Noncovalently functionalized hexagonal boron nitride nanosheets of poly(m-aminophenol) by enhanced corrosion protection of epoxy coating

Abstract

The incorporation of nanomaterials into epoxy coatings can significantly enhance their barrier properties. Hexagonal boron nitride (h-BN) demonstrates considerable potential for application in prevention of metal corrosion due to its excellent electrical insulation and outstanding barrier characteristics. However, the h-BN has been observed to exhibit poor dispersion within epoxy resin. In this study, h-BN/PmAP were prepared by non-covalent functionalization of h-BN nanosheets with PmAP in order to strengthen the coating corrosion protection. The coating containing 1 wt% h-BN/PmAP-10 showed a notable enhancement in long-term corrosion protection. 25 days of immersion in 3.5 wt% NaCl later, the modulus value (|Z|_{0.01 Hz}) of h-BN/PmAP-10/EP was maintained at 1.60 × 10⁷ Ω.cm², which is two orders of magnitude than that of the pure epoxy resin (1.28 × 10⁵ Ω.cm²). And from the Tafel plot of h-BN/PmAP-10/EP, the corrosion current is (I_corr = 4.68 × 10^-10 A/cm²) nearly three orders of magnitude lower than that of pure epoxy resin (I_corr = 1.30 × 10^-7 A/cm²). The main mechanism underlying these improvements is attributed to the enhanced dispersion of h-BN/PmAP-10 in the coating, which improves the densification of the coating and creates a ‘labyrinth effect’. It also retains the corrosion inhibition ability of PmAP, this helps the coating to resist corrosion.