Abstract:In order to explore the thermal safety characteristics of modified double base propellants， the thermal decomposition behaviors of modified double base propellants with RDX content of 0， 18%， 46% and 54.6% were studied by differential scanning calorimetry （DSC） respectively， and the thermal decomposition temperatures at different heating rates （2， 5， 10 and 20 ℃·min^-1）were obtained. The apparent activation energy， activation pre-exponential factor， reaction rate， Gibbs free energy， activation enthalpy and activation entropy were calculated by thermal reaction kinetics analysis， and the influence of RDX content on the double base components and apparent activation energy was also analyzed. The response characteristics of modified double base propellants with different RDX contents were obtained by slow cook-off and 5s burst point temperature tests. Results show that when RDX content is 18%， the apparent activation energy is the highest， and the response temperature and the response intensity of slow cook-off test and 5s burst point temperatures all are the lowest. The first decomposition peak temperature of samples moved backward， the apparent activation energy decreased， the slow cook-off response temperature moved to higher temperature， the thermal sensitivity of the system decreased， but the response level increased with the increase of RDX content. The response level is explosion， which could not pass the slow cook-off test when the RDX content is 46% or above. The 5s burst point temperature moves to high temperature with the increase of RDX content and presents a significant rising trend， and the thermal stability of modified double base propellants is improved.

Abstract:In comparison with the plasticizer only with azido， the one bearing multiple energetic groups not only generally has a higher density and oxygen balance， but also possesses more energy content. It endows the propellant with an increasing specific impulse and a better combustion performance， which has become a hot research topic in the field of the energetic material. However， it is an essentially important factor that how to precisely control the quantities and distributions of microscopic energetic groups in the plasticizer′s structure. To design and synthesize the plasticizer with high energy density， high thermal stability， high oxygen balance， insensitivity as well as low glass transition temperature， above-mentioned factor should be payed considerable attentions. This study reviews the previously reported azido plasticizers， containing nitro， nitrate， nitramine， difluoroamino and/or furazan group， from the design， synthesis and characterization of molecules to propellant applications since the late 1970s. Some drawbacks are sorted out in this paper. What′s more， several valuable suggestions to synthesize azido plasticizers with outstanding properties are presented here. It is essential worth noting that organic azido compounds with nitro and/or nitramine group are the most promising plasticizers used in propellant in the future， and the properties and synthetic difficulties of these materials are simultaneously taken into consideration. Finally， some guidance for researchers being engaged in the investigation of energetic plasticizers are provided.

Abstract:Taking tetrahydrofuran copolyether （PET）-based high energy solid propellant as the research focus， the 3D printed propellant was designed and formulated with PET/nitrate（NG/BTTN） as the binder system modified by shaping agent（MS）， ammonium perchlorate（AP） as the solid filler and polyfunctional aliphatic isocyanate （N-100） as the curing agent. The shaping effect of MS at 25 ℃， its compatibility with each component， and its rheological properties at 25， 35， 45， 55 ℃ were studied. The reasonable range of the processing parameters for 3D printing such as temperature， nozzle diameter and pressure were determined preliminarily by simulation. The results show that MS has good compatibility with PET/NG/BTTN and AP in the propellant， and it also improves the safety performance of the propellant to a certain extent. The obtained slurry exhibits the temperature-sensitive characteristics， capable of achieving good setting effect at 25 ℃. By applying the determined printing parameters involving the temperature of 50 ℃， the nozzle diameter of 1.2 mm and the pressure of 11 kPa， the actual printing rate can be approached to 8 mm·s^-1， which is the first time that the 3D printing of PET based high-energy solid propellant to be realized.

