Mg2NiH4对高氯酸铵热分解过程的影响

采用置换-扩散法制备了储氢材料Mg2NiH4, 用XRD, ICP和DSC-TG方法对其结构进行了表征. 用热分析法(DSC)研究了Mg2NiH4对高氯酸铵(AP)热分解过程的影响. 研究结果表明, Mg2NiH4对AP热分解过程有较大影响. Mg2NiH4可以显著促进AP的低温热分解过程, 降低高温热分解温度, 使DSC表观分解热明显增大. 随着加入量的增加, Mg2NiH4对AP热分解的催化促进作用增强, 当Mg2NiH4加入的质量分数为30％时, DSC表观分解热最大. 吸氢量越大, 储氢材料对AP的催化促进作用越强. Mg2NiH4催化促进AP分解过程的作用机理为: Mg2NiH4分解释放的H2及Mg和Ni与AP分解产物发生反应.     

干燥方式对高氯酸铵/石墨烯复合材料的结构和热分解行为的影响

通过溶胶-凝胶法制备了石墨烯水凝胶, 并将其与高氯酸铵(AP)复合, 然后分别采用自然干燥、冷冻干燥和超临界CO₂干燥三种干燥方式制备了AP/石墨烯复合材料, 并通过扫描电镜(SEM)、元素分析、X射线衍射(XRD)、差示扫描量热仪(DSC)和热重-红外联用技术(TG-FTIR)研究了不同干燥方式对其结构和热分解行为的影响. 结果表明, 干燥方式对AP/石墨烯复合材料的形貌具有明显影响, 其中通过超临界CO₂干燥制备的AP/石墨烯复合材料基本能保持与石墨烯气凝胶相似的外观和多孔结构. 通过自然干燥、冷冻干燥和超临界CO₂干燥制备的AP/石墨烯复合材料中AP的质量分数分别为89.97%、92.41%和94.40%, 其中通过超临界CO₂干燥制备的复合材料中AP的粒径尺寸为69 nm. DSC测试结果表明, 石墨烯对AP的热分解过程具有明显的促进作用, 能使AP的低温分解过程大大减弱, 高温分解峰温明显降低. 三种干燥方式相比, 通过超临界CO₂干燥制备的AP/石墨烯复合材料中石墨烯的促进作用最明显. 与纯AP相比, 其高温分解峰温降低了83.7℃, 表观分解热提高到2110 J·g^-1. TG-FTIR分析结果表明, AP/石墨烯复合材料的热分解过程中, AP分解产生的氧化性产物与石墨烯发生了氧化反应, 生成了CO₂.     

不同粒度高氯酸铵的热分解研究

利用高压差示扫描量热法(PDSC), 热重法(TG), 固体原位红外联用法(Thermolysis/RSFT-IR)和热分析与质谱和红外联用法(Thermal analysis-MS-FTIR)研究了不同粒度高氯酸铵AP在1.0 MPa压强下和常压下的热分解过程, 提出了不同粒度AP可能的热分解机理. 研究结果表明, 不同粒度AP的高压和常压下的热分解历程存在明显的差异, 较大粒度AP的受热分解过程中存在明显的低温分解阶段和高温分解阶段, 小粒度的AP则仅存在明显的高温分解阶段. AP的分解气体产物主要包括NO2, NO, N2O, O2, H2O和HCl.     

溶剂热合成Cu2O微球及其对高氯酸铵热分解的催化作用

以聚乙烯吡咯烷酮(PVP)为添加剂,利用溶剂热法合成了Cu2O微球.考察了PVP用量以及反应温度对产物形貌的影响,并在反应时间为2.5与4.5h时分别合成了直径为100-200nm和1μm的Cu2O微球.同时,利用差热分析(DTA)技术考察了不同直径的Cu2O微球对高氯酸铵(AP)热分解的催化效果,结果表明:添加2%(w)的直径为100-200nm和1μm的Cu2O微球使得AP的高温分解温度分别降低了116和118°C,AP在低温阶段的分解量也明显提高.     

