Analysis of the Anti-Corrosion Performance of Dextrin and Its Graft Copolymer on J55 Steel in Acid Solution

This paper studies the corrosion inhibition performance and mechanism of dextrin (Dxt) and its graft copolymer with caprolactam (Dxt-g-CPL) on J55 steel in 1 M HCl solution. Caprolactam is grafted and copolymerized with dextrin by a chemical synthesis method, to obtain a dextrin graft copolymer corrosion inhibitor. The composition of the synthesized graft copolymer was characterized by FTIR to identify whether the grafting was successful. Through weightlessness, electrochemical impedance spectroscopy (EIS), potentiodynamic polarization curve (TAFEL), scanning electrochemical microscope (SECM), scanning electron microscope (SEM), and contact angle experiments, the graft copolymer to J55 steel in 1 M HCl solution and the corrosion inhibition performance were evaluated. Moreover, we discuss its corrosion inhibition mechanism. The dextrin graft copolymer has good corrosion inhibition performance for J55 in 1 M HCl solution. When the concentration of the corrosion inhibitor increases, the corrosion inhibition efficiency will also increase. At a certain concentration, when the temperature rises, the corrosion inhibition efficiency will gradually decrease. When the concentration is 300 mg/L, it has a better corrosion inhibition effect, and the corrosion inhibition efficiency is 82.38%. Potential polarization studies have shown that Dxt-g-CPL is a mixed corrosion inhibitor, which inhibits both the cathode and the anode of the electrode reaction. SEM, SECM, and contact angle analysis results show that Dxt-g-CPL can significantly inhibit corrosion. Compared with Dxt, Dxt-g-CPL has a better inhibitory effect.