Abstract:To improve the compatibility of dihydroxylammonium 5，5′-bitetrazole-1，1′-diolate（TKX-50） with nitrocellulose（NC）， silane coupling agent （KH550） was used as the coating agent and three TKX-50/KH550 composites （TK1， TK2， TK3） were obtained.The morphology， structure and thermal stability of the composites were studied by using scanning electron microscopy （SEM）， Fourier infrared spectroscopy （FTIR）， and differential scanning calorimetry （DSC）. Accelerating rate calorimeter （ARC） and DSC were used to examine the compatibility of TKX-50/KH550 composites with NC. The results show that the apparent activation energy of thermal decomposition of the prepared TKX-50/KH550 composites are 190.03， 195.82 and 194.42 kJ·mol^-1 respectively higher than that of TKX-50 （138.86 kJ·mol^-1）， indicating the thermal stability of TKX-50 is improved by KH550 coating. In adiabatic conditions， the initial thermal decomposition temperature of the mixtures of TKX-50/KH550 composites and NC are 14.93， 18.18 and 17.90 ℃ respectively higher than that of TKX-50 and NC. After coated with KH550， the compatibility of TKX-50 and NC is improved， and the compatibility level of TKX-50/KH550 composites and NC is raised from Level 3 to Level 2.

Abstract:Boron-based hypergolic ionic liquids， which exhibited low viscosity， short ignition delay time and low cost， were considered as the powerful candidate for conventional liquid propellants. Here， the research progress of design， synthesis and physical chemical properties on boronium-anion-based HILs were systematically reviewed. The theoretical and applied studies including thermal decomposition， hypergolic reaction， combustion mechanism and relationship between structure and performance were briefly summarized. The practical application and development tendency of boronium-anion-based HILs were also discussed．

Abstract:The fluorescence properties and fluorescence stability of 2，4，8，10-tetrabroitro-benzopyrido-1，3a，6，6a-tetraazapentylene （BPTAP） were comprehensively investigated. The spectral properties of BPTAP in different solvents （acetonitrile， methanol， tetrahydrofuran， acetone， trichloromethane， ethyl acetate， N"-N"-dimethylformamide， dimethyl sulfone）， content of water （0-100%）， pH （2.0-12.0） were studied in detail. The effects of light， temperature and pH value on the fluorescence stability of BPTAP solution were investigated， and the mechanism of fluorescence decay of BPTAP solution was analyzed by ultra performance liquid chromatography-high resolution mass spectrometry （UPLC-HRMS）. The results show that although BPTAP has four nitro groups， it exhibits strong green fluorescence in some organic solvents. The fluorescence intensity of BPTAP in acetonitrile is the highest， and its maximum absorption/emission wavelength is 460 nm/508 nm. Low content of water （≤10%） can increase fluorescence intensity of BPTAP， while high content of water （>10%） decrease the fluorescence of BPTAP sharply. BPTAP has higher fluorescence in acidic， neutral and weak alkaline conditions. When the pH value is above 9.0， the fluorescence of BPTAP decreases rapidly with the increase of pH value. BPTAP shows good stability in room temperature and natural light. The closer the light wavelength is to the maximum absorption wavelength of BPTAP and the higher the temperature， the worse the fluorescence stability of BPTAP. The increase of pH value not only reduces the fluorescence intensity of BPTAP， but also accelerates the decline of BPTAP fluorescence. The mechanism of fluorescence decay of BPTAP under alkaline condition is based on nucleophilic substitution. The nitro group at para site of pyridine ring is replaced by the hydroxyl group in alkaline solution to form a new compound 1 （the elemental composition ［M-H］^- is C₁₁H₃N₈O₇）.

