Preparation And Characterization Of Composite Flame-Retardant Poplar

Wood is a renewable green material,with a strong ratio of weight,light weight,good decorative and so on,it is widely applied in many fields of human life.The forest resources in our country is limited,the development of large-diameter high-quality timber resources more scarce,making people turning round to the processing of fast-growing production.However,fast-growing wood has flammability poor dimensional stability,poor anti-swelling efficiency,loose materials and other shortcomings,limiting the development and utilization of fast-growing wood.Wood modification has become an important research field.In this paper,using the hydrothermal method,the poplar samples were treated with inorganic composites flame retardants and the results show as the followings:(1)The weight increasing rate of poplar wood samples in different stages was increased after treated with barium chloride,magnesium sulfate and diammonium phosphate.The weight gain rate of poplar samples increased continuously.The volume increase,antiswelling efficiency,dimensional stability and flame retardancy of modified poplar were improved with the increase of weight percent gain.After the final stage treatment(diammonium phosphate impregnated),the oxygen index of modified poplar samples can reach 57.49%.FTIR combined with XRD showed that barium sulfate and magnesium ammonium phosphate precipitate and flame retardants reduce the crystallinity of poplar.The initial degradation temperature and the pyrolysis rate of poplar wood treated with different stages decreased.Through pyrolysis kinetic analysis,after the final stage,the activation energy was reduced to 65.3kJ/mol.SEM images of chars indicated that the combustion process of modified poplar wood was effectively inhibited by the formation of a compacted carbonized layer.(2)In this paper,the flame-retardant properties and pyrolysis characteristics of poplar wood samples were studied,which were modified with ammonium borate and diammonium phosphate compound,the obvious synergistic effects when used together were found,the oxygen index and the remaining amount of carbon residue could approach to 61%and 53.5%,respectively,using 20%concentration treatment,it also exhibits superior flame retardancy at horizontal and vertical burning tests.Moreover,the onset decomposition temperature,peak decomposition temperature and activation energy of each stage were reduced,with the addition of the composites flame retardant,the SEM images indicating protective chars formed from the treated wood,terminating the transmission of heat and oxygen.