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.

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:The explosives and propellants containing hexanitrohexaazaisowurtzitane （CL-20） and aluminum （Al） powders show excellent energy properties， and Al/CL-20-based energetic materials have become the focus of research. By using polyvinylidene fluoride （PVDF） as binder combined with nano-aluminum （nAl） powders and CL-20， the nAl@PVDF and nAl@PVDF@CL-20 composite energetic particles could be prepared via microfluidic technology. The morphology， internal structure， and particle size of two composite particles were observed by scanning electron microscope （SEM） and laser particle size analyzer. Chemical structure of composite particles was analyzed by Fourier transform infrared spectrometer （FTIR）. Thermogravimetry-differential scanning calorimetry （TG-DSC） was used for thermal analysis. The results show that the as-prepared composite particles exhibit high sphericity， good dispersibility， and uniform particle size distribution with the particle size of 10-20 μm. The components of composite particles are well-distributed， and there is no chemical bond between the components. Thermal analysis results display that both nAl@PVDF and nAl@PVDF@CL-20 composite particles exhibit pre-ignition reaction between PVDF and surface oxidation layer of nAl. The heat released from the pre-ignition reaction could promote the decomposition of PVDF. The decomposition reaction of CL-20 could be accelerated by combining with nAl and PVDF. Compared with nAl/PVDF/CL-20 material acquired by mechanical mixing， nAl@PVDF@CL-20 composite particles prepared by microfluidic method possess homogeneous component distribution.

Abstract:Composite solid propellant contains more solid particles， so it is difficult to accurately simulate the extrusion process of the propellant in twin-screw extruder with traditional finite element analysis method. Whereas， the coupling of discrete element method （DEM） and computational fluid dynamics （CFD） is an effective method for simulation the production process of composite solid propellant， but it is very difficult to implement. In this paper， based on the calibrated contact model parameters， the simulation of solid particles in solid propellant with aluminum powder and ammonium perchlorate as main components in twin-screw extrusion process was realized with DEM， and then the DEM-CFD coupling calculation of the solid propellant solid particles and the liquid phase was realized. The results show that the transportation of solid propellant particles in twin-screw calculated by DEM is consistent with the experimental law. Comparing the results between DEM-CFD coupled simulation and DEM for solid particles， it can be seen that the fluidity of materials was significantly improved by adding the liquid phase The filling rate of materials in the screw conveying section increases from 20% to 40%， and the average conveying speed of solid particles increases by 150%， but the stress of screw does not change much.

Abstract:Slow cook-off test is one of the key tests of low vulnerability assessment for solid rocket motor. In order to study the influence of the charge size of HTPB composite propellant on the slow cook-off characteristics， slow cook-off tests and numerical simulation were carried out to compare and analyze the ignition growth laws of solid rocket motor under slow cook-off tests， with charge dimensions of Φ100 mm × 200 mm， Φ160 mm × 400 mm and Φ522 mm × 887 mm. Their corresponding ignition temperatures， ignition positions and response levels were determined. Results show that the ignition temperature of specimens of Ф100 mm×200 mm， Ф160 mm×400 mm and Ф522 mm×887 mm of solid rocket motors are 244 ℃， 172 ℃ and 155 ℃， respectively. Taking test data as inputs， the calculated ignition temperature is 250， 269， 154℃， and their corresponding calculation errors and response levelsare 2.88%， 1.17%， 0.64%， and explosion， explosion and deflagration. The calculated cloud diagram shows that the ignition position of medium and small test pieces is located in the center of charge cylinders， and the ignition position of full-scale solid motor is in the center of meat thickness of solid propellant front-end， which is a ring shape area.

Abstract:The thermal decomposition characteristics and thermal safety of methylhydrazine （MMH） were studied by means of differential scanning calorimetry （DSC）. The kinetics， thermodynamics and thermal safety parameters of MMH were calculated， respectively. The thermal explosion delay period of MMH of ball shaped with radius of 1 m at different supercritical ambient temperatures were also obtained. Based on the isoconversion rate method， the adiabatic induction period and self-accelerating decomposition temperature of MMH were further evaluated by using AKTS software. The results show that the thermal decomposition process of MMH has only one strong exothermic peak. The apparent activation energy values of MMH calculated by Kissinger and Ozawa methods are 159.13 kJ·mol^-1 and 158.89 kJ·mol^-1， respectively. The values of T_bp0 of MMH is 469.55 K. The values of entropy of activation （ΔS≠）， enthalpy of activation （ΔH≠）， and free energy of activation （ΔG≠） are 73.93 J·mol^-1， 155.32 kJ·mol^-1 and 121.46 kJ·mol^-1， respectively. The corresponding temperatures for adiabatic induction period at 8， 24 h and 168 h are 429.55， 424.05 K and 414.95 K， respectively. When the packing mass was 5， 25， 50 kg and 100 kg， the self-accelerating decomposition temperatures of MMH are 415.15， 414.15， 413.15 K and 412.15 K in turn. The results provide the necessary theoretical basis for evaluating the thermal safety of MMH in the processes of production， storage， transportation and use.

