A promising copolymer of p-phenylendiamine and o-aminophenol: Chemical and electrochemical synthesis, characterization and its corrosion protection aspect on mild steel

The poly (p-phenylendiamine-co-o-amino phenol) has been synthesised by chemical and electrochemical polymerisation method for corrosion protection of mild steel (MS) in acidic medium. The copolymer structure was confirmed by 1H NMR, FT-IR spectroscopy and its thermal stability was observed by TGA. The surface of copolymer coated MS revealed that uniform and relatively less porous morphology. The corrosion protection performance of copolymer coated MS were evaluated using potentiodynamic polarisation and EIS measurements. The copolymer coated MS by electropolymerisation exhibit a higher corrosion protection efficiency than homo polymers and copolymer prepared by chemical polymerisation, which can be due to strong interaction between the mild steel surface and conjugated copolymer.

► Investigate corrosion performance of poly (p-phenylendiamine-co-o-amino phenol) coated mild steel.
► Investigate the stability of copolymer in comparison with homo polymers.
► The surface morphology and porosity are critical factors to corrosion protection performance.
► The electrochemically synthesised copolymer coatings have excellent corrosion protection efficiency than chemically synthesised copolymer due to its strong adherent and interaction with metal surface.