Poly(epichlorohydrin) Modified (PECH/NTO/PO(OH)2) as a New Corrosion Inhibitor for Mild Steel in Hydrochloric Acid Medium: Synthesis, Electrochemical, Termodynamic, Surface Study

The synthesis and characterization of novel organic corrosion inhibitors based on poly(epichlorohydrin) (PECH) for mild steel immersed in 1 M HCl solution have been reported for the first time. In this way, the chlorine branches of poly(epichlorohydrin) (PECH) were substituted with 3-nitro-1,2,4-triazol-5-one (NTO) and Cl atoms in phosphoryl chloride (POCl3) were replaced by hydroxyl groups of poly(epichlorohydrin) containing NTO. UV-visible and Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR) and elemental analyzer (CHN) and thermogravimetric analysis (TGA) were used to characterize the chemical composition of the synthesized organic compounds. Electrochemical impedance spectroscopy (EIS) and electrochemical polarization techniques were used to evaluate the corrosion inhibition performance of the organic inhibitors. Polarization results revealed that the corrosion inhibition efficiency in the inhibitor-containing samples was increased by increasing the concentration of the inhibitors in the corrosive electrolyte. In addition, it was found that the sample containing 200 ppm of the (PECH/NTO/PO(OH)2) organic inhibitor had the maximum inhibition efficiency of 99.5% after 24 h immersion in the HCl solution.