Evaluation of Combustion Performance of Wood-Based Panels Treated with High-Concentration Boron-based Flame Retardants via Different Application Methods

In this study, the combustion performance of wood-based panels treated with a high-concentration boron-based flame retardant compounded with a phenolic resin binder was evaluated. Plywood was treated using surface spreading, immersion, and vacuum-pressure impregnation, whereas particleboard was treated using surface spreading, resin mixing, and chip pre-immersion. Retention and fire-performance analysis indicated that, in plywood, higher retention levels enhanced flame retardancy, whereas in particleboard, the effectiveness depended on the spatial distribution of the flame retardant. Vacuum-pressure-impregnated plywood and chip-pre-immersed particleboard exhibited the highest fire resistance, characterized by delayed ignition and reduced mass-loss rates. These improvements were attributed to the formation of a protective layer during thermal decomposition, which inhibited heat transfer and oxygen diffusion. Overall, both the application method and the distribution of high-concentration boron-based compounds significantly affected panel combustion behavior. The composite flame-retardant system showed strong potential for improving the thermal stability, durability, and sustainable fire resistance of engineered wood materials.