Study on the Crystal Structure and Properties of a New Crystal Form: ζ-HMX

Abstract

HMX is often used in military explosives and propellants due to its superior explosive properties. There already exist five different crystal forms of HMX. This paper synthesized a new form of ζ-HMX, in which the crystal is a trigonal system, and the space group is R3̅c. The crystal density is 1.330 g cm–3, and the calculated porosity is 31.0%, which provides the possibility for adsorption inside molecules and coating of military explosives. The crystal structure was tested by an X-ray single-crystal diffractometer. The thermal analysis, infrared spectroscopy, powder X-ray diffraction (XRD), explosion performance, and safety performance were compared with the most stable-state β-HMX. The detonation velocity of ζ-HMX is 7530 m s–1, and the detonation pressure is 20.03 GPa. It has certain advantages in sensitivity, and this experimental result is in good agreement with the theoretical calculation of the crystal structure and electronic energy. This study has a certain reference value for HMX application in mixed explosives and propellants.

Aggregate-Breaking Mechanism Response to Polyacrylamide Application of Purple Soils in Southwestern China Using Le Bissonnais Method

“…When PAM meets water, the hydrogen group in the molecular chain adsorbs the soil clay particles, the molecules entangle with each other in the form of a chain bridge, and the dispersed soil particles in the series are interwoven with each other such that the soil particles gradually agglomerate into macro-aggregates, thus forming strong water-stable aggregates [28,29]. In addition, PAM can form a protective film on the surface of soil when dissolved in water, and this film can effectively reduce the impact of raindrop beating and lessen the destruction and dissipation of soil [5,30].…”