Eco-friendly and mild synthesis of Poly(p-toluidine) for anti-corrosion in saline

Abstract

The scope of the current application of polyaniline is limited by its inherent defects, but the existence of donation groups and the external synthesis environment can improve its final process performance. Most of the organic polymers in the previous work were prepared in strong acid solutions, ignoring the potential hazard in this process. To solve this risk, one eco-friendly and moderate craft has been put on the agenda. Based on previous researches, the combination system of p-toluidine (pT) and buffer solution is rarely reported. In the present study, the electropolymerization of Poly(p-toluidine) (PpT) onto stainless steel (SS) combined with citric acid and sodium phosphate dibasic is reported. Cyclic voltammetry can produce stable PpT films with varying degrees of protrusions. The concentration of pT was optimized, and the influence of temperature on the corrosion resistance of the film was considered. The prepared PpT films were characterized by Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy to detect chemical composition. The surface analysis was confirmed by scanning electron microscope. The corrosion performance of PpT was characterized by impedance and potentiodynamic polarization tests after different temperatures or periods of immersion. The related electrochemical parameters suggested that the PpT film protects SS more significantly at a concentration of 0.05–0.08 mol L−1 in 3.5% sodium chloride solution under low-temperature conditions. This study will give researchers some inspiration to develop more environmentally-friendly and high-performance anticorrosion materials.