Theoretical study on the pyrolysis mechanism of key components of NEPE propellant

NEPE propellant has high energy and good mechanical properties. However, due to the lack of detailed research on its microscopic pyrolysis mechanism, the combustion rate and energy release rate are still difficult to control, which limits the further development of NEPE propellant. Based on this, quantum chemistry is used to study the pyrolysis mechanism of key components of NEPE propellant, including oxidants HMX and AP, binders PEG, NG and BTTN. The pyrolysis reaction path, rate-determining steps and main pyrolysis products of each component were calculated, and the pyrolysis kinetic parameters are calculated based on the transition state theory. The results show that HMX, BTTN and NG are all transformed into cyclic nitrogen compounds or chain carbon oxides by NO2 or NO3 shedding, and then gradually decomposed, while PEG is the gradual pyrolysis of long chain molecules. The main pyrolysis products are nitrogen oxides and various small fuel molecules containing C/H/N. The order of reaction rate constants of NEPE components is NG> AP> HMX> BTTN> PEG at 1500-2000 K. Among them, PEG and BTTN reaction rate constants are sensitive to temperature, and the reaction rate will rise rapidly with the increase of temperature. This study will provide an important theoretical reference for the regulation of NEPE high-energy catalyst pyrolysis behavior.