金属氢氧化物对沥青阻燃性能的影响

Influence of metal hydroxides on flame retardant performance of asphalt

采用氧指数、锥形量热仪试验研究对比了以氢氧化铝（ATH）、氢氧化镁（MH）、氢氧化钙（HL）阻燃处理沥青的阻燃抑烟性能，分析各金属氢氧化物阻燃特性与机理的异同。氧指数试验将沥青加热到160～170℃并搅拌均匀后，均匀浇附于玻璃纤维毡上。锥形量热仪试验将样品浇筑成内径为70mm、厚约10mm的圆饼，除加热面外的所有面用铝箔纸包覆，并用隔热棉隔断热量从样品背面向外传递。试验结果表明，ATH、MH、HL均可以提升沥青氧指数，延长沥青点燃时间，降低燃烧中热量和有毒烟气的释放。ATH、MH的气相阻燃效果较为显著，添加ATH后沥青氧指数的增加最为明显，燃烧平均热释放速率和CO产率下降最大；添加MH后沥青点燃时间最长，最大热释放速率最低。HL的凝聚相阻燃效果更为明显，添加HL后沥青的燃尽率显著降低，燃烧总热释放量和总烟释放量最小。

Limited oxygen index （LOI） and cone calorimeter were used to investigate the flame retardant and smoke Suppression perform of asphalt that treated by metal hydroxides,including aluminum hydro xide （ AT H）, magnesium hydroxide （MH） and hydrated lime （HID. The flame retardant characteristics and mechanism of these metal hydroxides were analyzed too. The asphalt was heated to 160-170℃ and stirred and dripped on the glass fiber mat in the LOI experiment. The asphalt was made as round cake with 70 mm in diameter and 10 mm in thickness. The surface of round cake was covered by aluminum foil except the heating surface. The thermal transit at the back of eh sample was insulated by heat insulation cotton. The re sults indicated that ATH, MH and HL could increase the LOI of asphalt, prolong the ignition time, and decrease the heat and toxic smoke release of asphalt combustion. ATH and MH showed obvious gas phase flame retardant effect. Adding ATH could significantly increase the LOI and give an optimal effect in reducing mean heat release rate and CO yield. While adding MH could give a maximum ignition time and minimum peak heat release rate. HL showed obvious condensed phase flame retardant effect. Adding MH could give a lowest burning out rate and least total heat and smoke release during asphalt combustion.