Char formation and smoke suppression mechanism of montmorillonite modified by ammonium polyphosphate/silane towards fire safety enhancement for wood composites

The low efficiency of montmorillonite (MMT) as a nano-flame retardant has limited its widespread application. In this work, a clay-based flame retardant was developed by modifying MMT with ammonium polyphosphate (APP) and 3-Aminopropyltriethoxysilane (SCA). Subsequently, wood composites treated with the clay-based flame retardant were prepared, and their char formation and smoke suppression behavior were investigated. MMT sheet effectively absorbed a significant amount of APP, and the broken edges of the sheet were successfully grafted with SCA. This promoted the formation of polyphosphoric acid and improved the interface compatibility among the components of wood composites. The clay-treated wood composites exhibited a reduction in total heat release (by over 27.0