Enhanced anticorrosion property of epoxy resin membrane by nano-organic montmorillonite

Montmorillonite (Mnt) and organic polymer composite membrane are widely used to enhance the corrosive resistance of metal materials due to their unique properties. Herein, a uniform anticorrosion membrane coated on aluminum plate was fabricated with organic-modified nano-Mnt (OMnt) and epoxy resin (EP) as raw materials, which showed good smoothness, wear property and resistance to acidic and salty corrosion. The surface morphology, crystal phase, chemical composition, and microstructure of the OMnt/EP membrane were characterized by optical microscopy, small-angle X-ray diffraction, FTIR, SEM, and TEM, respectively. The results showed that the OMnt/EP membrane was constituted of OMnt and EP. The interplanar distance of OMnt was expanded from 1.44 to 5.36 nm. Electrochemical corrosive resistance of the membrane was tested with Tafel polarization curves and electrochemical impedance spectroscopy. The results showed that the thickness of the membrane had a positive effect on its anticorrosion performance. When its thickness was 0.18 mm, its corrosion voltage (P_corr) increased along with its content of OMnt, while its corrosion current (I_corr) showed increasing, decreasing and increasing trend as the content increased from 1 to 5%, from 5 to 7% and from 7 to 9%, respectively. When its content of OMnt was the same, its P_corr increased along with its thickness, while its I_corr decreased along with its thickness. Its maximum impedance reached 2.29 × 10⁷ Ω, which was much greater than that of other EP membranes. Moreover, the corrosion resistance of the composite membranes decreased gradually as the immersion time increased, and the content of OMnt and the ratio of EP to OMnt could also affect the corrosion resistance of the membrane. These results show that the OMnt/EP composite membrane exhibits excellent anticorrosive property, which is highly promising for wide applications in industry.