Exploring the Relationship between Micromechanical Properties and Impact Sensitivity of Energetic Materials

Crystal structure and associated local mechanical properties are considered to be among the factors determining the impact sensitivity of reactive chemicals. However, their contribution can hardly be separated from those stemming from the molecular structure per se (number and presence of explosophores, energy content). In this work, we analyzed a set of structurally diverse energetic compounds to look for possible correlations among the level of response toward impact stimulation (sensitivity), local mechanical properties, and crystal structure. In line with previous literature, a strong correlation with the energy content and impact sensitivity emerges, but the target safety property is also affected by the average elastic modulus of the crystal. Since the mechanical properties of crystalline materials are largely determined by the crystal structure, we investigate the rigidity and anisotropy of intermolecular interactions. We find that an increase in the anisotropy of the intermolecular interactions’ network leads to a decrease in impact sensitivity. Our findings on the mechanical properties within a diverse data set of explosives and their correlations with the safety of materials might be used for prediction models and controlled design of future materials.