Abstract:Electrically controlled solid propellant （ECSP） has the characteristics of multiple ignitions and controllable burning rate， and can be widely used in propulsion systems from micro to macro. The research on ECSP with ammonium nitrate， hydroxylamine nitrate and perchlorate as oxidants was summarized at home and abroad， especially the characteristics of ignition， combustion and extinction for ECSP based on hydroxylamine nitrate and perchlorate were emphatically reviewed. Meanwhile， the effects of voltage， pressure and metal additives on the burning rate adjustment of ECSP were analyzed， and the mechanism of electric energy in the ignition and combustion process of ECSP was discussed. Furthermore， some suggestions were put forward for further in-depth study on the ignition， combustion and extinction mechanism of ECSP： study the chemical reaction mechanism on the solid and gas phases of ECSP， establish the model and framework of the reaction mechanism for ignition， combustion and extinction； explore the effect of electrode arrangement and electrode configuration on the combustion efficiency of ECSP and the relationship between ECSP formula and electrical conductivity systematically， and seek the method to decrease the interface resistance between electrode and propellant. Finally， optimizing the formulation of high-performance ECSP， perfecting the combustion reaction mechanism and burning rate adjustment mechanism of ECSP， and raising the pressure threshold of ECSP are the keys to the design， application and performance regulation of electronically controlled solid rocket motor.

Abstract:In order to explore the droplet ignition characteristics of a new type of hydroxylamine nitrate（HAN）-based liquid propellant EMP-01， a droplet electric ignition experimental platform was built by placing the droplet in a hemispherical groove and inserting the electrode. The electrical ignition characteristics of EMP-01 droplets under the conditions of droplet diameter of 6.5 mm， electrode spacing of 0.5 mm and voltage loading rate of 86.31 V·s^-1 were studied， and the ignition delay time under this condition was determined. At the same time， the variation law of droplet ignition delay time and combustion process was also studied within 34.20-246.37 V·s^-1 under the condition of constant droplet diameter and electrode spacing. The results show that the droplet separation of EMP-01 undergoes three stages： heating， thermal decomposition and combustion， and there is a periodic expansion and contraction process in the thermal decomposition stage. When the voltage loading rate is 34.20 V·s^-1， the EMP-01 droplet cannot be successfully ignited； When the voltage loading rate is 49.49-246.37 V·s^-1， the ignition delay time decreases gradually with the increase of voltage loading rate， but with the increase of voltage loading rate， the decrease rate of ignition delay time gradually slows down.

Abstract:Addition of high energy boron into the liquid fuel is an effective method to improve the energy density of the blended fuel. However， the added content of boron is limited， due to the dramatic increase in the viscosity of the blended fuel. So it is important to increase the boron content as much as possible without obvious viscosity increase. Four organosilanes including propyltrimethoxysilane （C3-silane）， octyltrimethoxysilane （C8-silane）， dodecyltrimethoxysilane （C12-silane） and hexadecyltrimethoxysilanes （C16-silane） were used to modify boron particles. First， the modified boron particles were characterized by scanning electron microscopy， contact angle measurement， X-ray diffraction， particle size analysis （using dynamic laser scattering） and thermogravimetric analysis. Then the rheological properties of organosilane modified boron/JP-10 blend fuels were investigated. Finally， the effect of temperature on the apparent viscosities at different shear rates was studied. The results show that boric acid on the boron surface was removed upon surface modification with organosilanes and the surface characteristics of boron powder were transformed from hydrophilicity to hydrophobicity. The content of organosilane was less than 1.5% in the organosilane modified boron particles， which would have marginal effect on the total heat value. Organosilane modified boron/JP-10 blend fuels with solids content of 50% showed good fluidity and their apparent viscosities were lower than 0.3 Pa·s at 25 ℃ and 100 s^-1 of shear rate. Keeping other conditions the same， the apparent viscosity of blend fuels depends on the length of side chain alkyl group of organosilane： C3-silane>C8-silane≈C12-silane≈C16-silane. Organosilane modified boron/JP-10 blend fuels showed shear-thinning characteristics and the relationship between the apparent viscosity and the shear rate could be well fitted by power-law equation. The apparent viscosity of blend fuels depends strongly on the temperature and their relationship could be well expressed by Arrhenius equation. The shear activation energy of blend fuels increases with increasing the length of side chain alkyl group of organosilane coated on the boron.

