Enhancement of the mechanical properties of the CFRP by cellulose nanofiber sheets using the electro-activated deposition resin molding method

Abstract

Cellulose nanofibers (CNFs) have high strength. Therefore, many studies have been conducted to improve the mechanical properties of carbon fiber reinforced plastics (CFRP) by dispersing CNF in the matrix. However, since CNFs are hydrophilic, a hydrophobic treatment is required. Previously, authors showed the bending strength of CFRP could be enhanced by CNFs without a hydrophobic treatment. Applying the electro-activated deposition resin molding (ERM) method to fabricate CFRP, CNFs can be applied on the surface since the electro-activated deposition solution is essentially water-based and contains a polymer with epoxy groups. In this study, the CNF sheet was prepared by drying CNF dispersion in advance. Shortly after the ERM, the CNF sheet was applied to the surface of the CFRP. The mechanical properties of the CFRP were enhanced, the maximum elastic modulus and tensile strength were 2.3 times and 1.7 times of the CFRP specimen without the CNF sheet, respectively.