Effects of Fiber Treatment on the Properties of Epoxy Curaua-Reinforced Composites

Natural fiber research is getting attention worldwide due to its sustainability and ecofriendly nature. It combines low density and interesting properties. Curaua fiber is an abundant natural fiber, which has low cost and several applications. The mechanical properties have a strong dependence on the interface adhesion between the fiber and the polymer matrix. In this work, surface modifications induced by sodium hydroxide (NaOH) on Curaua fibers were studied in order to investigate NaOH as a chemical agent in fiber reinforced epoxy polymer composites. Raw fibers were treated with 1%, 3% and 5 wt% sodium hydroxide solution for different periods of time (24, 72 and 168 h) at room temperature. Specimens of treated Curaua/Epoxy composites were tested and compared in tensile and in flexion to observe the mechanical properties. DMA analyses were performed to evaluate the composites physical properties due to temperature variation. Results showed that fibers treated with 5% of sodium hydroxide for 72 h produced improved superficial roughness increasing mechanical properties. The results also showed an increase in the viscoelastic stiffness of the epoxy matrix by the incorporation of Curaua fibers.