The Flame Retardant And Smoke Suppressive Effect Of MH And ATH On Composite Wood Material

With the development of industry, the demand for large-size timber is gettinggreater. But as a result of long-term deforestation, nature forest resources havebecoming deficient. Compsite wood material provides a new choice to us. It is thestratified structure of the composite wood material that can be took utilize to it’s flameretardant modification, giving the composite wood material intrgral flame retard.Magnesium hydroxide(MH) is a kind of environmental friendly flame retardant withthe advantages such as clean, smoke suppressive and cheap. By added to the adhesive,making up a veneer-retardant alternative repeating layered structure with the woodveneer, MH can absorbe heat from the wood veneer next to it and its residue MgO canplay the role of obstacle to oxygen and heat，which can overcome the the defects oftraditional flame retardants such as tendency to loss, complicated impregnating processand shallow impregnating depth. But to be effective, the additive amount of MH isusually high, which has an negative effect on mechanical property. Therefore, theinfluence of the content of MH on mechanical property and flame retardantperformance is decisive to whether this structure can be took use of in reality.In this work, the effect of MH on mechanical property and flame retardantperformance has been studied with two commom adhesive in wood industry: urea resinadhesive and phenolic resin adhesive. In the study with phenolic resin we modifiedMH through ultrasonic-assisted wet method and studied the relationship between thecontent of MH and the under testing properties by the testing method of tensile test,LOI, SEM, TG and FTIR. Results indicate that the samples have the best bondingstrength and relatively high LOI value when the content of MH equals to1.2times themass of solid content of adhesive. By compounded with ATH the LOI value can beeven higher. In the study with urea resin we modified MH and ATH throughultrasonic-assisted wet method and studied the relationship between the content of MHor ATH and the under testing properties by the testing method of tensile test and LOI.The results indicate that ATH is suitable for urea resin but MH is not. The test of theinfluence of MH and ATH on carbon residue and smoke suppression is also been made.The result shows that MH and ATH do not increase the carbon residue but can decrease smoke generation.In conclusion, this work not only brings some useful information for fire retardantengineering of wood industry, but also give some suggestion for the choice of the typeof fire retardants for wood material.