Abstract:

Abstract:Compared with traditional casting method， composite solid propellant manufactured by additive manufacturing （commonly known as “3D printing”） technology exhibits a series of technical advantages， such as arbitrary grain configuration without mold limitation and continuously controllable formulation as well as performance. In order to improve printing effect， printing formulation and technical parameters of composite solid propellant based on light-curing molding were studied， and the performance of printed propellant samples was evaluated. In addition， comprehensive additive manufacturing of composite solid propellant and resistive temperature sensor was achieved by integrating resistive temperature sensor into the printed propellant samples， and the resistance values of temperature sensor at different temperatures were examined. The results show that solid propellant slurry with 83% solid content displays a good pre-curing effect by adding no less than 3% ultraviolet （UV）-curable resin. The slurry with 77% or 80% solid content can be extruded through a 0.26 mm diameter needle， while solid content reaching 81% or above requires a 0.5 mm diameter needle. The printed propellant sample comprising 81% solid content possesses good dimensional stability and unconspicuous appearance defects， but computed tomography （CT） results reveal the existence of lamellar pores inside the sample. The tensile strength and elongation at break of printed propellant sample are equal to 0.94 MPa and 15.63% at 20 ℃， respectively. At 60 ℃， the tensile strength and elongation at break of sample are 0.70 MPa and 14.63%， respectively. The printed propellant owns comparable tensile strength and reduced elongation at break compared to conventional casting propellant. The bonding strength between temperature sensor and propellant is 0.21 MPa， showing favourable bonding effect. The resistance of temperature sensor varies linearly with temperature within testing temperature range （20-60 ℃）， demonstrating good temperature monitoring capability.

Abstract:Inkjet printing technology is an advanced micro-manufacturing technology based on ink droplets， which integrates jetting technology， discrete stacking numerical control manufacturing， and computer-aided design. It is one of the important loading approaches for micro-structured energetic devices such as MEMS pyrotechnics. In the ink-jet printing process， the precise control of droplets is the key to improving the printability and accuracy of the targeted materials. Based on the systematic investigation of the inkjet printing forming mechanism， the physical characteristics of ink and the influence of printing process parameters on the formation of ink droplets were discussed， and the reason and control methods for the "coffee ring" effect were also summarized. The controlling strategies of droplet formation and deposition in the ink-jet printing process were described. At the same time， the application of ink-jet printing technology in booster， nano-thermite， etc. was reviewed， and the development direction of inkjet printing technology in energetic materials was prospected. The drop-on-demand and control with picoliter of ink-jet printing technology provides a prerequisite for the precise charging of micro-nano-structured energetic agents and has good application prospects in MEMS pyrotechnics and special-shaped energetic devices.

Abstract:The effect of crosslinking catalyst Copper 2，4-glutarate-cyclooctadiene complex dosage on the properties of polytriazole-crosslinked solid elastomer was studied. Propargyl-terminated ethylene oxide-tetrahydrofuran copolymer （PTPET）was used as an adhesive and polyazide compound as an curing agent， a series of polytriazole-crosslinked solid elastomers S1-S4 were prepared by adding crosslinked catalysts of 0.01%， 0.02%， 0.05% and 0.10%. The chemical structure， thermal stability， mechanical properties and network structure of polytriazole-crosslinked solid elastomers were characterized by FTIR， TG， equilibrium swelling method and DMA. It was found that PTPET elastomer is more stable than PET elastomer， the dosage of the catalyst did not influence the thermal stability of the elastomer， and the decomposition temperature for all samples is at 405 ℃. The elastomer S2 with 0.02% crosslinking catalyst has the most perfect network structure and the best mechanical properties， and the glass transition temperature is -67.4 ℃.

Abstract:The rapid development of additive manufacturing technology provides an effective way for the flexibility and adaptability of traditional solid propellant casting molding， however， to meet the requirements of the casting， the thermosetting solid propellants with good fluidity could not deposite layer by layer. In order to realize the additive manufacturing， the hydroxyl-terminated polybutadiene （HTPB） was modified by adding a small amount of styling aids. The rheological properties of the modified-HTPB and slurry made by using the modified-HTPB were studied. The rheological curve test results show that apparent viscosity and viscous flow activation energy of the modified-HTPB increase significantly with the decrease of temperature. The rheological property of the modified-HTPB solid propellant slurry is consistent with Herschel-Bulkley equation， and the fluidity of modified-HTPB solid propellant slurry increases with the increment of temperature. Besides， the slurry possesses high storage modulus（G′＞10⁴ Pa） and small loss tangent（ω＜10 rad·s^-1，G″/G′＜0.5） at ambient temperature， showing a low fluidity. A small amount of styling aids has little effect on the thermal decomposition behavior of the propellant， which promotes the 3D printing of the modified-HTPB solid propellant .