Abstract:The new challenge to the existing coating layer process was put forward by the development of solid rocket motor technology. In recent years， thermosetting resin as the matrix was used， combined with continuous automatic coating technology， the popular coating production method of coating layer lies in whether complete molding and excellent performance can be obtained quickly. The flow properties and casting condition of unsaturated polyester （UPR） coating layer were studied. The chemical rheological model of the UPR coating layer during continuous automatic manufacturing is obtained by introducing exponential function based on Kinua-Fontana model. The functional relationship of viscosity versus time and temperature of cured UPR is established. The suitable temperature for casting operation was obtained. The filling volume fraction distribution， flow rate distribution and weld line position of coating layer were predicted by introducing of POLYFLOW simulation software， which the constitutive equations is established on the base of Bird-Carrea power-law equation. The casting process was simulated at the constant rate and pressure， respectively. The results show that the casting temperature is below 35 ℃， the casting pressure is more than 1 MPa， and the inlet flow rate is more than 150 mm³·s^-1 and less than 175 mm³·s^-1 in the coating layer casting process.

Abstract:High-energy-density hydrocarbon fuels are important aerospace power source， which mainly developing direction is high-energy and green， especially under the requirements of low carbon and sustainable development， the green synthesis of high-energy-density hydrocarbon fuel becomes essential. The green synthesis technology of high-energy-density hydrocarbon fuel has been reviewed. Compared with traditional synthesis of JP-10 （exo-THDCPD） and Adamantane， the advanced synthesis for fuel is improved by changing the synthesis route or using green catalysts such as solid acids and ionic liquids. Using biomass as feedstock is another strategy for green synthesis， covering terpenoids and lignocellulose-derived platform molecules such as cyclic ketones/alcohols， furanic aldehydes/alcohols， etc.， and the alternative fuels such as bio-based RJ-4（endo-THDMCPD and exo-THDMCPD） and JP-10 have been synthesized. In addition， the photocatalytic technology is used to synthesis of fuel with high tension and polycyclic structures from the perspective of green synthesis process view point， an outlook on further development of high-energy-density hydrocarbon fuel is also given. This review article will be helpful to explore and develop better approach and process for the synthesis of high-energy-density hydrocarbon fuel and upgrade for advanced aerospace vehicles.

Abstract:In order to improve the activity of hydrogenolytic debenzylation catalyst and reduce the dosage of noble metal palladium during the synthesis of hexanitrohexaazaisowurtzitane（CL-20）， carbon supports were prepared by ball-milling/carbonization method using sodium gluconate as a raw material. The effects of carbonization temperature， heating rate and additive addition of sodium gluconate on the support structure and the catalytic activity of the corresponding Pd（OH）₂/C catalysts in the hydrogenolytic debenzylation of hexabenzylhexaazaisowurtzitane（HBIW） and tetraacetyldibenzylhexaazaisowutzitane（TADB） were explored. The pore structure， particle morphology， crystal phase structure， chemical composition and surface chemical properties of carbon supports were characterized by nitrogen sorption isotherm measurement（BET）， scanning electron microscope（SEM）， transmission electron microscopy（TEM）， powder X-ray diffraction（XRD）， element analysis and temperature programmed desorption （TPD）. The results show that the optimized carbonization condition of sodium gluconate was calcination at 700 ℃ with a heating rate of 10 ℃·min^-1 in the presence of additive， NaHCO₃， which could adjust the puffing carbonization of sodium gluconate. The received carbon supports have rich hierarchical pore structure and appropriate amount of surface oxygen containing groups， and the corresponding Pd（OH）₂/C catalysts exhibit high activities in the hydrogenolytic debenzylation reaction of HBIW and TADB.

Abstract:The aim of this study is to explore the effect of absorption coefficient on propulsion performance of the laser ablated ammonium dinitramide （ADN）-acetone based liquid propellant. ADN and absorbent were mixed with different proportions in the range of 0-80% and a proportional distance of 10% to form ADN-acetone based liquid propellants. The absorption coefficients of propellants with different proportions were measured and calculated using a near-infrared spectrometer. Under the laser energy of 60 mJ and liquid film thickness of 300 μm condition， the impulses generated by laser ablation of propellants with different proportions were measured using a high-precision torsion pendulum. Results show that the absorption coefficient decreased with the increase of ADN content. In addition， the impulse decreased after peaking at ADN content of 30%， but increased again at ADN content of 80% sharply. The decrease of impulse in the ADN content range of 30%-70% is mainly caused by the decrease of absorption coefficient which leads to the decrease of laser energy deposited by the propellant. The impulse increase at ADN content of 80% is caused by the propellant whose absorption coefficient approaches to 0 and constitutes a “water cannon target” with the container. After the container is ablated by the laser， the propellant will act as a constraint， and result in the increase of impulse.

