Study On The Isothermal Decomposition And Mechanism Of Several Typial Energetic Materials

Under the condition of normal temperature and pressure without external stimulation,slow thermal decomposition reaction of energetic materials will also occur.Therefore,the thermal stability of energetic materials has become the focus of attention in the process of production,use,transportation and storage.Early,our research group independently developed a set of isothermal thermal decomposition gas metering device and it has been perfected and improved many times before and after.Finally,a longer period?several months?of isothermal thermal decomposition experiments can be performed to obtain the thermal decomposition reaction kinetic parameters and reaction mechanism of energetic materials,and to evaluate the storage life.In this paper,several typical energetic materials include CL-20/HMX co-crystal,PETN,FOX-12,NTO,NQ and D-NQ were studied by isothermal thermal decomposition gas metering device.?1?The thermal decomposition process of CL-20/HMX co-crystal was measured by the isothermal thermal decomposition gas metering device,the gas pressure versus time curves of the isothermal decomposition of CL-20/HMX co-crystal were obtained within the temperature range of 403.15 K⁴43.15 K.And the corresponding kinetic parameters of thermal decomposition and reaction mechanism functions were obtained.At the same time,complete decomposition of CL-20/HMX co-crystal was performed in the temperature range of 443.15 K⁴63.15 K to study its thermal decomposition mechanism.The pressure versus time curves of the gas generated by CL-20/HMX co-crystal decomposition had a significant inflection point.Furthermore,the CL-20/HMX co-crystal decomposition residues with different decomposition degrees were characterized by HPLC,FT-IR,and SEM to understand the decomposition process.The results show that CL-20/HMX co-crystal thermal decomposition is a coupling process.Before the inflection point,CL-20 and HMX are decomposed simultaneously,but mainly into CL-20.After the inflection point,CL-20 is completely decomposed,and HMX decomposition rate increased.Before the inflection point,the activation energy is 149.3 kJ·mol^-11 of CL-20/HMX co-crystal,the models conformed to No.33 with reaction order n=2.After the inflection point,the activation energy is 169.0kJ·mol^-1,the models followed the Avrami-Erofeev equation.?2?The self-established isothermal thermal decomposition gas metering device is used to measure the isothermal thermal decomposition of several typical explosives,including PETN,FOX-12,NTO,NQ and D-NQ.The kinetic parameters and the best mechanism function of five samples were obtained by the change curves of gas pressure with time.The time for five explosives to reach a certain decomposition depth is calculated by using the empirical equation,and the storage life of five samples at 298.15 K is estimated with the decomposition extent of 0.1%as the end point of life.Furthermore,the five samples decomposition residues with different decomposition degrees were characterized by FT-IR,and SEM to understand the decomposition mechanism.