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In this work, we studied the influence of the ratio of NTO and HMX on the thermal decomposition performance of the series of cast PBXs. DSC was used to study the nonisothermal thermal decomposition performance of different PBXs, and ARC was used to study the adiabatic thermal decomposition. Both DSC and ARC results show that among the five different PBXs, N30 is the cast PBX with the best thermal stability.

In this paper, the effect and action low of thermite on the explosion performance of HMX-based thermobaric explosive were studied. A series of near-ground explosion were tested for the explosives containing Fe 2 O 3 and CuO. The results showed that thermobaric explosive containing thermite had a significant thermal effect, the peak temper ature was about 15% higher than that of TNT, and the distribution of the fireball morphology and temperature was asymmetrical. Compared with CuO, Fe 2 O 3 could significantly increase incident wave ’s peak overpressure and duration of barotropic action, and Fe 2 O 3 had greater advantages than CuO in promoting thermite reaction to increase fireball temperature and duration of thermal effect. The results provide reference and guidance for the formulation design of thermobaric explosive.

In order to study the initiation technology of laser ignition driven flyer, the initiation principle of laser ignition driven flyer is analyzed. The velocity simulation design of laser ignition driven flyer and the velocity simulation of different flyers driven by the same charge are carried out with Autodyn, and the initiation verification test of laser ignition driven flyer is carried out. The test results show that RDX can be initiated by impact, and the effect consistency is good, Therefore, using HMX to drive the flyer to impact and detonate RDX has high reliability.

The design and synthesis of novel energetic compounds with integrated properties of high density, high energy, good thermal stability and sensitivities is particularly challenging due to the inherent contradiction between energy and safety for energetic compounds. In this study, a novel structure of 4-amino-7,8-dinitropyrazolo-[5,1- d ] [1,2,3,5]-tetrazine 2-oxide (BITE-101) is designed and synthesized in three steps. With the help of the complementary advantages of different explosophoric groups and diverse weak interactions, BITE-101 is superior to the benchmark explosive HMX in all respects, including higher density of 1.957 g·cm −3 , highest decomposition temperature of 295 °C (onset) among CHON-based high explosives to date and superior detonation velocity and pressure ( D : 9314 m·s −1 , P : 39.3 GPa), impact and friction sensitivities ( IS : 18 J, FS : 128 N), thereby showing great potential for practical application as replacement for HMX, the most powerful military explosive in current use. The design of high energy density materials (HEDM) with good detonation performance but which are also safe to handle is challenging. Here, the authors synthesize a PTX analogue and incorporate explosophoric groups to obtain an HEDM with improved detonation performance but low impact and friction sensitivity.

The interfacial interaction between HMX molecules and coating materials is the key to the safety performance of explosives and has received extensive attention. However, screening suitable coating agents to enhance the interfacial effect to obtain high-energy and low-sensitivity explosives has long been a major challenge. In this work, HMX-PEI/rGO/g-C3N4 (HPrGC) composites were innovatively prepared by a multi-level coating strategy of two-dimensional graphite rGO and g-C3N4. The g-C3N4 used for desensitization has a rich π-conjugated system and shows outstanding ability in reducing friction sensitivity. The hierarchical structure of HPrGC formed by electrostatic self-assembly and π-π stacking can effectively dissipate energy accumulation under heat and mechanical stimulation through structural evolution, thus exhibiting a prominent synergistic desensitization effect on HMX. The results show that rGO/g-C3N4 coating has no effect on the crystal structure and chemical structure of HMX. More importantly, the perfect combination of g-C3N4 and rGO endows HPrGC with enhanced thermal stability and ideal mechanical sensitivity (IS: 21 J, FS: 216 N). Obviously, the new fabrication of HPrGC enriches the variety of desensitizer materials and helps to deepen the understanding of the interaction between explosives and coatings. The graphite phase carbon nitride (g-C3N4) was innovatively exploited as a new coating material, and the HMX-PEI/rGO/g-C3N4 (HPrGC) composite was designed by combining with reduced graphene oxide (rGO) using multi-stage coating strategy. “Soft” materials play an important role in energy accumulation on the surface of HMX by electrostatic self-assembly and π-π stacking, which endows HPrGC with considerable thermal stability and mechanical sensitivity. [Display omitted] •g-C3N4 was innovatively exploited as a new coating material in reducing the mechanical sensitivity of explosives.•High performance composite HMX-PEI/rGO/g-C3N4 (HPrGC) was constructed by a multi-step coating strategy.•The synergistic desensitization of rGO and g-C3N4 endows HMX with outstanding thermal stability and mechanical sensitivity.•The design concept is environmental-friendly and suitable for practical applications.

Fused deposition modeling (FDM) as one of the additive manufacturing (AM) technologies has been widely used in various manufacturing industries to fabricate products with complex structures; however, the application of FDM in energetic materials (EMs) was still less common. In this work, the effect of HMX solid content and particle size on the viscosity of molten TNT/HMX explosives were investigated. Then, the computational fluid dynamics (CFD) and discrete element method (DEM) were used to simulate the influence of viscosity, pressure, temperature, nozzle diameter, and particles on the fluid flow inside the 3D printer nozzle. In addition, an FDM 3D printer was used to prepare TNT/HMX-based explosives, and various characterization methods were applied to explore the structure and morphology of printed samples. This work provided guidelines for FDM technology to fabricate EMs and proved that FDM was more suitable than the conventional melt-casting method to prepare explosives with high viscosity and special-shaped structures.

