Contrast Variation Small Angle Neutron Scattering Investigation of Micro- and Nano-Sized TATB

Song, Panqi; Tu, Xiaoqing; Bai, Liangfei; Sun, Guangai; Tian, Qiang; Gong, Jian; Gui-yu, Zeng; Chen, Liang; Qiu, Lili

doi:10.3390/ma12162606

Cited by 12 publications

(9 citation statements)

References 30 publications

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“…According to the results in Table 1, it can be found that for smaller particle size, large porosity and specific surface area can be obtained, which is consistent with the results of Song et al. [29]. It can be seen from these results that particle size can affect the structure of nano pores in LLM‐105.…”

Section: Resultssupporting

confidence: 87%

“…The results show that the pore volume per unit mass of LLM-105 increases with the decrease of the particle size, and the increase of pore volume when the particle size decreases from micron to 500 nm is much larger than that when the particle size decreases from 500 nm to 200 nm. According to the results in Table 1, it can be found that for smaller particle size, large porosity and specific surface area can be obtained, which is consistent with the results of Song et al [29]. It can be seen from these results that particle size can affect the structure of nano pores in LLM-105.…”

Section: Analysis Of Internal Pore Structuresupporting

confidence: 88%

“…Therefore, contrast variation smallangle scattering is a very effective method to study the nano pores in micro/nano energetic materials. Song et al [29] used the contrast variation small-angle neutron scattering (CV-SANS) to characterize the fractal characteristics and porosity of TATB, and determined the influence of particle size on the microstructure characteristics. The scattering results show that the external surface of micron TATB crystal is a continuous smooth interface, and its internal pores exhibit surface fractal structure, while the outer surface of nano TATB particles exhibits surface fractal structure (surface fractal dimension 2.36 < D s < 2.55).…”

Section: Introductionmentioning

confidence: 99%

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Characterization of the Internal Pores of LLM‐105 with Different Particle Sizes Using Contrast Variation Small Angle X‐Ray Scattering

Xing

Dong

Yao

et al. 2022

Propellants Explo Pyrotec

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To study the effect of particle size on the internal pore structure of micro/nano energetic materials, three kinds of micro/nano explosives 2,6‐diamino‐3,5‐dinitropyrazine‐1‐oxide (LLM‐105) with different particle sizes were selected as the research objects. The internal pore structure information, including porosity, pore volume distribution and fractal characteristics of micro/nano LLM‐105 were characterized by contrast variation small‐angle X‐ray scattering (CV‐SAXS). The scattering results show that the power‐law index of three samples with different particle sizes is between 3 and 4 in the measured q range (the surface fractal dimension Ds of 200 nm LLM‐105 is 2.16, Ds of 500 nm LLM‐105 is 2.20, and Ds of 3 μm LLM‐105 is 2.76). With the decrease of particle size, the interface between the internal pores and matrix becomes smooth. The pore volume per unit mass of LLM‐105 increases with the decrease of the particle size. The increase of pore volume per unit mass when the particle size decreases from 3 μm to 500 nm is much larger than that when the particle size decreases from 500 nm to 200 nm. The number of 2.5 nm–40 nm internal pores in LLM‐105 increases with the decrease of particle size. Especially for the pores of 11 nm, the number of pores increases most obviously with the decrease of particle size.

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Section: Resultssupporting

confidence: 87%

Section: Analysis Of Internal Pore Structuresupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Characterization of the Internal Pores of LLM‐105 with Different Particle Sizes Using Contrast Variation Small Angle X‐Ray Scattering

Xing

Dong

Yao

et al. 2022

Propellants Explo Pyrotec

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“…Moreover, by considering a succession of power-law decays interleaved with Guinier regions, one can describe hierarchically structured systems. This succession forms the basis of Beaucage [43,44] and Guinier-Porod [45] models, which are widely used as empirical models to analyze SAS data from random fractal and particulate systems, such as those occurring in some amphiphilic triblock polyelectrolytes [46], rocks [47], fertilizers encapsulated by starch-based superabsorbent polymers [48], silica-filled silicone rubber [49], aerosol nanoparticles [50] or micro/nano-sized TATB crystallites [51].…”

