title: Pressure-dependent decomposition kinetics of the energetic material HMX up to 3.6 GPa.
abstract: The effect of pressure on the global thermal decomposition rate of the energetic material HMX was studied. HMX was precompressed in a diamond anvil cell (DAC) and heated at various rates. The parent species population was monitored as a function of time and temperature using Fourier transform infrared (FTIR) spectroscopy. Global decomposition rates were determined by fitting the fraction reacted to the extended-Prout-Tompkins nucleation-growth model and the Friedman isoconversional method. The results of these experiments and analysis indicate that pressure accelerates the decomposition at low-to-moderate pressures (i.e., between ambient pressure and 0.1 GPa) and decelerates the decomposition at higher pressures. The decomposition acceleration is attributed to pressure-enhanced autocatalysis, whereas the deceleration at high pressures is attributed to pressure-inhibiting bond homolysis step(s), which would result in an increase in volume. These results indicate that both the beta- and delta-polymorphs of HMX are sensitive to pressure in the thermally induced decomposition kinetics.
authors.affiliation: Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94551, USA. glascoe2@llnl.gov
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Glascoe
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Zaug
authors.forename: Alan K
authors.initials: AK
authors.lastname: Burnham