A novel approach to fabricate polyacrylate modified graphene oxide for improving the corrosion resistance of epoxy coatings

Abstract

In the past decades, graphene oxide (GO) exhibited great potential for enhancing the performance of polymer composites. Homogeneous dispersion of GO sheets in the polymer matrix was still a main challenge for the application of GO materials. In this paper, the polyacrylate functionalized GO (PA-GO) was prepared through free-radical copolymerization technology, with the aim to enhance the dispersion of GO in epoxy coatings. Fourier transform infrared (FT-IR), 1H-nuclear magnetic resonance spectroscopy (1H-NMR), Raman, thermogravimetric analysis (TGA), scanning electron microscope (SEM) and transmission electron microscope (TEM) were conducted to inspect the structure and micromorphology of GO and PA-GO nanosheets. The results affirmed that the polyacrylate polymer has successfully grafted onto graphene oxide. The SEM results revealed that the GO nanoplatelets exhibited significantly improvement in the dispersion and interfacial interaction in the epoxy matrix after modification with polyacrylate polymer. Electrochemical measurements were also employed to evaluate the corrosion resistance of GO-based epoxy composite coatings. The EIS results indicated that the impedance modulus at low frequency (0.01 Hz) of epoxy coating containing PA-GO was increased by almost two orders of magnitude compared to the neat epoxy, demonstrating that the corrosion resistance of epoxy coating was significantly improved after introduction of PA-GO. Besides, the Tafel results showed that the corrosion rate of epoxy coating was also decreased from 4.814 × 10−7 mm/year to 1.701 × 10−8 mm/year, which also indicated that the incorporation of PA-GO effectively strengthened the corrosion protection performance of epoxy coating.