Date Published: August 01, 2018
Publisher: International Union of Crystallography
Author(s): Yan Liu, Chongwei An, Jin Luo, Jingyu Wang.
HNIW/TNT cocrystals are synthesized by a new chemical method. The performance of the cocrystals is improved from previous preparation techniques and this new method is a more environmentally friendly approach.
Currently, development of new energetic materials with insensitive high explosives is of great interest for applications in civil constructions, explosives, rocket propellants and airbag inflators (Liu et al., 2015 ▸). For this reason, cocrystallization has attracted considerable attention due to its ability to modify and optimize the physicochemical properties of energetic materials (Bennion et al., 2015 ▸; Wu et al., 2015 ▸). A cocrystal can be defined as multicomponent crystals of neutral molecular species in a specified ratio and is generally stabilized by hydrogen bonding, π–π stacking, p–π stacking, halogen bonds and van der Waals forces, instead of the common chemical bond (Bond, 2007 ▸; Stahly, 2009 ▸; Landenberger & Matzger, 2012 ▸). This new crystal engineering has been successfully applied broadly in the fields of explosives, propellants and pyrotechnics, and is recognized as a powerful tool for altering properties of existing energetic materials to create less-sensitive explosives (Shi et al., 2016 ▸; Sun et al., 2018 ▸).
Herein, we report a new HNIW/TNT cocrystal with higher density and better properties than previous reported (Yang et al., 2013 ▸) for the cocrystal, which was prepared via a green chemical method. The results indicate microscopically and macroscopically that the cocrystal is a new structure due to the new set of hydrogen bonds between the HNIW and TNT. Our investigations showed that this new cocrystal structure possesses preferable crystal quality, more stable thermal property and lower mechanical sensitivity. In particular, the crystal density and detonation velocity are excellent compared with those of the cocrystal reported by Yang et al. (2013) ▸. This synthesis is environmentally benign, scalable and a sustainable strategy.