Corrosion inhibition performance of threonine-modified polyaspartic acid for carbon steel in simulated cooling water

摘要

Green polymers as corrosion inhibitors are gradually used to protect metal in solution environment. A polyaspartic acid threonine derivative (PASP-Thr) was synthesized and its structure was characterized by Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance. The corrosion inhibition effect of polyaspartic acid (PASP) and PASP-Thr on carbon steel in simulated cooling water was investigated by weight loss tests and electrochemical measurements. Experimental results show PASP-Thr as a mixed-type inhibitor exhibits higher corrosion inhibition efficiency than PASP, and the inhibition efficiency of PASP-Thr reached 93.06% at the dosage was 200 mg L-1. The carbon steel surface in different situations was analyzed using atomic force microscope, scanning electronic microscope/energy dispersive X-ray, and FTIR, demonstrates the formation of a protective film on carbon steel surface. The inhibition effect of PASP-Thr was primarily attributed to the protective film formed on steel surface by physical and chemical adsorption. Moreover, quantum chemical calculation elaborated the relationship between the inhibition efficiency and the PASP-Thr molecular structure. (C) 2018 Wiley Periodicals, Inc.