Synthesis and evaluation of an environmentally benign terpolymer as a novel corrosion inhibitor for oil-well acidizing

A novel, environmentally friendly ternary polymer (PIAS) was synthesized using itaconic acid, acrylamide derivative, and sodium styrene sulfonate, through free-radical polymerization. The synthesized PIAS molecule was characterized using FTIR and NMR spectroscopy, and TGA techniques. It was evaluated as a corrosion inhibitor for X60 steel in a 15% hydrochloric acid environment simulating industrial oil-well acidizing conditions. A high inhibition efficiency of 73.16% was achieved at elevated temperature of 80 °C. Adsorption followed the Langmuir isotherm. Electrochemical studies (EIS and PDP) revealed a charge-transfer-controlled, mixed-type inhibition mechanism with a cathodic preference. Density functional theory calculations revealed that the protonated form of the inhibitor demonstrated superior reactivity, and both the neutral and protonated forms exhibited a tendency to donate electrons to the metal surface. Molecular dynamics simulations showed high binding energy for the inhibitor, thereby supporting its strong adsorption. The mean-square displacement indicated that the diffusion of the corrosive species was hindered in the presence of the inhibitor, and overall, the inhibitor demonstrated strong potential for industrial application.