Abstract:3，3′-Diamino-4，4′-azofurazan （DAAzF） is one of the main impurities that produced during the synthesis of 3，3′-diamino-4，4′-azoxyfurazan （DAAF）. However， the effect of DAAzF on the thermal performance of DAAF remains unclear in the past. To this end， a doping strategy based on the dissolution-precipitation method was developed to prepare DAAF@DAAzF explosives by uniformly doping 0.5%-10% DAAzF into DAAF， and the effect of DAAzF on the thermal performance of DAAF@DAAzF explosives was investigated by using simultaneous thermogravimetry and differential scanning calorimetry. The doping of DAAzF decreases the melting point of DAAF-based explosives， with the greatest decrease from 246.4 ℃ to 239.3 ℃ occurring at 10% DAAzF content. For the first time， it is found that the eutectic mixture can be formed when the mass ratio of DAAzF/DAAF is 5/95. Further， the presence of DAAzF decreases the activation energies and pre-exponential factors of DAAF-based explosives during the initial decomposition. Therefore， DAAzF as an impurity accelerates the thermal decomposition of DAAF@DAAzF explosives and reduces their thermal stability.

Abstract:To explore the curing reaction behavior of 3，3-bis（azidomethyl）oxetane-tetrahydrofuran copolyether （PBT） and toluene diisocyanate （TDI） binder system， the effects of curing temperature， curing ratio and plasticizer on the curing reaction of PBT-TDI system were investigated by microcalorimetry， and the curing reaction kinetics and thermodynamics of PBT-TDI system were studied and analyzed. The experimental results show that： （1） the higher the curing temperature and the higher the TDI content， the faster the curing reaction； （2） increasing the amount of plasticizer bis（2，2-dinitropropyl）acetal/bis（2，2-dinitropropyl）formal （A3） and dioctyl sebacate （DOS） would reduce the curing reaction speed of the PBT-TDI system； （3） the curing reaction of the PBT-TDI system fits well with the n-th order reaction kinetic model with an activation energy of 12.81 kJ·mol^-1 and a pre-exponential factor of 1.48×10^-2 s^-1.

Abstract:To prevent the agglomeration of cobalt ferrite （CoFe₂O₄） nanoparticles and improve their catalytic decomposition performance for Octogen （HMX） and HATO （TKX-50）， graphitic carbon nitride （g-C₃N₄） was applied as CoFe₂O₄ nanoparticles dispersant carrier. The in suit preparation of CoFe₂O₄/g-C₃N₄ binary nanocomposites were achieved through solvothermal method. Corresponding composition， structure morphology and catalytic decomposition performance of CoFe₂O₄/g-C₃N₄ were investigated through X-ray powder diffractometer， scanning electron microscopy， fourier transform infrared spectrometer and differential scanning calorimeter. The results showed that the morphology of CoFe₂O₄/g-C₃N₄ composites is uniform and dense， which reduces the thermal decomposition peak temperature of HMX and TKX-50 by 7.0 ℃ and 41.3 ℃， respectively， and the apparent activation energy by 341.1 kJ·mol^-1 and 21.0 kJ·mol^-1， respectively. Moreover， the introduction of g-C₃N₄ increases the heat release amount. The results of residue analysis showed that the catalytic decomposition of HMX was very complete， while TKX-50 presents incomplete catalytic decomposition， and its residua formed micron bulk mixtures with CoFe₂O₄/g-C₃N₄.

Abstract:The development of new combustion catalysts plays a key role in high performance propellants. Herein， the metal-organic complexes Mg（Salen） and Pb（Salen） were synthesized and characterized using X-ray diffraction， fourier transform infrared， and scanning electron microscope. Their catalytic effects on the thermal decomposition of 1，3，5，7-tetranitro-1，3，5，7-tetrazolidine （HMX） were further investigated by differential scanning calorimetry. The results indicate that the thermal decomposition of HMX is evidently enhanced by the introduction of Mg（Salen） and Pb（Salen）. Compared with HMX， the decomposition peak temperatures of HMX/Mg（Salen） and HMX/Pb（Salen） dropped by 3.0 ℃ and 34.0 ℃， and theoretical apparent activation energies decreased by 7.7 kJ·mol^-1 and 34.4 kJ·mol^-1， respectively. The catalytic decomposition mechanisms of Mg（Salen） and Pb（Salen） are also elucidated by exploring the decomposition kinetics and the reaction function models.

