Water-soluble polymers as corrosion inhibitors

Purpose - To determine the inhibition efficiency and adsorption characteristics of two water soluble polymers namely polyvinyl alcohol (PVA) and polyethyleneglycol (PGE) as corrosion inhibitors of mild steel in H ₂SO₄. Design/methodology/approach - The inhibition efficiencies of PVA and PEG were evaluated using the weight loss and hydrogen evolution techniques at 30-60°C. Findings - The inhibition efficiency (I per cent) of the inhibitors increased with increase in concentration and temperature. The inhibitors (PVA and PEG) were found to obey Temkin, Freundlich and Langmuir adsorption isotherms from the fit of the experimental data at all concentrations and temperatures studied. The phenomenon of chemical adsorption is proposed from the activation parameters obtained. PEG was found to be a better inhibitor than PVA. Research limitations/implications - The mechanistic aspect of the corrosion inhibition can be better understood using electrochemical studies such as polarization and AC impedance spectra. Practical implications - The findings may be useful in cooling water systems in industries under simulated conditions. Originality/value - This paper provides additional new information on the inhibiting characteristics of PVA and PEG as promising corrosion inhibitors.