Synergistic decoration of organic titanium and polydopamine on boron nitride to enhance fire resistance of intumescent waterborne epoxy coating

Abstract

Inorganic fillers are generally used as synergistic agent in waterborne epoxy resin intumescent fire-retardant coating. To enhance the flame retardant properties of the coating, modified hexagonal boron nitride (h-BN) was introduced. Firstly, the h-BN nanosheets were modified with polydopamine (PDA) through the strong π-π non-covalent interaction between the hexagonal structure of boron nitride and aromatic dopamine molecules. Then, the Ti-O compounds was formed on the surface of the hybrids by covalent modification, which can generate titanium dioxide (TiO2) and titanium pyrophosphate (TiP2O7) at high temperature to enhance the strength of the char layer. The enhancement of the synthetic material (BPT) was evaluated by fire performance measurements and thermogravimetric analysis (TGA). The structure and morphology of the char layer after the fire test were analyzed by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) techniques. The results showed that the introduction of BPT hybrids effectively enhanced the strength and oxidation resistance of the char layer and improved the barrier effect to heat and oxygen. Compared with EP, the back temperature of BPT3%/EP steel plate decreased from 259 ℃ to 198 ℃, the expansion ratio increased from 3.04 to 8.91, and the residual char increased from 20.5% to 29.1%.