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Pectin-g-polyacrylamide (denoted as Pec-g-PAAm) and pectin-g-polyacrylic acid (denoted as Pec-g-PAA) were synthesized using pectin, acrylamide, and acrylic acid as starting materials. The grafted polymers were characterized using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analyser (TGA), and scanning electron microscopy (SEM). The corrosion inhibition behaviour of the grafted polymers on mild steel in 3.5% NaCl was evaluated electrochemically through Tafel polarization and impedance studies. The corrosion inhibition performance of both the polymers was found to be around 85%.

Corrosion inhibitive behavior of newly synthesized water soluble semiconducting polymer composite poly(vinyl alcohol-proline) (PVAP) is focused in this article. The polymer was characterized by FTIR, SEM-EDX, and XRD techniques. Thermogravimetry and differential thermal analysis proved the thermal stability of PVAP. Gravimetry and electrochemical techniques were employed to study the corrosion inhibition performance of PVAP on mild steel in molar hydrochloric acid. 0.6 % (wt.) of PVAP provides a maximum inhibition efficiency of 94 % at 303 K. The role of concentration of PVAP, exposure time and solution temperature on the mild steel corrosion has been investigated. The polarization results showed that PVAP acts as mixed-type inhibitor and could serve as an effective corrosion inhibitor for mild steel in acid medium. Surface morphology of the mild steel specimen by FTIR spectroscopy proved the formation of polymer film.

A new corrosion inhibitor namely poly(vinyl alcohol‐leucine) composite (PVAL) has been synthesized and its influence on corrosion inhibition of mild steel in 1 M hydrochloric acid solution has been studied by weight loss and potentiodynamic polarization techniques. The composite (PVAL) showed more than 95% inhibition efficiency (IE) at an optimum concentration of 0.6% by weight. The inhibition efficiency of inhibitor has been found to vary with inhibitor concentration, solution temperature, and immersion time. Various kinetic and thermodynamic parameters (Ea, ΔHo, ΔSo for corrosion and ΔGads, ΔHads, ΔSads for adsorption) reveal a strong interaction between inhibitor and mild steel surface. The negative values of ΔGads indicate the spontaneous adsorption of the inhibitor on mild steel surface. Potentiodynamic polarization studies showed PVAL as mixed type inhibitor. It inhibits mild steel corrosion by blocking the active sites of the metal. Electrochemical impedance spectroscopic (EIS) techniques were also used to investigate the mechanism of corrosion inhibition.

A novel water‐soluble conducting polymer composite, poly(vinyl alcohol‐histidine) was synthesized from aqueous solution by free radical condensation using persulfate. The composite was characterized using UV–Visible, Fourier transform infrared, scanning electron microscopy, thermogravimetric analysis (TG/DTG), and differential scanning calorimetry techniques while its AC conductance was measured by LCZ analyzer. The inhibitive action of the composite on the corrosion behavior of mild steel in 1M HCl was studied by conventional weight loss method, potentiodynamic polarization studies (Tafel), linear polarization studies, and electrochemical impedance spectroscopy. The effects of inhibitor concentrations, exposure time, and temperature have been investigated. The corrosion rate, inhibition efficiency (IE), and other parameters have been evaluated for different inhibitor concentrations. The composite provided more than 95% IE at an optimum concentration of 0.6% by weight. The results showed the composite as an effective mixed type inhibitor. The adsorption of this inhibitor obeyed Temkin adsorption isotherm. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

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The inhibitive effect of Abelmoschus esculentus seed extract on the corrosion of mild steel in sulphuric acid was investigated using gravimetric, potentiodynamic and electrochemical impedance spectroscopy (EIS) techniques. The results obtained showed that Abelmoschus esculentus seed extract could serve as an effective inhibitor for the corrosion of mild steel in sulphuric acid. The percentage inhibition increased with increasing concentration of the extract at room temperature. Maximum inhibition efficiency of 90 % was obtained with 0.5 % v/v concentration. The inhibition efficiencies obtained from impedance and polarization measurements were in good agreement. Poteniodynamic polarization studies clearly revealed that the extract behave as mixed type inhibitor. The inhibition efficiency was significantly affected by the temperature of the medium. The synergism parameters (S) obtained was found to be greater than unity which indicates that the enhanced inhibition efficiency caused by the addition of halides is only due to synergism.

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