Synthesis of Amine Grafted Poly (Acrylic-Maleic) as an efficient inhibitor against stainless steel corrosion in a highly saline medium

In this study, a novel amine grafted poly-(acrylic maleic) (APAM) was synthesized and its efficiency was investigated against the corrosion of stainless steel 316 L in simulated saline (3.5 % NaCl) environment using electrochemical and weight loss experiments at various temperatures i.e. 25, 40 and 60 °C. The synthesized compound was characterized by FTIR, proton, and carbon-13 NMR techniques. The compound performed excellently and was observed to function as a mixed-type inhibitor, inhibiting both the cathodic hydrogen evolution and anodic iron dissolution reactions. The adsorption of APAM molecules obeyed the Langmuir adsorption theory and the estimated values of ∆G_ad^o obtained using weight and PDP data suggest that APAM adsorbed on the steel surface by both the chemisorption and physiosorption mechanisms. APAM molecules adsorbed to the steel surface to create an APAM layer that inhibits the corrosive medium from reaching the surface, according to surface morphological observations and examination of the protected steel surface using SEM, EDS, AFM, and FTIR spectra.