Coefficient of Thermal Expansion of the Beta and Delta Polymorphs of HMX

Weese, R K; Burnham, Alan K.

doi:10.1002/prep.200500024

Cited by 26 publications

(17 citation statements)

References 24 publications

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“…The LDA and GGA results on α agree with experimental data. 30,47 In contrast, α with vdW correction is far smaller than experimental data. Although vdW correction dramatically reduces the overestimation of the volume, it thus significantly deteriorates α.…”

Section: B Vibrational and Thermodynamic Propertiesmentioning

confidence: 78%

Vibrational and thermodynamic properties of β-HMX: A first-principles investigation

Kalia

Nakano

et al. 2011

The Journal of Chemical Physics

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Prediction of the phase behavior of acetonitrile and methanol with ab initio pair potentials. II. The mixture We present pair potentials for fluorinated methanes and their dimers with CO 2 based on ab initio potential energy surfaces. These potentials reproduce the experimental second virial coefficients of the pure fluorinated methanes and their mixtures with CO 2 without adjustment. Ab initio calculations on trimers are used to model the effects of nonadditive dispersion and induction. Simulations using these potentials reproduce the experimental phase-coexistence properties of CH 3 F within 10% over a wide range of temperatures. The phase coexistence curve of the mixture of CH 2 F 2 and CO 2 is reproduced with an error in the mole fractions of both phases of less than 0.1. The potentials described here are based entirely on ab initio calculations, with no empirical fits to improve the agreement with experiment.

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Section: B Vibrational and Thermodynamic Propertiesmentioning

confidence: 78%

Vibrational and thermodynamic properties of β-HMX: A first-principles investigation

Kalia

Nakano

et al. 2011

The Journal of Chemical Physics

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“…The current methods for CTE measurement include expansion gauge, X‐ray single‐crystal diffraction and X‐ray powder diffraction (XRD), etc. Making use of expansion gauge, the tested CTE of many explosives, such as HMX and TATB, are based on slender cylinders 4–7, which cannot display the thermal expansion of explosive crystals completely. Kolb and Rizzo 8, Evers et al.…”

Section: Introductionmentioning

confidence: 99%

Investigation on the Thermal Expansion and Theoretical Density of 1,3,5‐Trinitro‐1,3,5‐Triazacyclohexane

Sun¹,

Shu²,

Liu³

et al. 2011

Propellants Explo Pyrotec

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The CTE and the theoretical density are important properties for energetic materials. To obtain the CTE and the theoretical density of 1,3,5‐trinitro‐1,3,5‐triazacyclohexane (RDX), XRD, and Rietveld refinement are employed to estimate the dimensional changes, within the temperature range from 30 to 170 °C. The CTE of a, b, c axis and volume are obtained as 3.07×10−5 K−1, 8.28×10−5 K−1, 9.19×10−5 K−1, and 20.7×10−5 K−1, respectively. Calculated from the refined cell parameters, the theoretical density at the given temperature can be obtained. The theoretical density at 20 °C (1.7994 g cm−3) is in close match with the RDX single‐crystal density (1.7990 g cm−3) measured by density gradient method. It is suggested that the CTE measured by XRD could perfectly meet with the thermal expansion of RDX.

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“…At approximately 160 °C, HMX experiences a polymorphic transition, from the -to the -polymorph [8]. Because the -polymorph is approximately 7% larger in volume the explosive charge may experience irreversible volume expansion and a significant increase in sample porosity due to irreversible rearrangement of the crystal-binder packing [9]. These changes in morphology can change the performance of the explosive charge.…”

Section: Introductionmentioning

confidence: 99%

The response of the HMX-based material PBXN-9 to thermal insults: Thermal decomposition kinetics and morphological changes

et al. 2011

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, an HMX-formulation, is thermally damaged and thermally decomposed in order to determine the morphological changes and decomposition kinetics that occur in the material after mild to moderate heating. The material and its constituents were decomposed using standard thermal analysis techniques (DSC and TGA) and the decomposition kinetics are reported using different kinetic models. Pressed parts and prill were thermally damaged, i.e. heated to temperatures that resulted in material changes but did not result in significant decomposition or explosion, and analyzed. In general, the thermally damaged samples showed a significant increase in porosity and decrease in density and a small amount of weight loss. These PBXN-9 samples appear to sustain more thermal damage than similar HMX-Viton A formulations and the most likely reasons are the decomposition/evaporation of a volatile plasticizer and a polymorphic transition of the HMX from  to  phase.

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Coefficient of Thermal Expansion of the Beta and Delta Polymorphs of HMX

Cited by 26 publications

References 24 publications

Vibrational and thermodynamic properties of β-HMX: A first-principles investigation

Vibrational and thermodynamic properties of β-HMX: A first-principles investigation

Investigation on the Thermal Expansion and Theoretical Density of 1,3,5‐Trinitro‐1,3,5‐Triazacyclohexane

The response of the HMX-based material PBXN-9 to thermal insults: Thermal decomposition kinetics and morphological changes

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