Enhancement of mechanical properties of CFRP manufactured by using electro-activated deposition resin molding method with the application of CNF without hydrophobic treatment

Abstract Cellulose nanofiber (CNF) is high strength and lightweight, additionally, it is produced by sustainable natural resources such as wood. Therefore, it has been reported the mechanical properties of CFRP can be improved by dispersing CNF in the matrix. However, as CNF is hydrophilic, a hydrophobic treatment was applied in many previous studies. For efficient CFRP manufacturing, the authors have developed an electrochemical resin molding method by using aqueous electro-activated deposition which contains the polymer having an epoxy group. In this method, the carbon fiber fabric is immersed in the electro-activated deposition solution and energized, epoxy resin is precipitated around the carbon fiber and impregnated. In this study, shortly after electro-activated deposition, CNF without a hydrophobic treatment was applied to the surface of the resin-impregnated carbon fiber fabric. The mechanical properties of CFRP could be enhanced, and optimum weight fraction of CNF was revealed.