Study On The Preparation Of Phosphorus Nitrogen Boron Fire Retardant And Its Effect On Combustion Properties Of Particleboard

Particleboard with high strength, low cost, is extensively used in construction, decoration,furniture manufacturing, and vehicle shipping industry. However, wood is a combustiblematerial, and they can cause serious casualty and property lossing each year. So fire-retardanttreatment is very necessary. Fire-retardant can reduce the flammability of the material, andslow down the flame propagation speed, improve the fire resistance of materials to improvesafety. To avoid unnecessary casualties and loss of state property. Therefore, this studyindependently synthetize melamine phosphate and then mix boric acid and melaminephosphate physically to be the complex fire retardant. The complex fire retardant is used totreat particleboard. Test the fire retardant particleboard to analysis the the physical propertiesand combustion properties, then make sure the addition of the fire retardant and the ratio ofmelamine phosphate and boric acid. And analysis the mechanism of the fire retardant.The main research results are as follows:(1) The synthesis of melamine phosphateWith the pretreatment reaction, the optimum synthesis conditions of the melaminephosphate fire retardants are: molar ratio of melamine and acid1:1.2; reaction temperature80°C; response time four hours. The final yield of91%. And melamine phosphate fireretardants’s initial decomposition temperature is250℃, weight loss acceleratedat360℃. At600°C the residual carbon content is about10%. The fire retardant has good thermal stability,and its pyrolysis temperature range is very close with wood pyrolysis temperature range.⑵The complex physical properties and combustion properties of the fire retardantparticleboard.Compared with fire retardant particleboard’s physical and mechanical strength and thesample, there is a little change. The mechanical properties are much better than the standardvalue. But boric acid’s moisture absorption does affect the thickness swelling, therefore, choose the best ratio,boric acid and melamine phosphate1:2, to minimize the impact.Fire retardant compound significantly improved the combustion properties ofparticleboard, compared with the sample, HRR, THR, EHC, MLR decreased by about15%.TSR, and SEA decreased by about75%. And the residual material after combustion is graypowder, has no strength. Fire-retardant particleboard after12minutes of burning test, has dense,flat, solid carbon layer.Analyzing the physical and mechanical properties and combustion properties ofparticleboard, and ultimately determine the best dosage of the compound is10%, the best ratioof boric acid and melamine phosphate is1:2.⑶The mechanism of compound fire retardantThe mechanism of compound fire retardant is the result of the interaction of mechanism:gas dilution mechanism, the carbon mechanism, the covering mechanism, thermal mechanism.Phosphorus will produce a series of polycondensation reactions, generate strong acid, so thatthe timber quickly charring and the fire retardants will produce fire resistance gases H2O, NH3,CO2, NO2and dilution O2. Boric acid, in pyrolysis, the formation of glassy melt covering thesurface of the wood, isolated combustible gases, slowing the heat exchange and promotion ofcharring.