Synthetic polymeric antioxidants are promising building blocks for thin films that demonstrate excellent adhesive and antioxidant properties as well as facile control over the degree of material hydrophobicity. Here, we studied the efficiency of antioxidant polymers as anticorrosion agents, based on their ability to reduce oxygen, which is one of the triggers of corrosion. Polymers containing a polyphenol repeating unit, either 3,4-dihydroxybenzyl methacrylamide or 3,4,5-trihydroxybenzyl methacrylamide, as well as a hydrophobic repeating unit, hexyl methacrylamide, were studied as thin solution-cast polymer films. These films were deposited from tetrahydrofuran solutions onto a metal substrate, such as aluminum and steel, and annealed at 85°C for 2 hours. The resulting micron-thick films were transparent. Studies using the potentiodynamic polarization technique revealed that the antioxidant polymers acted as corrosion inhibitors showing better passivation and lower corrosion current densities in comparison with bare aluminum substrates or films of a control polymer which lacked antioxidant groups. Moreover, polymer films on aluminum substrates exhibited superior impedance characteristics in comparison with bare substrates as measured by electrochemical impedance spectroscopy after 4 hours of immersion in 0.001 M NaCl. The superior performance of the antioxidant polymer films is attributed to the dual effect of formation of a protective barrier due to chemical crosslinking of antioxidant polymers, as well as to direct reactions of synthetic polyphenols with oxygen. The effect of the chemistry of polyphenol rings on the anticorrosion performance will be discussed.

Antioxidant polymer coatings for corrosion protection of metal substrates

256th National Meeting (2018)

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