不同结构Cu_2O多晶的合成及其对高氯酸铵热分解的催化作用

利用均相反应器,在没有添加剂的条件下合成了具有多孔结构的Cu2O微球.考察了合成时间以及反应器旋转速度对Cu2O微球结构的影响.通过增加聚乙烯吡咯烷酮(PVP)的用量,使得Cu2O从多孔微球转变为立方体孪晶,最终形成十四面体孪晶结构.同时,将不同结构的Cu2O多晶应用于催化高氯酸铵(AP)的热分解,结果表明:多孔Cu2O微球较其它结构的Cu2O对AP的热分解具有更高的催化活性,使得AP的低温分解温度降低了37.4°C,而AP在低温阶段的分解量也由8.7%增加至49.0%.     

多孔纳米CoFe2O4的制备及其对高氯酸铵的热分解催化性能

采用胶晶模板法制备出具有三维多孔结构的纳米CoFe₂O₄。利用X射线衍射仪(XRD)、傅里叶变换红外(FT-IR)光谱仪、扫描电镜(SEM)、透射电镜(TEM)和N₂吸附-脱附对样品的晶型和形貌结构等进行表征,采用差示扫描量热法(DSC)对比研究多孔纳米CoFe₂O₄和球形纳米CoFe₂O₄对高氯酸铵(AP)的热分解性能的影响,并考察这两种催化剂对AP催化热分解的动力学参数。结果显示,制备出的多孔纳米CoFe₂O₄样品具有典型的尖晶石结构,孔径约200 nm;比表面积明显高于40 nm球形CoFe₂O₄,达到55.646 m²·g^-1。DSC测试结果表明：多孔纳米CoFe₂O₄的加入促进了AP的热分解,最高使AP的高温分解峰温降低91.46℃,能量释放最高达1120.88 J·g^-1,是纯AP分解放热量的2.3倍;多孔纳米CoFe₂O₄具有较高的比表面积,能提高催化反应的接触面积,使AP的高温分解峰温度更低,反应活化能较小,从而表现出比球形纳米CoFe₂O₄更高的催化活性。此外,对多孔纳米CoFe₂O₄催化AP的热分解机理进行初步探索,纳米多孔催化剂对气态中间产物的作用促进了AP的热分解。     

纳米NdCoO3催化高氯酸铵热分解的DSC/TG-MS研究

采用微乳液法制备了立方晶系的NdCoO3纳米晶.利用DSC/TG-MS研究了NdCoO3对AP热分解的催化作用.结果表明,在NdCoO3的催化作用下,AP的热分解反应峰值温度下降了113℃,表观分解反应热从655 J·g-1增加到1 363 J·g-1,分解的气相产物主要有NH3,H2O,O2,HCl,N2O,NO,NO2和Cl2.在金属氧化物表面吸附生成超氧化离子(O2-)和氧离子(O-,O2-),这是加速AP分解反应的主要原因.加入NdCoO3催化AP热分解,由于对氨的氧化深度不同而导致分解放热量的增加.     

低熔点DNAN/RDX混合材料的热行为及分解机理

利用动态测压热分析法(DPTA)、差式扫描量热法(DSC)、热重分析法(TG)、热烤法研究了低熔点含能材料DNAN/RDX的热行为和分解机理。研究得到结论：1)DPTA法测试结果表明DNAN/RDX的热安定性较好；在固相分解阶段，运用Satava-Sestak法得出20～100℃时非等温固相分解阶段机理函数为G(α)=[(1-α)^-1/3-1]²,E_S=85.64 kJ/mol, lgA_s=11.57;等温阶段的等温分解动力学机理函数为G(α)=[(1-α)^1/3,反应速率常数k=1.515 32×10^-4。2)DSC法和TG法研究结果表明RDX主要为熔融液相形式分解，DNAN主要为气相形式分解；混合体系中RDX促进了DNAN的分解过程，DNAN/RDX的受热质量损失过程主要为DNAN的挥发过程和RDX的热分解过程。运用DSC法研究升温速率为5℃/min时DNAN/RDX的热分解过程，普适积分法得出在224～320℃范围内的分解过程机理函数为G(α)=[-...     

