Study Inhibition of Armco Iron Corrosion by Some Polymers based on Poly (4-Vinyl Pyridine) (PVP) In 0.5M Sulfuric Acid Medium

This paper focuses on the corrosion inhibition performance of Armco iron in sulfuric acid using [(poly N-vinylpyrrolidone (PNVP) -block- poly ε-caprolactone (PCL)-ɷ-hydroxyethylmethacrylate (HEMA) -graft-poly-4-Vinylpyridine (PVP)] (KFC) and KFC quaternized by octyl bromide (C₈Br) (KFCQ). The corrosion inhibition was investigated by both weight loss and potentiodynamic measurements at different concentrations. Experimental results showed that inhibition efficiency increases with increasing concentration of the inhibitor and reached a maximum efficiency of 84.50% and 73.23% at 100 mg / l for KFC and KFCQ respectively. Polarization curves indicate that the tested polymers functioned as cathodic inhibitors. The corrosion behavior of Armco iron in 0.5 M H₂SO₄ with and without inhibitor was studied in the temperature range 298–338 K, which negatively influences the effectiveness of the inhibition. The thermodynamic parameters (ΔH_a°, ΔS_a°) and the negative values of the free energy (ΔG_a °) show the spontaneity of the adsorption process corrosion inhibition by the new synthesized products.