Phosphorous-based epoxy resin composition as an effective anticorrosive coating for steel

International Journal of Industrial Chemistry

دوره 9، شماره 3، آذر 2018، صفحه 231-240

نوع مقاله: research article

شناسه دیجیتال (DOI): https://doi.org/10.1007/s40090-018-0152-5

نویسندگان

O. Dagdag¹؛ A. El Harfi¹؛ A. Essamri¹؛ M. El Gouri^{1، 2}؛ S. Chraibi³؛ M. Assouag³؛ B. Benzidia⁴؛ O. Hamed⁵؛ H. Lgaz⁶؛ S. Jodeh^{* 5}

¹Laboratory of Agroresources, Polymers and Process Engineering, Team of Macromolecular and Organic Chemistry, Department of Chemistry, Faculty of Science, Ibn Tofail University, BP 133, 14000, Kenitra, Morocco

²Laboratory of Process, Renewable Energy and Environment, Department of Process Engineering, Height School of Technology, Sidi Mohammed Ben Abdallah University, Fez, Morocco

³Team of Materials, Metallurgy and Process Engineering, ENSAM, University Moulay Ismail, B.P. 15290, Al Mansour, Meknes, Morocco

⁴Laboratory of Materials, Electrochemistry and Environment, Department of Chemistry, Faculty of Sciences, Ibn Tofail University, Kenitra, Morocco

⁵Department of Chemistry, An-Najah National University, P. O. Box 7, Nablus, Palestine

⁶Department of Applied Bioscience, College of Life and Environment Science, Konkuk University, 120 11 Neungdong-ro, Gwangjin-gu, Seoul, 05029, South Korea

چکیده

Epoxy resin (ER) is an attractive material for metal protection against corrosion; it can form a strongly adhered film onto a metal surface through its multi coordination sites. In this study, an epoxy resin-based formulation was designed, prepared, and applied onto steel surface with and without a pigment. The anticorrosive formulation (ER–MDA–ZP) was prepared from the ER and the hardener 4,4′-methylene dianiline (MDA) in the presence of the anticorrosive pigment zinc phosphate (ZP). A second standard formulation (ER–MDA) was prepared without ZP. The epoxy and the hardener react to form a 3D cross-linked polymeric network with multicoordination sites (hydroxyl and amino groups) for metals. The characterization of the epoxy resin was performed using Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (¹H and ³¹P NMR). Both samples exhibited excellent thermal properties as they subjected to thermal analysis using differential scanning calorimetry. The ER–MDA–ZP formulation showed a higher glass transition temperature (T_g) than ER–MDA. The coated steel specimens were immersed for 1 h in a 3 wt% NaCl solution and their anticorrosive properties were monitored by electrochemical impedance spectroscopy (EIS). The total resistance (R_t) values obtained by the EIS method for the ER–MDA and ER–MDA–ZP formulations were 21,383 Ω cm² and 55,143 Ω cm², respectively. The coated steel samples after the acid treatment were subjected to aging by exposing them to a UV light for 2000 h. The aging caused the R_t values to drop to 1621 Ω cm² and 7264 Ω cm², respectively. The results indicate the formation of a highly stable film of ER–MDA–ZP formulation on the steel surface that withstands an accelerated corrosive environment of 2000 h exposure to UV light and 1 h of immersion in a 3 wt% NaCl.

کلیدواژه‌ها

Epoxy coatings · Zinc phosphate · Carbon steel · 3 wt% NaCl · Ultraviolet radiation · Electrochemical impedance spectroscopy