Abstract
For several decades, mild steel has been an ideal mandated material in many industrial applications. However, unlike stainless steel and other special steel alloys, mild steel is prone to corrosion attack, leading to devastating failures of equipment and metallic structures over time, causing losses worth billions. This situation has spurred researchers to find solutions for the corrosion phenomenon. The present work investigates the inhibition efficiency as a corrosion inhibitor of an ecofriendly and cost-effective composite developed from organic polymers. Synthesis of an environmentally friendly copolymer composite of Polyethylene glycol L-proline (PEGLP), from polyethylene glycol and L-proline, was carried out. A variety of analytical equipment was used to evaluate the characteristics of PEGLP. Results of Fouriertransform infrared spectroscopy, nuclear magnetic resonance spectroscopy, X-ray diffraction, scanning electron spectroscopy-energy dispersive spectroscopy, thermogravimetric and organic elemental analyser analysis show that a composite was produced. Fourier-transform infrared spectroscopy and nuclear magnetic resonance spectroscopy confirmed the presence of –COOH, -C-H, N-C and –OH in the PEGLP molecules, making the PEGLP ideal for corrosion inhibition. Spectroscopy-energy dispersive spectroscopy and organic elementary analysis showed that the mass percentages of nitrogen, carbon and oxygen were higher on the PEGLP than in the starting materials; which confirms that the PEGLP has bulk molecular weight that will improve inhibition efficiency. Thermogravimetric analysis revealed that PEGLP was thermally stable up to 200oC and could be used for a wide range of applications below 200oC without it degrading. Subsequently, the newly synthesised PEGLP was investigated as a corrosion inhibitor for mild steel in 1 M HCl, and its corrosion inhibition properties were studied by means of gravimetric and electrochemical techniques, from which corrosion rate, inhibition efficiency, thermodynamic parameters and adsorption were determined. The gravimetric technique focused on the effects on the mild steel of concentrations of the inhibitor between 200 ppm and 800 ppm, immersion time from 1 h to 9 h, and temperatures from 298 K to 338 K. It was found that an increase in inhibitor concentration led to a decrease in corrosion rate. The optimal concentration, with the...
M.Tech. (Extraction Metallurgy)