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Large-Scale Fabrication of Boron Nitride Nanosheets and Their Utilization in Polymeric Composites with Improved Thermal and Mechanical Properties

http://www.sciencemadness.org/talk/files.php?pid=302583&aid=26587

Azole-based energetic salts.

Metal organic frameworks (MOFs) are considered as a group of compounds, either metal ions or clusters, harmonized with organic ligands to form one or some dimensional structures. In addition to resilient bonds between inorganic and organic units, reticular synthesis creates MOFs, accurate selection of constituents of which can produce high thermal and chemical stability and crystals of ultrahigh porosity. Other solids have not shown the same accuracy normally used in chemical modification and even the capability of increasing their metrics with no modification of the underlying topology. With shape of building units and chemical compositions multiplying based on specific structures, MOFs might result in compounds that propose a synergistic mixture of features. This study presents up to date advances in both synthesis methods of MOFs and structural characteristics. Furthermore, the use of MOFs in different fields such as the removal of absorption and separation of toxic substances from gas and liquid, catalysts, a variety of sensors, storage of clean energies and environmental applications, medical and biological applications, and optoelectronic equipment is included.

A review on metal-organic frameworks: Synthesis and applications

Energetic materials, including explosives, pyrotechnics, and propellants, are widely used in mining, demolition, automobile airbags, fireworks, ordnance, and space technology. Nanoenergetic materials (nEMs) have a high reaction rate and high energy density, which are both adjustable to a large extent. Structural control over nEMs to achieve improved performance and multifunctionality leads to a fascinating research area, namely, nanostructured energetic materials. Among them, core-shell structured nEMs have gained considerable attention due to their improved material properties and combined multiple functionalities. Various nEMs with core-shell structures have been developed through diverse synthesis routes, among which core-shell structured nEMs associated with explosives and metastable intermolecular composites (MICs) are extensively studied due to their good tunability and wide applications, as well as excellent energetic (e.g., enhanced heat release and combustion) and/or mechanical properties. Herein, the preparation methods and fundamental properties of the abovementioned kinds of core-shell structured nEMs are summarized and the reasons behind the satisfactory performance clarified, based on which suggestions regarding possible future research directions are proposed.

Core–Shell Structured Nanoenergetic Materials: Preparation and Fundamental Properties

Synthesis, thermolysis, and sensitivities of HMX/NC energetic nanocomposites.

Preparation and Properties of HMX Coated with a Composite of TNT/Energetic Material

In this study, a novel Cu-MOF@Carbon nanomaterial composite was prepared to catalyze the thermal decomposition of ammonium perchlorate (AP). The structure was characterized by using scanning electron microscope (SEM), X-ray energy-dispersive spectrum (EDS), and X-ray diffraction (XRD); the specific surface area was estimated by Brunauer–Emmett–Teller (BET) method; and the pore volumes and pore size distributions were derived from the adsorption branches of isotherms using the Barrett–Joyner–Halenda (BJH) model. And the thermal decomposition behavior was investigated by using differential scanning calorimetry (DSC) and thermogravimetry analysis (TGA). The results indicated that all products showed excellent catalytic activity. Among the samples investigated here, Cu-MOF@CNT-rGO exhibited the best catalytic activity, since the high-temperature decomposition peak of AP decreased to 313.8 °C, which is reduced nearly 100 °C than the raw material (409.7 °C). And this was attributed to the high thermal and electrical conductivities of carbon nanomaterials, and the large surface area of both Cu-MOF and carbon nanomaterials. This study provides a new choice to be used as the promising catalysts in modifying the burning performance of AP-based composite propellant.

Synergistic effects between Cu metal–organic framework (Cu-MOF) and carbon nanomaterials for the catalyzation of the thermal decomposition of ammonium perchlorate (AP)

Spray drying method was used to prepare cocrystals of hexanitrohexaazaisowurtzitane (CL-20) and cyclotetramethylene tetranitramine (HMX). Raw materials and cocrystals were characterized using scanning electron microscopy, X-ray diffraction, differential scanning calorimetry, Raman spectroscopy, and Fourier transform infrared spectroscopy. Impact and friction sensitivity of cocrystals were tested and analyzed. Results show that, after preparation by spray drying method, microparticles were spherical in shape and 0.5ź5źµm in size. Particles formed aggregates of numerous tiny plate-like cocrystals, whereas CL-20/HMX cocrystals had thicknesses of below 100źnm. Cocrystals were formed by CźHźO bonding between źNO2 (CL-20) and źCH2ź (HMX). Nanococrystal explosives exhibited drop height of 47.3źcm, and friction demonstrated explosion probability of 64%. Compared with raw HMX, cocrystals displayed significantly reduced mechanical sensitivity.

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Nano-CL-20/HMX Cocrystal Explosive for Significantly Reduced Mechanical Sensitivity

A new insensitive booster explosive based on 2,6-diamino-3,5-dinitropyrazing-1-oxide (LLM-105) was prepared by a solvent-slurry process with ethylene propylene diene monomer (EPDM) as binder SEM (scanning electron microscopy) was employed to characterize the morphology and particle size of LLM-105 and molding powder The mechanical sensitivity, thermal sensitivity, shock wave sensitivity, and detonation velocity of the LLM-105/EPDM booster were also measured and analyzed The results show that both mechanical sensitivity and thermal sensitivity of LLM-105/EPDM are much lower than that of conventional boosters, such as PBXN-5 and A5 Its shock wave sensitivity is also lower than that of PBXN-5 and PBXN-7 When the density of charge is 95 % TMD, its theoretical and measured detonation velocities are 7858 m s−1 and 7640 m s−1, respectively These combined properties suggested that LLM-105/EPDM can be used as an insensitive booster

Jingyu Wang

Papers

Synthesis, thermolysis, and sensitivities of HMX/NC energetic nanocomposites.

Preparation and Properties of HMX Coated with a Composite of TNT/Energetic Material

Synergistic effects between Cu metal–organic framework (Cu-MOF) and carbon nanomaterials for the catalyzation of the thermal decomposition of ammonium perchlorate (AP)

Nano-CL-20/HMX Cocrystal Explosive for Significantly Reduced Mechanical Sensitivity

Preparation and Properties of An Insensitive Booster Explosive Based on LLM‐105