Molecular Theory of Detonation Initiation: Insight from First Principles Modeling of the Decomposition Mechanisms of Organic Nitro Energetic Materials

Abstract

This review presents a concept, which assumes that thermal decomposition processes play a major role in defining the sensitivity of organic energetic materials to detonation initiation. As a science and engineering community we are still far away from having a comprehensive molecular detonation initiation theory in a widely agreed upon form. However, recent advances in experimental and theoretical methods allow for a constructive and rigorous approach to design and test the theory or at least some of its fundamental building blocks. In this review, we analyzed a set of select experimental and theoretical articles, which were augmented by our own first principles modeling and simulations, to reveal new trends in energetic materials and to refine known existing correlations between their structures, properties, and functions. Our consideration is intentionally limited to the processes of thermally stimulated chemical reactions at the earliest stage of decomposition of molecules and materials containing defects.

Investigations on Chemical, Thermal Decomposition Behavior, Kinetics, Reaction Mechanism and Thermodynamic Properties of Aged TATB

“…Below a conversion of 0.4, the master plot does not exactly overlap with any theoretical master plots, indicating that the decomposition process is not described by a single reaction model. These results support recent theoretical studies published in the literature [36]. Our findings suggest that this type of material could probably best be described by multi-phase or parallel thermal decomposition reactions.…”

Predicting the reactivity of energetic materials: an ab initio multi-phonon approach

“…It is widely acknowledged that TATB is insensitive to impact. 12 Most reports state its impact sensitivity to be 'immeasurable'. Only a single source suggests that TATB has a sensitivity on the order of 50 J, 52 although no indication was provided as to its origin or the experimental method used.…”

“…Considerable effort has been devoted to identifying a set of parameters capable of rationalizing the impact sensitivity of EMs. 12 Noting that EM initiation necessarily involves bond rupture, models that are based on isolated molecules have oen aimed at correlating impact sensitivity with the stability of bonds in the explosive molecule. This is done, for instance, by computing dissociation energies 13 or analysing the topology of the electron density.…”

Trigger bond analysis of nitroaromatic energetic materials using wiberg bond indices

“…c) and seem unlikely to result in a chain reaction. In addition, work on 1,3,5‐triamino‐2,4,6‐trinitrobenzene (TATB) did not consider cyclization as the primary method of initiation due to high activation barriers …”