Sepiolite modified with phosphonium ionic liquids as anticorrosive pigment for epoxy coatings

摘要

The performance of sepiolite modified with different phosphonium-based ionic liquids (SepIL) as anti-corrosive pigment for epoxy resin (ER) coatings were discussed in this paper. The ionic liquids (IL) used to functionalize Sep clay mineral included trihexyl-(tetradecyl)phosphonium bistriflimide (IL1) and ethyl-tri(butyl-)phosphonium diethylphosphate (IL2) as commercial IL and the synthesized 11-carboxyundecyl-(triphenyl)-phosphonium bromide (IL3). All SepIL samples were characterized by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), elemental analysis (CHN) and X-ray diffraction (XRD). The effect of the incorporation of Sep and SepIL on the rheological properties of the ER-based dispersions and on anticorrosion properties of epoxy networks cured with isophorone diamine was investigated. The ER-based coatings loaded with Sep modified with different ionic liquids presented enhanced the anticorrosive properties with outstanding barrier properties against the diffusion of the electrolyte solution, as indicated by electrochemical impedance spectroscopy (EIS). The superior corrosion resistance of ER loaded with SepIL was also kept with scratched coating, due to the inhibition activity of the ionic liquid against corrosion process.