RDX和HMX的热分解Ⅱ．动力学参数和动力学补偿效应

用DSC、DTA和TG-DTG技术测定了RDX和HMX热分解的动力学参数。RDX和HMX在不同的分解阶段有不同的动力学参数和机理函数，其分解过程和动力学参数受试验条件、样品状态和试验方法的影响很大，但这些参数之间存在“动力学补偿效应’’和“等动力学点”。     

用微量热法研究RDX和HMX的稀释/结晶动力学

导出了描述结晶生长过程的3个热动力学方程和这些动力学方程的参数与常数间的2个关系式。用Calvet微热量计测定了RDX和HMX从二甲基亚砜、环已酮和硝酸中的稀释／结晶总放热量和产热速率。用导出的方程和关系式处理了RDX和HMX的放热稀释／结晶生长过程的动力学数据。结果表明,RDX和HMX的放热稀释／结晶过程服从Burton—Cabrera—Frank位错理论。     

RDX和HMX的热分解I.热分析特征量

用PDSC和TG-DTG研究了RDX和HMX的热分解,探讨了各种试验条件,包括试样量、升温速率和动静态高压等的影响。在分解过程中相态变化引起反应的加速是HMX的分解较RDX剧烈的主要原因,HMX的自加热和自催化也因此变得较RDX更显著。     

RDX基含铝炸药的热爆发活化能及动力学补偿效应

采用5s爆发点试验获得了12种RDX和铝粉含量不同的RDX基含铝炸药的热爆发动力学参数(lnA和Eb).结果表明,随着RDX含量的增加,Eb先下降后升高,发现该炸药体系的热爆发动力学参数lnA和Eb之间存在补偿效应.根据热爆发温度Tb与RDX和铝粉含量的关系以及动力学补偿效应,从理论上导出了热爆发活化能Eb与RDX和铝...     

TNT在HMX和RDX中的非等温结晶动力学

采用差示扫描量热仪(DSC)研究了TNT在HMX和RDX两种不同介质中的非等温结晶行为.结果表明,在HMX和RDX中加入少量HNS后都能降低TNT的过冷度,消除结晶过程的自加热.利用Avrami方程得到TNT在不同介质中的结晶动力学的指数n分别为2.76和2.86.通过Avrami-Ozawa方程获得了两种体系结晶过程的Ozawa指数m以及反映结晶速率快慢的温度函数F(T).同时,用Ozawa方程和Kissinger方程计算了结晶的活化能Ea和指前因子lnA,并与获得的结果进行了比较.     

热红联用研究AP与RDX和HMX混合体系的热分解

用DSC-TG-FTIR(热红)联用研究了RDX/AP,HMX/AP,RDX/HMX和RDX/HMX/AP混合体系的热分解,测定和比较了它们的热分析特征量和分解气相产物.结果表明,AP与RDX和HMX之间存在强烈的相互作用,尤其是与后者的作用更强烈.在AP(不含碳)分解的温度区间,混合体系的分解也出现CO、CO2和CH2O等碳氧化物,说明体系中RDX和HMX分解的部分产物或残渣与AP同时分解.     

RDX和HMX的热分解Ⅲ.分解机理

简述RDX和HMX热分解的各种机理,其热分解的初始过程是N—N和C—N键断裂的竞争反应,试验条件和样品相态等因素影响竞争过程。用DSC—FTIR联用技术和热裂解原位池／FTIR分析了主要分解气相产物和凝聚相中主要官能团的变化。结果表明,RDX和HMX热分解的主要分解气相产物为N2O,CH2O,CO,CO2,H2O和HCN。RDX的分解气相产物CH2O和H2O红外吸收率的温度关系曲线都产生双峰,RDX基团-NNO2的吸收带1589cm^-1和1278cm^-1有两个不同速率的变化过程。用N—N键和C—N键竞争断裂的观点解释了RDX与HMX热分析和产物分析的结果。     

由差热分析计算N级反应的动力学参数

从单一DTA曲线的特征温度,计算得到化学反应的三个动力学参数(反应级数、活化能和指前因子),本方法较yang和Steinberg方法简单。Mg(OH)_2和NaHCO_3的吸热分解、CaC_2O_4·H_2O的脱水吸热反应、CaC_2O_4、KMnO_4、RDX、PETN、HMX和Tetryl的放热分解的计算结果与文献值有较好的符合。     

