Material properties of sponge-gourd fiber–reinforced polylactic acid biocomposites: Effect of fiber weight ratio, chemical treatment, and treatment concentrations

Sponge-gourd fibers (SGFs) were subjected to chemical treatments such as alkalization, acetylation, and benzoylation by 5−15 wt% sodium hydroxide, acetic anhydride, and benzoyl chloride solutions, respectively, in order to improve fiber–matrix adhesion. SGF-reinforced polylactic acid (PLA) biocomposites were fabricated using melt compounding technique. Both untreated and chemically treated fiber-reinforced composites were subsequently characterized by using a field emission scanning electron microscope, a Fourier-transform infrared spectrometer, an X-ray diffractometer, a universal testing machine, and a thermogravimetric analyzer. Structural analyses show that the chemical treatment improves the crystallinity of SGF and exhibits chemical bond formation in the SGF-reinforced PLA composites. Surface morphology indicates that after the treatment of fibers and increase in the treated fiber content, the interfacial adhesion between PLA and fibers is improved. The effects of fiber loading of chemically treated SGF on physical and mechanical properties of the composites were analyzed. Compressive strength of the composites was increased by 10–35% with incorporation of treated fibers into the PLA matrix. The thermal stability of them is found to increase significantly. Soil burial test has confirmed that the composites are biodegradable. Benzoylation of SGF shows superior mechanical properties and enhances thermal stability among the composites.