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:To study the rheological properties and to cure the reaction process of branched polyglycidyl azide （B-GAP）-based propellent， the slurries were tested by rheological research methods， and the changes of viscosity with shear rate and modulus with time at 50， 55， 60 ℃ and 65 ℃ were studied. The results indicate： B-GAP propellant slurry has a shear thinning properties and belongs to pseudoplastic non-Newtonian fluid； The curing reaction rate of the propellant slurry increases as the curing reaction progresses， reaching a maximum value when the curing degree is 0.3， and then the reaction rate begins to decrease until zero； Temperature has a great influence on the kinetics of propellant curing reaction. Within a certain temperature range， the peak value of the curing reaction rate increases with the increase of temperature， and the maximum value of storage modulus decreases with the increase of temperature； Based on the power law equation and Arrhenius equation， the constitutive equation and curing kinetic reaction equation of B-GAP slurry was obtained.

Abstract:Aiming at the problem that the cohesive zone model parameters， describing the mechanical properties of the adhesive interface， which can′t be obtained by traditional experimental method accurately，the inversion research on the relevant parameters of bilinear cohesive zone model used for the adhesive interface is carried out by using the digital image correlation method and Hooke-Jeeves optimization algorithm based on the tensile test results of solid rocket motor rectangular adhesive specimens. The inversion results show that the maximum adhesive strength， modulus and failure fracture energy are 0.55 MPa， 0.57 MPa and 2.26 kJ·m^-2， respectively， when the tensile rate is 5 mm·min^-1. The relative error of simulated and measured stress-strain curves is corrected from 44.7% to 4.3%. When the tensile strain is 0.05 and 0.08， the maximum displacement errors of simulated and measured region of interest is 0.64 mm and 1.76 mm， respectively， and the average displacement errors of simulated and measured region of interest is 0.38 mm and 0.45 mm， respectively. The validation results indicate that the accuracy of the inversion identification method is high enough and the established cohesive zone model can be used to characterize the mechanical properties of the adhesive interface.

Abstract:To improve the hazard classification of anhydrous hydrazine， the extremely insensitive detonating substance （EIDS） gap test and external fire test were conducted for the standard packaging anhydrous hydrazine （18 kg and 120 kg） in accordance with the United Nations “Recommendations on the Transport of Dangerous Goods， Manual of Tests and Criteria”. The deflagration process， the highest temperature of the fireball surface and shock wave effect of samples were obtained by a high-speed camera， an infrared thermal imaging and a shock wave pressure acquisition system. The experimental results show that， under external fire conditions， the TNT equivalence of the anhydrous hydrazine-18 kg was 0.724， which was 1930.67 times that of anhydrous hydrazine-120 kg. Under certain conditions， anhydrous hydrazine has obvious explosive properties and can be assigned to Division 1.1 C or Division 1.3 C for different packaging design pressures. The hazard class of anhydrous hydrazine is closely related to the standard packaging design pressure. For safety purposes， the design pressure of packaged anhydrous hydrazine should be properly reduced within the allowable range to effectively reduce its hazard.

