Preparation and corrosion resistance of KTNT-waterborne polyurethane coatings

In this study, titanate nanotubes (TNTs) were prepared via the hydrothermal method and then modified with γ-aminopropyltriethoxysilane (KH550) to obtain KTNTs with good dispersion properties. A KTNT-WPU composite coating was prepared by blending KTNTs with waterborne polyurethane (WPU). Fourier transform infrared spectroscopy (FT-IR) was used to characterize TNT compositions before and after modification. Thermogravimetric analysis (TGA) and electrochemical impedance spectroscopy (EIS) were used to test the thermal stability and corrosion resistance of the composite coating. The results showed that KH550 was successfully connected to the TNT surface. This improved thermal stabilities and corrosion resistances of the KTNT-WPU coatings. The fastest thermal decomposition rate for the 0.5% KTNT composite coating was 2%/min lower than that of the pure WPU coating. At the same time, the impedance of the composite coating could reach 7.58×107 Ω·cm2, the corrosion current density was 3.20×10−9 A·cm-2, and the corrosion inhibition rate reached 99.87%. The composite coating had an effective corrosion protection time of 120 h and the protective effect of the coating weakened when the immersion time exceeded 360 h.