Corrosion Resistance of Mild Steel Coated with Phthalimide-Functionalized Polybenzoxazines

Coatings

Nayef S. Al-Muaikel¹  Shiao-Wei Kuo²  M. A. Hegazy³  MohamedGamal Mohamed⁴  Abdulsalam Mahdy⁴  Kamal. I. Aly⁴ 

[1] Chemistry Department, College of Science, Al-Jouf University, Skaka 72388, Al-Jouf, Saudi Arabia;Department of Materials and Optoelectronic Science, Center of Crystal Research, National Sun Yat-Sen University, Kaohsiung 804, Taiwan;Petrochemicals Department, Egyptian Petroleum Research Institute (EPRI), Nasr City, Cairo 11727, Egypt;Polymer Research Laboratory, Chemistry Department, Faculty of Science, Assiut University, Assiut 71516, Egypt;

关键词: polybenzoxazine;    ring-opening polymerization;    mild steel;    polymer coatings;   

DOI  :  10.3390/coatings10111114

来源: DOAJ

【 摘 要 】

Herein, we synthesized two new phthalimide-functionalized benzoxazine monomers, pPP-BZ and oPP-BZ, through Mannich reactions of 2-(4-hydroxyphenyl)isoindoline-1,3-dione (pPP) and 2-(2-hydroxyphenyl)isoindoline-1,3-dione (oPP), respectively, with p-toluidine and paraformaldehyde. The structures of these two monomers were confirmed using Fourier transform infrared (FTIR) and nuclear magnetic resonance spectroscopy. We used differential scanning calorimetry, FTIR spectroscopy, and thermogravimetric analysis to study the polymerization behavior and thermal stability of the monomers and their corresponding polybenzoxazines. Poly(pPP-BZ) and poly(oPP-BZ) were formed on mild steel (MS) through spin-coating and subsequent thermal curing polymerization. We used various corrosion testing methods to examine the effect of the curing temperature on the corrosion resistance of the coated MS samples in 3.5 wt.% aqueous solution of NaCl. Among our tested systems, the corrosion rate reached a low of 2.78 µm·Y⁻¹ for the MS coated with poly(pPP-BZ)₁₈₀ (i.e., the coating that had been cured at 180 °C); this value is much lower than that (4.8 µm·Y⁻¹) reported for a maleimide-based benzoxazine compound (MI-Bz)/33 wt.% ACAT (amine-capped aniline trimer) blend. Thus, the incorporation of the imide functional group into the PBZ coatings is an effective strategy for affording high-performance corrosion resistance.

【 授权许可】

Unknown