Abstract:XLDB and NEPE propellants with catalysts were prepared. Their burning rates were measured by strand burner method. The results show that pressure exponent of XLDB propellant decreases by 27.1% when the contents of lead monosalicylate and copper monosalicylate are 1.5% and 0.5%, respectively. But when other lead salts and copper salts are added to XLDB propellant, the burning rate of XLDB propellant increases, and pressure exponent of XLDB propellant does not decrease. The burning rate and pressure exponent of XLDB propellant with lead monosalicylate and nickel molybdate, or thorium dioxide are higher than that of XLDB propellant with lead monosalicylate and copper monosalicylate. The pressure exponent of XLDB propellant does not decrease and the burning rate of XLDB propellant increases a little when nickel molybdate and other catalysts are added to XLDB propellant. With the increasing of contents of lead carbonate, the pressure exponent of NEPE propellant decreases. The pressure exponent of NEPE propellant decreases by 34.7% when the contents of lead carbonate and carbon black are 2% and 0.5%, respectively. The effect of catalysts of multiple components influencing burning rate and pressure exponent of NEPE propellant is same as catalyst of two components, for example lead carbonate and carbon black.

Abstract:The thermal decompositions of RDX-CMDB modified double base propellants with a composite burning catalyst were investigated by using of PDSC and TG-DTG. It is shown that the influence of the burning catalysts with different components on the characteristic values of PDSC is different in the decompositions of RDX-CMDB, Which is similar to the catalyst on burning rate. The characteristic values, which are the square roots of heat release rate and pressures on PDSC tests, can be correlated to burning rates of RDX-CMDB by using a liner equation. The k_u, correlation factor of burning rate with PDSC characteristic value, can be used to study the effect of burning catalysts on burning rate of the propellants.

Abstract:Effects of temperature on coke and its precursors formation were studied during catalytic cracking of toluene over USY catalyst. The coke and its precursors were analyzed by TGA, solid-state ¹³C NMR，elemental analysis, GC-MS and temperature-programmed oxidation(TPO). The coke deposited on the catalyst is mainly composed of polyaromatic hydrocarbons (PAH). It reveales that the total amount of coke and the yield of PAH and its ring numbers in liquid phase increase with the increase of cracking temperature. It concludes that high temperature is bad for coke inhibition.

Abstract:Lead 5-(2,4-dinitroanilino)-salicylate (DNAS-Pb) was synthesized with yield of 70% by using 2,4-dinitrobenzyl chloride, 5-aminosalicylic acid and lead nitrate as raw materials. Its chemical structure was characterized by FT-IR spectra, MS, X-ray fluorescence diffraction and elementary analysis. The catalysis of DNAS-Pb on the combustion of double-base propellant was investigated. The results show that DNAS-Pb possesses good catalytic effect, and markedly increases the burning rate and makes the propellant produce plateau combustion and mesa combustion. The plateau zone extends from 6 MPa to 10 MPa, and the burning rate is approximately 13.2 mm·s^-1 and the pressure exponent is 0.03. The mesa zone extends from 10 MPa to 14 MPa.

Abstract:3-Nitratomethyl-3-ethyloxetane was synthesized by the process of cyclization,nitation from trimethlolpropane and diethyl carbonate, and the homopolymer of 3-nitratomethyl-3-ethyloxetane was synthesized with 1,4-butanediol as initator and boron trifluoride etherate as an catalyst by cationic ring-opening polymerization. The effect of catalyst/initator molar ratio and reaction temperature on polymerization was discussed. The study of properties indicates that PNIMEO has a glass translation temperature of -25 ℃, the temperature decomposition of 218 ℃, the decomposition enthalpy of +1212 J·g^-1 , the explosion probability of 0, the 50% point of 109.6 cm.

Abstract:The influence of bis(3-nitro-1,2,4-triazole-5-onato) lead(II) (Pb(NTO)₂), tetraaquo-bis(3- nitro-1,2,4-triazole-5-onato) copper(II) (Cu(NTO)₂) and tetraaquo-3-nitro-1,2,4-triazolato -5-onato copper(II) (Cu(NTO)) on the combustion characteristics and the thermal behavior of AP-CMDB propellants were experimentally studied. The results show that the thermal decomposition of NC and NG for the AP-CMDB propellants are affecteded obviously by the lead and copper salts of NTO, and the pressure exponents of the AP-CMDB propellants decreases obviously with the increase in burning rates of the propellants in the pressure range of 1~7 MPa and the decrease in the pressure range of 10~20 MPa. It is also found that Cu(NTO) has great effect on the combustion characteristics of the AP-CMDB propellant because the decompositions of both NC/NG and AP of the propellant are obviously promoted by Cu(NTO).

