Abstract:
In order to improve the morphology and structure of nanocomposites, improve their anti-corrosion properties, and reduce the economic losses and safety accidents caused by material corrosion, aniline (ANI) was combined with different ratios of graphene (RGO) and carbon nanotubes (CNTs) to synthesize RGO/polyaniline (PANI) primary doped products and CNTs/PANI primary doped products. After redoping with ammonia, the RGO CNTs/redoped PANI composite were prepared by secondary doping of the two products in the sulfuric acid system. The morphology and structure of different PANI products were characterized by means of scanning electron microscopy, transmission electron microscopy. The anti-corrosion properties of different products were tested by electrochemical workstation, the best performing PANI composite material was combined with resin to prepare PANI epoxy coating. Anticorrosive properties of the coatings soaked for a long time were studied by AC impedance test and verified by neutral salt spray test. The performances of the composite materials prepared by secondary doping alone are significantly improved compared to those prepared by direct blending, the product has the best morphology and anti-corrosion performance when RGO∶ANI is 1∶10 and CNTs∶ANI is 1∶15, with the corrosion inhibition rate of 81.18%, the PANI epoxy coatings still exhibit high impedance values after soaking in 3.5wt% NaCl solution for
1440 h, with the highest impedance value reaching 6.019×10
10 Ω·cm
2 when the PANI addition amount is 1wt%, and there is no obvious corrosion on the coating surface after
1440 h neutral salt spray test, the coating surface has no bubbling and other deterioration phenomena, only a small amount of rust in the scratch but not spread, reflecting excellent anti-corrosion properties. It is feasible to develop a heavy anticorrosive coating system based on polyaniline nanocomposites, which can provide long-term protection for metal materials.