Study of Plastic Explosives based on Attractive Cyclic Nitramines Part I. Detonation Characteristics of Explosives with PIB Binder

Four plastic explosives based on energetic nitramines and a non‐energetic binder were prepared and studied. The nitramines were RDX (1,3,5‐trinitro‐1,3,5‐triazine), HMX (1,3,5,7‐tetranitro‐1,3,5,7‐tetrazine), BCHMX (cis‐1,3,4,6‐tetranitro‐octahydroimidazo‐[4,5‐d]imidazole) and HNIW (ε‐2,4,6,8,10,12‐hexanitro‐2,4,6,8,10,12‐hexaazaisowurtzitane, ε‐CL‐20). The binder was in all cases polyisobutylene (PIB) as in the standard composition C‐4. These powerful plastic explosives were compared to standard PETN‐based commercially available explosives Semtex 1A and Sprängdeg m/46. The detonation velocities were experimentally measured and compared to the ones calculated by the Kamlet–Jacobs method, CHEETAH and EXPLO5 Codes. The experimental detonation velocities as well as the calculated detonation parameters decrease in the following order: HNIW‐PIB>HMX‐PIB≥BCHMX‐PIB>RDX‐PIB>Sprändeg m/46≥Semtex 1A. Urizar coefficients for the various binders were calculated from experimental data.     

Investigation on the Thermal Expansion and Theoretical Density of 1,3,5‐Trinitro‐1,3,5‐Triazacyclohexane

The CTE and the theoretical density are important properties for energetic materials. To obtain the CTE and the theoretical density of 1,3,5‐trinitro‐1,3,5‐triazacyclohexane (RDX), XRD, and Rietveld refinement are employed to estimate the dimensional changes, within the temperature range from 30 to 170 °C. The CTE of a, b, c axis and volume are obtained as 3.07×10⁻⁵ K⁻¹, 8.28×10⁻⁵ K⁻¹, 9.19×10⁻⁵ K⁻¹, and 20.7×10⁻⁵ K⁻¹, respectively. Calculated from the refined cell parameters, the theoretical density at the given temperature can be obtained. The theoretical density at 20 °C (1.7994 g cm⁻³) is in close match with the RDX single‐crystal density (1.7990 g cm⁻³) measured by density gradient method. It is suggested that the CTE measured by XRD could perfectly meet with the thermal expansion of RDX.     

Quantum Chemical Study on the Interactions of NO3 with RDX and Four Decomposition Intermediates

Recently, NO₃ (nitrate radical) was predicted to be formed during the decomposition of RDX. However, experimental studies of the gaseous products have never detected it. In order to verify the prediction, we studied the interactions of NO₃ with RDX and four RDX decomposition intermediates (RDR, C₃H₅N₅O₄, OST, and TAZ) by using density functional theory (DFT). It is found that NO₃ radical can be converted into NO₂ during the process of interactions with the above‐mentioned five molecules. In other words, NO₃ radical can be consumed in these processes, which gives an explanation for the disappearance of NO₃. Transition state theory (TST) calculations lead to the same results. The binding energies are calculated to estimate the strength of interactions. The energy of NO₃ with RDR is the largest, which indicates this process is most likely to occur. Our calculation provides a support to the prediction of the formation of NO₃.     

超临界水氧化法处理黑索今废水实验研究

用超临界水氧化法对黑索今废水进行了实验研究,考察了反应温度、时间和压力等影响因素。实验结果表明:在氧气过量的条件下,温度是超临界水氧化黑索今废水的主要影响因素,其次是反应压力和反应时间;当反应温度600℃,反应压力28MPa,反应时间大于120s,在此工艺条件下,废水的CODCr去除率高达99.8%。     

脉冲柱塞粉碎法制备超细RDX炸药

采用脉冲柱塞粉碎机制备了超细RDX炸药,并研究了物料水介质的配比、脉冲压力、循环次数对RDX粒径的影响.结果表明,水介质量、脉冲压力越大,得到的RDX粒经越小.在RDX与水质量比为15、脉冲压力为120 MPa条件下,RDX粒径可达到4.020 μm.适当增加循环次数,RDX粒径有少许降低.     

Biodegradation of 2,4,6-trinitrotoluene and hexahydro-1,3,5-trinitro-1,3,5-triazine by Actinomycetes species,first time isolated and characterized from water,wastewater, and sludge

Biodegradation has been applied to remediate explosives contaminants, and bacteria have a high potential for the degradation of explosives, such as hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and 2,4,6-trinitrotoluene (TNT). The present study aims to screen and characterize explosive biodegradable Actinomycetes from water, wastewater, and sludge. Actinomycetes isolates were recovered from 80 environmental samples from diverse environmental resources in explosive contaminated areas of Iran and identified to the genus and species levels using conventional and molecular methods. The growth rate in the presence of pollutants and chromatography was used to determine their biodegradation capability. Twenty-nine isolates (36.25%) of Actinomycetes were characterized from the cultured samples that belonged to 6 genus and 24 validated species. The most prevalent Actinomycetes isolated were genus Mycobacterium with 11 isolates (37.94%), genus Rhodococcus with seven isolates (24.13%), genus Nocardia with four isolates (13.8%), and genus Streptomyces with three isolates (10.33%). Moreover, our results showed that these isolates could degrade and consume 50–80% of RDX and TNT as their sole carbon and energy source. In conclusion, we showed that Actinomycetes from explosive-contaminated areas of Iran could degrade TNT and RDX. Hence, seeking and screening untapped ecosystems that possess unexplored Actinomycetes will increase the chances of discovering the resident microorganism that has been capable of degrading TNT and RDX for application in the bioremediation process. The results of this study can be useful in using intact bacteria in nature to eliminate environmental pollution, which is one of the major environmental problems in the world.     

The Decomposition of some RDX and HMX Based Materials in the One Dimensional Time to Explosion Apparatus. Part 2. Estimating the Violence of the Cook‐Off Event

Various methods of assessment have been applied to the One Dimensional Time to Explosion (ODTX) apparatus and experiments with the aim of allowing an estimate of the comparative violence of the explosion event to be made. Non‐mechanical methods used were a simple visual inspection, measuring the increase in the void volume of the anvils following an explosion and measuring the velocity of the sound produced by the explosion over 1 metre. Mechanical methods used included monitoring piezo‐electric devices inserted in the frame of the machine and measuring the rotational velocity of a rotating bar placed on the top of the anvils after it had been displaced by the shock wave. This last method, which resembles original Hopkinson Bar experiments, seemed the easiest to apply and analyse, giving relative rankings of violence and the possibility of the calculation of a “detonation” pressure.