Thermal decomposition of HMX: Low temperature reaction kinetics and their use for assessing response in abnormal thermal environments and implications for long-term aging
- Sandia National Labs., Livermore, CA (United States)
- US Army, ARDEC, Dover, NJ (United States). Energetic Materials Division
The thermal decomposition of HMX between 175 and 200{degree}C has been studied using the simultaneous thermogravimetric modulated beam mass spectrometer (STMBMS) apparatus with a focus on the initial stages of the decomposition. The identity of thermal decomposition products is the same as that measured in previous higher temperature experiments. The initial stages of the decomposition are characterized by an induction period followed by two acceleratory periods. The Arrhenius parameters for the induction and two acceleratory periods are (Log(A) = 18.2 {plus_minus} 0.8, Ea = 48.2 {plus_minus} 1.8 kcal/mole), (Log(A) = 17.15 {plus_minus} 1.5 and Ea = 48.9 {plus_minus} 3.2 kcal/mole), (Log A) = 19.1 {plus_minus} 3.0 and Ea = 52.1 {plus_minus} 6.3 kcal/mole), respectively. This data can be used to calculate the time and temperature required to decompose a desired fraction of a sample that is being prepared to test the effect of thermal degradation on its sensitivity or burn rates. It can also be used to estimate the extent of decomposition that may be expected under normal storage conditions for munitions containing HMX. This data, along with previous mechanistic studies conducted at higher temperatures, suggest that the process that controls the early stages of decomposition of HMX in the solid phase is scission of the N-NO{sub 2} bond, reaction of the N0{sub 2} within a ``lattice cage`` to form the mononitroso analogue of HMX and decomposition of the mononitroso HMX within the HMX lattice to form gaseous products that are retained in bubbles or diffuse into the surrounding lattice.
- Research Organization:
- Sandia National Labs., Livermore, CA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States); Department of Defense, Washington, DC (United States)
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 164904
- Report Number(s):
- SAND--96-8452C; CONF-951155--14; ON: DE96003250
- Country of Publication:
- United States
- Language:
- English
Similar Records
A global HMX decomposition model
Chemical and Physical Processes that Control the Thermal Decomposition of RDX and HMX