<p>The thermal decomposition of four energetic cocrystals
composed of 4-amino-3,5-dinitropyrazole (ADNP)/diaminofurazan (DAF),
2,4,6-trinitrotoluene (TNT)/
2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL20), 1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane
(HMX)/CL20, and 1-methyl-3,5-dinitro-1,2,4-triazole (MDNT)/CL20 were studied
using simultaneous differential scanning calorimetry (DSC), thermogravimetry
analysis (TGA), and hot-stage microscopy. The kinetic parameters of their
thermal decomposition reaction were determined using the Kissinger and Ozawa
kinetic analysis methods. Each cocrystal’s peak exothermic temperature
(decomposition temperature), activation energy, and pre-exponential constant are
reported. Furthermore, these parameters from each cocrystal were compared to
the same parameters from the corresponding stoichiometric physical mixture in
order to identify changes in behavior attributable to the cocrystallization
process. For ADNP/DAF, the cocrystal shows an 8% increase in the peak exotherm
temperature and a 11-13% decrease in peak activation energy as compared to its
physical mixture. For TNT/CL20, this comparison shows a much smaller change in
the peak exotherm temperature (<1%) but shows a 5% decrease in activation
energy. This cocrystal also experiences phase stabilization—where a phase
transition of one or both coformers is omitted from the decomposition process. The
HMX/CL20 cocrystal shows a 1% change in the peak exotherm temperature and shows
a 2% increase in activation energy. Finally, for MDNT/CL20, this comparison
shows nearly a 4% increase and a drastic decrease in peak activation energy by 42-44%.
Cocrystallization clearly affects the thermal decomposition and reaction
kinetics of these materials, offering the potential to create a hybrid-class of
energetic materials which combines the high performance of an energetic
material with the safety and insensitivity of another. </p>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/12217934 |
| Date | 29 April 2020 |
| Creators | Joshua Trevett Dean (8782151) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/The_Kinetics_of_Thermal_Decomposition_and_Hot-Stage_Microscopy_of_Selected_Energetic_Cocrystals/12217934 |
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