Theoretical simulation research on the hygroscopicity, stability, sensitivity, and mechanical properties of the cocrystals of ammonium nitrate with typical high energetic molecules

Ammonium nitrate (AN) is a classical ionic salt that possesses thriving prospects in civil and military fields. Nevertheless, the problems of multiple-phase transition and difficulty in processing (easy agglomeration and hygroscopicity) limit its practical application. Cocrystallization technology is one of the most emerging and effective strategies that can tune the physical and chemical properties of materials without changing the pristine molecular structure. In this paper, we employed the molecular simulation method for designing the AN cocrystals by pairing AN with three different types of energetic molecules (nitramine energetic molecule (RDX, HMX, and CL-20), nitro energetic molecule (TATB), and nitrate energetic molecule (PETN)) with a ratio of 1:1. Then, the hygroscopicity, stability, sensitivity, and mechanical properties of the five cocrystals were investigated from the perspective of adsorption heat, binding energy, cohesive energy density, and mechanical parameters. From the results of adsorption heat and binding energy, the AN/CL-20 cocrystal is the desirable cocrystal with the minimum hygroscopicity and strong stability. On the other hand, it is noteworthy that the AN/TATB cocrystal is a charming cocrystal with excellent machinability and lower sensitivity from the results of cohesive energy density and mechanical parameters. This work may provide substantial insights into the design of AN cocrystals.