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 (ΔHa°, ΔSa°) and the negative values of the free energy (ΔGa °) show the spontaneity of the adsorption process corrosion inhibition by the new synthesized products.