Ultrafine 2，6‑diamino‑3，5‑dinitropyrazine‑1‑oxide （LLM‑105） possesses high safety performance and low impact initiation threshold， showing promising applications in the initiation sequence. Solid‑phase ripening is the main aging behavior of ultrafine LLM‑105 during the storage process， which leads to the growth of particle size and performance degradation. Temperature and humidity are important environmental factors that affect solid‑phase ripening， but the microscopic mechanism is still unclear. In situ small angle X‑ray scattering （SAXS）， Scanning electron microscope （SEM） and in situ Atomic force microscopy （AFM） were used to capture the structural evolution of ultrafine LLM‑105 particles under different temperature and humidity environments， and the solid‑phase ripening mechanism was analyzed. Ultrafine LLM‑105 had obvious solid‑phase ripening after 30 days at 120 ℃， and its specific surface area （SSA） decreased by 41.6%. The ripening mechanism was dominated by Ostwald Ripening （OR）， accompanied with Smoluchowski Ripening （SR）. Humidity significantly accelerates the solid‑phase ripening of ultrafine LLM‑105 by promoting OR. After 30 days at 60 ℃ and 90% relative humidity， SSA decreased by 35.8%.

Thermal stability is one of the key factors that determine the engineering applications of energetic cocrystals (ECCs). Herein, in-situ morphology and structure characterization techniques were adapted to investigate the thermal stability of hexanitrohexoazaisowurtzitane/1-methyl-3,4,5-trinitro-1H-pyrazole (CL-20/MTNP) cocrystal. The cocrystal structure was observed to completely decompose when heating at 140 o C for 180 min and 180 o C for 140 min, which are much lower than the decomposition temperature (220 o C) determined by non-isothermal differential scanning calorimetry (DSC) test. Due to the low temperature, CL-20/MTNP cocrystal gradually transformed to porous γ -CL-20 after thermal treatment. More importantly, an obvious morphology evolution was observed on the crystal surface even at the temperature low to 100 o C, which indicates an even much poorer thermal stability of the cocrystal surface. Combined the experimental observation and theoretically structure analysis, a novel surface-induced decomposition mechanism was proposed to explain the unexpectedly low thermal stability of the CL-20/MTNP cocrystal. These results provide a new perspective on the thermal stability of ECCs and will have significant impacts on the evaluation and application of ECCs.

为了研究奥克托今(HMX)晶体的激光辐照效应,采用多种技术手段表征了HMX晶体在360 nm紫外激光下的微观结构演化.光学显微镜下观察了激光辐照下HMX晶体内部的缺陷积累直至细化开裂的过程.通过对原位拉曼光谱分析发现HMX吸收紫外光子后会激发HMX分子,引起环的振动.采用原位广角X射线散射(WAXS)、单晶衍射(SCXRD)和原位小角X射线散射(SAXS)技术研究了HMX在紫外激光辐照过程中的晶体变化及缺陷演化,发现HMX不会发生相变但会细化并产生新的缺陷.原位SAXS结果表明,激光辐照1170 min后HMX孔隙不断增多,并在10～20 nm和30～40 nm两个区域呈双峰分布.激光辐照过程中HMX的小尺寸孔隙不断增多并逐渐融合成更大尺寸的孔隙,缺陷不断累积,微孔隙延伸成微裂纹,再扩展成宏观裂纹.

ZIF‑8@Ag composites were prepared by in situ growth and modified with 4‑ATP as efficient probe. The Raman inactive TNT initiated the high Raman scattering of non‑resonated 4‑ATP through the π‑π conjugate between 4‑ATP and TNT.

