Anti-Corrosive Properties of an Effective Guar Gum Grafted 2-Acrylamido-2-Methylpropanesulfonic Acid (GG-AMPS) Coating on Copper in a 3.5% NaCl Solution

Guar gum grafted 2-acrylamido-2-methylpropanesulfonic acid (GG-AMPS) was synthesized using guar gum and AMPS as the base ingredients. The corrosion inhibition of copper was studied using weight loss, electrochemical, and surface characterization methods in a 3.5% sodium chloride (NaCl) solution. Studies including weight loss were done at different acid concentrations, different inhibitor concentrations, different temperatures, and different immersion times. The weight loss studies showed the good performance of GG-AMPS at a 600 mg/L concentration. This concentration was further used as the optimum concentration for all of the studies. The efficiency decreased with the rise in temperature and at higher concentrations of acidic media. However, the efficiency of the inhibition increased with the additional immersion time. Electrochemical methods including impedance and polarization were employed to calculate the inhibition efficiency. Both of the techniques exhibited a good inhibition by GG-APMS at a 600 mg/L concentration. Surface studies were conducted using scanning electrochemical microscopy (SECM), scanning electron microscopy (SEM), and atomic force microscopy (AFM) methods. The surface studies showed smooth surfaces in the presence of GG-AMPS and rough surfaces in its absence. The adsorption type of GG-AMPS on the surface of the copper followed the Langmuir adsorption model.