Mechanochemically Synthesized PEG-OTs as a Green Corrosion Inhibitor

Polymer corrosion inhibitors are reported to form dense films on carbon steel surfaces, and their thermostability enables survival in harsh downhole environments. In this paper, PEG-OTs was synthesized by mechanochemistry using ball mill by grafting tosyl on PEG. Using this solvent-free green chemistry, non-toxic PEG and PEG-OTs with various molecular weights (600, 2000, and 10,000 g/mol) were prepared and used as corrosion inhibitors. The corrosion inhibition performance of 5 × 10−3mol/L inhibitors on Q235 carbon steel in 0.5 M HCl solution was investigated using static weight-loss, electrochemical impedance spectroscopy, polarization curves, SEM, and contact angle measurements. The results show that, after modification, PEG-OTs has an elevated corrosion inhibition effect compared to PEG. A maximum of 90% corrosion inhibition efficiency was achieved using static weight-loss. The morphology study shows that a dense film formed to protect carbon steel. Thanks to their polymeric structure, a higher molecular weight leads to better corrosion inhibition.