Flame Retardant and Smoke Suppression Performance of Intumescent Fire-Retardant Coating Modified by Aluminum Hydroxide and Montmorillonite

To improve the flame retardant and smoke suppression performance of fire retardant coatings. Aluminum hydroxide (ATH) and montmorillonite (MMT) were used as reinforced fillers to prepare intumescent fire-retardant coatings. The results showed that when ATH and MMT were combined with a mass ratio of 9:2, the flame retardant and smoke suppression performance was best. The maximum temperature on the back decreased by 47.1 °C, the heat release rate (HRR) decreased by 15.9%, the total smoke production (TSP) decreased by 23.5%, the peak carbon dioxide yield (PCDY) decreased by 39.4%, the maximum carbon residue was 50.59%. The main reason is that ATH reacts with phosphoric acid to form Al(H 2 PO 4 ) 3 , which binds each component together to increase the carbon residue. At high temperatures, ATH generates a large number of Mg-O-P and Si-O-P bonds and the mesh structure of MMT synergistically improves the thermal stability of the coating and absorbs flue gas particles. The oxides decomposed by ATH adhere to the surface of MMT and migrate to the surface of the charcoal layer to form a protective layer, which enhances the flame-retardant and smoke-suppressant properties of the coating. In this study, ATH/MMT was used as the flame retardant filler, and the optimal addition amount of ATH/MMT was obtained for the preparation of intumescent fire retardant coatings, which provides a theoretical basis for the selection of reinforcing fillers.