Optimization of parameters through Taguchi method for enhanced corrosion inhibition of poly (vinyl alcohol-serine)

Abstract

Parametric optimization was carried out for the mixture of polyvinyl alcohol (PVA) and l-serine using Taguchi statistical approach. L₉ orthogonal array of experiments were designed and the results were analyzed with Qualitek software. Synergistic effect of the mixture was enhanced at the Qualitek predicted optimized conditions. The graft polymer, poly(vinyl alcohol-serine) (PVAS), was synthesized using free radical-initiated reactions of l-serine with PVA in order to achieve effective inhibition. PVAS was characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, and powder X-ray diffraction analysis. The thermal properties of PVAS were studied by thermogravimetry, differential thermal analysis, and differential scanning calorimetry. The corrosion inhibition property of PVAS on mild steel corrosion was continuously monitored using electrochemical techniques. Temperature effect on the inhibition properties of PVAS was studied using electrochemical and gravimetric measurements. AFM studies confirmed the formation of polymeric film on mild steel surface which inhibits the rate of corrosion. Theoretical calculations using Hyperchem 7.0 proved the better corrosion mitigation properties of PVAS compared to PVA. The experimental results and surface analysis confirmed the effective inhibition process of the graft polymer which was also supported by the theoretical calculations. A good correlation was obtained between the results of the electrochemical measurements, conventional gravimetric measurement, surface analysis, and theoretical calculations. All the studies proved the enhanced corrosion inhibition properties of PVA through grafting of polyserine.

Keywords:

• mild steel
• EIS
• polarization
• acid inhibition
• kinetic parameters
• theoretical Studies
• AFM

Acknowledgment

The authors wish to thank Avinashilingam Institute for Home Science and Higher Education for Women, Coimbatore, for providing the laboratory facility. One of the authors, Ali Fathima, is thankful to CSIR, New Delhi, for providing the Research Fellowship, [grant number 09/986(0001)/2009- EMR-I].

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the CSIR, New Delhi, for providing the Research Fellowship, [grant number 09/986(0001)/2009- EMR-I].