Comprehensive characterization of natural cellulosic fiber from Coccinia grandis stem.

The anatomical, physico-chemical, mechanical, thermal and surface characteristics of Coccinia grandis fiber (CGF) were studied for a potential substitute to the harmful synthetic fibers. The anatomical analysis of Coccinia grandis stem reveals the presence of high strength xylem fibers. Polarized light microscopy and scanning electron microscopy of CGF shows a hierarchical cell structure composed of a primary and a secondary cell wall, cell lumen and the middle lamellae. The average cross-sectional area and density of the CGF were 0.0111 mm2 and 1.5175 ± 0.005 g/cm3 respectively. The x-ray diffraction and Fourier transform infrared analyses of the fiber indicates the presence of cellulose Iβ with a crystallinity index of 46.09%. The mean Young's modulus and tensile strength of the CGF were 124 GPa and 775 MPa respectively, which is sufficient enough for the reinforcement in polymer composites. The thermogravimetric analysis confirms the thermal stability of CGF up to 250 °C, which is well within the polymerization process temperature.