Soy polyester urethane/TiO2 and Ce-TiO2 nanocomposites: preparation, characterization and evaluation of electrochemical corrosion resistance performance

Environment friendly soy polyester urethane nanocomposite coating materials were prepared by dispersing TiO2 and Ce-TiO2 nanoparticles in a 3-isocyanatopropyltriethoxysilane (IPTES) modified soy oil (SO) polyester urethane triethoxysilane (PEUTES) matrix via a sonication technique. Fourier Transform Infrared Spectroscopy (FT-IR), H-1 and C-13 Nuclear Magnetic Resonance (NMR) spectroscopy, Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray spectroscopy (EDX), X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), UV-visible spectroscopy (UV) were employed to characterize the synthesized coating materials. The anticorrosion ability of nanocomposites and that of PEUTES coatings on carbon steel (CS) in 3.5 wt% NaCl solution was investigated using potentiodynamic polarization (PDP), Electrochemical Impedance Spectroscopy (EIS) techniques and a salt mist test. The effects of dispersion of nano TiO2 and Ce-TiO2 fillers in PEUTES matrices on the hydrophobic, physico-mechanical, thermal and anticorrosive properties were also studied. The TiO2 and Ce-TiO2 nanofiller dispersed soy polyester urethane nanocomposite coatings have exhibited far superior corrosion resistance properties than those of other such reported systems. These studies revealed the presence of nanofiller in polyester urethane matrix, induces strong barrier and locking effects at the coating-metal interface. The higher impedance value (approximate to 108 Omega) and lower corrosion rate (7.8518 x 10(-6) mpy) confirm the superior protection ability of the nanocomposite.