Inhibition of the corrosion of metals by additions of bicyclic triazolopyrimidine in neutral chloride solutions. Part 3. Enhancement of the protective capacity of a bicyclic triazolopyrimidine by adding polyethylene glycol and triazoles

• M.O. Agafonkina¹, N.P. Andreeva¹, Yu.I. Kuznetsov¹ and Kh.S. Shikhaliev²

¹ Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31-4, Leninsky prospect, 119071 Moscow, Russia
² Voronezh State University, Universitetskaya pl. 1, Voronezh, 394018, Russia

Abstract: The enhancement of the adsorption, passivation, and protective properties of the pyrimidine derivative 2-methyl-5-phenyl-4,5,6,7-tetrahydro-[1,2,4]triazolo[1,5-α]pyrimidin-7-ol (MPTTP) by polyethylene glycol (PEG-115), 3-amino-1,2,4-triazole, and its 5-fluoromethyl derivative on copper in neutral borate buffer and chloride solutions were studied. It was shown that PEG-115 can act as a copper surface modifier for subsequent adsorption of MPTTP on it. Adsorption isotherms of PEG-115 on the oxidized copper surface and MPTTP on the electrode surface preliminarily modified with PEG-115 were obtained using the ellipsometric method. The adsorption kinetics of PEG-115 on copper was studied, and the thicknesses of conventional MPTTP monolayers on copper and on a PEG-115-modified copper surface were calculated. Corrosion tests of copper in a chloride solution containing PEG-115, MPTTP, and their mixture were conducted. The results of these experiments demonstrated the possibility of complete copper protection at lower concentrations of the PEG-115+MPTTP mixture than with its individual components.

Keywords: inhibition, copper, ellipsometry, polyethylene glycol PEG-115, substituted pyrimidines, degree of protection, protective effect, adsorption kinetics, Temkin isotherm

Int. J. Corros. Scale Inhib., 2026, 15, no. 2, 35-51
doi: 10.17675/2305-6894-2026-15-2-3

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