Due to the significantly reduced toxicity and shock sensitivity compared to TNT, DNAN is getting more and more attention in the study of insensitive munitions. However, the brittleness problem of DNAN limits its wide application. Inspired by mussels, DNAN particles with a thin and uniform coating based on the self-polymerization of dopamine were prepared by an oxidant-accelerated method in this work. XRD patterns indicated that the DNAN polymorph did not change during the coating process. FT-IR and XPS spectra manifested that the PDA was successfully distributed on the crystal surface. The results of TG-DSC analysis demonstrated that the mass ratio of PDA coating was as low as 1.71%. Meanwhile, Brazilian disk splitting test showed that the tensile strength, tensile strain, and fracture energy of DNAN@PDA cylinder were 16.1%, 32.0% and 53.0% higher than those of pure DNAN cylinder, respectively. The morphology of fracture surface after tensile test indicated that toughness fracture occurred in DNAN@PDA cylinder, while remarkable brittle fracture occurred in pure DNAN cylinder. The surface modification method could enhance the toughness of DNANbased explosives, and the fast fabrication of DNAN@PDA particles on a large scale could satisfy the application demands of insensitive munitions.

Utilizing insensitive explosives to form a eutectic with 3, 4-bis (3-nitrofurazan-4-yl) furoxan (DNTF) proved to be an effective method for reducing its sensitivity and melting point. In this study, the interaction between DNTF and 4-methoxy-1-methyl-3, 5-dinitro-1 H-pyrazole (DMDNP) was simulated using the interaction region indicator (IRI), revealing that the intermolecular forces in the mixture are stronger than those of the individual components. Co-molten mixtures of DNTF-DMDNP with varying compositions were prepared through electrostatic spraying technology, and a binary phase diagram was established using differential scanning calorimetry (DSC). The experimentally extrapolated molar ratio of the DNTF-DMDNP eutectic was determined to be 48.7/51.3, with a eutectic point at approximately 338.2 K. Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) tests confirmed that no chemical reactions or crystal transformations occurred during the preparation of the eutectic. The thermal decomposition temperatures at different heating rates and apparent activation energy of the eutectic fell within the range between those of DNTF and DMDNP. Addition of even just 10 % DMDNP significantly reduced mechanical sensitivity in co-molten mixtures, resulting in a rapid decrease from 100 % to 12 % friction sensitivity. The detonation velocity of the DNTF-DMDNP eutectic measured at 8.47 km s(-1) only experienced a slight decrease by about 0.78 km s(-1) (8.4 %) compared to pure DNTF, indicating efficient desensitization by incorporating DMDNP with minimal energy loss potentiality. Furthermore, adjusting composition allowed for control over detonation performance and sensitivity in melt-cast explosives composed of DNTF-DMDNP.

In order to study the morphology evolution of 1， 1‑diamino‑2， 2‑dinitroethylene （FOX‑7） particles under thermal stimulus and its influence on mechanical properties and mechanical sensitivities， four kinds of FOX‑7 particles with typical size and morphology differences were selected. By controlling heating time and temperature， the morphology， mechanical properties and mechanical sensitivities evolutions of FOX‑7 particles after heating were studied by scanning electron microscope， compressive stiffness experiment and mechanical sensitivities tests. The results show that the surface cracks of FOX‑7 particles appear after heating and returning to room temperature. With the increase of heating temperature or heating time， the surface cracks of large‑size particles （>100 μm） grow and break through ， thus the particles crack in layers and exfoliate. While， the surface cracks of small‑sized particles （<100 μm） do not grow with the increase of heating temperature or heating time. Kawakita equation was used to fit the compaction curves of FOX‑7 particles before and after heating. It is found that the modulus of FOX‑7 particles increase after heating， and the increase is even greater for small particle size. Under the condition of larger particle size， FOX‑7 has relatively low mechanical sensitivities， and still maintains low mechanical sensitivities after being heated and returning to room temperature. When the particle size is small， the mechanical sensitivities of FOX‑7 are relatively high， and after heating and returning to room temperature， the mechanical sensitivities increase significantly， which may be related to the greater increase of modulus.

