喷雾干燥前驱体纳米Al悬浮液的制备及分散稳定性

为制备具有良好分散稳定性的喷雾干燥前驱体纳米Al悬浮液,采用机械搅拌和超声分散两种分散方法制备了纳米Al悬浮液,研究了纳米Al粉在主炸药黑索今(RDX)溶液中的分散稳定性。利用紫外可见分光光度计研究了分散速度、分散时间、超声时间、悬浮液质量浓度、分散温度、纳米铝粉的粒径等对悬浮液分散稳定性的影响,采用扫描电子显微镜(SEM)分析了喷雾干燥后样品的形貌。结果表明:选择粒径为50～100 nm的铝粉,当分散速度为400 r·min~(-1),分散时间为30 min,超声时间为3～10 min,悬浮液质量浓度为1%,分散温度为25℃时,悬浮液的吸光度值最大,分散稳定性达到最佳。     

金属氧化物对RDX热分解影响的研究

采用差热分析技术研究了金属氧化物(CuO、CdO、Fe2O3、Cu2O、PbO)对黑索今(RDX)热分解性能的影响。试验结果表明：金属氧化物对RDX的热分解有不同程度的催化作用，当质量分数为1．0%／--2．0％催化效果最明显，催化能力比较结果为氧化亚铜与氧化铜接近，其次分别为三硫化二铁、氧化铅、氧化镉。     

Molecular dynamic simulations on TKX-50/RDX cocrystal

Dihydroxylammonium 5,5′-bistetrazole-1,1′-diolate (TKX-50) is a newly synthesized energetic material with excellent comprehensive properties. Cyclotrimethylenetrinitramine (RDX) is currently one of the most widely used energetic materials in the world. TKX-50 and RDX supercell models and TKX-50/RDX cocrystal model were constructed based on their crystal cell parameters and the formation mechanism of cocrystal, respectively, then they were simulated by molecular dynamics (MD) simulations. The maximum trigger bond (NNO₂) length(L_max), binding energy (E_bind), radial distribution function (RDF), cohesive energy density(CED) and mechanical properties were simulated at different temperatures based on the simulated equilibrium structures of the models. The simulated results indicate that hydrogen bond and van der Waals force interactions exist in the cocrystal system and the hydrogen bonds are mainly derived from the hydrogen atom of TKX-50 with the oxygen or nitrogen atom of RDX. Moreover, TKX-50/RDX cocrystal structure significantly reduces the sensitivity and improves the thermodynamic stability of RDX, and it also shows better mechanical properties than pure TKX-50 and RDX, indicating that it will vastly expand the application scope of the single compound explosives.     

Response surface optimization of the purification process of cyclotrimethylenetrinitramine explosive via digestion in binary solvent mixtures of acetone/water

The present study introduces a new route for the purification of cyclotrimethylenetrinitramine (RDX) explosive containing cyclotetramethylenetetranitramine (HMX) impurity, based on the digestion of crude materials in the binary solvent of acetone/water. Here, first, the solubility data, enthalpy of dissolution and mixing of RDX and HMX were determined experimentally in binary solvent. Then, the effects of various factors on the purification of RDX were studied statistically via response surface methodology (RSM) experimental design. In this technique, unlike the solubility data, unexpectedly HMX was dissolved with higher ratio and solid RDX was obtained with purity >99.5 wt.% and improved crystal morphology.     

Effect of solvent on the crystal morphology of royal demolition explosive

Important crystal faces that dominate the crystal morphology of royal demolition explosive (RDX) in vacuum were analyzed with the attachment energy (AE) method. Molecular dynamics (MD) simulations were used to calculate the interaction energies between these crystal faces and different solvent molecules for an attachment energy correction. Growth habits in the presence of different solvents were generated. The results showed that some crystal faces in solutions became morphologically more important than that in vacuum while others became less important. Thus, crystal shape and surface property changed a lot with the variation of crystal faces. The results from calculation were in agreement with those from the re-crystallization experiment, which indicated that cyclohexanone (CH) was a promising solvent to modify the crystal morphology of RDX for obtaining products with regular shape and high purity, while butyrolactone (BL) played a great role in improving the surface electrostatic property of RDX.     

