Abstract
Herein, two bifunctional macromolecular aromatic epoxy resins (ERs), namely, 4,4'-isopropylidenediphenol oxirane (ERH) and 4,4'-isopropylidene tetrabromodiphenol oxirane (ERBr), are synthesized, characterized, and evaluated as anticorrosive materials for carbon steel corrosion in acidic medium. ERs were characterized using proton nuclear magnetic resonance (H-1 NMR) and Fourier transform infrared spectroscopy techniques. Investigated ERs acted as effective corrosion inhibitors, and their inhibition effectiveness followed the order ERBr (96.5%) > ERH (95.6%). Potentiodynamic polarization results showed that ERH and ERBr behave as predominantly anodic type and the cathodic type of corrosion inhibitors, respectively. Adsorption of both the studied ERH and ERBr molecules obeyed the Langmuir adsorption isotherm model. Density functional theory and molecular dynamics studies showed that protonated forms of ERH and ERBr contribute more to metal (carbon steel)-inhibitor (ERH/ERBr) interactions than their neutral forms.