Abstract:The curing reaction kinetics of polyethylene glycol(PEG) with isophorone diisocyanate(IPDI) or toluene diisocyanate(TDI) were studied by means of chemical titraction. The reaction rate constant and activation energy (E_a) were obtained. The effect of the molecular weight of PEG ,activation of curing agent, temperature and combustion catalysts on curing reaction were discussed. The results show that the reaction order are second. The E_a of PEG/IPDI and PEG/TDI system are 46.89 kJ·mol_-1 and 41.12 kJ·mol_-1, respectively. With the increase of temperature and activation of curing agent, the reaction rate constants increase. The activation of cure agent and combustion catalysts have no effect on the order of reaction, but affect the reaction rate constants.

Abstract:The effect of CL-20, AP, Al power and combustion catalyst on combustion properties （burning rate and pressure exponent）of CL-20-NEPE propellant was studied with designed formulation ［NB(PEG/NG/N-100/C₂),NB/CL-20,NB/CL-20/AP,NB/CL-20/AP/Al,NB/CL-20/AP/Al/Ct］ , in which the ingredients are added one by one, and compared with that of RDX-NEPE propellant. The results show that the substitution of CL-20 for RDX in RDX-NEPE propellant increases the burning rate, but the pressure exponent of CL-20-NEPE propellant which is difficult to reduce is larger than that of RDX(HMX)-NEPE propellant.The burning rate of AP-NEPE propellant containing 70% AP reveals a plateau at 4-10MPa. Adding AP into CL-20(RDX)-NEPE propellant increases the oxygen coefficient and the burning rate, and decreases the pressure exponent. Addition of Al powder increases the burning rate of RDX-NEPE propellant although has little effect on that of CL-20 NEPE propellant. The pressure exponent of burning rate of CL-20-NEPE propellant is decreased by combustion catalyst PbCO₃ and Pb(NTO)₂·H₂O.

Abstract:The effects of seven lead salts, including PCDS, PDS, NIP, lead 3-nitro-1,2,4-triazol -5-one, lead 2,4-dihydroxybenzoate, lead phthalate and lead carbonate, on the combustion characteristics of the high energy smokeless modified double-base propellant(HESMDB) was studied in details. The results show that the catalyzed combustion of lead salts relates to the molecular structure of the lead salts. PCDS has the best catalytic effect on the combustions of the HESMDB. Whereas the mixtures of lead salts and carbon black used in the HESMDB, enhance the burning rate of the propellants at low pressure and decrease the pressure exponent of propellant.

Abstract:The thermal aging properties including the weight loss percent, the hardness, the gel fraction, the relative cross-linking density, the content of the plasticizers (BTTN and NG) were measured to analyze the aging characteristics of nitrate ester polyether (NEPE) propellant at three high temperature levels of 60 ℃, 70 ℃ and 80 ℃ under the thermal air condition. The results show that the hardness and the weight loss percent of NEPE propellant increases along with the aging time because of the volatilization and decomposition of the plasticizers, and the gel fraction and the relative cross-linking density decrease because of degradation of the binder matrix, and the contents of the plasticizers (BTTN and NG) decrease and are in conformity with first-order reaction. The reasons of NEPE propellant performances deterioration are the volatilization and decomposition of the nitrate ester plasticizers, the continued-curing reaction and the degradation of the binder matrix.

Abstract:In order to understand the influence of damage on the life of rocket motor, the damage and failure behavior of HTPB propellant was studied, and the methods to characterization of damage properties and the ability of propellant anti-damage were studied too. The influence of environment and stress on propellant damage was discussed. It is found that HTPB propellants have different anti-damage properties, depending on the dewetting point stain (ε_d). The damages in the propellant can be characterized by E_5%, dewetting energy, permanent stain, and S-shape curve of propellant. The environment humidity affects the damage properties of propellants significantly.

