Epoxy prepolymer as a novel anti-corrosive material for carbon steel in acidic solution: Electrochemical, surface and computational studies

Atetra-functional aromatic epoxy prepolymer namely, 4, 4'-(ethane-1, 2-diyl) bis (N, N-bis (oxiran-2-ylmethyl) aniline) (AA1) was synthesized as evaluated corrosion inhibitor for carbon steel. TheAA1 was characterized using H-1 NMR and FT-IR methods. The anti-corrosive property of AA1 for carbon steel corrosion in 1M HCl solution was evaluated using several experimental and computational techniques. The AA1 showed highest efficiency of 96.5 % at 10(-3)M concentration. PDP study suggested that AA1 behaves slight anodic predominance and its adsorption of the AA1 obeyed the Langmuir adsorption isotherm model. DFT study conducted in neutral as well as protonated forms suggested that AA1 acts as efficient anti-corrosive material under both the conditions and its adsorption mainly takes place through polar heteroatoms (N and O) and two aromatic rings as HOMO and LUMO are mainly localized over the center part of the AA1 molecule. MDS suggested that AA1 adsorbs using its flat orientation and its adsorption decreases with rise in temperature. Adsorption energies were in negative indicating that AA1 adsorption occurs spontaneously as all studied temperatures.