Effect of concentration of polyurethane on the anticorrosive property of Vanillin based benzoxazine - A Thermal, Electrochemical and Quantum approach

Abstract

Benzoxazine monomer prepared from vanillin and n-butylamine is characterized by 1H NMR, 13C NMR, FT-IR and UV visible spectroscopic techniques. The synthesized monomer is coated on the mild steel with polyurethane (PU) hardener and cured. The thermal properties of the monomer with and without polyurethane hardener were studied by TGA and DSC methods. The effect of various concentrations of the PU hardener with the benzoxazine monomer on hardness, water absorption, and gel absorption was investigated. Various concentrations of PU hardener with benzoxazine coating (VaBZ-PU) on the mild steel were investigated by the electrochemical impedance and polarisation studies. The study revealed that the increasing concentration of PU in the coating with the benzoxazine increased their thermal, chemical and anticorrosive properties. The DFT calculations are performed to support the anti-corrosive ability of the material.