Effect of graphene oxide concentration on flexural properties of CFRP at low temperature

A novel method to employ graphene oxide (GO) onto the surface of carbon fabrics to fabricate multi-scaled reinforced polymer composites by electrophoretic deposition has been popularly used in industry. In this study, various voltage supplies for depositing GO onto the surface of carbon fabrics with a controlled deposition time were applied. The flexural properties of GO/CFRP composites with different GO contents (0, 0.25, 0.5,0.75 and 1 wt%) conditioned at both room temperature and low temperature environments were investigated. Experimental results showed that 0.5 wt% and 0.25 wt% were the optimal GO contents to achieve better flexural strength and modulus of the composites by 20–54% at the room temperature and low temperature respectively as compared to pristine composites at room temperature. The addition of GO into CFRP composites helps improve the mechanical interlocking between carbon fibre and the matrix. The improvement of properties of GO/CFRP composites at low temperature is also attributed to the additional clamping force from contracted epoxy matrix to the expanded GO. Only 0.25 wt% of GO is sufficient to achieve the optimal flexural properties at low temperature due to the higher effectiveness of crack deflection provided by GO on the surface of carbon fabrics, leading to a high efficiency of energy dissipation by carbon fibre. Further increasing the GO content will form clusters, which may act as crack initiation sites.