Dual Protection of Wood Surface Treated with Melamine-Modified Urea-Formaldehyde Resin Mixed with Ammonium Polyphosphate against Both Fire and Decay

Abstract Surface coatings of melamine-modified urea-formaldehyde resins (MUFs) containing ammonium polyphosphate (APP) have been shown to significantly improve the fire retardancy of wood by prolonging the ignition time and reducing the heat release rate, total heat released, and mass loss rate. Dual protection of wood against both decay and fire has been proposed for remedial situations and interior construction. In this study, the fire retardant MUF resin type 3 (MUF3)/APP mixture system showed strong activity against wood decay fungi via an activity inhibition test. Two species of wood were subjected to steeping with the fire retardants MUF3/APP. The treatments were evaluated for fire and decay resistance using cone calorimetry and fungal decay resistance tests. The results showed that MUF3/APP surface treatment can provide dual protection to wood against degradation by decay fungi and fire.