Polyoxyethylene stearate of molecular weight 6000 as corrosion inhibitor for mild steel in 2.0 M sulphuric acid

• R.S. Abdel Hameed^1,2, A. El-Zomrawy¹, M. Abdallah^3,4, S.S. Abed El Rehim⁵, H.I. AlShafey⁶ and Sh. Nour Edin⁷

¹ Faculty of Science, Department of Chemistry, Al-Azhar University,11884, Cairo, Egypt
² Chemistry Departments, Faculty of Science, Hail University, Hail 1560, Saudi Arabi
³ Faculty of Applied Science, Umm Al-Qura University, 3712, Makkah Al Mukaramha, Saudi Arabi
⁴ Chemistry Department, Faculty of Science, Benha University, 13518, Banha, Egypt
⁵ Faculty of Science, Department of Chemistry, Ain Shams University, 11566, Cairo, Egypt
⁶ Egyptian Petroleum Research Institute, Nasr City, 11727, Cairo, Egypt
⁷ Environmental institute Ain Shams University, Abassya , 1156, Cairo, Egypt

Abstract: Polyoxyethylene stearate of molecular weight 6000 (P6000) as nonionic polymeric surfactant was prepared by the esterification reaction between citric acid with polyethylene glycol (Mwt. 6000) in the presence of para toluene sulfuric acid, PTSA as a catalyst. The chemical structure of the prepared polymeric surfactant was recognized by FT-IR spectra. The inhibition of P6000 on mild steel surface in 2.0 M H2SO4 solution was investigated using different techniques such as open circuit potential, potentiodynamic polarization and weight loss. The inhibition efficiency of the used polymeric surfactant increases with increasing its concentration, but decreases with rising temperature. The potentiodynamic polarization proved that P6000 acted as a mixed inhibitor controlling both cathodic and anodic reactions. The inhibition process is the result of the adsorption of P6000 on the mild steel surface through the formation of barrier film which separates the mild steel from the corrosive medium. The adsorption of P6000 on steel surface follows Langmuir’s isotherm.

Keywords: corrosion inhibitors; steel; polarization; polymeric surfactants

Int. J. Corros. Scale Inhib., 2017, 6, no. 2, 196–208 PDF (1 507 K)
doi: 10.17675/2305-6894-2017-6-2-8

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