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: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:The Arrhenius equation has been widely used as kinetics model for predicating aging property and shelf life of polymer materials by extrapolating high temperature accelerated test data. However， the suitability of the equation to composite solid propellants was questioned. Therefore the application history of the Arrhenius equation on aging of composite solid propellants has been reviewed. By combing the theoretical evolution process of Arrhenius equation， physical meaning of the equation parameters was clarified， and the misunderstanding on the equation was revealed. Theoretical analysis shows that only one of the two parameters （frequency factor and activation energy） is relative to temperature in the Arrhenius equation， and the parameters can be regarded as constants to solid propellants aged between the highest acceleration temperature allowed by current industry-standard and room temperature. The following conditions should be met to apply the Arrhenius equation： 1） it can be considered as the same aging mechanism in the range of temperatures involved in， 2） it has similar aging levels at the deadline of different acceleration temperatures， and 3） it has a parameter k with physical meaning of rate constant exactly. Mathematical models with logarithmic time are unsuitable to fit performance-time relationship， while those with logarithmic performance are suitable.

Abstract:The bonding interface of solid rocket motor will be damaged due to the creep effect from long-term vertical storage. This paper reviews the relevant research progress from three perspectives as the influencing factors of interface damage under creep condition， interface damage test， and numerical simulation of interface damage. It emphasizes that the cumulative damage of bonding interface under creep condition cannot be ignored， summarizes the shortcomings of test and numerical simulation research， and makes a prospect. According to the findings， the most difficult aspect of experimental research is devising reasonable tests and selecting variables that effectively characterize the timeliness of damage. The focus of numerical simulation research is to build a creep interface cohesion model with damage， in order to provide some reference for the performance evaluation of bonding interface under storage conditions.

Abstract:Energetic burning rate catalyst is a hot research direction in the field of solid propellant in recent years. The application research progress and development trend of energetic combustion-rate catalysts in solid propellants were reviewed from the following four categories： monometal-organic framework type， bimetal based multi-functional type， molecular supported type and other types. It was pointed out that the catalytic effect of mono-metal-organic frame type burning rate catalyst is relatively simple， and the catalytic effect is better when combined with other metal salts. Bimetal based multi-functional combustion rate catalysts have excellant catalytic performance and potential application prospects. Molecular supported burn rate catalysts are still in the preliminary exploration stage， and their preparation and application have become one of the development directions of burning rate catalysts. The application of other new energetic burning rate catalysts should be strengthened. Finally， the main research directions in the future were suggested as following： green and environmental protection， high energy and low sensitivity， and nano and multi-functional composite. Burning rate catalysts containing heavy metals will have adverse effects on the environment， and the development of green and environmental protection burning rate catalysts has become an inevitable trend. The energy loss of propellant can be reduced by giving certain energy characteristics to burning rate catalysts. High energy and low sensitivity have become an important direction of burning rate catalysts. Nanocrystallization of energetic burning rate catalysts is always an effective way to improve the catalytic activity of catalysts. Burning rate catalysts with multiple functions will be the development trend in the future.

Abstract:In order to study the performance of aluminum-based composite fuel in NEPE solid propellant， the aluminum-base composite fuel（Al@AP） was used in the NEPE solid propellant instead of aluminum powder， and the effects of Al@AP on the combustion， mechanics， and process performance of NEPE propellant were studied by explosion heat test， engine test， residual active aluminum test， high-speed photography， unidirectional tensile test and process properties test. And the combustion mechanism of Al@AP in NEPE propellant was derived. Results shows that by replacing FLQT-3 Al powder with 19.5% Al@AP， the explosion heat of NEPE propellant increased from 6029.4 J·g^-1 to 6924.8 J·g^-1， and the mass of residue decreased from 28.91 g to 7.64 g， and the active aluminum content of residue decreased from 14.64% to 0.37%， and the particle size of residue decreased from 94.12 μm to 24.21 μm. The injection efficiency of NEPE propellant with Al@AP is improved. The residence time of aluminum powder at the burning surface decreased from 55 ms to 40 ms， and there was no obvious agglomeration phenomenon. Al@AP powder has little effect on the dynamic burning rate， mechanics and process properties of NEPE propellant.

