Abstract:

To improve the fireproof performance of polyurea⁃based fireproof coatings，the effect of elosilicate nanotubes on the fireproof performance of polyurea⁃based coatings was investigated.Through the method of surface modification，the halloysite nanotubes were modified with methyltrimethoxysilane，and the modified halloysite nanotubes were introduced into the polyurea intumescent fireproof coatings.The cone calorimeter，infrared spectrum analyzer，thermal conductivity meter，field emission scanning electron microscope，transmission scanning electron microscope，and fire resistance testing device were used to characterize and analyze them.It was found that the peak heat release value of the paint sample with 5% modified halloysite nanotubes added was 95.89 kW/m²，which was 38.48% lower than that of the unadded sample.The total heat release was 7.20 MJ/m²，which was 76.50% lower than that of the unadded sample.The total smoke release value was 4.32 m²，which was 40.98% lower than that of the unadded sample.The thermal conductivity at room temperature was 0.067 W/（m·K），which was 17.30% lower than the unadded sample.In addition，the surface of the sample residue after combustion was denser and stronger，with better inhibition of the release of smoke and heat，showing excellent fire performance.The experimental results showed that the modified elosilicate nanotubes played a dual role in reducing the thermal conductivity of the composites and catalyzing the carbon formation of the matrix resin，which significantly improved the fire resistance of the polyurea⁃based fireproof coatings.

Key words: polyurea, fireproof coatings, halloysite nanotubes