Continuous band structure tuning, e.g., doping with different atoms, is one of the most important features of inorganic semiconductors. However, this can hardly be realized in organic semicondutors. Here, we report the first example of fine-tuning organic semiconductor band structures by alloying structurally similar derivatives into one single phase. By incorporating halogen atoms on different positions of the backbone, BDOPV derivatives with complementary intramolecular or intermolecular charge distributions were obtained. To maximize the Coloumbic attractive interactions and minimize repulsive interactions, they form antiparallel cofacial stacking in monocomponent or in alloy single crystals, resulting in efficient π orbital overlap. Benefiting from self-assembly induced solid state "olefin metathesis" reaction, it was observed, for the first time, that three BDOPV derivatives cocrystallized in one single crystal. Molecules with different energy levels serve like the dopants in inorganic semiconductors. Consequently, as the total number of halogen atoms increased, highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels of the alloy single crystals decreased monotonously in the range from -5.94 to -6.96 eV and -4.19 to -4.48 eV, respectively.

To explore the influence of cold‑pressed forming pressure on the microstructure of polymer bonded explosive (PBX), the small angle neutron scattering (SANS) signals of different pressure‑formed octogen (HMX)‑based PBX were measured by contrast variation SANS technique. The evolution of interfacial surface area between explosive crystal, binder and void in sample with the forming pressure was obtained by Porod’s theorem. Results show that when the forming pressure increases from 64MPa to 178 MPa, the density of sample increases from 1.55g·cm-3 to 1.72 g·cm-3 , and the interfacial binding rate between HMX and binder increases from 23.7% to 26.7%, and the total internal interfacial surface area per unit mass PBX, Stotal decreases by 6.1% (the error of experiment is 3%), and the interfacial surface area between HMX and binder (SHB) increases by 15.2%, and the interfacial surface area between HMX and void (SHV) basically remains unchanged, while the interfacial surface area between binder and void (SBV) decreases by 38.0%, indicating that the modeling powder and binder are gradually compacted during the process. When the forming pressure increases from 178 MPa to 382 MPa, the density of sample increases to 1.79 g·cm-3, and the interfacial binding rate between HMX and binder increases to 42.3%, and Stotal decreases by 11.2%, and SHB increases by 49.0%, and SHV decreases by 25.8%, and SBV decreases by 45.5%, indicating that in this process, except the compaction of modeling powder and binder, a great amount of binder flows to the surface of HMX crystal. In addition, when the forming pressure increases from 64 MPa to 382 MPa, the sum of SHB and SHV (i.e. total internal interfacial surface area per unit mass PBX sample) remains basically unchanged, indicating that the cold‑pressed process does not lead to a large number of transcrystalline breakage of HMX crystal, which is consistent with the optical microscopic results.

Through an in-situ controllable synthetic strategy, an energetic metal–organic framework comprising a gem-dinitromethyl-substituted dipotassium 4,5-bis(dinitromethyl)-1,2,3-triazole with a “cage-like” crystal packing was obtained. During its synthesis, trifluoroacetic acid played a significant role as an effective catalyst in the in-situ generation of the gem-dinitromethyl group. This new metal–organic framework displays a high density and high detonation velocity. Meanwhile, its detonation products are mainly nitrogen, suggesting it is also a “green” energetic material. The proposed strategy of incorporating gem-dinitromethyl groups into a 1,2,3-triazole (N3) framework holds great promise for developing new-generation lead-free primary explosives with a high-performing detonation level. More information can be found in the Communication by Hongwei Yang, Guijuan Fan et al. on page 2786 in Issue 19, 2018 (DOI: 10.1002/asia.201800722).

Polymeric composite membranes have emerged as the leading technology in industrial gas separation fields for decades, but there are still several unsolved fundamental problems on the interface between layers in composite membranes, which hinders the development of membranes with better performance. The penetrating layer locating between the selective layer and the supporting layer of composite membranes could strongly affect both gas separation performance and durability of membranes, the understanding of the penetrating layer is however limited. The bottleneck in studying penetrating layer is structure characterization, as the penetrating layer is hard to be distinguished from the selective layer and the supporting layer by an electronic microscope. Here, the nanoporous structure of the penetrating layer in the polydimethylsiloxane (PDMS)/polysulfone (PSf) composite membrane was characterized by small angle X-ray scattering (SAXS) that measures variations of nano-pore size distribution of membranes. The penetration degree was quantitatively described as a relative reduction in gyration radius of pores measured by SAXS. In the penetration process, the repeated cycles of penetration and drying of PDMS solution in pores occurred, which filled the small pores and divided the big pore into smaller ones. Moreover, the effects of penetrating layers on the gas transport property of composite membranes were estimated by using restriction factor in which the restriction effect of the supporting layer was also considered, and high correlation between penetration degree and restriction factor was presented.

