Non-isothermal Thermal Decomposition Characteristics Of Emulsion Explosives Prepared By Modified Composite Wax

Emulsion explosives were once considered a safe explosive.However,the emulsion explosives accidents have occurred frequently in recent years.Therefore,the thermal decomposition process,thermal decomposition mechanism and thermal stability of explosive attract great attention in civil explosive industry.The purpose of this paper is to explore the causes of the frequent safety accidents of emulsion explosives,and the thermal decomposition process and mechanism of emulsion explosives are studied in depth.Furthermore,the effect of oil phase materials on the emulsion explosive thermal stability are explored.In this paper,microcrystalline wax and polyethylene wax were used to modify the compound wax,and 3 groups of emulsion explosives were prepared with those wax.The TG-GC-MS was applied to the thermal decomposition process and the mechanism test of the emulsion explosives.The thermal decomposition process of emulsion explosives can be clearly measured by TG-GC-MS.Meanwhile,the thermal decomposition mechanism was analyzed,and the influence of oil phase materials on the thermal stability of emulsion explosives was explored preliminarily.The following conclusions are obtained:1.For the thermal decomposition measurement of emulsion explosives with multiphase and inorganic compounds,the TG-GC-MS technology can accurately measure the quality change of various samples at different temperatures,the types of gaseous products generated and their change trend with temperature and time.Furthermore,the thermal decomposition process and mechanism of emulsion explosives can be qualitatively analyzed.2.The test results of TG and TG-GC-MS all showed that:There are four stages in the process of thermal decomposition of emulsion explosives prepared by oil phase prepared from modified wax and microcrystalline wax and modified by polyethylene wax under linear temperature rise conditions:the secondary decomposition stage,the thermal accumulation stage,the main decomposition stage and the tail decomposition stage.The thermal stability of the emulsion explosives made from the modified oil phase of microcrystalline wax and polyethylene wax was higher than that of the compound wax,and the modified polyethylene wax had the better effect.3.Four methods of Ozawa,Starink,Vyazovkin-Wight and Tang coincide with the results of the Coast-Redfem model.The mean values of activation energy in the 15?95%phase of decomposition rate by 5 methods show that:the compound wax modified by polyethylene wax is superior to the compound wax modified by microcrystalline wax over compound wax.Combined with the results of the previous TG-GC-MS test,the corresponding thermal stability show that:the compound wax modified by polyethylene wax is superior to the compound wax modified by microcrystalline wax over compound wax.It is confirmed that wax modified by microcrystalline wax and wax modified by polyethylene wax all improve the thermal stability of emulsion explosives.The thermal stability of emulsion explosives prepared by wax modified by polyethylene wax is better than that of modification of microcrystalline wax.Compared with the compound wax,the addition of microcrystalline wax and polyethylene wax can reduce the rate of oil content and increase melting point and kinematic viscosity of compound wax.The oil film strength,matrix hardness,stability and the thermal decomposition activation energy of the emulsion explosives all increased,and the main reaction of thermal decomposition shifted to high temperature.4.Based on the results of the results of TG-GC-MS measurement,the qualitative analysis of the production process of the main gas products and the variation of gas products with temperature and time in the process of thermal decomposition was carried out.The emulsion explosives prepared by compound wax,wax modified by polyethylene wax and wax modified by microcrystalline all conform to the Avrami-Erofeev equation,and the mechanism of random nucleation and subsequent growth(n= 3).The kinetic equation of the thermal decomposition reaction of the emulsion explosives system in the original state(? = 0)was obtained by the kinetic calculation:1)Emulsion explosives prepared by compound wax:(?);2)Emulsion explosives prepared by compound wax modified by microcrystalline wax:(?);3)Emulsion explosives prepared by compound wax modified by polyethylene wax:(?).