Abstract:In order to realize the non-destructive measurement when predicting the storage life of nitrate ester plasticized polyether （NEPE） propellant， the high temperature accelerated aging， gas content monitoring and uniaxial tensile mechanical property experiment were carried out on NEPE propellant with 10% constant compression strain . The non-destructive storage life prediction model based on characteristic gas contents was proposed through correlation analysis and remaining life prediction model. The results show that during the storage and aging processes， the total amount of CO gas is the largest， reaching more than 1300 mg at different temperatures. The generating rates of NO and CO are growing slowly in the early aging period， and growing faster in the late period. The generating rate of HCl increases rapidly during the eraly and late aging period and slowly in the middle. Maximum tensile strength σ_m and maximum elongation ε_m increase slightly in the early aging period， the former oscillates slightly and the latter gradually increases in the middle period， and both of them decrease sharply in the late period. The correlation between the contents of CO and the maximum tensile strength is largest and there is a single correlation between them at different temperatures. The maximum correlation value reaches about 0.93-0.95. Four life prediction methods of NEPE propellant are established based on traditional and improved aging life prediction model， tensile strength and CO content. The maximum correlation coefficient and estimation results show that the improved prediction model based on the content of CO gas release is most effective.

Abstract:To study the mechanical properties of Hydroxyl-Terminated Polybutadience （HTPB） propellant/liner bonding interface for solid rocket motor at different temperatures accurately， the model-Ⅰ fracture properties of the interface were studied with experimental method and simulation. Firstly， the load-displacement curves of the test samples at different temperatures were obtained through uniaxial tensile tests and the failure process of the samples were also recorded with the high-speed cameras. It was found that the failure form of HTPB propellant/liner interface was cohesive failure of HTPB propellant， which indicated that the strength of bonding interface was higher than that of the propellant. From -40 ℃ to 60 ℃， the critical displacement first increased and then decreased， indicating that the effect of temperature on this parameter is obvious. And then a cohesion model with polynomial damage variable was developed， based on the bilinear cohesion law. According to the simulation data， the effects of the interface parameters on the predicted results of the interface properties at different temperatures were analyzed. Moreover， the load-displacement curves of the bonding interface at different temperatures were predicted with the critical displacement as a known parameter. It found that the predicted results by simulation were in agreement with the experimental results， which indicates that the developed interface model can more accurately reflect the temperature-dependent behavior of model-Ⅰfracture of the debonding interface for solid rocket motor than the bilinear cohesion model.

Abstract:It is reported herein that the interfacial adhesion between binder and filler has distinct effect on mechanical properties of propellant. The tensile fracture progress of propellant （nitrate ester plasticized glycidyl azide polymer （GAP） / hexanitrohexaazaisowurtzitane （ε-CL-20） polyether propellant and polyethylene glycol （PEG） / octogen （β-HMX） polyether propellant） was monitored by in-situ tensile scanning electron microscope. In addition， the interaction strength between binder matrices and solid fillers was characterized by adhesion work and binding energy. The adhesion work was studied by inverse gas chromatography （IGC） and contact angle method， and the binding energy was calculated via molecular dynamics （MD）. Results shows that the dehumidification and fracture expanding progress of GAP/ε-CL-20 propellant are more serious than these of PEG/β-HMX propellant during stretching progress. GAP/ε-CL-20 propellant breaks when the elongation is more than 60% while PEG/β-HMX propellant breaks when the elongation is more than 80%. Besides， the adhesion work 70.69 mJ·m^-2 and binding energy 259.90 kJ·mol^-1 between GAP matrix and ε-CL-20 are both lower than the adhesion work 98.61 mJ·m^-2 and binding energy 335.65 kJ·mol^-1 for PEG/β-HMX system， suggesting that the poor interfacial adhesion between GAP binder matrix and ε-CL-20 is one of main reasons for inferior mechanical properties of GAP/ε-CL-20 propellant.