Abstract:Meriting in green and pollution-free combustion products， large specific surface area， insensitive-safety ， large contact area with reactants and easy modification， nanocarbon has been widely focused on tuning the performances of energetic materials （EMs） such as high explosives， propellants and thermites. This work reviews the effects of nanocarbon on the decomposition characteristics， sensitivity， mechanical performances and combustion properties of EMs. In addition， it discloses the progresses in the detection， adsorption and degradation of EMs conducted by nanocarbon. The interaction mechanisms of typical nanocarbon materials （nano-diamond， fullerene， nanocarbon fiber， carbon nanotube and graphene） in EMs have been analyzed. Within this review， issues， challenges and promising research directions existing in the application of nanocarbon in EMs are highlighted and presented. （1） Optimizing the high-cost preparation processes of nano carbon. Easy agglomeration and large batch differences of nanocarbon. （2） Expanding the application scope of nanocarbon. Exploring the effects of new-type nanocarbon such as onion carbon and modified nanocarbon on the properties of energetic materials. （3） According to the specific environment and nanocarbon regulation mechanism， the application conditions of nanocarbon in improving the properties of energetic materials are optimized. It is expected that nanocarbon materials will provide a forum for future advancement in the modifications of multifunctional EMs.

Abstract:In order to establish a precise combustion heat measurement system and method suitable for energetic materials， a method and device for measuring the heat of combustion of energetic materials with tiny doses has been developed. This device is based on the thermal principle of differential heat flux and uses a three-dimensional thermopile consisting of 960 pairs of thermocouples as the core measuring element. The device was calibrated by using standard material benzoic acid. The heat of combustion of six typical energetic materials， including cyclotetramethylene tetranitramine， hexanitrohexaazaisowurtzitane， cyclotrimethylene trinitramine， 3，4-bis（3-nitrofurazan-4-yl）furoxan， 1，1-diamino-2，2-dinitroethylene and nitroguanidine， was measured by this device. The results show that the calorimetric coefficient of the instrument is （64.804±0.071） μV·mW^-1 and the corresponding relative uncertainty is 0.109%. The solid-phase standard molar heats of combustion （Δ_cU） of these six energetic materials at 298.15 K are -（2749.1±4.5）， -（3593.6±6.0）， -（2115.2±3.4）， -（3040.8±4.8）， -（1211.4±2.3） and -（898.4±2.0） kJ·mol^-1， respectively. The measurement results are in good agreement with the values reported in the literature， indicating that the developed small-mass combustion measurement device can be widely used in the determination of the energy of combustion of substances containing C， H， O， and N， especially precious samples and explosive substances.

Abstract:To solve the problems of igniting difficulty and combustion agglomeration， modification of Al powder by alloying and oxidant coating was studied. AP@Al/Ni composite fuels were prepared by acoustic resonance mixing technique. The heats of reaction of the composite fuels with different ammonium perchlorate （AP） contents were measured using a bomb calorimeter. The morphology characteristics of the optimized AP@Al/Ni composite fuel were analyzed by SEM. The thermal reactivity of AP， Al/AP mixture， Ni/AP mixture， and AP@Al/Ni composite fuel were comparatively studied by DSC/TG. The effects of additives including Al， Ni， and Al/Ni composite on the thermal decomposition kinetic parameters of AP were evaluated by the non-isothermal kinetic method. The results show that the heat of reaction of the composite fuel reaches its maximum when the mass content of AP is 38.90%， which is considered as the optimal content of AP in the formula. Compared with Al and Ni， the Al/Ni composite has the most significant influence on the thermal decomposition of AP， which reduces the peak temperature of AP in high temperature decomposition by 76.9 ℃ and increases the heat release by 84.8%. The apparent activation energy of AP decomposition in AP@Al/Ni composite fuel that obtained by Friedman method is 103.9 kJ·mol^-1， and this process obeys the three-dimensional random nucleation and nucleus growth （A3） model.