RDX基可燃材料的热力学性能,非等温反应动力学及安全性研究

用TG和DSC研究了RDX基微孔可燃材料的热行为,用非等温DSC研究了其放热反应动力学,用Kissinger和Ozawa方法计算了可燃材料的动力学参数;基于Kissinger方法,研究了组分间的相容性;采用耐热和吸湿试验进行了微孔可燃材料的耐热性和吸湿性评价.结果表明,可燃材料的分解被看作是两步反应:第一阶段是吸热熔融反应,无质量损失,第二阶段是放热反应,有质量损失;用Kissinger和Ozawa方法得到的活化能相近,可燃材料的活化能均低于纯RDX的分解活化能;黏结剂PMMA、CA与固体填料RDX相容性好,相容性等级为1级;热爆炸临界温度与RDX相近.新型微孔可燃材料的其他性能优于传统可燃材料.     

由差热分析计算N级反应的动力学参数

从单一DTA曲线的特征温度,计算得到化学反应的三个动力学参数(反应级数、活化能和指前因子),本方法较Yang和Steinberg方法简单。Mg(OH)_2和NaHCO_3的吸热分解、CaC_2O_4·H_2O的脱水吸热反应、CaC_2O_4、KMnO_4、RDX、PETN、HMX和Tetryl的放热分解的计算结果与文献值有较好的符合。从DTA测定动力学参数比等温实验测定具有明显的优越性,因此愈来愈引起人们的注意和兴趣。自五十年代Murray和Whire最早提出DTA的动力学分析以来,出现了许多计     

5,5′-偶氮四唑过渡金属含能配合物对RDX和HMX热分解行为的影响

用DSC研究了5种5,5′-偶氮四唑过渡金属配合物MATZ(H2O)n(M=Mn,Ni,Zn,n=6;M=Co,Pb,n=3;ATZ=5,5′-偶氮四唑离子)对RDX和HMX热分解行为的影响。用分解峰温、热爆炸临界温度等特征参数评价了含配合物的二元混合物与纯组分的热分解行为。结果表明,配合物对RDX的影响大于对HMX的。含配合物的二元混合物的热分解行为与纯组分的热分解行为类似,配合物的分解影响了RDX和HMX的热分解特征参数。     

Study of Thermal Reactivity and Kinetics of HMX and Its PBX by Different Methods

Vacuum Stability Test (VST) was used to determine the thermal behavior and kinetic parameters of 1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) and its mixture with hydroxyl-terminated polybutadiene (HTPB) as a binder coded as HMX/HTPB.Model fitting and isoconversional method were applied to determine the kinetic parameters based on VST results.For comparison,non-isothermal thermogravimetry analysis data (TGA) was also used to calculate the kinetic parameters by using Kissinger,OFW (Ozawa,Flynn,and Wall) and KAS (Kissinger-Akahira-Sunose) methods.Advanced Kinetics and Technology Solution (AKTS) software was also used to determine the decomposition kinetics of the studied samples.Differential Scanning Calorimetry (DSC) was employed to determine the decomposition heat flow properties of the studied samples.Results show that the activation energies obtained using VST results is 360.1kJ/ mol for pure HMX and 186.9kJ /mol for HMX/HTPB.The activation energies obtained by the three different methods using TGA results are in the range of 360-368kJ/mol for pure HMX and 190-206kJ/mol for HMX/HTPB.It is concluded that values of kinetic parameters obtained by VST are close to that obtained by the different techniques using TG/DTG results.The onset decomposition peak of HMX/HTPB is lower than that of HMX where the HTPB binder has negative effect on the thermal stability of HMX.The results of all the applied techniques prove that HMX/HTPB has lower activation energy and heat release than the pure HMX.HTPB polymeric matrix has negative effect on the kinetic parameters of HMX.     

