Chemical modification of epoxy prepolymers as anticorrosive materials: a review

Epoxy resins (ERs) represent a special class of industrially and biologically active materials. They are extensively used as anticorrosive materials for different metals and alloys. Because of their polymeric nature, ERs possess a high surface area that offers them high anticorrosive activity. Several pure and cured ERs have been used as corrosion inhibitors in aqueous as well as in coating phase. Instead of their macromolecular and polymeric nature, pure and cured ERs possess high solubility in the polar electrolytes, which is attributed to their high surface functionalities. The presence of numerous peripheral functional groups, such as amino (-NH2), hydroxyl (-OH), amide (-CONH2), etc., enhances their solubility in such electrolytes. Experimentally they showed better anticorrosive effect than pure ER, which is attributed to filling out the surface micropores of the coating structures through which corrosive species can penetrate and accelerates corrosion. Literature studies showed that ERs are used as corrosion inhibitors, especially in NaCl and acidic media. Most ERs act as interface and mixed type corrosion inhibitors. This chapter describes the collection of some major advancements toward metallic corrosion inhibition using ERs as anticorrosive materials.