reinforcement in polymer composites.