A DSC Study on the Effect of RDX and HMX on the Thermal Decomposition of Phase Stabilized Ammonium Nitrate

Phase stabilized ammonium nitrate(PSAN) was prepared by incorporating copper(II) diammine nitrate in the ammonium nitrate(AN) crystal lattice. The effect of two energetic materials viz., RDX and HMX on the thermal decomposition of PSAN was investigated using DSC. The decomposition temperatures of PSAN and RDX are almost in the same temperature range. The decomposition of PSAN is endothermic and that of RDX is exothermic, while that of a 1:1 mixture of the two is exothermic with a net heat release in excess of that of the individual reactions, which is attributed to the combustion reaction among the decomposition products of PSAN and RDX. Though HMX decomposes at a higher temperature, in presence of molten PSAN a substantial portion of it decomposes at a lower temperature along with PSAN with a net excess heat release, again due to the combustion reaction. The kinetic parameters of the two exothermic decompositions were computed using two equations based on variable heating rate method viz., Kissinger and Ozawa equations. The activation energy obtained from Ozawa method was refined by an iteration procedure. There is a close agreement among the values obtained by the three methods. The kinetic parameters for PSAN-HMX mixture are lower, probably due to the effect of its higher heat release.     

热红联用研究AP与RDX和HMX混合体系的热分解

用DSC—TG—FTIR（热红）联用研究了RDX／AP，HMx／AP，RDx／HMx和RDX／HMX／AP混合体系的热分解，测定和比较了它们的热分析特征量和分解气相产物。结果表明，AP与RDX和HMX之间存在强烈的相互作用，尤其是与后者的作用更强烈。在AP（不含碳）分解的温度区间，混合体系的分解也出现CO、CO2和CH2O等碳氧化物，说明体系中RDX和HMX分解的部分产物或残渣与AP同时分解。     

RDX和HMX的热分解III.分解机理

简述RDX和HM X热分解的各种机理,其热分解的初始过程是N-N和C-N键断裂的竞争反应,试验条件和样品相态等因素影响竞争过程。用DSC-FT IR联用技术和热裂解原位池/FT IR分析了主要分解气相产物和凝聚相中主要官能团的变化。结果表明,RDX和HM X热分解的主要分解气相产物为N2O,CH2O,CO,CO2,H2O和HCN。RDX的分解气相产物CH2O和H2O红外吸收率的温度关系曲线都产生双峰,RDX基团-NNO2的吸收带1 589 cm-1和1 278 cm-1有两个不同速率的变化过程。用N-N键和C-N键竞争断裂的观点解释了RDX与HM X热分析和产物分析的结果。     

Kinetic Deuterium Isotope Effects in the combustion of formulated nitramine propellants

The kinetic deuterium isotope effect was used to investigate the rate-limiting process in the combustion of formulated nitramine propellants. Model propellant formulations containing either octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), or their deuteriated analogues were pressed into pellets and burned under nitrogen pressure in a window bomb. The magnitudes of the observed deuterium isotope effects indicate that the HMX and RDX exert significant control over the combustion phenomenon of the propellants studied. Furthermore, assuming a consistent mechanism between decomposition and combustion, the observed isotope effects suggest that a carbon-hydrogen bond rupture in HMX or RDX is the rate-controlling step in the combustion of the model nitramine propellants. Observed isotope effect values for HMX-CW5 and RDX-CW5 formulated propellants at 1000 psig (6.99 MPa) pressure were 1.29 ± 0.09 and 1.24 ± 0.07, respectively, compared to a theoretical estimate of 1.29 for a primary effect due to C H bond rupture at 673 K.     

纳米铝粉对硝胺炸药热分解催化性能的影响

采用直流电弧等离子体蒸发法制备了高纯度的纳米铝粉,并用比表面积分析仪和扫描电子显微镜(SEM)对样品进行了表征.将纳米铝粉与硝胺炸药HMX和RDX用研磨混合法制成混合粒子,用DSC对单质HMX和RDX炸药以及纳米铝粉/硝胺炸药混合物进行催化特性测试,并对样品的热分解动力学和热力学参数进行了计算和对比.结果表明,加入纳米铝粉后,HMX和RDX在不同升温速率(2、5、10、20 K/min)下的放热峰峰温降低,活化能分别降低15和16 kJ/mol,热力学参数都有明显变化.纳米铝粉对HMX和RDX有明显的热分解催化作用.