Multi-analytical investigation of the physical, chemical, morphological, tensile, and structural properties of Indian mulberry (Morinda tinctoria) bark fibers

In this study, micro-cellulosic fibers were isolated from the bark of Morinda tinctoria (MT) and characterized for the first time. The anatomical, physical, chemical, thermal, and mechanical properties of the M. tinctoria bark fiber (MTBF) were investigated. The mean diameter and density values were determined to be 32.013 ± 1.43 μm and 1.4875 g/cm³, respectively. Zeta potential analysis and particle size measurements provided the evidence of enhanced micro-particle behavior on the fiber's surface. Various structural characterizations confirmed the presence of polysaccharide structures, monosaccharide compositions, glycosidic residues (sugar linkages), and cohesive reactions of TMSA (Trimethylsilyl alditol) derivatives, indicating the fiber's potential for strong surface absorption properties. X-ray diffraction analysis revealed a crystallinity index of 51 % and a crystallite size of 3.086 nm for MTBF. Fourier transform infrared analysis indicated the presence of cellulose, hemicellulose, and lignin constituents, along with their corresponding functional groups. The calculated values of Young's modulus and tensile strength were determined to be 75.7 GPa and 746.77 MPa, respectively. Thermogravimetric analysis demonstrated the thermal stability of the extracted MTBF up to 240 °C. Based on these findings, the MT microfibrils derived from the bark can be considered as potential substitutes for existing synthetic composites, offering reinforcement for novel bio composites.