Polymers as Corrosion Inhibitors for Metals in Different Media - A Review

Abstract

Several works have been done and more are on the pipeline on the influence of organic compounds containing polar functions on the corrosion inhibition of metals in various aqueous media. Corrosion inhibition by such compounds is generally attributed to their adsorption on the metal/solution interface. The specific action of an inhibitor depends on the nature of its interaction with metal surface, which causes a change in either mechanism of the electrochemical corrosion process or in the surface area available for the process. Thus, factors such as physiochemical properties of the inhibitors, the nature and surface charge of the metal, solution composition and pH are important considerations. Polymers function as corrosion inhibitors because of their ability to form complexes through their functional groups with metal ions which occupy large area and by so doing blanket the metal surface from aggressive anions present in solution.

Effect of molecular structure of aniline–formaldehyde copolymers on corrosion inhibition of mild steel in hydrochloric acid solution

“…The adsorption process, generally predominated by physisorption or chemisorption, is affected by the molecular structures of inhibitors, the nature and surface charge of metal, the distribution of charge in molecule and the type of aggressive media [3][4][5][6][7][8][9][10][11][12][13][14][15][16]23]. Physical adsorption, with characteristic of weak van der Waals forces, requires the presence of electrically charged metal surface and charged species in the solution in order to cause electrostatic and/or dipole attractions between adsorption centres of inhibitor molecules and metal surface.…”

Synergistic effect of polyethylene glycols and rare earth Ce4+ on the corrosion inhibition of carbon steel in sulfuric acid solution: electrochemical, computational, and surface morphology studies

“…These complexes occupy a large surface area, thereby blanketing the surface and protecting the metal from corrosive agents present in solution [7][8][9]. Many reviews, including extensive listings of polymers for use as corrosion inhibitors for various metals in various corrosive aqueous environments, have been published [10][11][12].…”

Recent Developments on the Use of Polymers as Corrosion Inhibitors - A Review

“…Interest in polymers is principally due to its availability, cost effectiveness, and eco-friendliness in addition to the inherent stability and multiple adsorption centers [14]. We have reported the use of polyacrylamide as inhibitor for aluminum in HCl solution [15], carboxymethyl cellulose for mild steel in sulphuric acid medium [16] and detailed information on the utilization of polymers as metal corrosion inhibitors in different corrosion inducing environments can be found in our earlier review [17] and in that of Kalaivani et al [18]. Nevertheless, most polymeric materials are not readily soluble in aqueous medium and this always have negative influence on the inhibition efficiency of polymers.…”