Epoxy resins as anticorrosive polymeric materials: A review

Epoxy resins (ERs) represent a special class of organic macromolecules that are comprehensively used for different industrial applications. Because of their macromolecular nature, ERs provide better surface coverage and anticorrosive activities than simple organic corrosion inhibitors. The peripheral polar functional groups of ERs act as adsorption centers during metal-inhibitor interactions. Several ERs in pure and cured forms had been used as anti-corrosive coating materials, especially for carbon steel in acidic and sodium chloride (3% and 3.5%) solutions. Most ERs act as interface and mixed-type corrosion inhibitors. Numerous computational simulations had been used to demonstrate the anticorrosive effects and adsorption behavior of ERs on metallic surfaces. However, most ERs have limited solubility; therefore they are better applied as coating materials for anticorrosive purposes. Literature survey showed that numerous ER-based coatings are developed and successfully employed for carbon steel and aluminum in brine solution. The anticorrosive effect of ER coatings can be further enhanced by adding organic and inorganic additives. The additives block the surface micropores present in ER coatings through which corrosive species can penetrate or diffuse and rapture the coating structures. This review article serves as a comprehensive collection of published reports on anticorrosive effects of pure and cured ERs for different metals and alloys in different electrolytes.