Research on the Size of Defects inside RDX/HMX Crystal and Shock Sensitivity

Intragranular defects inside RDX/HMX were studied by optical microscopy with matching refractive (OMS), sink‐float method (SFM), and micro‐focus CT (μCT) techniques. OMS results revealed the phenomenon that RDX/HMX had more defects and cracks than RS‐RDX/RS‐HMX. μCT results indicated that RDX/HMX had more defects with larger volume than RS‐RDX/RS‐HMX. The gap test showed that critical shock pressure/gap thickness was 6.4 GPa/19.4 mm for PBX based on RDX, while they were 7.5 GPa/17.5 mm and 8.6 GPa/16.2 mm for PBX based on M‐RDX and RS‐RDX, respectively. Meanwhile, an analysis of the relationship between defects inside RDX/HMX crystal and shock sensitivity was made. Finally, the shock pressure response under impact loading was investigated by discrete element method.     

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。     

Effect of Al/O Ratio on the Detonation Performance and Underwater Explosion of HMX‐based Aluminized Explosives

The performance of detonation and underwater explosion (UNDEX) of a six‐formula HMX‐based aluminized explosive was examined by detonation and UNDEX experiments. The detonation pressures, detonation velocities, and detonation heat of HMX‐based aluminized explosive were measured. The reliability between the experimental results and those calculated by an empirical formula and the KHT code was verfied. UNDEX experiments were carried out on the propagation of a shock wave and a bubble pulse of a 1 kg cylindrical HMX‐based aluminized explosive underwater at a depth of 4.7 m. Based on the experimental results of the shock wave, the coefficients of similarity law equation for the peak pressure and attenuation time constant of shock wave were in acceptable agreement. The bubble motion during UNDEX was simulated using MSC.DYTRAN software, and the radius time curves of bubbles were determined. The effect of the aluminum/oxygen ratio on the performance of the detonation and UNDEX for an HMX‐based aluminized explosive was discussed.     

一维热爆炸试验传热的数值模拟

针对加热过程所涉及的主要传热学问题,分别建立空气夹层复合传热模型和炸药受热分解放热数值模型;计算分析了473K下油浴和空气浴加热时系统辐射率、空气对流换热系数对RDX、HMX、TATB 3种炸药热点火延滞时间的影响。结果表明,473K油浴加热和空气浴加热时RDX分别在151.7s和3 372.6s时发生热点火,表明相同温度和炸药,油浴加热时热点火延滞时间远小于空气浴加热;空气浴加热时,同一种炸药在相同温度下,随系统辐射率的降低,热点火延滞时间增加;RDX、HMX和TATB炸药辐射率由0.9降至0.1时,热点火延滞时间分别增加了180.1%、168.9%和169.3%;相同温度、相同系统辐射率条件下,对流换热系数减小,热点火延滞时间增加。     

Delay Mechanism of β→δ Phase Transition of Cyclotetramethylene Tetranitramine in Polymer Bonded Explosive Formulations by Heat Conduction Obstacle

The β→δ phase transition (PT) of cyclotetramethylene tetranitramine (HMX) plays an important role in the safety of explosives when they are exposed to heat. In this work the effect of HMX content on the PT of HMX in Polymer Bonded Explosive (PBX) is reported. Using in situ X‐ray diffraction (XRD) test combined with quantitative analysis, the dependence of the PT temperature and dynamic behavior of HMX in PBX formulations [HMX+triaminotrinitrobenzene (TATB)+Olefin] on the content of HMX is investigated. The results show that the β→δ PT temperature gradually increases with the reduction of HMX content and with the increase of TATB content. Additives of TATB and olefin in high concentration can form compact coatings on the HMX crystals. Such coatings can delay the nucleations of δ‐HMX by inhibiting the volumetric expansion during PT. Moreever, these coatings separate the HMX crystals and build up a heat conduction obstacle. As a result the growths of δ‐HMX are also suppressed by the coatings. In contrast, fewer additives lead to larger free surface area of HMX, which accelerates the PT.     

Reaction Thresholds in Unconfined and Confined Charges by Shock Load

The threshold values were determined of putty type of high explosives, as C4 and uncured KS34 (HMX/polybutadiene 82/18), in unconfined and confined gap test arrangements. As expected, the initiation threshold is less in confined charges compared to unconfined charges.     

