硬脂酸镁改性氢氧化镁阻燃剂的实验研究

Study on surface modification of magnesium hydroxide flame retardant by magnesium stearate

采用硬脂酸镁对氢氧化镁进行湿法表面改性,考察了硬脂酸镁用量、改性温度及改性时间对改性效果的影响。通过改性前后氢氧化镁阻燃剂粉体的活化指数、吸油值及其在分散介质(液体石蜡)中的黏度等表面物化性能来评价氢氧化镁的改性效果,从而确定最佳改性条件,同时采用红外谱图研究了硬脂酸镁与氢氧化镁表面的作用机理。实验结果表明,在硬脂酸镁用量为3%,改性温度为90℃,改性时间为40min的条件下制备的产品性能优良,活化指数达99.4%,吸油值由改性前的78.6%降至40%,黏度较改性前明显降低,硬脂酸镁分子在氢氧化镁表面发生化学吸附键合。

Surface modification process of magnesium hydroxide （MH） by magnesium stearate was investigated. Influence of dosage of magnesium stearate, modified temperature, and time on modification effect was studied. Modified effects were evaluated by surface properties such as measurement of activation index, oil absorbility, and viscosity of the sysytem. The best conditions of modification were determined by these properties. Meanwhile~ modification mechanism of magnesium hydroxide was reserched by means of IR. Experimental results showed that the products with excellent modification effect as well as 99.4% activation index was prepared in the condition of 3% （mass fraction） in dosage,40 rain in time,and 90 ℃ in temperature. Oil absorbility of MH was reduced from 78.6% to 40% and its viscocity in atoleine was also decreased after modification. IR showed that magnesium stearate molecules are absorbed onto the surface of magnesium hydroxide mainly by chemisorption bond.