【作者】 王方；

【导师】 邹吉军；

【作者基本信息】 天津大学 ， 化学工艺， 2016， 硕士

【摘要】 金属铝的原子序数低、能量密度大且价格低廉,其与水和氧气反应生成氧化铝时能够释放大量的氢气和热量,在含能材料领域有着很高的应用价值,但是由于表面氧化层的存在使其应用受到限制。制备形貌规则且无表面氧化层的纳米铝颗粒,提高其中活性组分铝单质的质量分数尤为重要。本文采用了氧化还原法和前驱体分解法制备纳米铝颗粒,探究其形貌与粒径随制备条件的变化趋势,并研究纳米铝颗粒在碳氢燃料中的分散性。在有机溶剂和有机包覆剂存在下,通过氧化还原法直接制备并包覆纳米铝颗粒。在以油胺为包覆剂时,甲苯作溶剂制备的纳米铝颗粒与1,3,5-三甲基苯作溶剂制备的纳米铝颗粒相比,前者粒径较小;以油酸为包覆剂时,采用机械搅拌的反应方式,可得到形貌为纳米线的纳米铝颗粒,在此基础上研究反应时间的影响,发现随时间增加,铝颗粒的形貌由块状变为纳米线,然后继续向片状结构演化。为了更好的控制粒径,以氢化铝醚合物为前驱体,通过钛酸异丙酯均相催化分解前驱体并析出纳米铝晶粒,在此过程中应用不同的包覆剂即可得到不同粒径大小的纳米铝颗粒。通过热重和透射电镜分析不同包覆剂的纳米铝颗粒,综合失重情况和颗粒粒径,将油酸确定为包覆剂对象。以油酸为包覆剂的纳米铝颗粒在空气中可以稳定放置七个月而无氧化层生成。增加油酸包覆剂的摩尔比,合成的纳米铝颗粒尺寸呈现先减小后增大的趋势,最佳实验条件下得到的球形颗粒最小粒径为16 nm。通过表征提出包覆剂与内部活泼金属铝单质可能的结合方式。将前驱体分解法制备的纳米铝颗粒添加到高密度燃料JP-10中,在分散剂的作用下,分别采用超声分散和加热搅拌分散的方法制备悬浮燃料。增加分散剂加入量或者延长超声时间,均能增加悬浮燃料的吸光度,减小其纳米粒度,使分散稳定性不断提高。更多还原

【Abstract】 Aluminum nanoparticles(Al NPs)are valuable for many energy related applications because of it’s low atomic number,low density,high abundance,low cost and the high heat of reaction to form aluminum oxide(?Hr=31 kJ/g)via reaction with water and oxygen,processes which involve the evolution of a large amount of hydrogen gas and heat.But the presence of surface oxide layer hinders its applications.How to synthesis the particles with uniform morphology and avoid generating the oxide on the surface,enhance the mass fraction of active aluminum elemental is particularly important.In this paper we focus on two kinds of chemical synthesis methods of Al NPs,they are redox reaction and decomposition of precursor.Also we explore the diameter tendency of Al NPs with the changes of experimental conditions and dispersion into the hydrocarbon fuels.The preparation of the Al NPs is based on Haber method with the presence of the organic solvent and organic capping agent.The Al NPs will be capped as soon as it generated.It demonstrates that when oleyl amine is regarded as capped agent,the diameter of Al NPs prepared with Toluene as solvent is less than Al NPs prepared with 1,3,5-Trimethylbenzene as solvent.When the capping agent is changed from oleyl amine to oleic acid,the morphology of Al NPs is nanowires under mechanical stirring.With the increase of reaction time,the morphology of Al NPs can be transformed from nanowires to plate.In order to synthesis the particles with much smaller diameter,we attempted that the Al NPs prepared from the titanium-catalyzed thermal decomposition of a precursor solution.We explored Al NPs capped with oleyl amine,1,2-epoxyhexane,trioctylphosphine oxide and oleic acid.Those Al NPs have different particle diameter distribution.In the consideration of TGA and TEM,oleic acid is selected as the capping agent.Al NPs capped with oleic acid can be stable and have no oxidation when it is exposed in air at least seven months.with the increase of the ratio of oleic acid,the geometric mean diameters of the Al NPs capped with oleic acid decrease first and then increase.The minimum geometric mean diameter size of 16 nm are prepared by capped with oleic acid agents at the optimal synthetic conditions.This work infers that Al NPs maybe have special chemical bonds with capping agents.Al NPs which prepared from the titanium-catalyzed thermal decomposition of a precursor were dispersed in fuel JP-10.In the case of dispersant,we respectively used the ultrasonic treatment and magnetic stirring for the dispersion.With the increase of the amount of dispersant and ultrasonic time,the absorbance of suspension become larger,the stability can be improved and the diameter of nanoparticles in JP-10 is decreased.更多还原