Abstract:To explore the detailed thermal decomposition properties of the mixture system consists of ammonium perchlorate-based molecular perovskite energetic material （H₂dabco）（NH₄）（ClO₄）₃ （DAP-4， where H₂dabco²⁺ refers to 1，4-diazabicyclo［2.2.2］octane-1，4-dianiumion） and dihydroxylammonium 5，5"-bistetrazole-1，1"-diolate （TKX-50）， the thermal decomposition characteristics and gas products of DAP-4 and DAP-4/TKX-50 mixtures were comparatively analyzed by using differential scanning calorimetry-thermogravimetry/mass spectrometry/fourier infrared spectroscopy； meanwhile， the changes of characteristic groups in the condensed phase of DAP-4 and DAP-4/TKX-50 mixtures with temperature were investigated by in-situ FTIR. Based on the explorations the thermal decomposition mechanism of DAP-4/TKX-50 mixture was proposed. The results showed that after mixing DAP-4 with TKX-50， DAP-4 had little effect on the thermal decomposition of TKX-50， while the heat generated by the thermal decomposition of TKX-50 made the reversible phase transition endothermic peak of DAP-4 disappeared， but hardly affected DAP-4′s thermal decomposition at high temperature. The thermal mass loss of DAP-4/TKX-50 mixture was divided into two stages. The mass loss of the first stage was 43.4% and the mass loss of the second stage was 52.4%， leaving 4.2% of the decomposition residue. The main gas products produced by thermal decomposition of DAP-4 and DAP-4/TKX-50 mixture were NH₃/H₂O/HNCO/HCN/CO/HCl/CO₂ and H₂O/NO/N₂O/HCl/NH₃/N₂/HNCO/HCN/CO/CO₂， respectively. The thermal decomposition mechanism of the DAP-4/TKX-50 mixture was proposed as follows： the reversible transfer of hydrogen ions occurs first in the molecule of TKX-50 to generate hydroxylamine and 1，1"-dihydroxy-5，5"-bitetrazole （BTO）， then hydroxylamine decomposed into small molecular gases at high temperature while the fragments generated by BTO decomposition partially polymerized into coupling products. Finally， the ionic bond of DAP-4 was broken， leading to instantaneous collapse of the cage-like skeleton. The strongly reducing and strongly oxidizing gas components underwent violent redox reactions at high temperatures and release a large amount of heat.

Abstract:To investigate the effect of deuteration on the vibrational properties of chemical bonds of triacetone triperoxide （TATP） and its thermal decomposition behavior， TATP and deuterated triacetone triperoxide （TATP-d₁₈） were prepared by using acetone and acetone-d₆ as raw materials， respectively， with hydrogen peroxide acting as the oxidant source and sulfuric acid as the catalyst. TATP and TATP-d₁₈ were characterized by nuclear magnetic resonance spectroscopy （NMR）， Fourier transform infrared spectroscopy （FTIR） and differential scanning calorimetry （DSC）. The non-isothermal reaction kinetic parameters of TATP and TATP-d₁₈ were calculated with Kissinger， Ozawa， and Friedman methods. The results show that the deuteration of TATP results in an evident red-shift phenomenon， and the ratio of the stretching frequencies of C—H（D） bonds （ν_C—H/ν_C—D） is about 1.36. The apparent activation energy of TATP-d₁₈ （E_K=80.54 kJ·mol^-1， E_O=83.56 kJ·mol^-1， E_F=72.27 kJ mol^-1） is higher than that of TATP （E_K=67.91 kJ·mol^-1， E_O=71.01 kJ·mol^-1， E_F=63.79 kJ·mol^-1）， indicating that TATP-d₁₈ has higher thermal stability. The calculated thermal explosion critical temperatures for TATP （T_b=402.37 K） and TATP-d₁₈ （T_b=423.46 K） also confirm that deuteration improves the thermal stability of TATP-d₁₈. Finally， the calculated thermodynamic parameters for the non-isothermal decomposition processes of TATP and TATP-d₁₈ indicate that TATP and TATP-d₁₈ would not spontaneously undergo thermal explosions.

