CL-20/TNT decomposition under shock: cocrystalline versus amorphous

Abstract

The cocrystallization strategy is considered to be an effective means to adjust the properties of explosives. Nevertheless, the underlying mechanism of the effect of the special cocrystal structure on the decomposition process is not clear enough. The present work compares the response processes of a CL-20/TNT cocrystal structure and an amorphous structure under shock waves with different velocities. The thermodynamic evolution, reactant decay, product formation, main initial reactions and cluster evolution are analyzed. As a result, we find that the amorphous structure is easier to compress than the cocrystal structure, achieving higher stress and temperature. These thermodynamic parameters have a strong correlation. For the amorphous structure, the chemical reaction of the system is more intense, the reactants decay faster, the products are more abundant, and the intermediate products can complete the transformation to stable products earlier. Furthermore, NO₂ is the most important intermediate product, and its quantitative change can directly reflect the reaction process. The amorphous structure is more prone to decomposition reaction, and the cocrystal structure is more prone to polymerization reaction. The cluster size in the amorphous structure is smaller and more conducive to decomposition.