Nano CaAlCO3-layered double hydroxide-doped intumescent fire-retardant coating for mitigating wood fire hazards

Abstract

A novel approach was proposed to reduce the risk of fire posed by wood by using a flexible and highly efficient intumescent coating doped with CaAlCO3-layered double hydroxides (LDH). The fire-retardant performance of the coating was investigated through fire tests, cone tests, and thermogravimetry. After the fire tests, the residual char layer was characterized using X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. The coating with 2.2 wt% CaAlCO3-LDH exhibited the fire resistance of more than 20 min, reduced the specific extinction area by 54.78%, and increased the residual mass to 13.5%. Density functional theory illustrated that the superior porous honeycomb char layer and oxidation resistance obtained are due to the chelation effect of Ca and Al on the changes in polyaromatic structures. This study presents a new type of LDH-doped fireproof coating for minimizing the fire-hazardous nature of wood.