An Investigation into the Effects of Additives on Crystal Characteristics and Impact Sensitivity of RDX

Wang, Dongxu; Chen, Shusen; Yan-yue, LI; Yang, Jia-Yun; Wei, Tongbo; Jin, Shaohua

doi:10.1080/07370652.2013.812160

Cited by 14 publications

(9 citation statements)

References 27 publications

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“…As the growth unit further approaches the growth surface of the crystal, the growth unit selectively combines to the crystal face in a particular direction, ultimately achieving a growth from the liquid phase to the interior of the crystal lattice and promoting crystal growth in a particular crystallographic direction. Due to the anisotropy of the crystal structure, the three-phase regions which play an important role in the crystallization process will have different crystallographic directions, and the single crystal thereby establishes an anisotropic growth morphology surrounded by different crystal faces 43 .…”

Section: That the O•••h And N•••hmentioning

confidence: 99%

Crystal Morphology Prediction and Anisotropic Evolution of 1,1-Diamino-2,2-dinitroethylene (FOX-7) by Temperature Tuning

Song

Zhao²,

Xu³

et al. 2020

Sci Rep

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Temperature-induced morphological changes are one of the strategies for designing crystal shapes, but the role of temperature in enhancing or inhibiting crystal growth is not well understood yet. To meet the requirements of high density and low sensitivity, we need to control the crystal morphology of the energetic materials. We studied the crystal morphology of 1,1-diamino-2,2-dinitroethylene (FOX-7) in dimethyl sulfoxide/water mixed solvent by using the modified Hartman-Perdok theorem. Molecular dynamics simulations were used to determine the interaction of FOX-7 and solvents. The results showed that the crystal shape of FOX-7 is hexagonal, the (101) face is the largest exposed face and is adjacent to six crystal faces at 354 K. As the temperature goes down, the area of the (001) face is significantly reduced. The crystal morphology of FOX-7 at 324 K has a smaller aspect ratio of 4.72, and this temperature is suitable for tuning the morphology from slender hexagon into diamond. The prediction results are in remarkable agreement with the experiments. Moreover, we predicted the evolution path of FOX-7 morphology by Gibbs-Curie-Wulff theorem and explained the variation of crystal shape caused by different external conditions in the actual crystallization process. Crystallization as a green separation process is characterized by low energy consumption and high efficiency 1-3. The growth shape that a crystal obtains in the course of its formation is also highly sensitive to growth conditions, and reflects the growth mechanism, as does the surface morphology 4-7. Therefore, the growth shapes make it possible to judge the formation conditions and to correct the growth parameters in experiment. Based on the periodic bond chain (PBC) theory, Hartman and Perdok stated that the growth rate of a face is lower if fewer chains of strong bonds cross this face 8,9. This is the well-known Hartman-Perdok theorem (H-P theorem). The equilibrium crystal morphology can be determined by calculating the attachment energy. Gibbs stated that the polyhedral features of the crystal shape reduce the total surface energy. Curie defined that the normal growth rate of the crystal face is in proportion to the surface free energy 10. Wulff further proved that the distance from the crystal center to crystal face is proportional to the specific surface free energy in equilibrium 11. This relationship is also called the Gibbs-Curie-Wulff theorem 12,13. The prediction and regulation of crystal morphology is essential in the fields of pharmaceuticals 14,15 , catalysis 16,17 , functional ceramics 18 , thin film materials 19 , energetic materials 20,21 , etc. For example, the crystal morphologies influence the sensitivity of the energetic materials. In the formation of a drug product, crystals with high aspect ratio shapes are troublesome in the subsequent processing steps. In the field of catalysis, it is efficient for the catalyst to expose more active crystal face. Anisotropic morphologies, especially the large aspect ratio of one-dimensional needl...

