Thermal decomposition studies of energetic materials using confined rapid thermolysis/FTIR spectroscopy

An experimental setup for performing rapid thermolysis studies of small samples of energetic materials is described. In this setup, about 8 μL of a liquid sample or about 2 mg of a solid sample is heated at rates exceeding 1500 K/s to a set temperature where decomposition occurs. The rapid heating is achieved as a result of confining the sample between two closely spaced isothermal surfaces. The gaseous decomposition products depart from the confined space through a rectangular slit into the region of detection. The evolved gases are quantified using FTIR absorption spectroscopy by accounting for the instrument line shape. To illustrate the use of this setup, the thermolysis behaviors of three different energetic materials are examined. These materials include HMX, RDX, and HAN, all of which are considered as highly energetic propellant ingredients. The results obtained in this study of the temporal evolution of species concentrations from these ingredients are in reasonably close agreement with results available in the literature.