【作者】 王栋；

【导师】 解立峰；

【作者基本信息】 南京理工大学 ， 安全科学与工程， 2015， 硕士

【摘要】 纳米CeO2在国防、电子、航空等领域具有重要的应用价值。本文对爆轰法合成的球形纳米CeO2的性能进行了实验研究,研究内容主要围绕纳米CeO2初级产品的提纯和分散,纳米CeO2对废水的降解作用、紫外屏蔽性能、对含能材料热分解的催化性能等展开,主要研究内容如下：(1)爆轰合成的纳米CeO2中主要杂质是Fe203和Al2O3,其占比约3%。通过正交试验,得到最佳提纯参数为：温度80℃,时间24h,硝酸量0.33mL·g-1,-蒸馏水量6.67mL·g-1,PEG量16.67mg·g-1。其中,温度和时间是影响纯度的重要因素。利用此参数提纯后的纳米CeO2纯度为99.59%,其中残留0.12%Fe2O3和0.17%A12O3。(2)以去离子水为分散介质时,六偏磷酸钠对Ce02分散效果较好；以乙醇为分散介质时,聚乙二醇对CeO2分散效果较好。在不添加分散剂的情况下,乙醇为分散介质时,纳米CeO2的分散效果更佳。(3)纳米CeO2添加量为3.5g·L-1时,甲基橙的降解率和降解友应速率常数达到最大,降解率为83.90%。降低溶液的初始pH值会促进降解活动的进行,使降解率和降解反应速率常数变大。纳米CeO2颗粒在没有紫外光照下对甲基橙溶液进行处理时,由于其自身的吸附作用,依旧存在一定的降解效果。60min后达到吸附平衡,降解率为33.66%。(4)纳米Ce02在190nm～400nm波段表现出较强的紫外屏蔽作用,环氧树脂(EP)薄膜中添加0.8%的纳米CeO2, EP薄膜的紫外吸光度达到最大值。在经过老化后,与未添加纳米CeO2的相比,添加纳米CeO2的EP使用寿命增加62.82%,对抗拉强度的保持率提高35.25%。由此得出,纳米CeO2具有较强的紫外屏蔽作用,提高了EP对紫外光的抗老化能力。(5)利用静电喷雾法制得黑索金(RDX)和CeO2混合物,混合物中RDX为球形颗粒,粒径约为1μm。RDX-CeO2混合样品中,两者混合较均匀,没有明显的团聚现象。(6)利用差式扫描量热仪(DSC)对RDX-CeO2混合物进行热分解分析,纳米CeO2对RDX的热分解过程表现出较好的催化作用。在混合体系中,添加的5%纳米CeO2使RDX的主要分解峰温降低了5℃左右,且放热量增加了343J·g-1, RDX的表观活化能降低了16.69kJ·mol-1。更多还原

【Abstract】 Nano-scaled ceria has important application value in the national defense, electronics, aerospace and other fields. In this paper, the performance of spherical nano-scaled ceria synthesized by detonation method was studied. The work of purification and dispersion was researched firstly. The study on the performance of nano-scaled ceria included three aspects: waste water degradation, UV shielding, catalytic action on energetic material about thermal decomposition. The main research contents are as follows:(1) The main impurity are Fe2O3 and Al2O3 among the nano-scaled ceria, the proportion accounts for 3 percent. Orthogonal test was designed to get the best purification parameters of nano-scaled ceria. The parameters are that temperature is 80 ℃, time is 24h, the amounts of distilled water, nitrate and PEG are 0.33mL,6.67mL and 16.67mg each gram of detonation ash. Among them, time and temperature are the important factors to purity.0.12 percent Fe2O3 and 0.17 percent Al2O3 are left over after purifying.(2) Deionized water as the dispersion medium, the effect of six partial sodium phosphate on dispersion is better; Alcohol as the dispersion medium, the effect of polyethylene glycol on dispersion is better. When alcohol as the dispersion medium, the dispersion effect is better without the addition of dispersing agent.(3) When the content of nano-scaled ceria is 3.5g·L-1, the degradation rate and degradation rate constants on methyl orange are maximum, the degradation rate is 83.90 percent. Decreasing the initial pH of solution will promote the degradation activity, the degradation rate and degradation rate constants become larger. Because of the adsorption effect, nano-scaled ceria still has certain degradation effect to methyl orange solution without Ultra Violet light, it reaches adsorption equilibrium after 60 min, the degradation rate is 33.66 percent.(4) Nano-scaled ceria shows a strong ability of ultraviolet(UV) shielding on 190nm-400nm band. The UV absorbance of epoxy resin(EP) film reaches the maximum value with 0.8 percent nano-scaled ceria addition. Compared with no nano-scaled ceria, the service life of EP increases by 62.82 percent, the retention rate of tensile strength increases by 35.25 percent after aging. Conclude from this:nano-scaled ceria has a strong UV shielding effect, it improves the anti ageing capacity to UV of EP.(5) Hexogen and nano-scaled ceria mixed samples synthesized by electrostatic spraying method. RDX is spherical particles and its size is about lum. The mixture of nano-scaled ceria and RDX is uniform, and the reunion phenomenon is inconspicuous.(6) Thermal decomposition of RDX and nano-scaled ceria mixture was studied by Differential Scanning Calorimetry(DSC). The nano-scaled ceria shows good catalysis action on the thermal decomposition of RDX. In the mixed system, the decomposition peak temperature of RDX decreases about 5℃, and the heat release increases 343 J·g-1, the apparent activation energy reduces 16.69 kJ·mol-1.更多还原