Performance evaluation of polypropylene glycol as corrosion inhibitor for X60 pipeline steel in 15% HCI solution

The toxic nature of most organic and inorganic corrosion inhibitors has necessitated the search for corrosion inhibitors with an excellent environmental profile. The present work is focused on the utilization of polypropylene glycol (PPG) for metallic corrosion control and reports on the corrosion inhibition effect of polypropylene glycol for typical X60 pipeline steel in 15% HCI solution using weight loss, electrochemical impedance spectroscopy, linear polarization resistance and potentiodynamic polarization techniques. Water contact angle measurements and scanning electron microscopy (SEM) were employed for surface morphology characterization. Results obtained show that polypropylene glycol acts as a good corrosion inhibitor for X60 steel in the strong acid environment. Inhibition efficiency increased with increase in PPG concentration. Immersion time and temperature were found to have profound effect on the corrosion inhibition performance of PPG. The potentiodynamic polarization studies revealed that PPG functions as a mixed-type inhibitor. The effective corrosion inhibition potential of PPG could be related to the adsorption of PPG molecules at the metal/solution interface which was found to accord with Langmuir adsorption isotherm model and a protective film formation.