含能配合物2，6-二氨基-3，5-二硝基吡啶-1-氧化物合钴(Ⅲ)的合成、晶体结构及催化性能

培养了含能配合物2,6-二氨基-3,5-二硝基吡啶-1-氧化物(ANPyO)合钴(Ⅲ)晶体,用X射线单晶衍射法测定了其分子结构。该配合物的分子式为[Co(ANPyO)3]。用DSC,TG-DTG技术对该配合物的热分解进行了研究,结果表明,该配合物的热分解由1个缓慢吸热峰和2个剧烈的放热峰组成,剩余残渣量为3.7277%。感度测试结果表明,该配合物感度较ANPyO有一定程度的降低,是一种不敏感含能材料。同时研究了配合物对高氯酸铵(AP)热分解的影响,结果表明,[Co(ANPyO)3]可以使AP的高温分解峰温提前65.15℃,使分解速度加快,对AP热分解具有良好的催化效果。     

甲磺酸帕珠沙星的热分解机理及动力学

采用热重(TG)和差示扫描量热(DSC)法测定了甲磺酸帕珠沙星(PZFX)在氮气氛和空气氛中的热分解过程,测定了PZFX及其在热分解过程中不同阶段残余物的红外光谱,运用量子化学GAMESS软件计算了PZFX分子的键级,推断了PZFX的热分解机理.结果表明PZFX的热分解过程的起始步骤是甲磺酸的分解.采用Ozawa方法计...     

纳米Co-B非晶态合金对高氯酸铵分解的催化性能

 利用化学还原法制备了纳米 Co-B 非晶态合金,并用透射电镜、X射线衍射、差示扫描量热和N2吸附表面积测试等技术对样品进行了表征. 运用差热分析研究了纳米 Co-B 非晶态合金对高氯酸铵(AP)分解的催化性能. 结果表明,加入 Co-B 非晶态合金后AP的高低温放热峰相连,合并成一个高而大的放热峰,且峰温有很大程度的降低, 这说明纳米 Co-B 非晶态合金对AP热分解有很好的催化活性. 同时, Co-B 非晶态合金能使AP的表观分解热显著增大.     

Preparation of nano-cerium dioxide and its effect on the thermal decomposition of ammonium perchlorate

Detonation synthesis method was introduced to prepare nano-cerium dioxide. Nano-cerium oxide was obtained by this novel method and its effect on the thermal decomposition of ammonium perchlorate (AP) was studied. X-ray diffraction and transmission electron microscope were used to characterize as-prepared materials. Results showed that as-prepared cerium dioxide was cubic phase and its morphology was nearly spherical. The mean size of as-prepared cerium dioxide particles was 55 nm. Differential scanning calorimetry (DSC) was used to test the effect of as-prepared nano-cerium dioxide on the thermal decomposition of AP. Kissinger method was introduced to calculate activation energy of different specimens according to DSC data. Results indicated that nano-cerium dioxide synthesized by detonation method had catalytic effect on thermal decomposition of AP and could decrease activation energy of AP/CeO₂ mixture.     

Evaluation of the catocene/graphene oxide nanocomposite catalytic activity on ammonium perchlorate thermal decomposition

A novel nanocomposite catalyst for thermal degradation of the ammonium perchlorate (AP) has been synthesized, and its effect on the thermal behavior of AP has been investigated. Preparation of the catalyst was carried out via functionalization of the graphene oxide with phenyl isocyanate and its noncovalent bonding to catocene. The catalytic activity of the catalyst was studied by thermal gravimetric analysis/differential scanning calorimetry at various heating rates. In addition, the effect of the catalyst on the AP thermal decomposition has been investigated by Kissinger and Friedman methods as two model-free methods for calculation of the activation energy parameter. According to the Kissinger method calculations, the E_a of AP decomposition reduced about 151 kJ⋅mol⁻¹ lower than the reported value for pure AP in the presence of the catalyst. Calculation of the E_a value for various reaction conversion rates by the Friedman method also confirmed the Kissinger method results.     

