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As a new structural motif, an interesting 3D energetic metal – framework of silver ions and 3,4-diaminofurazan, [Ag+(daf)NO3−]n, is successfully synthesized and the structure is determined by single-crystal X-ray diffraction. The effects of hydrogen bond, coordination bond, adsorption and filling interactions make this compound have a high density (2.694 g·cm−3 at 293 K). The calculated detonation velocity and the sensitivities are all comparable with trinitrotoluene (TNT). The onset decomposition temperature is equal to hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), state-of-the-art explosive. This framework provides a potential superiority of E-MOFs for energetic materials. [ABSTRACT FROM AUTHOR]

Chitosan microspheres(HTCC) were prepared by hydrothermal method,and Amino-modified chitosan adsorbent (AHTCC) was prepared by epoxidization and amination method to adsorb low concentration uranium in wastewater. The structure, composition and thermal stability of AHTCC were characterized by infrared spectrometer, elemental analyzer and thermogravimetric analyzer, and the adsorption and desorption properties of AHTCC for uranium were investigated. The results show that AHTCC has a good adsorption effect on uranium in solution at pH=5~8. Under the condition of equilibrium mass concentration of uranium adsorption of 120 mg/L,the adsorption capacity reaches the 151. 6 mg/g. Its adsorption rate is faster in the initial 60 min and reaches equilibrium at 180 min. Using 80 g/L Na2CO3+20 g/L NaHCO3 as the desorption agent, the desorption rate of uranium is 97. 5%. For real uranium containing wastewater with high concentration of impurities, the removal rate of uranium can reach 95. 6% after single adsorption by AHTCC. [ABSTRACT FROM AUTHOR]

Polyurethane (PU) coatings display several advantages such as easy construction, adjustability, and excellent mechanical properties, and therefore have potential applications in the coating of rocket engines and warheads. However, mechanical strength, high ductility and thermal stability are often difficult properties to combine, which has become a key limitation in efforts toward developing PU coatings for these applications. In this paper, a fast‐curing PU film was developed by reacting between polytetrahydrofuran and diphenylmethane 4,4'‐diisocyanate. The mechanical strengthening effect of SiC nanoparticles on the film was studied and compared with other common fillers, including TiO2, XFM13. The results revealed that SiC nanoparticles substantially increased the mechanical properties in PU coating, increasing the material's tensile strength and elongation at break to 34.14 MPa and 434% respectively. In addition, the inclusion of SiC nanoparticles generally improved the thermal stability and low temperature resistance of PU film. The results generated in this research has established a foundation for the application of PU materials in fields requiring high performance properties, such as rocket engines coatings and warhead manufacture. [ABSTRACT FROM AUTHOR]

A novel solvent‐free energetic coordination polymer [Ag(3,4‐dnp)] was performed by dehydration. The structure was confirmed by single‐crystal X‐ray crystallography and the Ag(I) ions are coordinated in bidentate‐bridging mode. The results of thermal analysis (thermogravimetric and accelerating rate calorimeter) show that this compound has higher thermal stability than that of the traditional CHON‐containing energetic materials, RDX, HMX and CL‐20. The detonation velocity and detonation pressure of [Ag(3,4‐dnp)] are 5.532 km s−1, 15.88 GPa, respectively, which is lower than that HMX, RDX and TNT, and comparable with the 2D MOFs [Ag(Mtta)] based on the Ag ions and 5‐methyl tetrazole. The impact and friction sensitivities of this compound are infinitely close to RDX, state‐of‐the‐art explosive. The coordination polymers based on metal ions and nitropyrazole are promising potential as energetic materials. [ABSTRACT FROM AUTHOR]