Effect of Crystal Quality and Particle Size of HMX on the Creep Resistance for TATB/HMX Composites

Two kinds of reduced sensitivity high explosive 1,3,5,7‐tetranitro‐1,3,5,7‐tetrazocane (RS‐HMX) with different particle sizes were selected to enhance the energy output and the mechanical properties of insensitive high explosive 1,3,5‐triamino‐2,4,6‐trinitrobenzene (TATB). Mechanical sensitivities, dynamic mechanical analysis, and non‐linear time dependent creep behaviors of TATB/HMX composites were investigated and discussed in relation to the structural characteristics. Compared with TATB/conventional HMX (C‐HMX) sample, both the impact and friction sensitivities of TATB/RS‐HMX were reduced. It revealed that TATB/fine grains RS‐HMX composites had the highest storage modulus and minimum steady‐state creep strain rate due to the increased coherence strength and the inhibited slide of the single layer of TATB crystal. The creep resistance also showed clear dependence on the particle size of RS‐HMX. The overall results indicated that RS‐HMX had good potential in high energetic, safe, and load‐bearing material applications.     

Laser‐Induced Deflagration of Unconfined HMX – The Effect of Energetic Binders

The effect of three energetic binders [poly(3‐methyl‐3‐nitratomethyloxetane (polyNIMMO), polyglycidyl nitrate (polyGLYN) and an energetic polyphosphazene (PPZ‐E) – all at 10%] on the unconfined laser‐induced deflagration of cyclotetramethylene tetranitramine, commonly known as High Melting point Explosive (HMX) by a near IR (NIR) diode laser (801 nm) has been examined. Hydroxyl terminated polybutadiene (HTPB) and PPZ (the precursor to PPZ‐E – before nitration) were used as reference materials. The formulations required the addition of an optical sensitizer – carbon black (CB) – for ignition. At the designated threshold flux density of 2.3 kW cm⁻², a minimum of ∼1 wt.‐% CB was needed for the reliable ignition of unbound HMX and its formulations with polyGLYN, PPZ‐E and PPZ. Under similar conditions HMX/polyNIMMO and HMX/HTPB required 3% CB. Ignition maps (ignition time versus laser flux density) have been constructed for the five formulations. Comparison of ignition times and ignition energy densities for HMX and HMX/polyGLYN showed this binder to have only a marginal effect. In contrast, HTPB, PPZ and PPZ‐E all retarded HMX ignition at the threshold flux density, but showed negligible effect at higher flux densities. As PPZ and PPZ‐E produced both similar delays in the ignition time and similar increases in the flame development times (10–90%) at the threshold flux density, the inhibition of the HMX ignition by these PPZs appears to be largely independent of the polymer energy content. Such characteristics could be useful for high performance and insensitive energetic formulations. PolyNIMMO (3% CB) increased the ignition time of HMX only slightly at 2.3 kW cm⁻². However, at this threshold flux level the HMX flame development times with polyNIMMO or HTPB were much longer than that for the unbound material; this effect is attributed to the enhanced CB content.     

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。     

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。     

Burning Rate Augmentation of BAMO Based Propellants

Thermal decomposition and the burning properties of BAMO based propellants with HMX or AN/HMX have been investigated. The heat generated by the azide binder decomposition initiated and accelerated the thermal decomposition of HMX and AN. Ammonium perchlorate (AP) and lead stearate with carbon black significantly altered the mechanisms of the thermal decomposition and the burning properties of the HMX based propellants. AP showed an increase in burning rate with a slight decrease in burning rate pressure exponent. The lead catalyst yielded high value of the burning rate with the lowest pressure exponent. The ammonium dichromate also influenced the mechanisms of the thermal decomposition and the burning properties of the AN/HMX samples. The combination of ammonium dichromate and copper chromite was the most effective on the burning rate augmentation of AN/HMX based propellants. AN sublimed and evaporated from the condensed phase and mainly reacted exothermically in the gas phase HMX and AN/HMX based propellants showed smokeless burning characteristics in the small rocket motor combustion tests.     

HMX/ANPZO共晶炸药的制备及表征

运用分子动力学方法,计算了1,3,5,7-四硝基-1,3,5,7-四氮环杂辛烷(HMX)分子、2,6-二氨基-3,5-二硝基-吡嗪-1-氧(ANPZO)分子以及HMX/ANPZO共晶分子的分子间作用力、结合能和内聚能密度。通过气相扩散法制备了HMX/ANPZO共晶炸药,用红外光谱(IR)、差示扫描量热(DSC)和X射线衍射(XRD)表征了其结构,并测试了其机械感度。结果表明,HMX/ANPZO共晶分子间的相互作用力大于HMX分子间以及ANPZO分子间的相互作用力。与HMX和ANPZO相比,HMX/ANPZO共晶炸药的晶体结构和热分解特性变化较大,特性落高为59cm,与HMX相比提高了96.7%;理论爆速达9 060m/s。     