Section: Introductionmentioning

confidence: 99%

Small-Angle Scattering from Fractals: Differentiating between Various Types of Structures

Anitas

2020

Symmetry

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Small-angle scattering (SAS; X-rays, neutrons, light) is being increasingly used to better understand the structure of fractal-based materials and to describe their interaction at nano- and micro-scales. To this aim, several minimalist yet specific theoretical models which exploit the fractal symmetry have been developed to extract additional information from SAS data. Although this problem can be solved exactly for many particular fractal structures, due to the intrinsic limitations of the SAS method, the inverse scattering problem, i.e., determination of the fractal structure from the intensity curve, is ill-posed. However, fractals can be divided into various classes, not necessarily disjointed, with the most common being random, deterministic, mass, surface, pore, fat and multifractals. Each class has its own imprint on the scattering intensity, and although one cannot uniquely identify the structure of a fractal based solely on SAS data, one can differentiate between various classes to which they belong. This has important practical applications in correlating their structural properties with physical ones. The article reviews SAS from several fractal models with an emphasis on describing which information can be extracted from each class, and how this can be performed experimentally. To illustrate this procedure and to validate the theoretical models, numerical simulations based on Monte Carlo methods are performed.

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“…The selectivity of the sensitivity of ultra-fine explosives is the key to their performance in applications. According to the hot spot theory, the selectivity of the sensitivity is highly related to the size and number of defects in explosives [ 4 , 5 ]. A lot of numerical simulation works have reported the process of forming hot spots from defects in explosives such as atomic scale local distortion structures and nano pores [ 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ].…”

Section: Introductionmentioning

confidence: 99%

Effects of Grain Refinement and Thermal Aging on Atomic Scale Local Structures of Ultra-Fine Explosives by X-ray Total Scattering

et al. 2022

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The atomic scale local structures affect the initiation performance of ultra-fine explosives according to the stimulation results of hot spot formation. However, the experimental characterization of local structures in ultra-fine explosives has been rarely reported, due to the difficulty in application of characterization methods having both high resolution in and small damage to unstable organic explosive materials. In this work, X-ray total scattering was explored to investigate the atomic scale local distortion of two widely applicable ultra-fine explosives, LLM-105 and HNS. The experimental spectra of atomic pair distribution function (PDF) derived from scattering results were fitted by assuming rigid ring structures in molecules. The effects of grain refinement and thermal aging on the atomic scale local structure were investigated, and the changes in both the length of covalent bonds have been identified. Results indicate that by decreasing the particle size of LLM-105 and HNS from hundreds of microns to hundreds of nanometers, the crystal structures remain, whereas the molecular configuration slightly changes and the degree of structural disorder increases. For example, the average length of covalent bonds in LLM-105 reduces from 1.25 Å to 1.15 Å, whereas that in HNS increases from 1.25 Å to 1.30 Å, which is possibly related to the incomplete crystallization process and internal stress. After thermal aging of ultra-fine LLM-105 and HNS, the degree of structural disorder decreases, and the distortion in molecules formed in the synthesis process gradually healed. The average length of covalent bonds in LLM-105 increases from 1.15 Å to 1.27 Å, whereas that in HNS reduces from 1.30 Å to 1.20 Å. The possible reason is that the atomic vibration in the molecule intensifies during the heat aging treatment, and the internal stress was released through changes in molecular configuration, and thus the atomic scale distortion gradually heals. The characterization method and findings in local structures obtained in this work may pave the path to deeply understand the relationship between the defects and performance of ultra-fine explosives.

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Contrast Variation Small Angle Neutron Scattering Investigation of Micro- and Nano-Sized TATB

Cited by 12 publications

References 30 publications

Characterization of the Internal Pores of LLM‐105 with Different Particle Sizes Using Contrast Variation Small Angle X‐Ray Scattering

Characterization of the Internal Pores of LLM‐105 with Different Particle Sizes Using Contrast Variation Small Angle X‐Ray Scattering

Small-Angle Scattering from Fractals: Differentiating between Various Types of Structures

Effects of Grain Refinement and Thermal Aging on Atomic Scale Local Structures of Ultra-Fine Explosives by X-ray Total Scattering

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