Preparation of amino-functionalized graphene oxide/sulfonated polyaniline and its application in waterborne epoxy anticorrosive coatings

Sulfonated polyaniline (SPANI) was synthesized from chlorosulfonic acid, aniline and ammonium persulfate. Amino-functionalized graphene oxide composite (PG) was obtained by reduction graphene oxide (GO) with polyethyleneimine (PEI). Amino-functionalized graphene oxide/sulfonated polyaniline composite (SPG) was prepared by combining SPANI with PG using the active site on GO. The waterborne epoxy anticorrosive coating was prepared by blending SPG with waterborne epoxy resin. The structure of SPG was characterized by FTIR and XRD. The corrosion resistance of waterborne epoxy coating was measured by salt spray and electrochemical experiments, and the physical properties of the coating were analyzed. The results showed that the amino group on PEI successfully combined with GO, and SPANI successfully increased the layer spacing of PG. The waterborne epoxy anticorrosive coating with 2% SPG (based on the total mass of epoxy resin and waterborne epoxy curing agent, the same below) had the best corrosion resistance. The corrosion inhibition efficiency could reach 99.19%. Compared with those of pure waterborne epoxy resin (EP), the corrosion current density decreased from 1080 nA/cm2 to 307 nA/cm2, and the corrosion voltage increased from -0.840 mV to -0.347 mV. © 2022, Editorial Office of FINE CHEMICALS. All right reserved.