Sensitivity of energetic materials: Evidence of thermodynamic factor on a large array of CHNOFCl compounds

Abstract

• Impact, friction, and thermal sensitivity data for 150 CHNOFCl species is reported. • Impact testing of high-melting and low-sensitive compounds is most challenging. • Mechanical sensitivity generally increases with the energy content of compound. • Increasing of detonation performance without compromising sensitivity is possible. Mechanical and thermal hazards are critical for chemical compounds. Foremost, the design of novel energetic materials that are stable, insensitive, but have a detonation performance superior to in-service materials is of great interest. However, a single source of safety data for hazardous materials with explosophoric functionalities is still missing. Herein, an experimental database on thermal stability, impact, and friction sensitivity for 150 CHNOFCl compounds is presented. Mechanical sensitivity is discussed in detail: particle size and shape effects, instrument design, and experimental protocol are considered. The entire dataset was analyzed using the simple descriptors of molecular structure. Mechanical sensitivity was found to be linearly correlated with the maximal heat of explosion for certain classes of compounds (nitrobenzenes, furazans, pyrazoles, etc.). Consideration of all species shows that previously proposed sensitivity increase with an energy content rise is relevant, although it is not strict line, as was assumed, but rather a widened “strip”. A new parameter, safety factor, is proposed to combine two types of sensitivity data. With this factor, the limiting values of mechanical sensitivity at a given energy content are provided that represent the state-of-art development of energetic materials and may be used for screening and design of novel compounds.