Abstract:In order to reducing the acidic impurity B₂O₃ and H₃BO₃，the amorphous boron powder was neutralised respectively with ammonia in gas phase（B-1），ammonia in liquid phase（B-2）and sodium hydroxide in solution（B-3）.The rheological characteristics of B-1，B-2 and B-3 with HTPB were researched. The results indicate that the apparent viscidity and yield value of B-1/HTPB mixture increase rapidly with mixing time increasing，those of B-2/HTPB mixture increase slowly and those of B-3/HTPB mixture almost don′t increase. The mechanisms of three neutralization methods of the amorphous boron powder were discussed through acidity meter，TG，IR and XRD analysis. The results show that the improvement in rheological property of B-1/HTPB mixture is due to NH₃ absorbed to the boron surface，which maybe obstructs the reaction between H₃BO₃ and HTPB，but disabsorbs in mixing process and results in the gelatinization of B-1/HTPB mixture. Due to a soluble compound formed by the reactation between ammonia and H₃BO₃ on boron surface，the rheological property of B-2/HTPB mixture improves. The better rheological property of B-3/HTPB mixture is owing to the soluble NaBO₂ formed by the reactation between NaOH and H₃BO₃，which reduces the content of H₃BO₃ on the boron powder.

Abstract:On the mechanical properties of NC/NG/AP/Al composite modified double-base (CMDB) propellant, the effects of the content of NC, the ratio of solid components granularity and the system of solidifying agents, were studied. The results show that the maximum stress ( σ_m, +20 ℃ and +50 ℃) of the CMDB propellant decreases with the content of NC decreasing, and the maximum elongation ( ε_m, +20 ℃ and +50 ℃) of the propellant reaches the maximum value when the content of NC is 20%. The ratio of solid components granularity affects the mechanical properties of CMDB propellant obviously which reaches the maximum value when the ratio of AP(96.8 μm)∶RDX(44.9 μm)∶Al(10.8 μm) is 1∶1∶1. It is found that for the CMDB propellants with low content of NC, the maximum stress of the propellant can be increased at a certain extent and the maximum elongation of the propellant can be increased obviously when the cross linking agents is added suitably.

Abstract:The effects of chain extenders and cross linkers on the mechanical characteristics of the binder film of the NEPE propellant at 50 ℃ were experimentally studied. The results indicate that the aliphatic and low molecular polyether diols (chain extenders) improves the mechanical characteristics of the binder films at high temperature, and the three types of triols (cross linkers) increases the maximum stress of the binder film and decreases the maximum elongation of the bind film. It is found that the aliphatic diols might cause the exudation of nitrate esters from the binder film during the curing process.

Abstract:A novel interpenetrating polymer network, which based on modified hyperbranched polyester and HTPB polyurethane, was prepared for enhancing mechanical properties of HTPB based composite solid propellants. The results indicate that with the modified hyperbranched polyester added, the tensile strength and elongation of HTPB polyurethane elastomer improves obviously. Specially, when the content of modified hyperbranched polyester of generation 4 rises up to twenty percentage of the whole weight, the resultant elastomer has the best tensile strength and elongation, which increase 3.36 times and 3.69 times than pure elastomer, and reach 2.3 MPa and 1860% respectively. Therefore, the modified hyperbranched polyester can serve as a better modifer for HTPB propellants.

Abstract:The stress-strain relations and fracture behavior of the PEG/N-100 matrix were investigated by methods of unilateral tensile testing, scanning electron microscopy, etc.. The experimental results indicate that maximum tensile strength of the PEG/N-100 matrix is above 7 MPa and approximately 10 MPa at the yield point, and the elongation percentage of fracture is over 400%. The spherulites of about 7 μm in diameter were found in the fractured matrix of PEG/N-100. The process of the matrix fracture has been proved to undergo the growth of micro-cracks, the expansion of micro-cracks and the final fracture of PEG/N-100 matrix.

Abstract:HTPB composite solid propellant containing slant internal cracks under uniaxial tensile load were measured by using of material testing device WDN-10KN, with the tensile rate of 2 mm·min^-1.The whole progress of Crack propagation was recorded by camera. Curves of the Loading-Displacement, crack initiation angle and fracture loading were obtained. By comparison with series fracture criteria including T-Criterion, S-Criterion, σ_θ-Criterion, the crack initiation angle of solid propellant obtained is in approximately agreement to that from T-Criterion, showing that the T-Criterion can be used as a theory prediction to the crack initiation angle of the composite solid propellant.

Abstract:Full geometrical optimizations of 1,1-dimethylhydrazine, (CH₃)₂NNH₂, have been carried out by quantum-mechanical methods RHF, DFT/B3LYP and MP2 respectively. The optimal geometric structure parameters have been obtained. The effects of basis set are investigated. The predicted structure parameters are compared to the experimental ones also. Except two predicted parameters, C—N—N—H dihedral angle and C—H bond length, show smaller values, the others agree well with the experimental ones. All of these calculations indicate a gauche conformation. The predicted N—N bond length is about 0.143 nm and C—N bond length is about 0.147 nm. The bond angles of N—N—C and C—N—C are about 112° and 113.8° respectively. The C—N—N—H dihedral angle is about 86°。The calculations at 6-31G basis set can get enough precisions.