During application, energetic materials may suffer different temperature environmental stimulation. In order to study the influence of temperature environmental on performance of HNIW/FOX-7 based PBXs, HNIW/FOX-7 based PBX modeling powders and PBX columns were treated by LT (low temperature), HT (high temperature), HLC (high-low temperature cycle) and HLS (high-low temperature shock). Then scanning electron microscope (SEM), infrared spectra (IR), X-ray diffraction (XRD) and differential scanning calorimetry (DSC) were used to study the variation of PBX modeling powders after LT, HT, HLC and HLS treatments; in addition, the mass, size and mechanical properties of PBX columns were characterized after different temperature adaptability treatments as well. The results indicate that the change ratios of mass and size of HNIW/FOX-7 based PBX columns are less than 1%, illustrating that mass and size of PBX columns are at acceptable level after different temperature adaptability treatments. The unevenness degree of the surface of PBX modeling powders followed the order of HLC > HT > LT > HLS, which agrees well with mass loss order. Moreover, IR and XRD results indicated that the molecular structure and crystal form of HNIW and FOX-7 did not change after different temperature adaptability treatments. Additionally, thermal stabilities of PBX modeling powders are decreased after different temperature adaptability treatments, among which HLS has the largest influence on HNIW/FOX-based PBX modeling powders. The compression strengths and elastic moduli of HNIW/FOX-based PBX columns are enhanced after different temperature adaptability treatments, among which the strength of PBX columns after HLC has the maximum increase, indicating that HLC has more significant effect on mechanical property. [ABSTRACT FROM AUTHOR]

To study the influence of twinned crystals on the performance of TKX-50, normal TKX-50 (N-TKX-50) and twinned TKX-50 (T-TKX-50) supercells are constructed, and ReaxFF-lg reactive molecular dynamics simulations are performed to study the thermal decomposition and oxidation of N-TKX-50 and T-TKX-50 at 1000, 2000 and 3000 K. The mechanism of thermal decomposition and oxidation of N-TKX-50 and T-TKX-50 are analyzed in terms of potential energy evolution, primary reaction paths, and the intermediate and final products. We find that T-TKX-50 possesses higher decomposition and consumption rate than N-TKX-50 at the same temperature conditions, while the decomposition and the oxidation end-products of N-TKX-50 and T-TKX-50 are the same. These results confirm that the T-TKX-50 crystal is unfavorable for the thermal stability of TKX-50. We believe that this work can provide some guidance for investigating the decomposition and oxidation of other materials. [ABSTRACT FROM AUTHOR]

TKX-50/GO composite was prepared and characterized. The results suggested that the morphology of TKX-50 was improved from tabular crystal to polyhedron after coating with GO. The thermal stability of TKX-50/GO composite was essentially unchanged. Both impact sensitivity and friction sensitivity of TKX-50/GO composite was more insensitive than those of TKX-50. [ABSTRACT FROM AUTHOR]

The thermal behavior and decomposition kinetics of CL-20-based plastic-bonded explosives (PBXs) composed of main explosive CL-20 and additives were first time explored by means of DSC, TG and ARC techniques. The DSC study at different heating rates was performed and showed the effect of the additives on the exothermic peaks of CL-20-based PBXs. The thermal stability of CL-20-based PBXs was evaluated by DSC, TG and ARC, indicating that the largest influence on lowering the activation energy is the presence of plasticizer. The kinetic parameters after addition of additives were compared with those of raw CL-20 by means of Kissinger and Ozawa methods. Moreover, the mechanical sensitivities of investigated CL-20-based PBXs were supported, which was well consistent with the data from DSC and ARC measurements. [ABSTRACT FROM AUTHOR]

4,4′-Azo-bis(1,2,4-triazolone) (ZTO) based salts from alkaline (Li+, K+, Na+, and Cs+), alkaline earth metal salts (Mg2+, Ca2+, Sr2+, and Ba2+) and hydrazinium salt were synthesized in a simple, straightforward manner and were characterized by IR and NMR spectroscopy, elemental analysis. The single-crystal X-ray diffraction of seven salts (Na+, K+, Cs+, Mg2+, Ca2+, Sr2+, Ba2+, and N2H5+) are also reported. The X-ray structures show that in the title compounds, the metal atoms are bonded to the nitrogen and oxygen atoms in the bistetrazole ring to form a sandwich structure. In addition, the thermal stabilities of all the title compounds were determined using thermogravimetric-differential thermal analysis (TG-DTA). All these new materials exhibit excellent thermal stability, high density, acceptable detonation properties, and excellent insensitivity to impact (h50 ＞ 60 cm). In particular, the barium, caesium and strontium salts are of great interest as potential high-density insensitive materials. [ABSTRACT FROM AUTHOR]