Electron Properties and Thermal Decomposition Behaviors for HMX/HTPB Plastic-Bonded Explosives

Abstract

We study the microscopic structure properties and early thermal decomposition of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX)/hydroxyl-terminated polybutadiene (HTPB) composites on the basis of density functional theory calculation and quantum-based molecular dynamics simulation. The results show that the HMX crystal surfaces are significantly stabilized by electrostatic adsorption between nitro-O and HTPB-H (both for alkyl and hydroxyl H). The corresponding electronic structure has an obvious modification, with some impurity states derived from HTPB in the forbidden band area. The initial reaction energy barrier may be reduced due to the extra active electron, but the earliest reaction sites of HMX thermal decomposition are not considerably changed. The thermal dissociation of HMX is mainly initiated with the breaking of the C–N bond, which is followed by NO2 elimination and alkyl dehydrogenation. After that, many HTPB-Hs are transferred to nitro-O to form water molecules, resulting in a delay of carbon and hydrogen oxidation of HMX. More intriguingly, the carbon chains of HTPB display considerable stability. Most of them even keep their original carbon backbone, which would act as an initial carbon nucleus and promote the carbon aggregation of small molecular residues. The presence of the HTPB binder should retard the reaction progress and reduce the reaction intensity of the HMX thermal decomposition.

An Integrated Production of Diesel Fuel Precursors from Carbohydrates and 2‐Methylfuran over Sn‐Mont Catalyst

“…Hydroxyalkylation‐alkylation (HAA) reaction of MeF with furfurals (HMF and FUR) provides condensation products [bis/tris(furyl)alkanes] containing C 15 and C 21 units, respectively. Bis/tris(furyl)alkanes have wide range of industrial applications ,. Numerous synthetic methods are available on synthesis of bis/tris(furyl)alkanes by condensation of MeF with carbonyl compounds over mineral acids,,, acidic resins,,, functionalized silica and carbon, AuCl 3 , zeolites, Cu(OTf) 2 , I 2 and TFA/ZrO 2 .…”

Reaction mechanism and electronic properties of host–guest energetic material CL-20/HA under high pressure by quantum-based molecular dynamics simulations

“…35 The energy cutoff was set to 400 Ry in the plane wave expansion of the electron density. 36 In addition, after energy testing, the convergence of the results was acceptable.…”

Theoretical investigation on intermolecular interactions, co-crystal structure, thermal decomposition mechanism, and shock properties of 3-nitro-1,2,4-triazol-5-one (NTO) and ammonium perchlorate

“…Therefore, theoretical calculations have become a common part of energetic materials research. 4–6 In the case of DFT and AIMD methods, which are considered to be able to accurately describe atoms and electrons, these methods have been used in various fields of energetic materials research, such as intermolecular interactions between explosives, 7–10 impact behavior of plastic bonded explosives (PBX), 11 thermal decomposition of explosive molecules or crystal, 12–15 and crystal structure. 16 These research methods have been proven to be effective and reliable, and can even obtain theories that are difficult to be achieved by experiments alone, which will provide guidance for the design and understanding of the internal mechanism of energetic materials in the future.…”