Corrosion inhibition behavior of hydroxyl-terminated hyperbranched poly (amine-ester) for Q235 steel in HCl solution

Herein, we reported to use a hydroxyl-terminated poly(amine-ester) hyperbranched polymer (HPAE-OHs) as a green, effective and economic corrosion inhibitor for mild steel (Q235) in 1 M HCl solution. HPAE-OHs is a third generation hyperbranched polymer which can be synthesized through a simple "one-pot" solvent-free esterifi-cation. Weight-loss tests show that the presence of HPAE-OHs can inhibit the corrosion of Q235 and the corrosion inhibition efficiency (eta (%)) can reach 94.9% at the dosage of 100 mg L-1 for 24 h. The study of the adsorption thermodynamic indicates that the adsorption of HPAE-OHs on the surface of Q235 steel follows Langmuir adsorption isotherm model. Polarization measurements and electrochemical impedance spectroscopy (EIS) suggest that HPAE-OHs works as a mixed-type inhibitor, which forms a layer of protective film on the metal surface to prevent metal corrosion. Moreover, theoretic studies further indicate that the corrosion inhibition is the result of the strong adsorption of HPAE-OHs inhibitor on Q235 steel surface. All these results clearly show that the synthesized hyperbranched polymer HPAE-OHs is an efficient corrosion inhibitor for steel and has a great application potential in industrial metal anticorrosion.