多齿螯合酰腙配体的合成及其防腐性能

Synthesis and Anticorrosive Properties of Polydentate Chelated Acylhydrazone Ligand

针对常用无机缓蚀剂存在螯合固化速率较慢,形成的无机锈蚀螯合物与有机涂层相容性差等缺点,以2-噻吩甲酰肼和1H-苯并咪唑-2-甲醛为原料合成了多齿螯合酰腙配体(THL)。采用傅立叶变换红外光谱仪(FT-IR)、核磁共振氢谱仪(1H NMR)、紫外分光光度计等对其结构进行了表征。并将THL作为有机缓蚀剂添加至环氧树脂中制备环氧清漆,通过电化学阻抗谱(EIS)测试、中性盐雾实验、附着力测试、扫描电子显微镜(SEM)等手段研究了不同THL添加量的清漆涂层耐腐蚀性,并探索了其缓蚀机理。结果表明:掺杂THL后的清漆涂层耐腐蚀性显著优于纯环氧涂层,当THL添加量为2%时,清漆涂层具有最佳的耐盐雾性以及附着力(16.25 MPa),涂层初始电化学阻抗模值可达6.27×108Ω·cm2,在3.5%NaCl溶液中浸泡20 d后,仍高达1.89×108Ω·cm2,保持在较高水平。由此可见,有机缓蚀剂(THL)的掺杂可有效提高环氧涂层与基体间的结合力,进而提高涂层的耐腐蚀性。

In view of the shortcomings of common inorganic corrosion inhibitors,such as slow chelating curing rate and poor compatibility between the formed inorganic rust chelation and organic coatings,the polydentate chelated hydrazone ligand(THL)was synthesized from 2-thiophene hydrazide and 1H-benzimidazole-2-formaldehyde.Its structure was characterized by infrared spectroscopy(ATR-FTIR),nuclear magnetic hydrogen spectroscopy(1H NMR),ultraviolet spectroscopy(UV).THL was added to epoxy resin as an organic corrosion inhibitor to prepare epoxy varnish.The corrosion resistance of varnish coatings with different amount of THL was studied and analyzed by means of electrochemical impedance spectroscopy(EIS),salt spray resistance test,adhesion test,scanning electron microscope(SEM),and its corrosion prevention mechanism was preliminarily explored.The experimental results showed that the corrosion resistance of the varnish coating doped with THL was significantly better than that of the pure epoxy coating.When the amount of THL was 2%,the varnish coating had the best salt spray resistance and adhesion performance(16.25 MPa),and the initial electrochemical impedance modulus could reach 6.27×108Ω·cm^(2),after soaking in 3.5%NaCl solution for 20 days,it was still as high as 1.89×108Ω·cm^(2),maintained at a high level.The doping of organic corrosion inhibitor(THL)could effectively improve the adhesion between the epoxy coating and the substrate,thereby improving the corrosion resistance of the coating.