Study on the Synthesis and Corrosion Inhibition Performance of Mannich-Modified Imidazoline

A novel Mannich-modified imidazoline (MMI) as cationic emulsifier was synthesised for corrosion harm reduction, through three steps — acylation, cyclization, and Mannich reaction. The surface activity was characterized by determination of surface tensions and critical micelle concentration (CMC). The corrosion inhibition performance of five types of steels in the simulated corrosion solution in the presence of the MMI was investigated by static weight loss tests. The results showed that the MMI had good surface activities, with CMC of 19.8 μg g−1 and surface tension of 36.4 mN m−1. The corrosion test results indicated that the corrosion rates of different materials were decreased significantly, and degrees of corrosion inhibition were always higher than 80.0 %. The main inhibition mechanism was most likely due to the adsorption of the corrosion inhibitor on the steel surface, leading to the prevention of corrosion medium from the metal surface.