Study On Flame Retardancy Modification Of Wood Compounds To Wood

As natural polymer materials, wood and wood materials are important green building materials which have been widely used in many fields due to their natural green properties. However, wood is mainly composed of carbon, hydrogen and oxygen, which determines its flammability. In this paper, various metal compounds were added to the wood powder to prepare flame retardant wood products through physical blending method. The flammability of the products was tested.The flame retardancy of different metal chloride and metallic carbonates treated wood was characterized by limiting oxygen index(LOI) and cone calorimeter(CONE). The results indicate that calcium chloride, ferric chloride, sodium carbonate, potassium carbonate could increase the LOI values of wood. Heat release rate and smoke release of retardant wood are greatly reduced, indicating the excellent flame retardant properties. Monovalent metal carbonate is expanded during the combustion. Potassium carbonate is expanded most obviously and its flame retardant effect is the most notable in carbonate product. Potassium carbonate treated wood has good flame retardant property.The samples were burned at 600℃ and were characterized by X-ray diffraction(XRD). XRD results show that cellulose crystal regions in calcium chloride, ferric chloride, potassium carbonate and sodium carbonate treated wood are destructed and changed. The results indicate that these metal compounds except sodium chloride are changed into other substance to improve the flame retardancy of wood.TG results show that the pyrolysis temperature of these metal compounds treated wood is advanced. The pyrolysis mechanism of calcium chloride, ferric chloride, potassium carbonate and sodium carbonate except sodium chloride treated wood is changed. Thus, it is plausible to speculate that metal compounds which can participate in the combustion of wood have good flame retardant effect.