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An extract of Mentha rotundifolia leaves (EMRL) was tested as a corrosion inhibitor of steel in 1 M HCl using electrochemical impedance spectroscopy, Tafel polarization methods, and weight loss measurements. The inhibition efficiency of the extract of Mentha rotundifolia leaves was calculated and compared. We note good agreement between these methods. The results obtained revealed that the inhibitor tested differently reduced the kinetics of the corrosion process of steel. Its efficiency increases with the concentration and attained 92.87 % at 35 %. The effect of temperature on the corrosion behavior of steel in 1 M HCl was also studied in the range 298 and 338 K. The thermodynamic data of activation were determined. Mentha rotundifolia extract is adsorbed on the steel surface according to a Langmuir adsorption model.

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Poly(methacrylic acid) (PMAA) was functionalized with a hydroquinone/catechol under the reaction conditions of Minisci. Optimum conditions for maximum functionalization (52%) were found to be as follows: [benzoquinone]/[PMAA] ratio, 0.75; reaction time, 3 h; temperature, 75°C; and a nitrogen atmosphere. Redox properties of hydroquinone/catechol-modified PMAA (PMAA-HQ) were evaluated by their midpotentials potentiometrically estimated to be 898 mV at 20°C. At 35°C, a two-stage oxidation was observed with a midpotential of 1000 mV. These midpotentials were found to be higher than those of hydroquinone, catechol, and a 1 : 1 hydroquinone-catechol mixture, under the same conditions of potentiometric titration. Under the modification reaction conditions, the modified PMAA underwent severe degradation.