The Application Of Thermal Analysis Kinetics On Energetic Materials

Thermal analysis has important significance on the research of various fields. It is widely used in research of inorganic complexes, metals, petroleum, polymer and energetic materials. In this paper, the advantages and disadvantages of many kinetic equations are studied. The error of Kissinger method is investigated deeply. A new kinetic equation is proposed. Combined with IR, MS, as well as multi-nonlinear regression, we study the application of thermal analysis on the decomposition of energetic materials.The relative errors (e%) in the determination of the activation energy from the slope of the Kissinger straight line ln(β/Τ(_p²)) vs.1/Τ_p (βis the heating rate) are evaluated in deep, and the evaluation method of Kissinger erro proposed by P. Budrugeac is modified. Our work shows the relative errors is a function contained x_p andΔχ_p, not a function contained only x_p (x_p=E/RT_p, E is the activation energy, T_p is the temperature corresponding to maximum process rate, R is the gas constant); the bigger the value of x is and/or the lower the value of Ax is, the lower the relative error between Ek and E_p is. So the low and close heating rates in thermal analysis experiments are proposed from the viewpoint of kinetic theory.The heat conduction is an inherent factor in thermal analysis tests. But this factor is not considered in most of the kinetic equations. In this paper, a kinetic equation which consided heat conduction is proposed. The study of the dehydration of calcium oxalate monohydrate show that:the activation energy error of this equation is 2.19-4.7%; But the activation energy error of Friedman, Ozawa and Kissinger equation is 3.8-23%.TG-DSC-QMS-FTIR method can measure the weight loss, heat, the MS and FTIR of gas products simultaneously in the process of thermal decomposition. So the effects of several nano-materials on the thermal decomposition of TEGDN/NC propellants are studied by TG-DSC-QMS-FTIR method. The results show that:The addition of MnC₂O₄ nanoparticles gets the gas products of macromolecular significantly reduce, while small molecules increase significantly. Secondly, the MnC₂O₄ gets the activation energy of first stage increase. This increases the thermal stability of TEGDN/NC propellant, and makes TEGDN/NC propellant more safte in storage; the MnC₂O₄ gets the activation energy of second stage decrease, and makes the decomposition more complete. Cerium oxide significantly reduces the activation energy of main reaction zone, and makes the decomposition more complete. For zirconium oxide and chromium oxide, they only reduce the apparent activation energy of the first reaction effectively, and increase the stability of TEGDN/NC propellant.The non-linear multivariate regression is an indispensable method to derive kinetic models. This technique is the only way to decide between different reaction models and get a global model which gives reliable results for the whole parameter range. Ordinarily, the thermal decomposition of explosives are multi-step reaction, the usual kinetic method can not give accurate results. In this paper the thermal decompositions of NQ, RDX and HNS are studied by TG/DSC-MS-FTIR and non-linear multivariate regression. The study show that the decomposition process of NQ and RDX can be described by kinetic model A→(?)B→(?)C→D(?), while the decomposition process of HNS can be described by kintic model A→(?)B(?)→C(?)The burning rate empirical formulas of B/Pb3O₄, B/CuO and B/BaCrO₄ delay compositions are studied by numerical simulation method. At the same time the thermal reaction of boron type delay composition are studied under linear heating condition. The reaction of boron type delay composition is solid-solid phase reaction. There are pre-ignition reactions.