Epoxy composites reinforced by alkaline–acid treated yucca fibers

Abstract

This study investigates the impact of chemical treatments on the physico–chemo–mechanical properties of mechanically extracted yucca fibers and the mechanical performance of epoxy-based bio-composites. Initially, yucca fibers are treated with sulfuric acid (H2SO4 at 1% and 4%, during 30 min) and sodium hydroxide (NaOH at 3% and 8%, during 120 min), aiming to enhance their properties. Scanning electron microscope (SEM) analysis reveals improved surface quality of fibers and reduced diameters, while fourier transform infrared spectroscopy (FTIR) confirms their functional groups. Yucca-treated fibers exhibit significant tensile strength improvements, with increases of 101.22% (518 MPa) for fibers treated with 3% NaOH and 93.33% (497 MPa) for those treated with 1% sulfuric acid, compared to untreated fibers (257 MPa). Subsequently, bio-composites elaborated via mold casting technique and using these treated fibers demonstrate enhanced mechanical performance. Tensile strength increases by 25% (29.6 MPa) and 45% (34.4 MPa) for composites reinforced with fibers treated with 3% NaOH and 1% sulfuric acid, respectively, compared to untreated fiber composites (23.6 MPa). Similarly, compressive strength improves by 23.35% (79.5 MPa) and 9.85% (89.3 MPa), while bending strength reaches 41.03 MPa (4.3%) and 45.27 MPa (15.1%) for composites reinforced with fibers treated at 3% NaOH and 1% sulfuric acid, respectively