Reaction mechanism of aluminum nanoparticles in explosives under high temperature and high pressure by shock loading.

Aluminum nanoparticles (ANPs) can greatly improve the power of explosives. However, the rapid reaction mechanism of ANPs under simultaneous high temperature and high pressure by shock loading is not fully understood. In this study, a detonation wave was generated by impact of an explosive supercell on the reflect wall, and the reflected wave was eliminated by changing the end-boundary velocity.

Mechanism of the improvement of the energy of host-guest explosives by incorporation of small guest molecules: HNO and HO promoted C-N bond cleavage of the ring of ICM-102.

Host-guest materials exhibit great potential applications as an insensitive high-energy-density explosive and low characteristic signal solid propellant. To investigate the mechanism of the improvement of the energy of host-guest explosives by guest molecules, ReaxFF-lg reactive molecular dynamics simulations were performed to calculate the thermal decomposition reactions of the host-guest explosives systems ICM-102/HNO, ICM-102/HO, and pure ICM-102 under different constant high temperatures and different heating rates. Incorporation of guest molecules significantly increased the energy level of the host-guest system.

A quantum-based molecular dynamics study of the ICM-102/HNO host-guest reaction at high temperatures.

The contradiction between energy and safety of explosives is better balanced by the host-guest inclusion strategy. Understanding the reaction mechanism of the host-guest explosive is necessary. To deeply analyze the role of the small guest molecules in the host-guest system, a quantum-based molecular dynamics method was used to calculate the initial decomposition reaction of the new host-guest explosive ICM-102/HNO3 against the pure ICM-102 at several high temperatures.

Chemical reactions of a CL-20 crystal under heat and shock determined by ReaxFF reactive molecular dynamics simulations.

Studying the chemical reactions of hexanitrohexaazaisowurtzitane (CL-20) under heat and shock is helpful to understand its sensitivity and shock initiation mechanism. In this work, several molecular dynamics simulations were performed under three different conditions: high temperature, high temperature and pressure, and shock. The formation and breakage of chemical bonds, changes of bond lengths, and initial reactions were analysed.

Thermal stability mechanism via energy absorption by chemical bonds bending and stretching in free space and the interlayer reaction of layered molecular structure explosives.

Layered molecular structure explosives have the characteristic of great thermal stability. Understanding the mechanism of thermal stability and the reactions of layered molecular structure explosives can provide new ideas for the design of thermally stable explosives. In a molecular dynamics simulation of thermal decomposition of the layered molecular structure explosive 2,4,6-triamino-5-nitropyrimidine-1,3-dioxide, we find that the layered molecular structure provides free space for chemical bond deflection and expansion so that the external energy absorbed by chemical bonds on nonbenzene rings can be converted into angle bending energy and bond-stretching energy, which makes chemical bonds difficult to break and increases the thermal stability of the explosives.

Decomposition and Energy-Enhancement Mechanism of the Energetic Binder Glycidyl Azide Polymer at Explosive Detonation Temperatures.

Replacing existing inert binders with energetic ones in composite explosives is a novel way to improve the explosive performance, on the proviso that energetic binders are capable of releasing chemical energy rapidly in the detonation environment. Known to be a promising candidate, the reaction mechanism of glycidyl azide polymer (GAP) at typical detonation temperatures higher than 3000 K has been theoretically studied in this work at the atomistic level. By analyzing and tracking the cleavage of characteristic chemical bonds, it was found that at the detonation temperature, GAP was able to release a large amount of energy and small molecule products at a speed comparable to commonly used explosives in the early reaction stage, which was mainly attributed to the decomposition of azide groups into N and the main chain breakage into small fragments.

Polymerization Effects on the Decomposition of a Pyrazolo-Triazine at high Temperatures and Pressures.

4-amino-3-aminopyrazole-8-trinitropyrazolo-[5, 1-c] [1, 2, 4]triazine (PTX, CHNO) has good detonation performance, thermal stability and low mechanical sensitivity, which endow it with good development prospects in insensitive ammunition applications. To study the effects of polymerization on the decomposition of PTX, the reaction processes of PTX at different conditions were simulated by quantum chemistry and molecular dynamics methods. In this paper, the effects of polymerization on the decomposition of PTX were studied in terms of species information, reaction path of PTX, bond formation and bond cleavage, evolution of small molecules and clusters, and kinetic parameters at different stages.

Effect of density on the thermal decomposition mechanism of ε-CL-20: a ReaxFF reactive molecular dynamics simulation study.

The explosive detonation reaction occurs when explosives are compressed by different shock strengths, and the degree of compression affects the chemical reaction of the detonation process. The thermal decomposition mechanism of explosives under different compression densities has thus attracted significant research interest, and a better understanding of this mechanism would be helpful for determining the mechanism of the detonation reaction of explosives. In this study, a ε-CL-20 supercell was constructed, and the thermal decomposition was calculated at different compression densities and temperatures using molecular dynamics simulations based on the ReaxFF-lg reactive force field.

Reactive Molecular Dynamics Simulations of the Thermal Decomposition Mechanism of 1,3,3-Trinitroazetidine.

1,3,3-Trinitroazetidine (TNAZ) has a molecular formula of C H N O and the characteristics of low melting point, low impact sensitivity and good thermal stability. It is suitable for melt casting and pressed charges, and it has broad prospects for applications in low-sensitivity ammunition. In this study, the thermal decomposition of TNAZ crystals at high temperature was calculated by molecular dynamics simulation with the ReaxFF/lg reactive force field.

Thermal Decomposition Mechanism of CL-20 at Different Temperatures by ReaxFF Reactive Molecular Dynamics Simulations.

Hexanitrohexaazaisowurtzitane (CL-20) has a high detonation velocity and pressure, but its sensitivity is also high, which somewhat limits its applications. Therefore, it is important to understand the mechanism and characteristics of thermal decomposition of CL-20. In this study, a ε-CL-20 supercell was constructed and ReaxFF-lg reactive molecular dynamics simulations were performed to investigate thermal decomposition of ε-CL-20 at various temperatures (2000, 2500, 2750, 3000, 3250, and 3500 K).