Effect of quinacridone content on the performance of graphene/epoxy coatings

In this article, long‐lasting anti‐corrosion graphene/epoxy coatings were successfully prepared using quinacridone as dispersant by solution mixing method. The results showed that quinacridone and graphene can form π–π bonds and improve the dispersibility of each other in epoxy coatings. Mechanical and anti‐corrosion properties of epoxy coatings with different contents of quinacridone and graphene have been tested, the results showed that the optimum weight ratio of graphene to quinacridone was 2:5. The tensile strength of the epoxy coatings with 0.2 wt% graphene and 0.5 wt% quinacridone reached 8.12 MPa, which was 1.44 times of the pure epoxy coatings. Moreover, the impedance modulus of the coatings reinforced with quinacridone and graphene was greater than 1011 Ω·cm2 after being immersed in 3.5 wt% NaCl solution for 140 days, which was two orders of magnitude higher than that of the pure epoxy coatings. We found that the reason for the improved performance of the epoxy coatings was not only that quinacridone improved the dispersibility of graphene in the coatings, but also more importantly, quinacridone adsorbed on the surface of graphene to form scale‐like crystalline structures, which enables graphene to reduce folds and wrinkles, thus giving full play to the shielding effect of graphene against corrosion factors.