The newly synthesized ionic triple salt Ru-Er, {[RuII(bpy)2(dbim)][ErIII(hfac)4][CF3COO]·H2O} (bpy = 2,2'-bipyridine; hfac- = hexafluoroacetylacetonate; dbim = 2,2'-dibenzimidazole) exhibits near-infrared (NIR) emission at 1535 nm by intermolecular Ru → Er (d → f) energy transfer across supramolecular interactions when pumped within the Ru(ii) 3MLCT band. It is the first such observation for a transition metal-lanthanide ionic pair.

To explore the crystal habits of β-HMX in acetone,we prepared β-HMX single crystals by solvent evaporation method and applied powder X-ray diffractions to determine all the crystal surfaces,using powder GeO2 as the internal standard sample for the refinement and the zero shift correction.A model was established for the crystal habit ofβ-HMX in acetone and compared to those reported in literature.The crystal surface ofβ-HMX are indexed as (1 0 0),(0 1 1),(-1 1 1) and (0 2 0).Among them,the (1 0 0) crystal face is the largest one,following by (1 1 0) and (-1 1 1) and (0 2 0),which consists with the theoretical calculated AE model with solvent effect correction.Because of the weak interactions with acetone molecules,(1 1 0) and (0 2 0) crystal faces disappeared gradually during the crystal growth process,which indicates the solvent environment has significant effect on the morphology of β-HMX.

Mixed matrix membranes (MMMs) for gas separation show promising applications in energy and environment related fields. However, the poor compatibility between particles and polymers in MMMs is the main problem. Zeolitic imidazolate frameworks (ZIFs) as inorganic-organic hybrid porous materials have better compatibility with polymers than other inorganic particles, but interfacial defects between ZIFs and polymers still have been observed in MMMs. In this work, the interfacial compatibility in MMMs has been enhanced by building covalent bonds between amine modified ZIF-8 (NH2-ZIF-8) and polyamide in thin film nanocomposite (TFN) membranes prepared by in situ interfacial polymerization (IP). The attendance of amino groups on the surface of NH2-ZIF-8 was confirmed by both experiments and molecular simulation. The covalent bonds formed between NH2-ZIF-8 and trimesoyl chloride (TMC), the monomer in organic phase of IP, were characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Compared with the TFN membrane with ZIF-8, the TFN membrane with NH2-ZIF-8 exhibits both higher CO2 permeance and higher CO2/N-2 selectivity, which is mainly attributed to the enhanced interfacial compatibility and disturbed chain segment of polyamide by covalent bonds. Moreover, at high content of NH2-ZIF-8 in membranes, no interfacial crack appears between NH2-ZIF-8 and polyamide in membranes, which also confirms the excellent compatibility between NH2-ZIF-8 and polyamide. The TFN membrane with NH2-ZIF-8 shows high separation performance for CO2/N-2, CO2/NO, and CO2/He gas pairs, which surpasses the Robeson's upper bounds.

Monodisperse hollow hexanitrostilbene-piperazine compound microspheres were fabricated successfully through a facile one-pot procedure based on the reaction of hexanitrostilbene (HNS) and piperazine without any template or surfactant. Synthesis conditions (ratio of reactants, stirring rate, reaction temperature and time) have been optimized to obtain compound microspheres with good monodispersion and narrow size distribution. And the results indicated that as-obtained microspheres possessed central hollow structures. Moreover, a possible formation mechanism for assembling hollow compound microspheres was proposed. This work may introduce a novel idea towards designing and fabricating the new hollow spheres materials. (C) 2017 Elsevier B.V. All rights reserved.

Two novel efficient burning promoters of solid propellants based on Ni salt and azotetrazole have been successfully prepared and characterized.

Two novel, efficient metal organic framework photocatalysts based on silver salts and tetrazolate derivatives have been successfully prepared and characterized.