Synthesis and anticorrosive properties of polymer-clay nanocomposites via chemical grafting of polyaniline onto Zn-Al layered double hydroxides

The polymer-clay nanocomposites (PANI/AD-LDH) were prepared by chemical grafting based on polyaniline (PANI) and corrosion inhibitor (decavanadate)-intercalated and γ-aminopropyltriethoxysilane (APTS)-modified Zn-Al layered double hydroxide (AD-LDH). The chemical grafting of PANI onto decavanadate-intercalated LDH (D-LDH) was confirmed by Fourier transformation infrared (FTIR) spectroscopy. The interlayer and surface changes of the clay in the prepared nanocomposite materials and the grafted nanoparticles were studied by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The corrosion resistance behavior of PANI/AD-LDH/epoxy coating was investigated by open circuit potential (OCP), potentiodynamic polarization and electrochemical impendence spectroscopy (EIS) techniques in 3.5% NaCl solution and also compared with that of PANI and D-LDH. The results indicated that the PANI/AD-LDH coating offered better protection against corrosion than the PANI and D-LDH coating did.