Design and evaluation of a siloxane-amine hybrid additive for high-performance eco-friendly UV-curable anticorrosive coatings on mild steel.

Mild steel is widely used in industrial applications but remains highly susceptible to corrosion, leading to significant economic losses. Conventional chemical coatings and inorganic inhibitors are effective but environmentally hazardous, motivating the search for bio-based alternatives. In this study, UV-curable coatings were developed using epoxidized soybean oil acrylate (ESOA) and tripropylene glycol diacrylate (TPGDA), modified with varying concentrations of poly(di-triethanolaminesiloxane-oleate) (PDTSO). The optimized formulation (4% PDTSO) exhibited a remarkable increase in charge transfer resistance (R ct) from 83 Ω cm2 for bare steel to 21 000 Ω cm2, demonstrating a substantial improvement in corrosion resistance. Water contact angle improved from 69° to 85°, indicating reduced surface wettability. Salt spray testing further demonstrated a performance upgrade from grade 2G to 7G. These coatings also showed balanced mechanical properties, combining hardness with flexibility, due to increased crosslinking density. The results highlight PDTSO's effectiveness as a sustainable corrosion inhibitor and its potential in next-generation eco-friendly protective coatings for mild steel.