Preparation of NdCrO3 nanoparticles and their catalytic activity in the thermal decomposition of ammonium perchlorate by DSC/TG-MS

Orthorhombic structural perovskite NdCrO₃ nanocrystals with size of 60 nm were prepared by microemulsion method, and characterized by XRD, TEM, HRTEM, SEM, EDS and BET. The catalytic effect of the NdCrO₃ for thermal decomposition of ammonium perchlorate (AP) was investigated by DSC and TG-MS. The results revealed that the NdCrO₃ nanoparticles had effective catalysis on the thermal decomposition of AP. Adding 2% of NdCrO₃ nanoparticles to AP decreased the temperature of thermal decomposition by 87° and increased the heat of decomposition from 590 to 1073 J g⁻¹. Gaseous products of thermal decomposition of AP were NH₃, H₂O, O₂, HCl, N₂O, NO, NO₂ and Cl₂. The mechanism of catalytic action was based on the presence of superoxide ion O₂ ⁻ on the surface of NdCrO₃, and the difference of thermal decomposition of AP with 2% of NdCrO₃ and pure AP was mainly caused by the different extent of oxidation of ammonium.     

Pure CuCr2O4 nanoparticles: Synthesis,characterization and their morphological and size effects on the catalytic thermal decomposition of ammonium perchlorate

In the present paper a pure phase of the copper chromite spinel nanoparticles (CuCr₂O₄ SNPs) were synthesized via the sol–gel route using citric acid as a complexing agent. Then, the CuCr₂O₄ SNPs has been characterized by field emission scanning electron microscope (FE-SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). In the next step, with the addition of Cu–Cr–O nanoparticles (NPs), the effects of different parameters such as Cu–Cr–O particle size and the Cu/Cr molar ratios on the thermal behavior of Cu–Cr–O NPs + AP (ammonium perchlorate) mixtures were investigated. As such, the catalytic effect of the Cu–Cr–O NPs for thermal decomposition of AP was evaluated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). TGA/DSC results showed that the samples with different morphologies exhibited different catalytic activity in different stages of thermal decomposition of AP. Also, in the presence of Cu–Cr–O nanocatalysts, all of the exothermic peaks of AP shifted to a lower temperature, indicating the thermal decomposition of AP was enhanced. Moreover, the heat released (ΔH) in the presence of Cu–Cr–O nanocatalysts was increased to 1490 J g⁻¹.     

Thermal behavior of ammonium perchlorate and metal powders of different grades

The effects of aluminum (Al) and nickel (Ni) powders of various grain sizes on the thermal decomposition of ammonium perchlorate (AP) were investigated by TG and DSC in a dynamic nitrogen atmosphere. The TG results show that Al powders have no effect on the thermal decomposition of AP at conventional grain size, while the nanometer-sized Ni powders (n-Ni) have a great influence on the thermal decomposition of AP with conventional and superfine grain size. The results obtained by DSC and an in situ FTIR analysis of the solid residues confirmed the promoting effects of n-Ni. The effects of n-Ni have been ascribed to its enhancement on the gas phase reactions during the second step decomposition of conventional grain size AP.     

钛酸锌的制备及其对高氯酸铵热分解的催化性能

ZnTiO₃ nanocrystals were prepared by sol-gel method, using Zn(NO₃)₂ and Ti(C₄H₉O)₄ in the topic. The as-prepared ZnTiO₃ nanocrystals were characterized by XRD, FTIR and TEM, and the catalytic performance of ZnTiO₃ nanocrystals of different contents for the ammonium perchlorate(AP)decomposition was investigated by thermal analysis. The results indicate that ZnTiO₃ with pure cube structure can be synthesized at 600 ℃ by this procedure,which was spheroid with particle size of about 60~100 nm. The results expressed that the low temperature decomposition peaks of AP is advanced by 17 ℃ and the high temperature decomposition peaks of AP is advanced by 24 ℃ when adding 5% nanoparticle ZnTiO₃ powder. The catalytic effects of ZnTiO₃ powders on the high temperature decomposition of AP are less than that of nanometer metal powders, but all the micron metal powders decrease the low decomposition temperature of AP.