An Eco-Friendly PVA/XG/AP Nanocomposite Multifunctional Shield for Wood with High Flame Retardancy and Superior Thermal Insulation

Traditional flame-retardant methods for wood, which employ organic reagents and halogens, are detrimental to human health and the environment. Therefore, a PVA (Polyvinyl alcohol)-based coating (PX-AP) incorporating xanthan gum (XG), phytic acid (PA), and aluminum phosphate (AP) was developed to enhance flame retardancy, antibacterial performance, and thermal insulation of wood. XG improves viscosity, stabilizes AP suspension, facilitates carbon formation, and collaborates with AP to form a dense char layer. PX-AP achieves UL-94 V-0 rating with LOI > 60%; TGA results show residual carbon content increases by 102.8% compared to natural wood; cone calorimeter tests indicate Total heat release (THR) decreases by 36.9% and Peak heat release rate (pHRR) by 43.7%; and the maximum backside combustion temperature drops by 44.1% in thermal insulation tests. Bio-inorganic carbon armor enhances fire-resistance & structural integrity of wood for safer evacuation. It also exhibits strong adhesion, meeting diversified demands for wood applications.