Effects of surface treatment of TiO2 nanoparticles on the adhesion and anticorrosion properties of the epoxy coating on mild steel using electrochemical technique

Abstract

Macromolecular coupling agents (MCA) containing epoxide and silanol functional groups were synthesized by radical copolymerization of glycidyl methacrylate (GMA) and γ-methacryloxypropyltrimethoxysilane (MPS), (F1–F3). The MCAs were successfully grafted on the surface of TiO2 nanoparticles via direct reaction, (TiO2-Fs). The homogeneous mixture of TiO2-Fs nanoparticles and epoxy resin was coated on the commercial grade mild steel (St-37) and cured using triethylenetetramine (TETA) as curing agent. The beneficial effects of homogeneous mixing and interfacial binding between TiO2-Fs nanoparticles and epoxy matrix on the long term anticorrosion performance on the steel were investigated by electrochemical impedance spectroscopy (EIS) before and after immersion in 3.5 wt% NaCl solution. The effect of interfacial binding was also investigated on the mechanical properties and water diffusion of the TiO2-Fs/epoxy resin nanocomposite samples. The highest tensile strength and modulus with the lowest water adsorption were observed for the coating samples prepared from MCA contained 50/50 mol ratio of GMA/MPS.