In order to hunt for a high-energy and insensitive eutectic, differential scanning calorimetry (DSC) method was used to investigate the melting process of DNTF-DFTNAN co-molten mixtures with different compositions. Based on the experimental T-x phase diagram, the experimentally extrapolated molar ratio of DNTF-DFTNAN eutectic mixture is 30.1/69.9, which is consistent with the result from the H-x phase diagram, and the eutectic point is about 335.5 K, showing that the addition of DFTNAN can effectively reduce the melting temperature of DNTF. The FT-IR and XRD measurements of raw DNTF, raw DFTNAN and the DNTF-DFTNAN eutectic indicate that no chemical reaction occurred and the structure of crystal doesn't change during the preparation of the eutectic. The thermal decomposition temperatures at different heating rates and the apparent activation energy of eutectic are basically between DNTF and DFTNAN. The drop height (H-50) for the DNTF-DFTNAN eutectic increases by 27.4 cm (85.1%) compared with that of DNTF, and the detonation velocity decreases only by 0.5 km/s (5.5 %), implying that the DFTNAN can efficiently desensitize the DNTF explosive with a slight energy loss. In addition, the polynomial equations of mechanical sensitivity and detonation velocity with DNTF content were fitted to adjust the detonation performance and sensitivity of DNTF-DFTNAN co-molten mixture, which provides an opportunity to design DNTF-DFTNAN expected melt-cast explosives.

为研究碳纤维对浇注PBX力学性能的影响规律,在不同温度下(25℃、50℃、75℃),测定了不同碳纤维添加量(0、0.05％、0.10％)试样的抗压强度、拉伸强度、断裂伸长率.实验结果表明:在25℃下,添加0.05％碳纤维即可使试样抗压强度、拉伸强度、断裂伸长率分别提高21.81％、25.89％、5.20％,具有显著的增强、增韧效果.随着碳纤维添加量增至0.10％,试样的断裂伸长率进一步增加,但抗压强度、拉伸强度随之下降.当温度上升至75℃,添加了0.10％碳纤维的试样抗压强度、拉伸强度均小于空白试样.适宜的碳纤维添加量及其与浇注PBX聚合物基体的界面性能改善是优化浇注PBX综合性能的关键因素.

A facile coating method was used to control the number of layers precisely through multistep coating cycles. Effect of multilayers on the impact sensitivity of HMX were studied. Impact sensitivity of HMX significantly increased after one coating cycle, but decreased within increasing coating cycles subsequently. This changing trend of impact sensitivity of HMX with the increasing of coating layer thickness could be caused by the growth of surface roughness, the reduction of thermal stability, and the changing of the quasi-static compression properties. (C) 2020 Published by Elsevier B.V.

含能材料是武器系统的毁伤源和动力源,是战略性的基础材料,也是武器高能和安全的重要保证.在颠覆性含能材料获得工程应用前,传统CHON类含能材料对提升炸药的威力作用有限,而高活性金属材料具有巨大发展潜力,对提升武器装备毁伤效能具有重要意义.适用于炸药的高活性金属材料泛指点火燃烧性能好,可明显提升炸药威力的金属粉体,包括但不限于超细粉体、超级铝热剂、亚稳态合金、贮氢材料等,涉及金属冶炼、复合材料设计与制备、应用与性能评价等多个方面的研究,对推动学科发展,提升我国在本领域科技自立自强能力具有重要意义.

为明确含铝炸药冲击起爆过程中爆轰产物状态方程参数的确定方法,采用2,4-二硝基苯甲醚(DNAN)基熔铸含铝炸药RA1(奥克托今(HMX)/DNAN/Al)和对应含氟化锂(LiF)炸药RF1(HMX/DNAN/LiF)开展φ50 mm标准圆筒试验.利用电探针测速法和光子多普勒速度测试技术获得RA1和RF1炸药的爆速和圆筒膨胀速度,并通过遗传算法和数值模拟技术分别确定两种炸药的爆轰产物状态方程参数.对比RA1与RF1炸药的圆筒速度变化曲线发现:在0～4.6μs时间内,两曲线重合度较高;在4.6μs以后,随着铝粉反应量的增加,两曲线出现明显分离.结果表明:铝粉在爆轰阶段反应量很少,反应主要发生在产物膨胀阶段,由此可得在含铝炸药冲击起爆过程中铝粉的反应量可近似忽略,冲击起爆数值模拟时含铝炸药爆轰产物的状态可由对应含LiF炸药的产物状态方程描述.