Abstract:In order to analyze the factors affecting the ignition delay time in the gas phase reaction process between hydrazine fuel and NO₂， the reaction process was simulated by using density functional theory. The reaction activities， active sites， potential energy surfaces and reaction rate constants in hydrogen extraction reaction process of hydrazine （N₂H₄）， methyl hydrazine （MMH） and unsymmetrical dimethyl hydrazine （UDMH） were calculated. The results showed that the energy difference between the highest occupied orbital and the lowest vacant orbital of UDMH was the smallest among the three hydrazine fuels， which was 0.20522 eV， indicating that UDMH had the highest activity， so it has the fastest reaction rate with NO₂， which in line with the characteristic of the shortest ignition delay time. The active sites of three hydrazine fuels were identified， N（1） or N（4） for N₂H₄， N（1） for MMH and N（1） for UDMH. The active sites of hydrogen extraction reaction of three hydrazine fuels were calculated， it was found that the reaction barrier of UDMH is the smallest， which is 3.589 kJ ·mol^-1， and the reaction rate constant is the largest， which is 9.81×10⁵ L·s^-1·mol^-1， which is consistent with the shortest ignition delay time， it is concluded that in hydrazine fuel， the smaller the hydrogen extraction reaction barrier with NO₂， the larger the reaction rate constant， and the shorter the ignition delay time.

Abstract:To explore the aging mechanism and performance of antioxidants N-（1，3-dimethyl）butyl-N"-phenyl-p-phenylenediamine（4020）， N-isopropyl-N"-phenyl-p-phenylenediamine （4010NA）， N-phenyl-2-naphthylamine （D） in hydroxyl-terminated polybutadiene polyurethane （HTPB-TDI） system， quantum mechanics （QM） simulation， molecular dynamics （MD） simulation， monte carlo （MC） simulation were used to calculate the dissociation free energy， diffusion coefficient， solubility parameter and permeability coefficient of the HTPB-TDI system and each component. Results show that the order of the bond dissociation free energy of the three antioxidants is ΔG_D>ΔG_4010NA>ΔG₄₀₂₀， and they are all less than the minimum free energy of dissociation of HTPB-TDI （345.63 kJ·mol^-1）， indicating that the three antioxidants can preferentially react with the active free radicals in HTPB-TDI and slow down the progress of the free radical chain reaction in HTPB-TDI. The difference of diffusion coefficient and solubility parameter between antioxidant 4020 and HTPB-TDI is the smallest， which shows that antioxidant 4020 has poor diffusion ability and good compatibility with HTPB-TDI， so it can exist in HTPB-TDI stably and uniformly； The order of the permeability coefficient of oxygen in the three kinds of hydroxyl-terminated polybutadiene polyurethane antioxidant systems is P_HTPB-TDI/D＞P_{HTPB-TDI/4010NA}＞P_{HTPB-TDI/4020}， which manifests that D has the worst oxygen barrier ability. According to the chemical reaction difficulty， mobility， compatibility and oxygen permeability of the three kinds of antioxidants， the order of antiaging properties of the three kinds of antioxidants is 4020>4010NA>D.

Abstract:To explore the effect of solid boron hydrogen fuel on the burning mechanism of aluminum powder， the simultaneous thermal analysis-infrared mass spectrometry technology and the pyrolysis in-situ cell-Fourier transform infrared spectroscopy technology were employed. Combining with the numerical model of the effect of BHN-12 on the burning reaction of aluminum powder in the explosion flow filed， the mentioned experiment was introduced to study the reaction time， dispersion characteristics and combustion-supporting effect of boron-hydrogen fuel. Results show that the thermal decomposition process of BHN-12 started from 314 ℃， and ended at 360 ℃. There are three exothermic peaks and two endothermic peaks during the decomposition process with a total mass loss 32.3%-33.9%. The decomposition process obeyed the law of power series （Mampel power）， and the dynamic mechanism function is . The gaseous products of the thermal decomposition are mainly H₂， C₂H_4， C₂H₆ and NH₃， and the solid products are simple substances of amorphous C and B. The component transportation model was introduced to simulate the after- burning process of the Al/BHN-12 system. During the process， the dispersion speed of Al fuel was slower than that of BHN-12 particles. At the time of 20 ms， the dispersion radius of Al fuel was about 2.5 m， but it was 3m for BHN-12. In the first 2 ms of the reaction， there was no gaseous product produced， until 4m the gaseous products came out with a temperature 1800 ℃ in the middle of the fire ball. BHN-12 could increase the after-burning temperature of the entire system by about 300 ℃.

