Formulation of thiosemicarbazide based epoxy resin as inhibitor for corrosion of mild steel in 1M HCl: electrochemcial and theoretical studies

The study presents the development of a new pentafunctional epoxy resin, pentaglycidylthiosemicarbazide (PGTSC), synthesised through a simple condensation process. The molecular structure of PGTSC was characterised using FTIR and 1H NMR spectroscopy. Viscosity measurements indicated that PGTSC's viscosity is significantly influenced by solution concentration and temperature, demonstrating its improved inhibition performance. Electrochemical tests showed that PGTSC achieves a maximum corrosion inhibition efficiency of 92% at a concentration of 10-3 M, with a notable reduction in corrosion current density from 608.60 mu A/cm(2) to 36.67 mu A/cm(2) in 1.0 M HCl. The polarisation studies revealed a mixed-type inhibition mechanism affecting both anodic and cathodic reactions, and the polarisation resistance increased, enhancing the protective properties of steel. The findings were corroborated by additional studies, including PDP, EIS, SEM observations, and computational DFT, MD, and MC calculations support the experimental findings and were in good agreement.