New epoxy resin as a corrosion inhibitor for the protection of carbon steel C38 in 1M HCl. experimental and theoretical studies (DFT, MC, and MD)

In this work, we synthesized a new organic compound type epoxy resin namely N, N, 1-tri(oxiran-2-ylmethoxy)-5-((oxiran-2-ylmethoxy)thio)-1H-1,2,4-triazol-3-amine (TTA) used as corrosion inhibitor of carbon steel C38 in an acid medium 1 M HCl. The corrosion inhibition process of carbon steel in 1 M HCl has been studied by the potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS), the surface morphologies without and with inhibitor was examined by the scanning electron microscopy (SEM) and in the theoretical calculations we used the Density Functional Theory (DFT) and Molecular Dynamics (MD) simulations. Potentiodynamic polarization curves showed that the TTA affects both cathodic and anodic current density; we can classify it as a mixed type inhibitor, the electrochemical impedance measurements confirm the results obtained by the polarization curves, they indicate that inhibitory efficiency increases with the increasing concentration to reach 92% at 1 mM TTA. The effect of temperature on the corrosion behaviour with the addition of TTA was studied in the temperature range 293–323 K. The adsorption of this compound on carbon steel C38 surface obeys Langmuir's adsorption isotherm.