Phys Chem Chem Phys. 2015 May 14;17(18):12013-22. doi: 10.1039/c5cp00006h.

Cluster evolution during the early stages of heating explosives and its relationship to sensitivity: a comparative study of TATB, β-HMX and PETN by molecular reactive force field simulations.

Physical chemistry chemical physics : PCCP

Yushi Wen, Chaoyang Zhang, Xianggui Xue, Xinping Long

PMID: 25872486 DOI: 10.1039/c5cp00006h

Abstract

Clustering is experimentally and theoretically verified during the complicated processes involved in heating high explosives, and has been thought to influence their detonation properties. However, a detailed description of the clustering that occurs has not been fully elucidated. We used molecular dynamic simulations with an improved reactive force field, ReaxFF_lg, to carry out a comparative study of cluster evolution during the early stages of heating for three representative explosives: 1,3,5-triamino-2,4,6-trinitrobenzene (TATB), β-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) and pentaerythritol tetranitrate (PETN). These representatives vary greatly in their oxygen balance (OB), molecular structure, stability and experimental sensitivity. We found that when heated, TATB, HMX and PETN differ in the size, amount, proportion and lifetime of their clusters. We also found that the clustering tendency of explosives decreases as their OB becomes less negative. We propose that the relationship between OB and clustering can be attributed to the role of clustering in detonation. That is, clusters can form more readily in a high explosive with a more negative OB, which retard its energy release, secondary decomposition, further decomposition to final small molecule products and widen its detonation reaction zone. Moreover, we found that the carbon content of the clusters increases during clustering, in accordance with the observed soot, which is mainly composed of carbon as the final product of detonation or deflagration.

Publication Types

• Journal Article