The influence of NaOH concentration on the mechanical properties of Corypha gebanga fiber-reinforced composites

Textile composites can be manufactured utilizing both synthetic and natural fibers, such as Corypha gebanga fiber, being a viable option. The weaving of Corypha gebanga fiber with cotton thread in a plain weave configuration enables its application as a reinforcement material in textile composites involving a resin matrix. This research aims to investigate the mechanical characteristics of plain woven Corypha gebanga fiber textile fabric-reinforced polymer hybrid composites made from epoxy resin. This study utilized four different variations: a control group without any treatment, and three treatment groups using solutions with NaOH concentrations of 2.5%, 5%, and 7.5%. The result showed that NaOH concentrations above 2.5% seem to have a detrimental effect, as indicated by the gradual decrease in mechanical performance observed in the 5% and 7.5% NaOH-treated specimens. The decrease in tensile strength suggests that prolonged exposure to alkaline conditions leads to permanent alterations in the cellulose structure and morphology. The optimal concentration of NaOH for maximum mechanical performance enhancement is found to be 5%, which balances the removal of impurities and the avoidance of excessive fiber damage. Microscopy image analysis showed that fiber pullout occurred in all specimens tested that were cut in the direction of the warp during tensile testing. The onset of fracture was characterized by the resin breaking initially, followed by the fibers stretching and ultimately breaking.