Biopolymer-based corrosion inhibitor from chitosan grafted with poly(2-hydroxyethylmethacrylate) (CS-g-PHEMA) synthesized by ultrasound-assisted method

Abstract

A biopolymer-based corrosion inhibitor was developed from CS grafted with PHEMA. The CS-g-PHEMA was successfully synthesized by using an ultrasound-assisted method. The synthesized CS-g-PHEMA was employed as corrosion inhibitor for mild steel. The corrosion test by gravimetry under 0.2 M H2SO4 revealed that, in comparison with CS, the inhibition efficiency of CS-g-PHEMA was higher reaching 90% at 500 ppm, while the corrosion rate with CS-g-PHEMA was reduced to a half. Furthermore, Ea of the corrosion was higher with CS-g-PHEMA compared to that with CS, indicating a higher energy barrier for the corrosion reactions. The potentiodynamic polarization measurement clearly showed a superior effect of CS-gPHEMA on retarding anodic oxidation and cathodic reduction on the mild steel surface. This is because adsorbed CS-g-PHEMA limits the diffusion of H3O+ to participate in anodic metal dissolution or cathodic hydrogen evolution on the mild steel surface.

Keywords

• ultrasound
• chitosan
• poly(2-hydroxyethylmethacrylate)
• corrosion inhibitors
• biopolymers