Fabrication of graphene-coated poly(glycidyl methacrylate) microspheres by electrostatic interaction and their application in epoxy anticorrosion coatings

The uneven dispersion of graphene in the resin matrix hinders its application in anticorrosion coatings. This study reports a new method where graphene oxide (GO) is coated on the surface of the poly(glycidyl methacrylate) (PGMA) microspheres to promote the dispersion of GO in epoxy resin (EP) to improve the anticorrosion performance of EP. GO-coated PGMA microspheres (PGMA@GO) were successfully fabricated by electrostatic interaction, which was confirmed by Fourier transform infrared spectroscopy, X-ray diffraction, Raman spectroscopy, transmission electron microscopy, and zeta potential analysis. The scanning electron microscopy results showed that the PGMA microspheres were uniformly coated with GO, when the weight ratio of PGMA@GO was 1:2 (PGMA: GO). Electrochemical impedance spectroscopy and salt immersion experiments were performed to evaluate the corrosion resistance of the EP composite coatings. Comparing with pure EP and GO/EP coatings, the mechanical properties and anticorrosion properties of coatings were improved after adding PGMA@GO. When the addition amount of PGMA@GO (of 50 g EP) was 1.0 wt% and about 0.67 wt% GO was only needed, the PGMA@GO/EP composite coating possessed a high impedance of 5.68 × 108 Ω cm2 and a low breakpoint frequency of 0.39 Hz for 21-day immersion in 3.5 wt% NaCl solution. The anticorrosion mechanism of PGMA@GO/EP composite coating was also discussed.