Abstract:To investigate the quasi-static tensile mechanical properties of aging high solid content modified double-base propellants （CMDB）， the uniaxial tensile tests of CMDB propellant were carried out at four different temperatures （323， 293， 273， 253 K） and different strain rates （3.3×10^-5， 3.3×10^-4， 3.3×10^-3， 3.3×10^-2 s^-1）. The CMDB propellant samples with different aging time （0，10，20，35，50，65，80，100 d） were tested by gas chromatography. The mechanical properties of CMDB propellant and the change of stabilizer content after aging were studied. The results show that the maximum elongation and the content of stabilizer decrease significantly during the aging process， which can be used as the failure criterion of the aging CMDB propellant. By using the time-temperature superposition principle （TTSP）， the maximum tensile strength curve of CMDB propellant was obtained， and the aging strength main curve equation was established， which could be used to predict the maximum tensile strength of CMDB propellant with different aging time in the range of quasi-static strain rate.

Abstract:In order to realize the efficient application of TKX-50 in field of solid propellants， the energy performance of poly（glycidylaminopropyl ether） （GAP）-based solid propellants containing TKX-50， CL-20， and TKX-50/CL-20 was calculated using the minimum free energy method， and the feasibility of TKX-50 and CL-20 combination application was analyzed. The application efficiency of TKX-50/CL-20/GAP-based solid propellant was also estimated. The results show that when TKX-50 content increases， balance combustion temperature of propellant in combustion chamber（T_c） and combustion gas average relative molecular mass（） of propellant decrease at the same time， and the theoretical ratio of impulse was first increased and then decreased. The compatibility of TKX-50 and CL-20 was moderate compatibility. It has good thermal stability and safety performance of the TKX-50/CL-20 mixture propellant. It can significantly broaden the choice of the content of each component of the formulation with TKX-50/CL-20 mixture propellant. The lower limit of CL-20 content in the compound propellant with theoretical specific impulse greater than 272 s was only 40% of pure CL-20 propellant. At the same energy level， TKX-50/CL-20 mixture has the characteristics of low cost and low characteristic signal， and has the potential of engineering application.

Abstract:In order to obtain accurate and reliable physicochemical properties of condensed phase combustion products （CCPs） of composite propellants， a method of ethylenediamine tetraacetic acid （EDTA） titration based on microwave digestion was proposed to achieve the quantitative analysis of the total components of condensed phase combustion products. Four groups of condensed phase combustion products of propellant were obtained by using self-developed condensed phase combustion products collection system. The determination accuracy of EDTA titration， inductively coupled high frequency plasma emission spectrometry （ICP）， gas volumetric method and potassium dichromate titration were compared and analyzed for the content of active Al. The results show that the EDTA titration method based on microwave digestion can accurately determine the contents of Al， Al₂O₃， AlN， Fe₂O₃ and C in the condensed phase combustion products of composite propellants. Microwave digestion can effectively dissolve the Al₂O₃ shell coating on the surface of active Al. The optimal parameters of microwave digestion is supposed to be V_H3PO4∶V_H2SO4∶V_HNO3=10∶2∶1. The temperature was 240 ℃， and the digestion time was 150 min. ICP spectroscopy can also detect all component contents of condensed combustion products， with a precision slightly lower than EDTA titration. The content of active Al in condensed phase combustion products determined by gas volumetric method and potassium dichromate titration was significantly lower than that determined by EDTA titration and ICP spectrometric method. EDTA titration is the most accurate method to determine the content of active Al. Compared with gas volumetric method， potassium dichromate titration method and ICP spectrometric method， the accuracy of EDTA titration is improved by 60%， 40% and 22%， respectively.

Abstract:A high-speed camera， a high-precision pressure sensor， an R-type thermocouple and a micro-thrust test bench has been used to investigate the controllable combustion behaviors and thrust performance of the laser-controlled solid propellant （LCSP） under laser irradiation. The burning rate， ignition delay time， chamber pressure， combustion flame temperature and micro-thrust under different laser power densities were obtained. The results showed that the burning rate and chamber pressure increased linearly， while the ignition delay time decreased with increasing laser power density. Combining the thermocouple temperature curves， it was concluded that the combustion process of LCSP might be divided into five zones： pre-heating zone， condensed phase zone， triple zone， gas phase zone and flame zone. Meanwhile， the combustion flame temperature of the LCSP was 1202.3 ℃ under the laser power density of 1.343 W·mm^-2. Dependence of the combustion status on laser power density makes sense to realize the accurate adjustment of micro-thrust. In the experiment， the thrust control of LCSP is successfully realized by changing the laser power density. As the laser power density increased from 0.344 W·mm^-2 to 1.343 W·mm^-2， thrust of the LCSP increased from 1.58 mN to 2.28 mN.

