Effects of Different Guests on Pyrolysis Mechanism of α-CL−20/Guest at High Temperatures by Reactive Molecular Dynamics Simulations at High Temperatures

The host–guest inclusion strategy has the potential to surpass the limitations of energy density and suboptimal performances of single explosives. The guest molecules can not only enhance the detonation performance of host explosives but also can enhance their stability. Therefore, a deep analysis of the role of guest influence on the pyrolysis decomposition of the host–guest explosive is necessary. The whole decomposition reaction stage of CL-20/H(2)O, CL-20/CO(2), CL-20/N(2)O, CL-20/NH(2)OH was calculated by ReaxFF-MD. The incorporation of CO(2), N(2)O and NH(2)OH significantly increase the energy levels of CL-20. However, different guests have little influence on the initial decomposition paths of CL-20. The E(a1) and E(a2) values of CL-20/CO(2), CL-20/N(2)O, CL-20/NH(2)OH systems are higher than the CL-20/H(2)O system. Clearly, incorporation of CO(2), N(2)O, NH(2)OH can inhibit the initial decomposition and intermediate decomposition stage of CL-20/H(2)O. Guest molecules become heavily involved in the reaction and influence on the reaction rates. k(1) of CL-20/N(2)O and CL-20/NH(2)OH systems are significantly larger than that of CL-20/H(2)O at high temperatures. k(1) of CL-20/CO(2) system is very complex, which can be affected deeply by temperatures. k(2) of the CL-20/CO(2), CL-20/N(2)O systems is significantly smaller than that of CL-20/H(2)O at high temperatures. k(2) of CL-20/NH(2)OH system shows little difference at high temperatures. For the CL-20/CO(2) system, the k(3) value of CO(2) is slightly higher than that for CL-20/H(2)O, CL-20/N(2)O, CL-20/NH(2)OH systems, while the k(3) values of N(2) and H(2)O are slightly smaller than that for the CL-20/H(2)O, CL-20/N(2)O, CL-20/NH(2)OH systems. For the CL-20/N(2)O system, the k(3) value of CO(2) is slightly smaller than that for CL-20/H(2)O, CL-20/CO(2), CL-20/NH(2)OH systems. For the CL-20/NH(2)OH system, the k(3) value of H(2)O is slightly larger than that for CL-20/H(2)O, CL-20/CO(2), CL-20/N(2)O systems. These mechanisms revealed that CO(2), N(2)O and NH(2)OH molecules inhibit the early stages of the initial decomposition of CL-20 and play an important role for the decomposition subsequently.