Synthesis and characterization of kaolinite/polyaniline nanocomposites and investigating their anticorrosive performance in chlorinated rubber/alkyd coatings

Kaolinite/polyaniline nanocomposites (KPAns) were prepared by in situ chemical oxidative polymerization. The nanocomposites were synthesized with four different aniline to kaolinite weight percentage; 5, 10, 15, and 20% to produce KPAn5, KPAn10, KPAn15, and KPAn20, respectively. The structural, morphological and thermal properties of the nanocomposites were characterized using Fourier transform infrared, X‐ray diffraction, scanning electron microscope (SEM)–energy dispersive X‐ray analyzer, transmission electron microscope, and Thermogravimetric analysis. The results revealed a very slight increase in the d‐spacing of kaolinite XRD peaks. SEM images showed hexagonal platy sheets of kaolinite crystals that are indistinguishable in KPAn nanocomposites images, especially on using a high amount of polyaniline (PANI). The increase in the percentage of carbon and nitrogen elements in EDAX data proved the adsorption of PANI on the surface of kaolinite platelets. To investigate the anticorrosive performance of the synthesized nanocomposites, kaolinite and KPAn nanocomposites were loaded in various amounts (1, 5, and 9%) in a blend of chlorinated rubber/medium oil alkyd resin (CR/MA) to prepare different formulations that were applied and evaluated as protective coats on steel substrates. Visual corrosion test revealed that 5% KPAn‐loaded CR/MA coats exhibited the best protection against corrosion amongst other formulations as indicated by their lowest degree of rusting and blistering. Potentiodynamic polarization measurements confirmed the highest protection of 5% KPAn10‐loaded CR/MA coat as indicated by the quantitative corrosion rates obtained from Tafel extrapolation. POLYM. COMPOS., 40:2777–2789, 2019. © 2018 Society of Plastics Engineers