Enhanced anticorrosive performance of waterborne acrylic coatings doped with phosphated alkynediol modified boron nitride nanosheets

Boron nitride nanosheets (BNNSs), a two-dimensional (2D) insulating material with exceptional barrier properties, are susceptible to aggregation, which restricts their application in anti-corrosive coatings. In this work, phosphate butynediol ethoxylate (PBEO), a readily available corrosion inhibitor, was utilized to modify BNNSs via π-π interaction, as demonstrated by Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS) and Raman spectra analyses. The synthesized BNNSs@PBEO exhibited enhanced dispersibility in water and improved compatibility with waterborne acrylic latex. Electrochemical impedance spectroscopy (EIS) clearly manifested that the impedance at low frequency (|Z|_{0.01 Hz}) of the acrylic coating containing 1 wt% BNNSs@PBEO remained significantly at 10¹⁰ and 10⁹ Ω·cm² on Q235 carbon steel and 5052 aluminum alloy, respectively, after 28 days of immersion in a 3.5 wt% NaCl solution, which was approximately two orders of magnitude higher than that of the pure waterborne acrylic coating. Furthermore, for Q235 carbon steel, the water diffusion coefficient of the 1 wt% BNNSs@PBEO/acrylic composite coating was three orders of magnitude lower than that of the pure waterborne acrylic coating. This substantial reduction indicates an improvement in the barrier performance of the coating, which is crucial for achieving exceptional corrosion resistance.