Anticorrosion behavior of polyvinyl butyral (PVB) / polymethylhydrosiloxane (PMHS) / chitosan (Ch) environment-friendly assembled coatings

• Published in: Progress in organic coatings 2020-07, Vol.144, p.105662, Article 105662
• Main Authors: Ma, Zhidong, Sun, Min, Li, Anhang, Zhu, Guiyu, Zhang, Yue
• Format: Article
• Language: English
• Subjects: Aluminum base alloys; assembled coatings; Chitosan; Corrosion currents; Corrosion prevention; Corrosion resistance; Corrosion resistant alloys; Crosslinking; Electrochemical impedance spectroscopy; Fourier transforms; Hydrophobicity; Immersion tests (corrosion); Infrared spectroscopy; Marine environment; Poly (methyl hydrosiloxane); Polyvinyl acetal resins; Polyvinyl butyral; Protective coatings; Spectrum analysis; Substrates
• ISSN: 0300-9440; 1873-331X
• DOI: 10.1016/j.porgcoat.2020.105662

[Display omitted] •A novel environment-friendly composite coating was prepared by layer-by-layer assembly.•Poly (methylhydrosiloxane) (PMHS) had been innovatively applied to P/P'-Ch-P/P' composite coating.•The long-term corrosion resistance and hydrophobicity of the composite coating was tested. A novel environment-friendly composite coating (P/P'-Ch-P/P') was prepared by layer-by-layer assembly of polyvinyl butyral (PVB), polymethylhydrosiloxane (PMHS) and chitosan (Ch) on AA 2024 substrate to improve the corrosion resistance of AA 2024 sample. The properties of the coatings were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM) and laser confocal microscope. The results showed that the addition of PMHS increased the hydrophobicity of composite coating；as the intermediate layer, Ch also crosslinked other components while forming the film. At the same time, the corrosion resistance of the coating in 3.5 wt.% NaCl solution was characterized by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization. Compared with the bare aluminum substrates, the impedance modulus of the composite coating was increased by 3 orders of magnitude; the corrosion current density (Icorr) of the composite coating was reduced by 5 orders of magnitude. The results of long-term immersion test showed that the composite coating still had good anticorrosion ability after 60 days. This study provides a simple and environment-friendly method for corrosion protection of aluminum alloy in marine environment.