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。     

硝酸脲与RDX共晶炸药研究

为解决RDX生产过程中废硝酸的再利用问题,采用(a)在分离出RDX后,直接加入一定量尿素水溶液,废硝酸与尿素反应制成硝酸脲,(b)RDX和硝酸脲在稀硝酸中共结晶,生成共晶混合炸药(RDX的质量分数60%～70%).经测试,其爆炸性能优于两者直接混合炸药,爆速可达7 500m/s左右,提高了4%;红外光谱分析结果表明,这种混合炸药是一种具有分子间氢键的共晶体.     

RDX和HMX晶体压制方程的对比研究

分别选取经过不同重结晶工艺处理的RDX和HMX晶体和一种工业级原料颗粒样品进行准静态压制实验，由实验应力／位移曲线获得压制曲线，采用Kawakita和Heckel方程对压制曲线进行拟合。结果表明，拟合所得的常数具有模量倒数量纲，能区分重结晶和原料样品，用作含能晶体品质评价的定量参数。比较两个压制方程的模拟情况，对RDX颗粒两个方程均拟合得很好，而对HMX颗粒存在一定的误差，尤其是Heckel方程误差较大。选取压制过程的形变破碎阶段的数据所得结果其区分度有明显提高，同时两个方程的拟合情况均得到明显改善。对于含能材料颗粒，Kawakita方程更合适。     

From Synthesis to Formulation and Final Application

Meeting the requirements for insensitive munitions remains a complex route, where all the steps of the production process have to be addressed. NTO is a choice component, especially for large munitions. Various compositions have been optimized, which are now available, in pressed or cast PBX as well as melt cast formulations. Standard products such as RDX have been improved by the synthesis or crystallization methods, giving reduced sensitivity formulations. Some cast PBX can sustain severe shaped charge jet impacts, thanks to their large critical diameter, and are candidates as main filling of large munitions such as IM Mk82. The formulation step is addressing not only new binder principles, allowing an increase in the filler and thus energy contents, but also a bi‐component innovative method to get a semi continuous filling process where the pot life is no longer an issue. Finally a partial toolset for designing IM features is proposed with a recent example of successful application.     

Thermal Stability Studies Comparing IMX‐101 (Dinitroanisole/Nitroguanidine/NTO) to Analogous Formulations Containing Dinitrotoluene

The 2,4,6‐trinitrotoluene (TNT) replacement, IMX‐101, containing 43.5 % 2,4‐dinitroanisole (DNAN), 19.7 % 3‐nitro‐1,2,4‐triazol‐5‐one (NTO) and 36.8 % nitro‐guanidine (NQ), has been certified for use as an insensitive munition. IMX‐101 has passed standardized performance, stability, and aging tests but in some categories was not necessarily an improvement over TNT or RDX. This study compared the thermal stability of DNAN and another low‐melting nitroarene, 2,4‐dinitrotoulene (DNT). When examined individually, DNAN was more stable; but formulated in IMX‐101 with NTO and NQ, the opposite was true. In two part mixtures, NQ had a similar acceleratory effect on the decomposition of both nitroarenes, while NTO had a greater impact on DNAN than on NTO. Ammonia, a reported decomposition product of both NQ and NTO, also accelerated the decomposition of both DNAN and DNT, with a larger impact on DNAN. The formation of dinitroaniline, potentially due to the interaction between the nitroarenes and ammonia, was detected by LC/MS as a decomposition product when either nitroarene was combined with NTO and/or NQ, indicating that this molecule may play a significant role in the decomposition mechanism. While not advocating the use of DNT in insensitive munitions formulations, this study addresses the importance of chemical compatibility as a criterion for selecting replacement components in formulations.