A New Device To Study The Isothermal Decomposition Of Energetic Materials

A new device to messure gas pressure during the isothermal decomposition of energetic materials has been successfully developed in this research.It keeps the virtue of Bourdon pressure gauge that the vacuum system and reaction system are in the same temperature environment.And it overcomes the shortcomings of Bourdon pressure gauge in which fire sealing process is explosive,the gauge isn't reusable,and it cannot measure pressure timely and successively.A highly sensitive,accurate,and heat resisting?250??pressure sensor is integrated with specialized miniature vacuum valve.The equipment consists of the computer control,heating,thermal reaction,and data acquisition units.It can record data continuously and automatically.With secure system,it can be used to do experiments with longer periods.The pressure sensor and transmitter are separated,which can reduce influence of temperature on transmitter and decrease experiment error.The pressure sensor,specialized miniature vacuum valve,and reactor are in the same temperature environment,which can avoid the coacervation of gaseous product.In addition,it can be used to study the thermal decomposition of grain with a little improvement of the sample cell.The whole testing system is economic and easy to operate.The thermal decomposition of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane?CL-20?is examined via the self-modified Bourdon pressure method.The activation energy is 182.5 kJ mol^-1and the pre-exponential factor?ln A?is 37.04,which shows good agreement with previously published results.The storage life of CL-20 at 50,70,90,110,and 130°C are calculated using the Semenov equation.And,the storage life of CL-20 is extrapolated to 18.14 h,8.20 d,21.22 d,and 27.30 d at 130°C,while taking the reaction extents of 1%,2%,3%,and 4%as the end points of storage life respectively.These values are corresponded to the values obtained in the practice work.Moreover,the thermal decomposition of three composite explosives,include JOLC-9,JOLC-10 and aluminized HMX,are also studied by this device.The time dependence of the gas pressure and corresponding kinetic parameters,reaction machanism,and storage life are obtained successfully.It is indicated that the initial decomposition of JOCL-9 and JOLC-10 is controlled by the decomposition rate of nitrate.The activation energy of aluminized HMX is149.4 kJ mol^-1.And at 110¹50?,the decomposition process is corresponded with the anti-Jander equation which was described as 3D diffusion.