Study On Thermal Decompostion Behavior Of Typical Explosive Hazardous Chemicals And Influence Of Transition-Metal Compounds On It

With the development of technology,more new substances are found and produced to satisfy people's requirements.85%of them can be grouped into hazardous chemicals,which can cause serious accidents on fire and explosion to endanger people's life and property.In this kind of materials,the explosive hazardous chemicals are the most dangerous.Their accidents can be not only induced by external factor such as heat,impact,friction and so on,but also aroused by heat accumulation due to the poor capability of heat loss in the process of transportation and storage.Hence,in order to ensure thermal safety of the explosive hazardous chemicals,the research on thermal decomposition characteristics of these substances must be done adequately and carefully.In this paper,two typical explosive hazardous chemicals were selected,one is double base propellant,and the other one is multi-nitro ester propellant.And the researches were proceeded,using C80 calorimetry,TG-FTIR and GC/MS,from these three aspects:â‘ Thermal decomposition behavior of double base propellant and multi-nitro ester propellant;â‘¡Influence of environmental factors on thermal decomposition characteristics of these two propellants;â‘¢Effect of transition-metal compounds on thermal decomposition characteristics of multi-nitro ester propellant.In the fist research topic,thermal decomposition behavior was observed under the constant heating rate experiment;the reaction mechanism function on slow thermal decomposition of these two propellants were obtained using thermal analysis method based on constant temperature kinetics;and the thermal decomposition kinetics parameters of these two propellants were calculated using thermal analysis method based on single constant heating rate kinetics.And the variation on gas product of thermal decomposition of these two propellants was studied by this work using TG-FTIR and GC/MS.At last,in this topic,according to the above results and previous work,the thermal decomposition steps of these two propellants were discussed,and then the thermal decomposition mechanism of these two propellants was revealed.In the second topic,the used environmental factors include the initial quantity of sample,heating rate,moisture content,open/closed system,and different atmospheres. The influences of these five factors on thermal decomposition characteristics of two propellants were researched by this topic.The thermal decomposition kinetics parameters of these two propellants were calculated and compared under these factors, using thermal analysis method based on single constant heating rate kinetics.The difference on thermal decomposition behavior between double base propellant and multi-nitro ester propellant under the initial quantity of sample,heating rate,or moisture content was found.And this phenomenon was explained reasonably.In the third topic,the influences of six transition-metal oxides,such as Fe₂O₃, and five transition-metal organic acid salts,such as NiFe₂O₄,on the thermal decomposition characteristics of multi-nitro ester propellant were researched by using C80 calorimetry.And the influences of initial quantity of sample and ambient pressure on the thermal decomposition characteristics of multi-nitro ester propellant with transition-metal compounds,including Fe₂O₃ and NiFe₂O₄,were analyzed in detail.Except for the above-mentioned works,a new autocatalytic kinetics method based on the experiments using C80 calorimetry,was devised in accordance with the deficiency of thermal kinetic methods available.According to this method,the thermal kinetic parameters on the two stages within first-order autocatalytic reaction of explosive hazardous chemicals can be calculated accurately.