Relationships of Component and Composition with Inhibition Abilities of Copolymers Composed of Acrylic Acid and Acrylamide on Corrosion of Mild Steel in Cooling Water Systems

Abstract

Copolymers composed of the acrylic acid (AA) and acrylamide (AAm) derivatives were synthesized and these inhibition effects on corrosion of steels were investigated in cooling water systems. In particular, the relationship between the component and composition, and the inhibition ability of the copolymers was discussed. In a high concentrated solution, the copolymers at AA/AAm molar ratio of 5/1 showed the most effective as inhibitors. In the substituent effect of amido group (-CONR₂), the inhibition ability of the copolymer increased in the order of (R=)H (acrylamide: AAm)<CH₃ (dimethyl acrylamide: DMAAm)<C₂H₅ (diethylacrylamide: DEAAm). In low and high concentrated solutions, the copolymer at number average molecular weight of ca. 10⁴ depressed strongly the corrosion of steel.