Synthesis, characterization and application of acrylate-based poly ionic liquid for corrosion protection of C1020 steel in hydrochloric acid solution

Abstract

Poly ionic liquids (PIL) are eco-friendly in addition to being sustainable compounds that can be easily prepared and tailored according to the application. In this study, a novel PIL polymer based on acrylate was chemically synthesised via free radical polymerization method controlled by quenching the reversible reaction. The prepared 1-Butyl-3 Methylimidazolium Acrylate polymer (PAL) was characterised using FTIR as well as NMR to confirm the chemical structure. GPC was employed to determine the average molecular weight of the new polymer. PAL was applied as an effective corrosion inhibitor for C1020 steel in 1M HCl aqueous solution. Weight loss and electrochemical techniques, PDP and EIS, were applied to evaluate the corrosion inhibition performance. The electrochemical results showed that PAL acts as a mixed-type inhibitor reaches 91.8% at room temperature. The thermodynamic calculations showed that the adsorption process is exothermic. Furthermore, PAL molecules were adsorbed on the metal surface by both chemisorption and physisorption processes. SEM analysis was carried out to confirm the corrosion evaluation results. Also, quantum chemical calculations, at the B3LYP/DND level of theory, were carried out to correlate the electronic structure parameters of PAL inhibitor to its adsorption behaviour which in turn is relevant to the inhibition efficiency. Additionally, Monte Carlo simulation (MC) was conducted to investigate the adsorption modes and the interaction energies of the inhibitor on iron surface.