Characterization of Seed Shell and Pod Vascular Fiber Bundles from <i>Caesalpinia Spinosa</i> : A Renewable Andean Biomaterial for Future Engineering Applications

Natural fibers are increasingly valued as alternatives to synthetic materials given their renewability, affordability, and abundance. This study presents the characterization of Caesalpinia spinosa vascular fiber bundles (CSVFB) and powder obtained from its seed shells (CSSSP), focusing on their physical and thermochemical properties. Morphology was assessed using scanning electron microscopy (SEM), density by gas pycnometry, chemical compositions through ANKOM procedures, crystallinity by X-ray diffraction (XRD), thermal stability by thermogravimetric analysis (TGA), and molecular structure using Fourier-transform infrared (FTIR), 13C Solid State Nuclear Magnetic Resonance (NMR), and Raman spectroscopy. ANKOM analysis revealed cellulose contents of 16.2% and 32.3%, hemicellulose contents of 43.5% and 22%, and lignin contents of 3.3% and 2.4% for CSSSP and CSVFB, respectively. SEM revealed rough surfaces with crystalline and amorphous regions. Densities were 1.51 and 1.29 g/cm3 for CSSSP and CSVFB, respectively. TGA revealed moisture losses of 8.9% and 3.6%, with maximum degradation rates at 301°C and 350°C for CSSSP and CSVFB, respectively. XRD showed crystallinity indices of 24 and 40. Spectroscopic analysis confirmed the low lignin content and distinct cellulose-hemicellulose ratios. These results highlight CSSSP and CSVFB as underutilized renewable materials suitable for diverse engineering applications.