Effect of carbon nanotubes on thermal decomposition of CL-20 explosive: a molecular dynamics simulation study

CNT is a promising candidate that can improve the characteristics of energetic materials as an additive, while its effects on the reaction of the explosives have not yet been fully elucidated. To understand the role of carbon nanotubes in the explosive reaction, reactive molecular dynamics simulations were performed to investigate the thermal decomposition of CL-20 with/without CNT system at various temperatures. Results indicate that CNT does not alter the initial reaction pathway of CL-20 but can slow down its thermal decomposition rate. By tracking the time evolution and distribution of a critical intermediate product: NO₂ within the system, it was revealed that NO₂ had a longer lifetime and some NO₂ molecules were observed encircling the carbon nanotubes. It may be because the CNT decreases NO₂ collision frequency with other activity fragments due to steric hindrance and NO₂ absorption on the CNT, which slows down the further reaction of NO₂, as well as the total reaction rate. Additionally, during the system heating stage and the initial reaction stage, CNTs will deform and absorb energy, which may help reduce the reaction rate and sensitivity of the system. Our results reveal the effect of CNT in the initial reaction of explosives and can help to understand its sensitivity-reducing effect from the atomic reaction view.