Abstract
The polymer-polymer complexes [(PMAAN/PAAmM)c], composed of polymethacrylic acid [PMAAN, N=1(Mn=1.0×104), 2(Mn=5.0×103) and 3(Mn=2.5×103)] and polyacrylamide [PAAmM, M=1 (Mn=5.0×103) and 2(Mn=2.5×103)] were investigated as inhibitors for corrosion of mild steel in cooling water systems. The inhibition abilities of (PMAAN/PAAmM)c against corrosion and scale deposition were evaluated by corrosion tests and physicochemical methods. In a solution with low concentration of ionic species (LC solution), the corrosion inhibition abilities of (PMAAN/PAAmM)c improved at an addition of the polymer higher than 50ppm. This effect is due to the control of adsorption of the polymers on steel surfaces based on the formation of polymer-polymer complexes. In a solution with high concentration of ionic species (HC solution), the corrosion inhibition abilities of (PMAAN/PAAmM)c were also favorable at an addition of the polymer higher than 20ppm. This effect is attributed to control of the adsorption of the polymers on steel surfaces and the scale dispersion based on the formation of polymer-polymer complexes.