Abstract:In order to obtain high energy density liquid propellant fuels and increase the payload of the launch vehicle， 20 different methyl-substituted bicyclobutyl derivatives were designed， and the influence of the structure of bicyclobutyl derivatives on performance was studied through theoretical calculations. Results show that with the increasing number of methyl substituents， the heat of formation and specific impulse of bicyclobutyl derivatives show a decreasing trend. When the substituent is para-substituted， its molecular stability is the best， and the heat of formation and specific impulse are larger， while the ortho-position substitution has a weakening effect on the heat of formation and specific impulse of bicyclobutyl derivatives. Among the designed compounds， the specific impulse of bicyclobutyl is the highest. When the mixing ratio of bicyclobutyl and liquid oxygen is 28.5∶71.5， the specific impulse can reach 304.52 s， and the main combustion products are CO（34.64%）， CO₂（13.89%） and H₂O （29.54%）. The comprehensive performance of all designed products is better than that of rocket kerosene. This study provides theoretical support for the design and synthesis of high-energy fuels.

Abstract:In order to prevent the spacecraft from being damaged due to the high pyroshock of the separation nut， an orifice is used to suppress the pyroshock response of the separation nut during separation. Throttle holes with three diameters of Φ2 mm， Φ4 mm and Φ6 mm are set on the powder gas channel of the separation nut. The pressure， acceleration and preload of the separation nuts of different orifices in the separation process are tested simultaneously， so as to analyze the separation process of the separation nuts. According to the sequence of movement， the pyroshock load is decoupled into three types of pyroshock sources： powder combustion， preload release and piston impact. The time-acceleration （a-t） curve is transformed into a shock response spectrum （SRS）， and the contribution of each shock source is calculated. The relationship between the orifice diameter and the shock response is obtained. The results show that in the frequency domain of 500 to 10000 Hz， the contribution of gunpowder action is 8.3% to 11.0%； the contribution of preload release is 44.0% to 51.5%； and the contribution of piston impact is 40.2% to 45.0%. The maximum pyroshock response during the separation process is： 1416 g （Φ6 mm）， 1251 g （Φ4 mm） and 852 g （Φ2 mm）. It can be seen that the use of the orifice can effectively suppress the impact response of the separation nut.

Abstract:In order to explore the solid propellant combustion catalyst， a new type of bi-ligand containing energy complex ［Cu（MIM）₂（AIM）₂］（DCA）₂ was synthesized from 1-methylimidazole （MIM）， 1-allyl imidazole （AIM）， copper nitrate and NaDCA， and its structure was characterized by infrared spectroscopy， X-ray single crystal diffraction and powder diffraction. The thermal decomposition process of the energetic complex was analyzed by DSC and TGA. Within the temperature range of 40-500 ℃， there is a melting peak （peak temperature is 93.5 ℃） and an exothermic decomposition peak （peak temperature is 199.4 ℃） in DSC curve. The sensitivity test of the complex shows that the friction sensitivity and impact sensitivity are low and the operation process is safe. Comparing the bi-ligand ［Cu（MIM）₂（AIM）₂］（DCA）₂ with ［Cu（MIM）₄］（DCA）₂ and ［Cu（AIM）₄］（DCA）₂ catalyses on the thermal decomposition of AP， the results show that the bi-ligand complex has better catalytic effect， which advanced the exothermic peak temperature of AP by 88.8 ℃， increased the heat release from 782 J·g^-1 to 2458 J·g^-1， and lowered the thermal decomposition activation energy by 47.1 KJ·mol^-1， implying the potential application as a composite propellant catalyst .

Abstract:In order to study the damage and failure process of adhesive interface of solid rocket motor， rectangular adhesive specimen of solid rocket motor was made based on QJ2038.1A-2004 regulation standard and tensile tests was carried out. The damage and failure mode of the adhesive interface specimen was obtained. The parameter inverse identification method which is based on step inverse and Hooke-Jevees optimization algorithm was adopted. The relevant parameters of the bilinear cohesive model of mix mode at the propellant/liner/insulator interface were obtained and were applied into the numerical simulation of the damage and failure process of adhesive specimen in tensile tests. Results show that the main failure form of adhesive interface specimen is the debonding at the interface of the propellant/liner/insulator layer； the proposed parameter inverse identification method can obtain the interface parameters of solid rocket motors well. The initial modulus， maximum bonding strength and fracture energy of the propellant/liner/insulator layer of solid rocket motors are 0.86 MPa， 0.63 MPa and 3.13 kJ·m^-2 at tension speed of 2 mm·min^-1， respectively. The damage of the propellant/liner/insulation layer interface makes the increase rate of stress decrease with the tensile strain. The initiation interface crack at the tip of the artificial debonding layer and the expansion along the center of the specimen， and finally penetration of the bonded specimen is the main damage and failure mode of the adhesive specimen.