Enhanced corrosion resistance and weathering resistance of waterborne epoxy coatings with polyetheramine-functionalized graphene oxide

Polyetheramine (D230), an epoxy curing agent, was grafted on graphene oxide (GO) surfaces, which can be stably dispersed in a waterborne curing agent for more than 8 months. Waterborne epoxy coatings reinforced by D230-functionalized GO (DGO) were prepared on carbon steel surfaces. According to the electrochemical impedance spectra, the impedance modulus at 0.1 Hz remained at 2.2 x 10(9) omega after 150 days of immersion in 3.5% NaCl electrolytes for 0.2 wt% DGO-reinforced waterborne epoxy coatings, while that of the neat epoxy coatings dropped below 1 x 10(7) omega after 10 days. Besides, the addition of DGO enhanced the weathering resistance of waterborne epoxy coatings. After 60 days of the UV aging test, the yellow color index of neat epoxy coatings was 1.6 times that of 0.5 wt% DGO/epoxy coatings. The residual pencil hardness of the 0.5 wt% DGO/epoxy coatings was three levels higher than that of neat epoxy coatings.