【作者】 何昌洪；

【导师】 张密林；

【作者基本信息】 哈尔滨工程大学 ， 应用化学， 2004， 硕士

【摘要】 氢氧化镁主要用作高分子材料的阻燃剂，与其它阻燃剂相比，它主要优点是分解温度较高，故当一些热塑材料需要较高温度加工时（200℃），用氢氧化镁作阻燃剂可避免加工时，因阻燃剂分解而引起塑料的质变。除此之外，纳米氢氧化镁主要用于橡胶、塑料制品的填充材料及增强剂，在医学上作抑酸剂，在化学工业作催化剂及制造其它镁的化合物、陶瓷、玻璃等原料，作石棉防火填充物，绝缘保温材料等。该产品有广泛的应用前景，所以开展纳米氢氧化镁的研究意义非常重大。 纳米MgO是一种粒径介于1～100nm的新型功能精细无机材料，由于其颗粒细微化而具有不同于本体材料的热、光、电、力学和化学等特殊功能。采用纳米MgO，不使用烧结助剂便可实现低温烧结，制成高致密的细晶陶瓷，可望开发为高温、高腐蚀气体等苛刻条件下的尖端材料，它还可作为氧化锆、氧化铝、氧化铁等其它纳米粒子的烧结助剂和稳定剂而获得高质量的纳米陶瓷。 本实验表明：合成纳米Mg（OH）₂阻燃剂较理想溶剂为乙醇和水比例为1：1～1：2的混合溶剂，在水-乙醇体系下可合成出外貌为针状、片状，粒径为20～100nm的Mg（OH）₂。 合成纳米MgO的最佳工艺条件为：制取前驱物Mg（OH）₂的反应温度25℃～35℃，反应时间4～5h，反应物配比MgCl₂：NH₃. H₂O为1：4.5，MgCl₂摩尔浓度为0.40mol／L，煅烧Mg（OH）₂的温度为450℃，时间为3小时。其产物MgO粒径分布均匀、平均粒径28nm。 以纳米Mg（OH）₂作为阻燃剂填加到聚氯乙烯中，其对聚氯乙烯阻燃性能的影响表现为：随着Mg（OH）₂填充量增加，PVC／Mg（OH）₂燃烧速度显著下降。纯PVC的燃烧速度为38mm／min，当Mg（OH）₂填充量为1％～3％时，其燃烧速度为37.5mm／min，阻燃作用不明显，当Mg（OH）₂填充量为5％～15％时，其燃烧速度为8.15～0.34mm／min，阻燃效果显著，达到GB2408—80／Ⅱ—8标准。更多还原

【Abstract】 Magnesium hydroxide is mainly used as a fire retardant chemical of macromolecule material and its main merit is that it has a high decomposing point, when compared with other fire retardant chemicals.The use of magnesium hydroxide as an fire retardant chemical can avoid the qualitative change of plastic caused by the decomposing of fire retardant chemical when the thermoplastic material need a high temperature to be processed (200癈), and besides, nano magnesium hydroxide can be used as stuffing and intensifier in making rubber and plastic, as polymerization inhibitor in the field of medicine, as catalyzer in the field of chemical industry, as marerial of magnesian product, as asbestos fireproofing stuffing,as insulated or heat preservation material and so on. So the magnesium hydroxide has a good future. The study on magnesium hydroxide has much meaning.Nano magnesia is a new kind of high-function fine inorganic material which diameter is between 1 nanometer and 100 nanometers, There are differences in performance of optics, performance of calorifics, performance of mechanics, performance of chemistry between nano magnesia and ordinary magnesia. By using nano magnesia the sinter process can be carried out in a lower temperature without the use of agglomeration. The nano magnesia can also be used as agglomeration and stabilization in making zirconia , alumina, ferric oxide and other nano particles for high quality nano chinaware,The experiment show that the ethanol-water solvent of which the ratio is bewteen 1:1 and 1:2 is a ideal solvent for the preparation of nano magnesium hydroxide used as fire retardant chemical. Acerate or sheet magnesium hydroxide which diameter is between 50 nanometers and 100 nanometers can be prepared by using ethanol-water solvent. The best technical conditions for making nano magnesia are as follows: the reaction temperature for making magnesium hydroxide is between 25 C and 35 C; the reaction time is between 4 hour and 5hour, the ratio of MgCl2to NH3 H2O is 1:4.5; the concentration of MgCl2 is 0.40mol/L; the temperature for the preparation of magnesium hydroxide is 450C with time of three hour. The magnesia has uniform diameter which is about 28 nanometers.The nano magnesium hydroxide can affect the combustion inhibitor of PVC, when it is filled into the PVC as a fire retardant chemical. Burning velocity of PE/Mg(OH)2 drop markedly when the amount of filled Mg(OH)2 is rising. There are no marked difference in burning velocity between the pure PE with a velocity of 38mm/min and the PE filled with 1% ~ 3% Mg(OH)2 with a velocity of 37.5mm/min. But the burning velocity can be 8.15~0.34mm/min which can meet the requirements of GB2408-80/ II -8,when the amount of filled Mg(OH)2 is更多还原