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Section: That the O•••h And N•••hmentioning

confidence: 99%

Crystal Morphology Prediction and Anisotropic Evolution of 1,1-Diamino-2,2-dinitroethylene (FOX-7) by Temperature Tuning

Song

Zhao²,

Xu³

et al. 2020

Sci Rep

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“…Reference [ 18 ] shows that the liquid surface tension of PVAc, FKM DS2603, and VITON A is always greater than 0, for the use of the same binder in PBX. Combined with Equation (4) and Young equation, we obtain the following: W a RDX > W a H-RDX where W a is the adhesion work (mJ•m −2 ).…”

Section: Resultsmentioning

confidence: 99%

“…Along with improvements in the quality of RDX crystal, the application research and performance evaluation of H-RDX has also been conducted over the years. The use of H-RDX is mainly concentrated in cast formulations and melt-cast formulations owing to its higher density, lower shock wave sensitivity, better thermal stability, and detonation performance [ 15 , 16 , 17 , 18 , 19 ]. Despite the application of H-RDX to pressed formulations coming later than to other kinds of formulations [ 20 ], RS-RDX can keep their reduced shock sensitivity feature in pressed formulations, even with some extra-granular pores in the bulk of the binder.…”

Section: Introductionmentioning

confidence: 99%

The Effect of High-Quality RDX on the Safety and Mechanical Properties of Pressed PBX

et al. 2022

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In order to investigate and compare the effects of RDX crystal quality on the safety and mechanical properties of pressed PBX, different RDX-based PBXs were prepared by a water suspension granulation method. The surface morphology, thermal decomposition properties, impact sensitivity, and mechanical properties of high-quality RDX (H-RDX) and PBX were characterized by SEM, optical microscope, DSC, impact sensitivity tester, and universal material testing machines. The results have shown that the H-RDX crystal has a smoother surface, regular shape, higher density, fewer defects, better thermal stability, and lower impact sensitivity than raw RDX. The activation energy of H-RDX-based PBX is 26.0% higher than that of raw RDX-based PBX, and H50 increased by 2.8 cm, indicating that the application of H-RDX to PBX can effectively improve its thermal stability and reduce the impact sensitivity in the safety performance. However, the compressive strength of pressed H-RDX-based PBX is 36% lower than that of pressed raw RDX-based PBX, showing that H-RDX results in the deterioration of the compressive strength of pressed PBX in mechanical performance. Fortunately, this study found a strategy on how to effectively improve mechanical performance, which is changing the type of binder and increasing the pressing pressure. Under the same pressing conditions, the order of compressive strength of PBX prepared by the three binders is FKM DS2603 > Viton A > PVAc. Moreover, the compressive strength of H-RDX-based PBX with FKM DS2603 can be increased by 33.7% compared with PVAc. When the pressing pressure is 200 MPa, the average compressive strength of H-RDX-based PBX with FKM DS2603 reaches 10.00 MPa, which can basically meet application requirements.

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“…A significant trend is that energetic materials need to have higher detonation performance and lower sensitivity. With the in-depth study of high energy and insensitive explosives, the influence of crystal shape, crystal surface state, and crystal internal defects on the performance of explosives has attracted wide attention from researchers [6][7][8][9][10][11][12][13]. Compared to the explosive crystals in the form of flakes and needles, spherical explosives can significantly increase the charge density and improve the detonation performance of the charge.…”

Section: Introductionmentioning

confidence: 99%

Molecular Dynamics Simulation of β-HMX Crystal Morphology Induced by Polymer Additives

et al. 2022

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To simulate the crystal morphology of β-HMX crystallized in the presence of different polymer additives in the solution, a modified attachment energy model was used to simulate the crystal morphology of β-HMX recrystallized in PVA-DMSO solution when the mass fractions of PVA were 0.5%, 1%, 3%, 5%, and 10%, respectively. When the mass fraction of additive was 10%, the simulation results were in good agreement with the experiment. Molecular dynamics simulations were performed on the solution systems of different types of polymer additives to predict the morphology of β-HMX crystals. In addition, the effect of water on the crystal morphology of β-HMX was studied, and the effect of additive PVA on the solute and solvent diffusion ability during crystal crystallization was studied. The simulation results have certain reference significance in the crystallization process of β-HMX under additive conditions.

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An Investigation into the Effects of Additives on Crystal Characteristics and Impact Sensitivity of RDX

Cited by 14 publications

References 27 publications

Crystal Morphology Prediction and Anisotropic Evolution of 1,1-Diamino-2,2-dinitroethylene (FOX-7) by Temperature Tuning

Crystal Morphology Prediction and Anisotropic Evolution of 1,1-Diamino-2,2-dinitroethylene (FOX-7) by Temperature Tuning

The Effect of High-Quality RDX on the Safety and Mechanical Properties of Pressed PBX

Molecular Dynamics Simulation of β-HMX Crystal Morphology Induced by Polymer Additives

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