Abstract:The ignition and combustion characteristics of NEPE propellant were studied based on a CO₂ laser ignition test platform established， in which the combustion processes of NEPE propellant in different gas environments were photographed using a high-speed camera and the ignition delay times of NEPE propellant were measured under the pressure of 0.1-3.0 MPa in nitrogen and air through a signal acquisition system. The results show that the ambient pressure and gas environment strongly affect the ignition and combustion process of NEPE propellant. The combustion of NEPE propellant becomes more intense as the increase of ambient pressure， and the burning of NEPE propellant appears more violent in air as compared to that in nitrogen. The ignition delay time of NEPE propellant decreases with the ambient pressure increases in the range of 0.1 MPa to 3.0 MPa. Specifically， the reduction in ignition delay time of NEPE propellant is observed from 0.51 s to 0.29 s in nitrogen and from 0.32 s to 0.18 s in air. However， when the ambient pressure exceeds 0.5 MPa， the influence of the ambient pressure on the ignition delay time becomes insignificant. In addition， the burning rate of NEPE propellant is also found to be effectively affected by the ambient pressure. With the ambient pressure increases from 0.1 MPa to 3.0 MPa， the enhancement in burning rate of NEPE propellant can be seen from 1.71 mm·s^-1 to 4.54 mm·s^-1 in nitrogen and from 2.51 mm·s^-1 to 11.4 mm·s^-1 in air， and thus a stronger increase in the burning rate is observed in air. Finally， the experimental data of burning rate were fitted by an empirical formula， which indicates the Vielle burning rate formula is more suitable for reproducing the burning rate characteristics of NEPE propellant especially at 0.1-3.0 MPa.

Abstract:The agglomeration of condensed phase during the combustion process of propellant is one of the main reasons for energy loss and nozzle ablation， and the introduction of fluorine into propellant is considered to be an effective way to solve the agglomeration. In order to solve the condensed phase agglomeration of aluminum， a fluoroalcohol compound was introduced into the traditional HTPE propellant， and it was integrated into the binder cross-linked network through the curing reaction to form a solid propellant based on a novel fluorocarbon binder. Thermogravimetric （TG） and laser ignition were used to characterize the thermal decomposition and the burning intensity of the propellant. The combustion surface flame morphology and particle size distribution of combustion condensed phase products were characterized by scanning electron microscope （SEM） and EDS. The results show that the weight loss of the propellant after adding PFD still includes three main stages， but PFD will cause the decomposition of RDX in the propellant to be delayed by 15-20 ℃.Moreover， the fluorine-containing segment will completely decompose and lose weight before 250 ℃. Compared with the blank propellant sample， the propellant containing PFD has higher burning brightness at the same ignition time. With the increase of PFD， the intensity of the combustion flame of the propellant sample increases significantly， and the flame jet is more intense. The average particle size of condensed phase products decreased gradually from 5.13 μm （1%PFD） to 1.04 μm（5%PFD）.

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:As an energetic material， octogen（HMX） is widely used in solid propellants. While improving the energy performance of the propellant， it also changes the combustion process of the propellant. To study the effect of HMX content on the ignition， combustion， and agglomeration properties of propellant and its condensed phase combustion products （CCPs）， burning surface photography， laser ignition and collection of the CCPs were used for testing and studying typical AP/HTPB/Al/HMX propellants with HMX contents ranging 0%-10%. Results show that as the HMX content increases from 0 to 10%， the ignition delay time increases from 191 ms to 286 ms， and both the burning rate and pressure exponent of the propellent decreases. The volume average particle size of the CCPs increased from 48.1 μm to 138.3 μm. The propellent with 10% HMX has the highest agglomeration degree on the burning surface， while the propellent with 8% HMX has the highest active aluminum content in the CCPs.

Abstract:Rapid detection of unsymmetrical dimethylhydrazine （UDMH） and its transformation products in water is of great significance for its pollution control. This paper reviewsthe research progress of chromatographic methods （including gas chromatography， high performance liquid chromatography， and ion chromatography） and non-chromatographic methods （including the electrochemical method， spectrophotometry and chemiluminescence） in the detection of UDMH in water. Then， application of chromatography in in the detection of UDMH conversion products in water was briefly introduced. The advantages and disadvantages of different detection methods in the detection concentration range， sample pretreatment and anti-interference ability， etc.，were pointed out. It was suggested that the design of efficient automatic chromatographic pretreatment device and the combination of various separation and detection technologies would be the future development direction to solve the detection problem of UDMH and its transformation products in water.