Abstract: The effect of nano-silica on the UV resistance of intumescent fire-retardant coatings were studied.Artificial ultraviolet accelerated aging experiments were carried out on the intumescent fireproof coating KB (no nano-SiO2 added), SY-1 (1% nano-SiO2), SY-2 (2% nano-SiO2) and SY-3 (3% nano-SiO2).The physical and chemical properties of the samples were analyzed using cone calorimeter, scanning electron microscope, thermogravimetric analyzer and Fourier infrared spectrometer. The results showed that the addition of nano-SiO2 improved the fire resistance and ultraviolet resistance of intumescent fire-retardant coatings, and the effected of adding 2% nano-SiO2 was the most obvious. From the analysis of the aging mechanism of SY-2 and KB, it is found that nano-SiO2 can improve the thermal stability and UV resistance of intumescent fireproof coatings, mainly by promoting the cross-linking of the resin with ammonium polyphosphate, inhibiting the formation of amide, and forming cross-linking with pentaerythritol.

Key words: nano-silica, intumescent fireproof coating, UV-aging