氢氧化铝热解对沥青阻燃和加工性能的影响

Effects of Aluminum Hydroxide Pyrolysis on Performance of Fire-Retardation and Manufacture Asphalt

根据Al(OH)3的热解行为,采用气泡生长动力学模型,分析了温度对Al(OH)3阻燃性能的影响.结果表明:随着温度的升高,气泡半径增大,低升温速率致使Al(OH)3脱去更多结晶水,阻燃效果更好;气泡界面推进速度出现了迅速减小、维持相对稳定、与Al(OH)3失重率相一致这3个阶段,升温速率对这种变化趋势没有明显影响;气泡外围沥青的径向速率呈明显增大趋势,相同温度下,沥青径向速率随升温速率的增加而成倍增加,易导致沥青外溢,建议加工阻燃沥青时其升温速率应遵循"两头快,中间慢"的原则.可见,金属氢氧化物的热解行为影响着阻燃沥青的性能和加工工艺.

The effects of pyrolytic temperature on fire-retardation performance of aluminum hydroxide in asphalt were analyzed based on pyrolytic behavior of aluminum hydroxide and kinetic model of bubble growth. The results indicate that the diameter of vapor bubble increases with pyrolytic temperature rising, and more combined water was decomposed from aluminum hydroxide at low temperature rising rate, so the fire-retardation effect was better. Three marked sequential stages of bubble moving speed were found that is quick decrease, relatively stable and complicated change with rate of aluminum hydroxide mass loss when the interface velocity of bubble was discussed, and the influence of heating rate on the transformation tendency of bubble moving speed was negligible. The radial speed of liquid around the bubble rapidly increases with increasing heating rate at the same pyrolytic temperature, so as to cause hot asphalt overflowing. It is suggested that the heating principle of low rate in the medium temperature stage, but high rate in the other temperature stages should be observed. It is obvious that the performance and manufacture techniques of fire-retardation asphalt are affected by pyrolytic behavior of metal hydroxides.