Traditional selection of combustion catalysis is time-consuming and labor-intensive. Theoretical calculation is expected to resolve this problem. The adsorption energy of HMX and O atoms on 13 metal oxides was calculated using DMol3, since HMX and O are key substances in decomposition process. And the relationship between the adsorption energy of HMX, O on metal oxides (TiO2, Al2O3, PbO, CuO, Fe2O3, Co3O4, Bi2O3, NiO) and experimental T30 values (time required for the decomposition depth of HMX to reach 30%) was depicted as volcano plot. Thus, the T30 values of other metal oxides was predicted based on their adsorption energy on volcano plot and validated by previous experimental data. Further, the adsorption energy of HMX on ZrO2 and MnO2 was predicted based on the linear relationship between surface energy and adsorption energy, and T30 values were estimated based on volcano plot. The apparent activation energy data of HMX/MgO, HMX/SnO2, HMX/ZrO2, and HMX/MnO2 obtained from DSC experiments are basically consistent with our predicted T30 values, indicating that it is feasible to predict the catalytic activity based on the adsorption calculation, and it is expected that these simple structural properties can predict adsorption energy to reduce the large quantities of computation and experiment cost. [Display omitted]

The cocrystallization of 1,3,5,7-tetranitro-1,3,5,7-tetrazolidine (HMX) with cyclopentanone was achieved via a controlled cooling method, followed by comprehensive characterization that confirmed the α-configuration of HMX within the cocrystal. The enthalpy of dissolution of HMX in cyclopentanone was assessed across a range of temperatures using a C-80 Calvert microcalorimeter, revealing an endothermic dissolution process. Subsequently, the molar enthalpy of dissolution was determined, and kinetic equations describing the dissolution rate were derived for temperatures of 303.15, 308.15, 313.15, 318.15, and 323.15 K as follows: dα⁄dt = 10−2.46(1 − α)0.35, dα⁄dt = 10−2.19(1 − α)0.79, dα⁄dt = 10−1.76(1 − α)1.32, dα⁄dt = 10−1.86(1 − α)0.46, and dα⁄dt = 10−2.02(1 − α)0.70, respectively. Additionally, molecular dynamics (MD) simulations investigated the intermolecular interactions of the HMX/cyclopentanone cocrystallization process, demonstrating a transformation of HMX from β- to α-conformation within the cyclopentanone environment. Theoretical calculations performed at the ωB97XD/6-311G(d,p) level affirmed that α-HMX exhibited stronger binding affinity toward cyclopentanone compared to β-HMX, corroborating experimental findings. A comprehensive understanding of the dissolution behavior of HMX in cyclopentanone holds significant implications for crystal growth methodologies and cocrystallization processes. Such insights are pivotal for optimizing HMX dissolution processes and offer valuable perspectives for developing and designing advanced energetic materials.

To explore the effects of adulteration crystal defect on performances of hexanitrohexaazaisowurtzitane/octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (CL-20/HMX) cocrystal explosive, the CL-20/HMX cocrystal model was established based on its lattice parameters. Besides, defective CL-20/HMX cocrystal models with adulteration ratios of 1.85%, 3.70%, 5.56%, 7.41%, and 9.26% were also established, respectively. Molecular dynamics (MD) method was selected to optimize the crystal structure and predict performances of each model. The correlated energies and parameters, including binding energy, trigger bond rupture energy, cohesive energy density (CED), and detonation parameters were calculated and compared. Results show that binding energy in defective CL-20/HMX models is decreased by 12.02–307.05 kJ/mol, implying that the intermolecular interaction energy between CL-20 and HMX molecules is decreased and stability is weakened. Adulteration crystal defect makes the trigger bond rupture energy and CED decreased by 1.06–22.04 kJ/mol and 0.003–0.122 kJ/cm 3 respectively, indicating that the sensitivity of defective models is increased and safety is worsened. The crystal density of defective cocrystal models is decreased by 0.005–0.142 g/cm 3 , detonation velocity is decreased by 53–508 m/s, and detonation pressure is decreased by 0.52–5.09 GPa, meaning that defective cocrystal models have lower energy density than that of primitive model. Hence, adulteration crystal defect will bring passive influence on stability, safety and energetic performance of CL-20/HMX cocrystal explosive.

Modifying the surface properties of energetic materials with coating has theoretical and practical significance in the field of their application. Wax, in its role as a functional lubrication layer, has extensive utility in mitigating the sensitivity of explosives to external stimuli. This study aims to investigate the friction behavior and temperature rise of β-octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (β-cyclotetramethylenetetranitramine, or β-HMX) crystals with and without the wax coating, and the friction coefficient, frictional temperature rise, and frictional work-heat conversion rate were systematically analyzed. The experimental results show that regardless of single and reciprocating scratch conditions, the wax coating significantly reduced the coefficient of friction of the β-HMX surface by up to 63% and effectively suppressed the temperature rise during friction by up to 83%. Further analyses reveal that under single scratch conditions, the frictional work-heat conversion rate of the pristine β-HMX surface is approximately 42%, whereas that of the wax-coated surface increases to about 30% with the frictional power density, which involves the contact pressure, sliding speed, and friction coefficient. In contrast, under reciprocating scratch conditions, the frictional work-heat conversion rate of the uncoated β-HMX surface decreases with increasing number of sliding cycles, which is related to the increase in surface temperature and potential surface damage. The frictional work-heat conversion rate of wax-coated surfaces increases with increasing number of sliding cycles until the contact pressure is high enough that the lubricating effect of the wax layer diminish and the conversion rate begin to decrease. The obtained results not only pave the way for understanding the friction energy regulation and desensitization mechanism of wax on the surface of energetic crystals at the micro and quantitative levels but also provide a necessary basis for establishing friction hotspot models under dry friction and wax lubrication conditions from the aspects of friction characteristic parameters, frictional temperature rise, and the work-heat conversion rate.