Effects of oxidizing molecules on the thermal decomposition of TTDO by ab initio molecular dynamics simulations.

Oxidizing molecules play a very important role in improving the comprehensive properties of energetic materials. Recently, a series of energetic cocrystals containing 2,4,6-triamino-1,3,5-triazine-1,3-dioxide (TTDO) and oxidizing molecule have been successfully prepared. Therefore, ab initio molecular dynamics were used to simulate the thermal decomposition process of TTDO, TTDO:HO, TTDO:HNO, and TTDO:HClO crystals at 3000 K to study the role of oxidizing molecules during the thermal decomposition of TTDO. The initial decomposition paths of the TTDO crystal include N-H bond breaking, C-N bond breaking, and intramolecular and intermolecular H transfers. The formation mechanisms of HO, N, and CO in the four crystals are completely different. The key formation mechanism of HO is the combination of O with OH, that of N is the formation of the -N-N- structure, and that of CO is to form the intermediate CO-R with carbonyl structure that form the fragment with the -O-C-O- structure. All the oxidizers HO, HNO, and HClO involve in the formation of HO, N, and CO. The formation mechanisms of urea during the decomposition process of the four crystals are completely different, but the key step is to produce the structure of -N-CO-N-. An analysis of N shows that HO, HNO and HClO affect not only the types of N, but also its formation mechanisms. Among them, HNO has the greatest influence on N.