Studying the Corrosion Protection Behavior of an Epoxy Composite Coating Reinforced with Functionalized Graphene Oxide by Second and Fourth Generations of Poly(amidoamine) Dendrimers (GO-PAMAM-2, 4)

In this research, graphene oxide (GO) nanoparticles were modified by second and fourth generations of poly(amidoamine) dendrimers in order to improve the particle dispersion quality in the epoxy matrix and therefore its barrier anti-corrosion performance. Confirmation on the GO surface modification by Polyamidoamine generation 2 (PAMAM2) and polyamidoamin generation 4 (PAMAM4) was carried out by Fourier transforms infrared (FT-IR) spectroscopy and thermogravimetric analysis (TGA). The corrosion protection properties of the epoxy composites against corrosive electrolyte (3.5 wt.% NaCl solution) was investigated by salt spray and electrochemical methods. The dispersion of unmodified and modified GO sheets in the epoxy matrix was studied by FE-SEM analysis. The FT-IR test results evidenced that the GO sheets were successfully modified with PAMAM 2 and 4 via the covalent binding mechanism. Salt spray and EIS test results revealed that the epoxy composites loaded with GO-PAMAM4 and PAMAM4 showed the highest improvement in the corrosion resistance. FE-SEM images from the fracture surface of the coatings revealed that the dispersion of GO sheets within the epoxy coating was improved after modification by PAMAM4.