分子结构对咪唑啉缓蚀剂膜在Q235钢表面生长和衰减规律的影响

Effect of Molecular Structure of Imidazoline Inhibitors on Growth and Decay Laws of Films Formed on Q235 Steel

采用弱极化法、电化学阻抗谱等手段研究了烷基咪唑啉和硫脲基烷基咪唑啉缓蚀剂对Q235钢在饱和CO2盐溶液中的缓蚀行为变化,探讨了吸附膜的形成与衰减规律.结果表明,烷基咪唑啉和硫脲基烷基咪唑啉缓蚀剂都是以控制阳极过程为主的混合界面型缓蚀剂.在85℃下,烷基咪唑啉成膜相对较慢,吸附能力较弱,容易发生脱附;而硫脲基的引入,使得硫脲基烷基咪唑啉缓蚀剂溶液存在自动修复能力,增强了咪唑啉环的吸附性能,提高了缓蚀剂的缓蚀性能;硫脲基烷基咪唑啉水解开环后,成膜性能下降,膜寿命和缓蚀效率也大大降低.最后采用量子化学计算对上述结论进行了验证和解释.

Inhibition performance as well as the growth and decay laws of films formed on Q235 steel in a saturated carbon dioxide salt solution of imidazoline and imidazoline with a thioureido group were investigated by polarization curve and electrochemical impedance spectroscopy （EIS） techniques. Results showed that both types of imidazoline derivative inhibitors were mix-type inhibitors which mainly inhibited anodic processes. At 85 ℃, the film formed in 40 mg·L^-1 of the non-thioureido imidazoline inhibitor formed slowly and had poorer adsorption capability than the thioureido-containing imidazoline inhibitor. The non-thioureido imidazoline inhibitor also disrobed easily from the steel. The film of thioureido-containing imidazoline can auto-repair itself. It also had better adsorption and inhibition efficiency compared with the non-thioureido imidazoline inhibitor. The hydrolyzed imidazoline with a thioureido group has poor absorption capability and its film life and inhibition efficiency decreased compared with the thioureidocontaining imidazoline inhibitor. In this paper electrochemical results are also explained using quantum chemistry analysis.