Abstract:To promote the stable production and wide application of silver acetylide-silver nitrate （Ag₂C₂·AgNO₃）， the structural morphology and thermal decomposition characteristics were systematically studied by X-ray powder diffractometry， Fourier tranform infrared spectrometer， scanning electron microscopy， differential scanning calorimeter and thermogravimetric-mass-infrar- ed spectrometry techniques. The results indicate that the prepared Ag₂C₂·AgNO₃ sample is in the form of nanospheres with particle sizes ranging from 400 to 500 nm. There is only one exothermal decomposition process of Ag₂C₂·AgNO₃ with a peak temperature of 234.9 ℃， a weight loss of 8.72%， and a heat release of 1449 J·g^-1，at a heating rate of 10 ℃·min^-1. The apparent activation energy and pre-exponential constant of decomposition process are obtained as 108.9 kJ·mol^-1 and10^8.94 s^-1， respectively. Moreover， the gaseous decomposition products of Ag₂C₂·AgNO₃ were NO， NO₂ and CO₂.

Abstract:To alleviate the aggregates of n-Al particles and improve its combustion performance， high-energy low-sensitivity nitrochitosan （NCh） with a honeycomb network structure was used as coating agent to prepare a binary nanocomposite with uniform structure through an acoustic resonance method. The morphology， structure and combustion performance of NCh/n-Al were investigated by XRD， SEM， TEM and laser ignition， and compared with that of NC/n-Al composite. The results show that the prepared NCh/n-Al has uniform morphology and good dispersion. Compared with pure n-Al and NC/n-Al， the ignition delay time of NCh/n-Al is shortened by 6 ms and 20 ms， respectively. The combustion of NCh/n-Al is more complete， the condensed combustion products are mainly Al₂O₃， a very small amount of unburned Al and carbon residue， and the particle size is significantly smaller.

Abstract:In order to meet the requirements of explosives， thermoplastic elastomers with different number-average molecular weight （M_n） were prepared. Controllable polymerization and application of glycidyl azide polymer （GAP）-based energetic thermoplastic elastomers （GETPE） were conducted. The influence of polymerization medium and solid content on controllable polymerization of GETPE was investigated， and on-line viscosity monitoring on M_n was explored. The results show that M_n of GETPE can be accurately controlled by on-line viscosity monitoring. The error of M_n in the range of 20000-50000 can be tuned within ±2000， and the error rate can be controlled within 5%. GETPE has excellent compatibility with commonly used explosives and good application potential in high solid content propellant and high energy polymer bonded explosives （PBXs）.

Abstract:Mechanically mixed and electrostatic sprayed RDX/NC/AP/Al composite explosive using nitrocellulost （NC） as binder， ammonium perchlorate （AP） as oxidant， cyclotrimethyltrnitramine （RDX） and nano aluminum powder （Al） as combustion agent were prepared based on zero oxygen balance. The morphology， structure， thermal properties， combustion process and mechanical sensitivity of the different samples were analyzed by the scanning electron microscopy （SEM）， the Fourier transform infrared spectroscopy（FT-IR）， thermogravimetric differential scanning calorimeter （TG-DSC）， mechanical sensitivity and high-speed photography. The component（NC， RDX， AP and Al） in RDX/NC/AP/Al composite explosives obtained by both method are physical composite. However， the microstructure of mechanically mixed RDX/NC/AP/Al demonstrated in spheres and the electrostatic sprayed samples are microspheres. The mass loss process of RDX/NC/AP/Al composite explosive obtained by two methods contained two stages （200-210 ℃ and 250-350 ℃）. The first stage is the decomposition of part of RDX and AP， while the second stage is the decomposition of the remaining RDX and NC. Compared with the mechanical mixed samples， the activation energy and the critical temperature of thermal explosion of electrostatic sprayed RDX/NC/AP/Al increased by 41.25 kJ·mol^-1 and 4.09 K， respectively. Besides， the mechanical sensitivity is reduced， and the combustion rate is also improved.

Abstract:In order to explore a continuous， safe and controllable microfluidic synthesis strategy of emulsion explosive， silicon-based microporous array chips with four apertures（10 μm，20 μm，30 μm，40 μm） were designed and prepared by MEMS technology， and the microfluidic reaction device of emulsion explosive was constructed. It is found that the main factors affecting the droplet size of dispersed phase in latex matrix are micropore diameter and continuous phase velocity. The effects of pore size and oil-water two-phase flow rate on the particle size distribution and exothermic properties of emulsion droplets were studied. The results show that the particle size distribution of dispersed droplets in the matrix is the narrowest when the pore size is 30 μm and the continuous phase flow rate is 0.5 mL·min^-1 and D₅₀=8.169 μm. Microporous array chip can generate highly homogeneous droplets in batch， which provides a new choice for emulsification in the preparation of emulsion explosive.