The detection of low-concentration hydrogen peroxide (H2O2) has important theoretical-significance and practical value in many fields, such as medical science, biological chemistry, and food safety inspection. Traditional commercial H2O2 test paper and detection technology can only reach the detection limit of 10(-3)-10(-5) (mass fraction). In this paper, we report a simple method to prepare 2D MOF (metal-organic frameworks) [Co-3(HOB)(2)](n) films based on Langmuir-Blodgett (LB) method combined with layer-by-layer growth technique. Even 3-layer [Co-3(HOB)(2)](n) films can realize the lowest H2O2 detection limit of 1.05 x 10(-8) wt% (3.08 nmol.L-1) based on the resultant 2D MOF catalyst. Meanwhile, density functional theory (DFT) calculations revealed that Co2+ ions of the LB films decreased the energy of [HOOH] transforming into [HO2] during the H2O2 reduction reactions, thus speeding up the decomposition of H2O2.

为了解决聚合物黏结炸药(PBX)中小分子石蜡钝感剂力学性能差、与高分子黏结剂相容性不佳等问题,基于不同壁材石蜡微胶囊(MePW)的合成,采用浇注成型的方法,制备其与石蜡、端羟基聚丁二烯型聚氨酯(HTPB)的复合材料;研究了该复合材料的化学组成、脆断面形貌、表面和界面热力学性质、力学性能,以及它们之间的关系.结果 表明,加入MePW可以有效减少石蜡从HTPB基体脆断面脱离,以MF MePW和PS MePW改善效果最佳.与PW/HTPB相比,加入MePW后使材料表面张力(γs)最高降低了14.801 2 mN/m(60％ MF MePW/PW/HTPB),明显提高石蜡与HTPB间的相容性;同时力学性能显著增强,其压缩模量、压缩强度、拉伸模量、拉伸强度和断裂伸长率最高分别提高了10.4 kPa(PS-SiO2 MePW)、94 kPa(PMMA MePW/PW/HTPB)、44 kPa (MF MePW/PW/HTPB)、519kPa(MFMePW/PW/HTPB)和796.16％ (MF MePW/PW/HTPB).由此可见,4种壁材MePW中,MF MePW对PW/HTPB的改性效果最显著,最有利于其在PBX体系的应用.

Superamphiphobic coatings have attracted great attention in academia and industry. However, the fabrication of durable superamphiphobic coatings with high repellency towards liquids with low surface tension and high viscosity is still very challenging. Here, we report a simple method for the fabrication of durable superamphiphobic coatings with high static and dynamic repellency to such liquids. First, a homogeneous suspension was fabricated by hydrolytic condensation of silanes in the presence of the chain-like aggregates of SiO2 nanoparticles. Subsequently, the superamphiphobic coatings were fabricated by spray-coating the polyurethane adhesive onto the substrates followed by spray-coating the as-prepared suspension onto the polyurethane adhesive layer. The coatings show high repellency to liquids with low surface tension and high viscosity, e.g., high apparent contact angles, low sliding angles, high impact resistance, low horizontal deformation and fast rolling velocity. Furthermore, the coatings show excellent mechanical durability against intensive sandpaper abrasion (60 m of abrasion under 10.5 kPa), water impact (60 min under 100 kPa) and tape peeling (200 cycles). The coatings also exhibit good aging stability. Based on these merits, the superamphiphobic coatings may have great potentials in various applications, e.g., handling with natural and synthetic polymer solutions.

The bioinspired anti‑wetting surface can decrease the interfacial adhesion between the container and the high viscosity liquids, which was further testified with the well anti‑adhesion phenomenon by the PBX slurry pouring into the treated mould.

Plasticization of A16 energetic plasticizer to HTPB was studied based on a combination of numerical calculations and experimental tests. The compatibility of A16 with HTPB was simulated by molecular dynamics method. And the apparent viscosities and the mechanical properties of HTPB/A16 and HTPB/DOS systems were studied to compare the plasticizing properties of two plasticizers.

