Multi-stage Thermal Decomposition Mechanism of Energetic Plasticizer DNTN Triggered by Cleavage of the Nitrate Ester Bond

2?3-Bis(hydroxymethyl?-2?3-dinitro-1?4-butanediol tetranitrate(DNTN? is energetic material? which is the densest nitrate. The unclear thermal decomposition mechanism of DNTN has seriously hindered its application in propellants. The thermal decomposition process of DNTN was investigated by a combination of reactive force field molecular dynamics(ReaxFF MD? simulation? solid-phase in situ infrared spectroscopy(in situ IR? and TG-DSC-FTIR-MS simultaneous techniques? and the gas and solid products of the thermal decomposition were analysed? the thermal decomposition mechanism was elucidated. The results showed that the decomposition of DNTN was revealed that the process occurred in three stages. During the first stage from 127 degrees C to 147 degrees C? the O-N bond in DNTN was partially broken? releasing a minor amount of NO2 gas. In the second stage? between 147 degrees C and 220 degrees C? DNTN underwent rapid decomposition? removing the nitro groups and decomposing the quaternary carbon skeleton?accompanied by the formation and cleavage of the microcyclic structure? releasing a large amount of gases such as NO2 and CO2? and at the same time emitting a large amount of heat. The third stage? taking place within the temperature range of 240-350 degrees C? involved the high temperature pyrolysis of the remaining solid product of DNTN?which resulted in a limited release of CO2 gas? and above 300 degrees C? the remaining solidphasematerial would further react to result in the production of cyano. In this paper? the thermal decomposition mechanism of DNTN was illustrated from a multistage perspective? which had important guiding significance for its application in propellants and the follow-up research on stability mechanism