Study On Combustibility And Flame Retardance Of Five Major Species In Greater Khingan Mountains

The study of the forest fuel combustibility provide theoretical basis to screen fire tree species and develop biological fire isolation belt. The development of forest flame retardant with chemical method is a kind of advanced and efficient way in the world. With paying more and more attention to forest flame resistant agent, ammonium polyphosphate (APP) is an important non-halogen flame retardant but it can not achieve the effect of flame retardant because of its low polymerization degree. In this study, low polymerization degree of ammonium polyphosphate were modified with 3-(Methylacryloxyl) propyltrimethoxy silane(KH-550), and used it to treat with the pine needles. The aim of this work was to study the effect of the modified and flame retardancy properties of the mainly 5 forest fuel of Greater Khingan Mountains, it was studied based on FTIR Spectrometer、 XRD、Thermal analyser、Cone calorimeter et al.In this study, mainly 5 forest fuel of Greater Khingan Mountains were selected for the flammability of branches and leaves. Study shows that all the combustion process of the samples can be divided into three stages:smoldering stage, flaming stage, glowing stage and their heat release rule are basically identical. Quercus mongolica、Juglans mandshurica can be used as primarily flame resistant tree species.The results showed that significant changes occured on surface of modified APP, the hydroxyl of silane coupling agent and the hydroxyl of APP occurred chemical reaction generating P-O-Si. At the same time, the dispersion of modified APP is improved, the thermal decomposition rate of is slowed, carbon rate is increased, the decomposition temperature is increased and the modified APP was more stable. The introduction of coupling agent on the thermal decomposition of APP into carbon have a positive impact.Modified ammonium polyphosphate made hemicellulose, cellulose decompose at low temperatures, forming a char layer on the surface of pine needles. And the APP can decompose nonflammable gases, dilute oxygen in the air, isolated pine needle with heat、oxygen, have the effect of flame retardant.The mass loss at high temperatures was less, the char residue at 650℃ was increased from 42.3% to 47.4%, the maximum heat release rate was decreased from the 103.1 kW·m-2 to 82.9 kW·m-2, the total heat release rate was decreased by 5.6%.Modified ammonium polyphosphate had a positive impact on the retardant of a variety forest fuel, the maximum heat release rate, the total heat release rate and total smoke release were decreased obviously, the char residue was increased. It played a significant flame retardant role on forest fuel, particularly when the branch of Pinus tabulaeformis var.mukdensis were treated.