Detection of the alpha and gamma polymorphs of HMX in beta-HMX by Raman spectroscopy. [Beta-HMX]
HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) is an important military explosive which exhibits four polymorphic forms- alpha, beta, gamma, and delta. Commercial lots of this compound are analyzed for polymorphic composition in order to achieve predictable firing characteristics. This analysis may be done qualitatively with powder diffraction, while quantitative results are typically obtained through infrared spectroscopy performed of a nujol mull. The grinding action inherent in the preparation of a nujol mull causes changes in two of the polymorphs. These changes are caused by the pressure generated during the grinding process. Larger errors result when significant amounts of the gamma or delta form are present due to the composition-altering effects of sample grinding. Delta-HMX is normally absent from samples that have been solution processed because this form is thermodynamically favored only at high temperatures ( >/approx gt/140/degree/ C). In addition, small amounts of delta-HMX that might be present can readily transform morphology under the mechanical action of normal handling. It is for both these reasons that it is impractical to pursue the quantitative analysis of this form, and we will not do so here. The Raman spectra of beta-HMX have previously been measured and shown to have many intense peaks. The Raman spectra have been used to measure the transformations between polymorphs as a function of pressure and temperature. The results reported here show that Raman spectroscopy can be used to detect the alpha and gamma phases in beta-HMX at concentrations well under 1%. 13 refs., 6 figs.
- Research Organization:
- Monsanto Research Corp., Miamisburg, OH (USA). Mound
- DOE Contract Number:
- AC04-76DP00053
- OSTI ID:
- 7126632
- Report Number(s):
- MLM-3501(OP); CONF-880473-5; ON: DE88012867
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
450100* -- Military Technology
Weaponry
& National Defense-- Chemical Explosions & Explosives
CHEMICAL EXPLOSIVES
COMMINUTION
EXPLOSIVES
GRINDING
INFRARED SPECTRA
MACHINING
PHASE TRANSFORMATIONS
PRESSURE EFFECTS
RAMAN SPECTRA
SPECTRA
TEMPERATURE EFFECTS