Influence of stem maturity on the properties of cellulosic fibres extracted from Sesbania rostrata for polymer composites

In this study, plant fibres were obtained from Sesbania rostrata plant stems with diameters ranging from 2 to 10 mm to investigate the effect of stem maturity on fibre properties. The physical analysis revealed that fibre density increased from 1308 to 1367 kg m −3 , while water absorption decreased from 202% to 141% as the stem matured. The chemical composition showed a reduction in cellulose content from 68% to 63%, with the crystallinity index ranging from 64.01% to 57.81%. Fourier transform infrared spectroscopy confirmed the presence of both cellulose and non‐cellulose components, with variations in peak intensities indicating changes in chemical composition. Thermal analysis demonstrated that the fibres could withstand temperatures from 356 to 376 °C. Mechanical testing showed a variation in tensile strength from 422 to 347 MPa, along with a Young's modulus range of 41.3–39.8 GPa. Surface morphology evaluation showed rough fibre surfaces and increased wax and impurity deposition with stem maturity. The findings highlight the importance of selecting the optimal stem diameter to obtain fibre properties suitable for targeted applications.