Although significant attention has been paid, most of superamphiphobic surfaces suffer from high sliding angles (SA) for liquids with low surface tension and complicated preparation methods. Also, superamphiphobic coatings with high repellency to the liquids with very high viscosity and low surface tension are rare. Here, we report preparation of clay-based superamphiphobic coatings with low SAs for viscous liquids. A homogeneous suspension was prepared by hydrolytic condensation of 1H,1H,2H,2H-perfluorodecyltriethoxysilane and tetraethoxysilane in the existence of attapulgite, a kind of natural clay mineral with nanorods-like microstructure. The superamphiphobic coatings were readily prepared by spray-coating the suspension onto substrates. The effects of attapulgite on microstructure and superamphiphobicity of the coatings were studied. Also, the static and dynamic superamphiphobicity were investigated. The attapulgite concentration has great influences on superamphiphobicity and solid-liquid adhesion force of the coatings, as it determines microstructure of the coatings. The superamphiphobic surfaces feature high contact angles and low SAs for various liquids including those with extremely high viscosity and low surface tension, e.g., hydroxyl-terminated polybutadiene (HTPB) and the HTPB/Al mixture (1:1, w/w). The coating also shows low solid-liquid adhesion force, high impact resistance and fast rolling of various liquids.

Hydrogen peroxide has been widely studied in cell biology and liquid fuel cells as an oxidant or fuel, and highly efficient and durable electrocatalysts for H2O2 reduction and detection are in high demand. Here, a simple strategy to fabricate conductive 2D single/several-layer [Co-3(HHTP)(2)](n) MOF nanosheets, based on 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP) and Co(2+ )ions, was developed by the Langmuir-Blodgett (LB) method combined with layer-by-layer (LbL) growth technology. The [Co-3(HHTP)(2)](n) MOF nanosheets successfully boosted H2O2 reduction with ultrahigh mass activity and good durability, and a new method to detect the H(2)O(2 )concentration with an ultralow detection limit of 10(-7) (2.9 mu mol L-1) was developed. Meanwhile, a series of factors like layer number, surface tension, pH value, ion concentration, and annealing were systematically investigated to further prove the ultrahigh accuracy, sensitivity, and durability of the as-developed H2O2 detection method. The reaction mechanism and energy transfer process of H2O2 reduction catalyzed by the metal-organic nanosheets were investigated by first principles calculations using density functional theory (DFT), showing good agreement with the experiment.

Novel HMX (octahydro-1.3,5,7-tetranitro-1,3,5,7-tetrazonicine) based metalized explosive formulations, containing boron and aluminum (B/Al) powders, hydroxyl-terminated polybutadiene (HTPB) and belonging to the enhanced blast explosive, were designed and prepared. Investigations of the energetic characteristics of the new metalized explosives were undertaken to improve such composite explosive formulations. The impact sensitivity and friction sensitivity were measured which made a full acknowledgement of the safety of metalized explosive under different external energy stimuli. The detonation velocity and detonation pressure were measured using spring electric pin method and plate dent test, respectively. The explosion heat was measured in a calorimetric bomb filled with nitrogen (N-2) and the cylinder expansion test was performed. From the cylinder test data the wall velocity and the Gurney energy of the explosives were determined. Then, the isentrope exponents of the composite detonation products were estimated numerically with hydrodynamic code. Finally, the JWL equation of state of the detonation products was determined for each explosive according to our test data. The effect of the Al and B content on the detonation characteristics is also checked.

为研究某奥克托今(HMX)基塑料粘结炸药(PBX)炸药对不同材料金属壳体的驱动加速能力,参照25 mm标准圆筒试验,研究了该炸药对无氧铜(Cu)、钛合金(TC4)和高强度钢(G50)三种壳体材料的做功能力,获得了圆筒壁的膨胀过程及最大膨胀速度;并与理论计算值和数值模拟结果进行了对比.研究表明:该炸药爆轰驱动不同壳体材料的膨胀破裂时间和破裂半径存在差异;且对低密度钛合金壳体材料的驱动能力最强.圆筒试验件破片初速理论计算值、数值模拟结果与试验值吻合较好,相对误差均在10％以内;相比标准圆筒试验只考虑炸药对单一金属铜管的驱动加速能力,研究结果可为该炸药与武器弹药壳体材料的匹配设计提供参考.

The cover picture shows the comparing combustion performance of the original HMX and the bioinspired composite HMX@PDA@TiO2 . The mussels in the sea represent the bioinspired fabrication method for the composite in the paper. The hollow bubbles are polydopamine film and dopamine molecular in solution with different pH values. The yellow particles represent the nanocatalysts TiO2 anchored via bonding on the surface of HMX. The picture reveals that the interaction properties of the composite greatly influence the composite performance. Details are discussed in the articles by Q. Zhu et al. on page 438 ff.