Effect of Chemical Modifications on Surface Morphological, Structural, Mechanical, and Thermal Properties of Sponge-gourd Natural Fiber

Sponge-gourd (SG) natural fibers obtained from Luffa cylindrica plant were chemically treated separately using alkali (5, 10, and 15 wt%), acetic anhydride (5, 10, and 15 wt%), and benzoyl chloride (5, 10, and 15 wt%). Both untreated and chemically treated SG fibers (SGFs) were subsequently characterized using a field emission scanning electron microscope, a Fourier transform infrared spectrometer, an X-ray diffractometer, a universal testing machine, and a thermogravimetric analyzer. Surface analysis by scanning electron microscopy shows that the alkali treatments promote better outer surface layer than other treatments of the SGF with the exposition of inner fibrillar structure, thereby increasing roughness of the fiber surface. Alkali treatment also improves the crystallinity and exhibits new chemical bond formation in the SGF. The tensile strength and Young's modulus have been analyzed through a two-parameter Weibull distribution model, where a significant increase in mechanical property of benzoylated fibers has been observed. The thermal stability of the modified fibers is also found to increase by acetic anhydride treatment.