Green approach in anticorrosive coating for steel protection by Gliricidia sepium leaf extract and silica hybrid

Abstract

The lack of non-toxic, biodegradable and easily available green corrosion inhibitor that offer analogous anticorrosive property as that of commercial toxic inhibitors is the main tailback in the area of anticorrosive coatings. Current work presents a novel green corrosion inhibitor Gliricidia sepium leaf extract and investigation of its anticorrosive activity on steel in saline environment. Promising results from preliminary analysis of crude extract prompted to the isolation of active fraction and subsequent identification of major corrosion inhibitor in it. Structural elucidation substantiated the presence of disaccharide sucrose along with two other low yield components in the active fraction. The –OH functional group present in the sucrose moiety contributes towards developing a protective layer at the metal-electrolyte interface thereby retard corrosion. The crude extract explored as a novel green alternative in epoxy protective coatings via engineering an organic–inorganic hybrid GSL-PAS. The prepared hybrid coating offered an exceptional corrosion resistance than that of reported hybrids and commercial anticorrosive pigments. Two months continuous electrochemical study validated the durability of the prepared hybrid epoxy coating, authenticated the advantage of harmonious action of active and passive inhibitor GSL and PAS, respectively, in the epoxy matrix. The present work provides a new hope to the future researchers for the application of plant extract inhibitor in protective polymer coatings without hesitation.