Current state of knowledge on the sensitivity of polynitro compounds to electric spark

The results of 32 years of research on the determination of the electric-spark sensitivity (EES) of energetic materials (EMs), carried out at the University of Pardubice, have been incorporated into STANAG 4490 and adopted as the Czech defense standard ČOS137601. This article presents the rationale behind the design of the spark gap in the relevant testing device. It explains the mechanism of electron addition to the most reactive nitro group and outlines the methods for identifying the electrosplitting reaction centers in energetic molecules containing X–NO2 (X = C or N) trigger bonds, including the splitting mechanism. The paper also confirms the presence of hot spots during electric-spark initiation and discusses the impact of foreign impurities in the sample tested on this sensitivity. Furthermore, it documents how EES is affected by lattice free volume, intrinsic molecular volume and the heat of fusion. Finally, it shows how EES is influenced by the energy content and performance of nitramines and polynitroarenes and demonstrates the relationship between this sensitivity and the thermal reactivity of the EMs studied.