Study On Thermal Decomposition Kinetics And Safety Based On Autocatalytic Reaction Of Energetic Materials

The autocatalytic reaction is generally considered to be extremely dangerous due to the unknown initiation and the release of a large amount of heat and gas in a short time.The goal of thermal safety evaluation is to determine the critical conditions of thermal runaway and the time elapsed before the thermal runaway occurs.In recent years,the theoretical safety evaluation method of energetic materials based on thermal decomposition kinetics is a very important topic.In our study,four kinds of energetic materials with typical thermal decomposition reactions are chose,such as FOX-12,LLM-105,BTF,and CL-20/BTF cocrystal.Combined with other experimental technical such as differential scanning calorimetry(DSC),accelerated adiabatic calorimetry(ARC),the kinetic-based method was used to establish thermal decomposition kinetic models by nonlinear iterative optimization method.On the basis,the thermal safety parameters were predicted combined with heat transfer equations.The specific research contents are as follows: DSC and ARC were used to study the initial thermal decomposition temperature,reaction heat and other characteristic parameters;Taking four kinds of research objects as examples,the kinetic models of each reactions were established by kinetic-based method based on the above thermal behavior,and the thermal decomposition kinetic parameters were obtained,correspondingly;Based on the thermal decomposition kinetic model,the thermal safety parameters under different conditions were obtained,and the simulations of FOX-12,LLM-105,CL-20/BTF cocrystal under different conditions in large quantities were performed.And the parameters affecting SADT value were discussed.It is found that the thermal decomposition of FOX-12 is a typical autocatalytic reaction.The kinetic model of FOX-12 was successfully obtained by using nonlinear optimized model-based method.Nitrogen oxide can be used as a catalyst to accelerate the reaction rate of thermal decomposition and some important thermal safety parameters were predicted.The thermal decomposition behavior of LLM-105 can be described by two-step consecutive autocatalytic reactions.Based on the kinetic model,the two overlapping reactions are dynamically decoupled,revealing the contribution of each step to the whole reaction.Based on the established kinetic model,the thermal safety parameters of LLM-105 under different conditions were evaluated.The thermal decomposition model of the melt-decomposable BTF was established,and the impact of the melting process on thermal safety was revealed.Thermal decomposition behavior of CL-20/BTF cocrystal were described by two-step parallel full autocatalytic reaction,and the contribution ratio of the two steps varies with the heating rate.On this basis,the thermal safety parameters of cocrystal were predicted.