Effect of flame retardant treatment on dimensional stability and thermal degradation of wood

To produce flame resistance wood-based product with increased physical properties, wood were treated with nitrogen-phosphorous based flame retardant coupled with reactive urea-formaldehyde (UF) oligomer (denoting as APPUF). Flame retardancy and dimensional stability of treated wood in antiswelling efficiency (ASE) and water repellent efficiency (WRE) were evaluated. Thermogravimetry (TG) and differential thermal analysis (DTA) technique were used to investigate the thermal degradation of treated wood. The results indicated that the dimensional stability was significant improved with impregnation of APPUFs. The largest ASE value of 52% was obtained by treatment of APPUF1.0 with 20% concentration. The flame retardant was found to be incorporating into the cell wall structure with scanning electronic microscopic (SEM) test. Flame retardant treated wood could approach to the nonflammable material range with the highest LOI value of 78% using 25% concentration treatment. Thermal decomposition analysis demonstrated that the improvement of flame retardancy of treated wood was achieved through dehydration of polysaccharides and forming of protective char shield, terminating heat and oxygen transferring.