Submicron-Sized Gamma-HMX: 1. Preparation and Initial Characterization

Lee, K.-Y.; Moore, David S.; Asay, B. W.; Llobet, Anna

doi:10.1080/07370650701399312

Cited by 17 publications

(8 citation statements)

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“…1,9 Details of the determination, as well as corroborating evidence, are given in Ref. The crystallographic polymorph of the sm-HMX was determined to be the -form by comparison to published Raman spectra (the Raman spectrum of -HMX was from Alex Tappan of Sandia National Laboratory, Albuquerque, NM, USA).…”

Section: Resultsmentioning

confidence: 99%

“…We have recently prepared and characterized a submicron form of HMX (sm-HMX). 1 The material as produced exhibits somewhat improved friction, drop, and electrostatic discharge sensitivity over conven-tionalˇ-HMX (Holston Impact Test Standard). 3 -5 The tetrazocine ring in theˇ-form has the chair conformation (exhibits a center of symmetry) and has the largest molecular packing lattice energy, while the other three polymorphs have the ring in a basket-like shape (two-fold symmetry) and differ from each other in the way the baskets are stacked and arranged in the unit cell.…”

Section: Introductionmentioning

confidence: 99%

“…Note the lack of any vibrational features fromˇ-HMX (1150-1190 cm1 ). 2, at four sample aging times, one short (4 h), one middle (480 h), and the two long (1416 and 5000 h).…”

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confidence: 99%

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Raman spectroscopy as a tool for long‐term energetic material stability studies

Moore

Lee

2007

J Raman Spectroscopy

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Raman spectroscopy is shown to be useful as a tool for long-term stability studies. The stability of a novel submicron-size g-polymorph form of the explosive HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) was monitored up to 1 year using Raman spectroscopy. The preparation and characterization of this submicron HMX has been previously discussed. It is important to know the long-term stability of this submicron g-polymorph material under ambient conditions for its eventual utilization. This submicron HMX material has been found to be stable both chemically and polymorphically (to the order of 1% impurity level), even though HMX normally converts to the b-polymorph at ambient conditions.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Raman spectroscopy as a tool for long‐term energetic material stability studies

Moore

Lee

2007

J Raman Spectroscopy

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“…Previous studies using scanning electron microscopy technique have been limited to surface structural analysis of the explosive particles [2,3]. Techniques such as scanning electron microscopy cannot be adopted to acquire 2D and 3D images visualizing the internal characteristics of a plasticbonded explosive, and it is not possible to quantify the spatial distribution of material in three dimensions using this method [2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Characterization of RDX-Based Thermosetting Plastic-Bonded Explosive by Cone-Beam Microfocus Computed Tomography

Zhang¹,

Huang²,

Tian³

et al. 2012

Journal of Energetic Materials

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In this study microfocus computed tomography (lCT), a nondestructive technique, was used for 3D characterization of cyclotrimethylenetrinitramine (RDX)-based thermosetting plastic-bonded explosives. Quantitative information on RDX crystals including the packing status of the crystal and binder system, as well as the inner structure characteristics of partially solidified and fully solidified samples, was obtained using cone-beam lCT technology. The CT images show that the CT value of RDX crystal grains was obviously higher than that of crystal powder=binder. The results also show that after vacuum casting and thermosetting, the RDX grains were dispersed evenly and there were no air pores or cracks observed in the sample. Small pores exist inside the RDX grains with a porosity of less than 0.3%. The analysis results indicate high quality of the explosive part after employing thermosetting molding. The binder system and RDX crystals were integrated sufficiently, yet the grain packing was not maximum. The estimated average density and maximal difference in density of the sample were both in accordance with the testing results by Archimedes' method and it was proven that complete curing may enhance the overall density and density uniformity of the product.

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“…Gen-erally,i nsensitive explosive materials have low reactivity, as ignificant drawback. Nanoenergetics, therefore, are exciting because they exhibit an apparent paradox of high reactivity and low sensitivity.The key challenges in producing compositions containing HMX and CL-20 is obtaining the target crystal size, while retaining the desired polymorph, and achieving auniform binder coating without ripening the explosive [2,[16][17][18].I nt his study,t he approach used to produce the nano-HMX based compositions was ac ombination of mechanical particle size reduction and spray drying. Mechanical particle size reduction was utilized to achieve the desired crystal size of b-HMX.…”

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confidence: 99%

Investigation of HMX‐Based Nanocomposites

Patel

Степанов

Swaszek

et al. 2014

Propellants Explo Pyrotec

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1I ntroductionNanoenergetics, in comparison with traditional energetics, exhibit enhanced performance, insensitivity,a nd mechanical strength, all of which are attributes required for next generation munition systems. Crystal size has as trong influence on the mechanical properties and the void size distribution of an explosive composition. These, in turn, govern the mechanical response of an explosive charge to shock stimuli by affecting the distribution of incident energy and thereby hot spot formation [1][2][3][4][5].I mproved mechanical properties can lead to reduced shock sensitivity in explosives [6,7].T he increased strength and stiffness of explosive compositions due to crystal size reduction, as described by the Hall-Petch relationship [8,9],c ontributes to reduced susceptibility to plastic deformation, which is ak ey precursor to initiation by mechanisms such as shear-band formation [10] and adiabatic void collapse [1]. Furthermore, significant evidence links higher reactivity with smaller crystal size in energetic materials. Some of the demonstrated improvements include:as maller critical diameter [11,12],s horter shock to detonation transition length [13,14],e nhanced sensitivity to initiation by short duration, high amplitude incident shocks [11],a nd improved detonation spreading [15].T hese improvements in performance are largely attributed to the higher number density of hot spots and al arger specific surface area. Gen-erally,i nsensitive explosive materials have low reactivity, as ignificant drawback. Nanoenergetics, therefore, are exciting because they exhibit an apparent paradox of high reactivity and low sensitivity.The key challenges in producing compositions containing HMX and CL-20 is obtaining the target crystal size, while retaining the desired polymorph, and achieving auniform binder coating without ripening the explosive [2,[16][17][18].I nt his study,t he approach used to produce the nano-HMX based compositions was ac ombination of mechanical particle size reduction and spray drying. Mechanical particle size reduction was utilized to achieve the desired crystal size of b-HMX. Am echanical (top down) process was em-Abstract:A dvanced munition systems require explosives which are more insensitive, powerful, and reactive. For this reason, nano-crystalline explosives present an attractive alternative to conventional energetics. In this study,f ormulations consisting of 95 %o ctahydro-1,3,5,7-tetranitro-1,3,5,7tetrazocine (HMX) and 5% polyvinyl alcohol (PVOH) were prepared with mean crystal sizes ranging from 300 nm to 2 mm. The process to create these materials used ac ombination of mechanical particle size reduction and spray drying, which has the advantages of direct control of crystal size and morphology as well as the elimination of ripening of crystals (which occurs during slurry coating of nanomaterials). The basic physical characteristics of these formulations were determined using av ariety of techniques, including scanning electron microscopy and X-ray diffraction. Compressive st...

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Submicron-Sized Gamma-HMX: 1. Preparation and Initial Characterization

Cited by 17 publications

References 3 publications

Raman spectroscopy as a tool for long‐term energetic material stability studies

Raman spectroscopy as a tool for long‐term energetic material stability studies

Characterization of RDX-Based Thermosetting Plastic-Bonded Explosive by Cone-Beam Microfocus Computed Tomography

Investigation of HMX‐Based Nanocomposites

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