Abstract:The comprehensive performance of explosives depends not only on their chemical components， but also on their structures and morphologies to a greater extent. Microfluidics has become a new research focus owing to its superb mass transfer and heat transfer efficiency， precise parameter control and intrinsic safety. This paper analyzed and summarized the research status of droplet flow and continuous flow in the aspects of particle size， particle size distribution， crystal morphology and aggregate structure of primary and high explosives. The stable reaction environment and flexible residence time of the droplet flow are applicable to the structural control of the primary explosives， and the superior size uniformity and monodispersity of the droplet flow are appropriate for the preparation of spherical explosive particles. The high mixing efficiency of the continuous flow is in line with the crystalline properties of the high explosive. Combined with the deficiencies of current related research in post-processing methods， theoretical applicability， microfluidic manipulation methods and the degree of intelligence， suggestions and ideas for the further development of microfluidic technology in the field of explosives were put forward.

Abstract:Hexanitrohexaazaisowurtzitane （CL-20） and nano-aluminum powder are commonly used for the improvement of energy density in explosive formulations， however， the high mechanical sensitivity of CL-20 or their mixture has been impeded further applications. Therefore， it is very meaningful to obtain a low-sensitivity of CL-20 and Al uniform mixture. In this paper， the Pickering emulsion was prepared by using nano-aluminum powder modified by perfluorocarboxylic acid as the surfactant （F-Al）， and the ethyl acetate solution of CL-20 and TNT as the oil phase. The influence law of F-Al powder content and static duration on the stability of the emulsion was investigated. The spheroidicity core-shell CL-20/TNT co-crystal@Al composite was successfully prepared. Its morphology， crystal form， thermal decomposition properties， safety， etc. were characterized. Results show that stable emulsions can be obtained when the content of F-Al powder is 1%， 10%， and 20% and static duration is less than 100 min. XRD results showed that the CL-20 and TNT cocrystals was obtained. The crystal size （20-40 μm）， the ellipsoid-like morphology， the uniformly coated nanosized F-Al powder were shown by the SEM images. An H₅₀ value of 35 cm and a friction sensitivity explosion probability of 30% have been realized for that of composites， which is much higher than that of CL-20. The preparation method used in the present paper does not sacrifice the energy density in the spheroidicity core-shell CL-20/TNT co-crystal/Al composite， which is expected to provide a pathway to the design and prepare of high-energy propellants and explosives containing CL-20 and Al.

Abstract:A measurement method of explosive crystallization thermodynamic parameters based on optofluidics was proposed to obtain the crystallization thermodynamic parameters such as solubility and metastable zone width of explosive crystal， and the applicability of this method was verified by taking HNS explosive as a sample. The solubility of HNS in DMSO/DMF solvent system with volume ratio of 10∶0， 7∶3， 5∶5， 3∶7 and 0∶10 from 318.15 to 353.15 K and the metastable zone width of HNS in the above DMSO/DMF solvent system from 318.15 to 333.15 K were measured with a step of 5 K. Apelblat model and λh model were employed to fit the collected solubility data. The effect of solvent system on the metastable zone width was studied， and the crystallization parameters were screened. According to the classical nucleation theory， the apparent nucleation order m of HNS was calculated， and the nucleation mechanism of HNS by cooling crystallization was analyzed. The results indicate that the measurement method of crystallization thermodynamic parameters based on optofluidics exhibit exceptional applicability to HNS crystals. With the increase of temperature and the volume ratio of DMSO in the system， the solubility of HNS increases. With the increase of DMSO volume ratio in the system， the width of metastable zone becomes narrower. The optimum crystallization conditions are as follows： pure DMSO is utilized as solvent， the solution temperature is set at 333.15 K， and the solute concentration is 0.029 g·mL^-1. The value of m is approximately 4， which is not affected by the initial temperature. It can be inferred that the nucleation mechanism of HNS belongs to continuous nucleation.