Improvement of corrosion resistance, antimicrobial activity, mechanical and chemical properties of epoxy coating by loading chitosan as a natural renewable resource

Abstract

Chitosan is the most plentiful, renewable marine polymer; it is also one of the most potential eco-friendly candidates for surface coating purposes with excellent film forming ability, corrosion protection ability due to its barrier property and affinity towards metals. In this study, extraction and characterization of chitosan were investigated via several analyses such as elemental analysis, FTIR, 1HNMR and degree of deacetylation. The extracted chitosan was mixed as natural organic filler with epoxy coating in varying loading levels from 2% to 20% to form chitosan − epoxy coating composite. This work represents the corrosion resistance and the antimicrobial activity of a composite formed by chitosan and epoxy coating. The corrosion resistance was evaluated via salt spray test; Gram-negative bacteria, Gram-positive bacteria and fungi were used to study the antimicrobial activity of different concentrations of chitosan − epoxy coating composite. The dynamic mechanical analysis (DMA) of the coating composite was also studied, to characterize the viscoelastic properties of the extracted chitosan. Mechanical and chemical resistance was also investigated. The obtained results showed that, the chitosan − epoxy coating composite showed uniform and lower corrosion rates than that of blank epoxy coating. The antimicrobial effect of chitosan in different loading showed that, the antimicrobial effect strengthened as the loading of chitosan increased. The antimicrobial activity of chitosan for Gram- positive bacteria were higher than to Gram- negative bacteria and fungi. The DMA reported in this work showed that, chitosan may be useful to improve the viscoelstic characteristics of epoxy coating. The mechanical and chemical resistance was also improved and this improvement increases with increase chitosan loading up to, and including, a 15% chitosan.