RDX and HMX with Reduced Sensitivity Towards Shock Initiation–RS‐RDX and RS‐HMX

Reduced Sensitivity RDX (RS‐RDX) has received a lot of attention and interest from the explosive community in the recent years. There are several producers of RS‐RDX, most of them using a direct nitration (Woolwich process) for the RDX synthesis, while Chemring Nobel uses the Bachmann process. The processes for obtaining the RS properties probably differ between the various producers. Chemring Nobel has also developed an HMX quality that shows Reduced Sensitivity (RS‐HMX) of different particle size distributions. The shock sensitivity is at the same level as for RS‐RDX in comparable compositions. Reduced shock sensitivity has been obtained for RS‐RDX and Reduced Sensitivity (RS‐HMX) in both pressable and cast‐cured compositions. By using a pressable composition, it is possible to get the results from a BICT gap test faster than from a cast‐cured composition that has to go through a curing process. Chemring Nobel in cooperation with FFI have performed an extensive accelerated ageing testing of RS‐RDX produced by the Bachmann process. The samples have been aged at 60 and 70 °C and the shock sensitivity tested by two different gap tests. The results demonstrate that the Chemring Nobel RS‐RDX retain the insensitivity towards shock during ageing and show no degradation at all. Accelerated ageing testing of RS‐HMX has also been performed and shows no degradation in the shock sensitivity.     

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。     

New adducts of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX)

A new series of relatively stable adducts of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) with derivatives of pyridine-N-oxide were prepared. In addition, relative stable new adducts of HMX were prepared with 5-membered, 6-membered, and condensed-ring heterocyclic compounds. Most of the adduct-forming compounds (AFC's) contain an oxygen and/or nitrogen heteroatom, while several contain a sulfur heteroatom. Most of the adducts are equimolar with HMX; however, several contain 2 moles of AFC per mole of HMX and other ratios of AFC:HMX. Some properties of the new adducts are presented.     

CPB改性沸石处理奥克托今废水的研究

奥克托今废水含有多种毒性物质,如果不经处理直接排放,会危害人类健康。为了处理奥克托今废水,研究了CPB改性沸石的用量、pH值、反应时间、反应温度对CPB改性沸石处理奥克托今废水效果的影响。结果表明:CPB改性沸石对奥克托今废水有较好的处理效果,在反应温度为30℃,pH为7,奥克托今废水初始浓度为160mg/L,CPB改性沸石的用量为2.4g,反应时间为120min,奥克托今去除率达到92.9%,CODcr去除率为78.6%。     

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.     

LX-04炸药大隔板试验的数值模拟

为研究不同条件下LX--04（HMX／氟橡胶／85／15）大隔板试验（LSGT）的冲击波感度G。,运用ANSYS／LS．DYNA对整个爆炸冲击波传爆过程进行了数值模拟,观察了LSGT中爆轰冲击波的传播过程,分别讨论了主发炸药PE4、TNT、B炸药产生的爆轰波经过有机玻璃隔板、铝隔板、钢隔板衰减后的冲击波压力变化情况,最终找出了3种不同主发炸药和3种隔板下LX-04冲击波感度G50。同时,定性地分析了3种隔板对爆炸冲击波的衰减系数。其中,铝隔板的衰减系数最大,有机玻璃隔板的衰减系数最小。     

超临界流体反溶剂法制备超细HMX传爆药

为了克服超细炸药在常规包覆过程中易团聚的缺点,采用超临界流体反溶剂法( SAS)制备了以亚微米HMX为主体炸药的超细传爆药,探讨了工艺条件对亚微米HMX包覆效果的影响.结果表明,影响亚微米HMX包覆效果的主要因素有初始浓度、系统温度、系统压力、平均压力升高速率和平均压力下降速率.在加入20 mL的乙酸乙酯、系统压力9....     

Stationary phases. Part 39(1): Trace analysis of RDX in HMX on a novel copoly(vinylthiazole-vinylimidazole) stationary phase by HPLC

A method for the HPLC analysis of RDX and HMX on a novel copoly(vinylthiazole-vinylimidazole) stationary phase [P(Th-Im) phase] is described. Special elution order of RDX and HMX on this phase using methanol/water (60/40∼90/10) as mobile phase is HMX > RDX, which is quite different from those on a commercial RP-18 phase. The chromatographic selectivities (α-values) between RDX and HMX are 2.40∼2.55. This advantage can be used to identify the limited impurity of ca. 1 ppm RDX in HMX during the manufacture of HMX.