Silane-functionalized polybenzoxazines: A superior corrosion resistant coating for steel plates

Abstract and figures
Effective and economic coating of polymeric materials onto steel protects it from corrosion. Among the choices, polybenzoxazines emerged as one of the most promising candidates for such purposes because of their low water adsorption, high thermal stability, zero volume shrinkage, and low flammability. In this current work, silane-functionalized bisphenol-F-based polybenzoxazine coatings were synthesized, characterized, and successfully coated onto steel substrates to inhibit corrosion. First, the pure (4, 4′-BPF) and mixture (4, 4′-BPF, 2, 4′-BPF, and 2, 2′-BPF) of bisphenol-F-based benzoxazine isomers were functionalized with aminosilane, followed by thermal-assisted polymerization onto steel substrates. The coating's corrosion resistivity was measured by electrochemical impedance spectroscopy (EIS) and also from Tafel slopes. The different corrosion behavior was also explained based on the material's dependence on the contact angles and critical surface tension. This study is expected to aid the future development of corrosion resistant coatings especially derived from benzoxazine-based polymers.