The Influence of Sodium Hydroxide (NaOH) Solution Concentration on Tensile Strength of Corn Husk Fiber-Epoxy Resin Composite

Abstract Alkalization is one of the important parameters in the treatment process of composite specimens. In this study, alkalization was carried out using a basic solution (NaOH) with the aim of improving the mechanical strength of the composite material. The addition of a basic solution to the composite matrix can enhance the bond between the Dibers and the matrix, thus expected to increase the strength of the material. The alkalization process was conducted by immersing natural Dibers (corn husk Diber) in NaOH solution at room temperature with variations in NaOH concentration values of 0%, 10%, 15%, and 20% for 2 hours. After the alkalization process, the corn husk Diber was placed in a mold for standard ASTM D638-01 tensile test specimens with direction of unidirectional Diber orientation and mixed with epoxy resin, which acted as the matrix. The resulting Diber and epoxy resin mixture was then formed into composite specimens using Vacuum Assisted Resin Infusion (VARI) method. Subsequently, the specimens underwent a mechanical test, namely a tensile test, and the fracture shapes resulting from the tensile test were analyzed using macroscopic photographs. The results indicate that the NaOH solution concentration affects the specimens’ tensile strength. Tensile strength increases with an increase in the concentration of NaOH solution and then decreases at a NaOH concentration of 20%.