Abstract:The energy parameters of the propellant containing octanitrocubane（ONC） are calculated by CAD system of propellant energy calculation under standard condition（p_c/p_o=70∶1）. Replacing ammonium perchlorate with octanitrocubane in HTPB propellant increases the specific impulse for 125 N·s·kg^-1，NC/NG/ONC smokeless MDB propellant has a specific impulse of 2545 N·s·kg^-1，GAP/ONC/RDX smokeless propellant has a high specific impulse over 2600 N·s·kg^-1 in very wide scope.

Abstract:Cohesive energy density and solubility parameter of nitrate ester plasticizers，azide prepolymer and azide thermoplastic elastomers which consisted of different soft segment and hard segment were calculated respectively by molecular dynamics simulation method. The results show that the miscibility of azide prepolymer or azide thermoplastic elastomer with diethyl-eneglycol dinitrate (DEGDN), triethyleneglycol dinitrate (TEGDN) is better than that with (nitroglycerin) NG, (1,2,4-butanetrioltrinitrate) BTTN or NG+DEGDN; and PAMCMO shows much better miscibility with nitrate ester plasticizer than GAP, BAMO, AMMO. Although the solubility parameter of azide thermoplastic elastomers calculated is higher than that of prepolymer, the miscibility is still not well. The homopolymer of azide prepolymer show better miscibility with nitrate ester plasticizers than their copolymer with THF.

Abstract:For better combustion performance of high burning rate composite modified double base（CMDB）propellant with ACP, a novel fast-burning energetic coordination compound of copper(Ⅱ) salt with one of triazole derivatives, ACP particles were coated with polyurethane adhesive. The thermal decomposition behaviors of ACP and coated ACP were studied by thermogravimetry (TG), and their effects on combustion performance of CMDB propellant in the pressure region of 11-20.5 MPa (high pressure range) and 3-9 MPa (low pressure range) were comparatively studied. Experimental results show that the thermal decomposition process of ACP or coated ACP includes four phases, and total loss of weight after decomposition are 90.70% and 76.22%, respectively. ACP and coated ACP are effective to enhance burning rates under low and high pressure and have about the same increments, and led to burning rate exponents enhancement under low pressure but reduction under high pressure. The propellants containing coated ACP show about 0.1 decrease in burning rate pressure exponent under high and low pressure in comparison with that of containing uncoated ACP with the same content in propellant. The experimental results indicate that the coating agent on the surface of ACP particles plays an important role in the thermal decomposition behaviors of ACP and affects combustion properties of propellants.

Abstract:The thermal behavior of different boron powder coated with AP and LiF was investigated by means of DTA-TG. The effects of coating and agglomeration on combustion heat of agglomerated boron and explosive heat of boron based fuel-rich propellant were studied. The results show that boron coated with AP promotes the oxidation degree of boron in oxygen environment while boron coated with LiF reduces the temperature of boron oxidation. The coated boron has improved combustion and released more heat. Small particle size of agglomerated boron is beneficial to boron combustion.

Abstract:The superfine boron powder was coated by aggradation method with AP using methanol or acetone as the solvent. The coating effect were characterized by FT-IR, heat analysis, atom force microscope, transmission electron microscope et al, and the influencs on the coating of the solvent, vaporized velocity and amido-silicon alkyl were studied. The results show that the optimized vaporized velocity is 10 g·h^-1. The pretreatment of boron power by amido-silicon alkyl in advance brings a good coating effect of superfine boron powder.

Abstract:ε-HNIW was coated with aqueous polyurethane emulsion by demulsification. The factors affecting the coating efficiency and the impact sensitivity of coated ε-HNIW were investigated and analyzed via orthogonal L9(3⁴) test design and single factor experiment. The experiment results show that the important factors are coating temperature, the add-on of solvent and demulsifier solution, and agitating rate. The temperature and the add-on of solvent are directly related with the particle size, size distribution of the coated ε-HNIW and the coating efficiency. The optimum conditions are reaction temperature 45 ℃, the weight ratio of solvent PU 8∶1, the weight ratio of demulsifier solution PU 4∶1, agitating rate 300 r·min^-1. The surfactant is added to the reaction system after demulsification to control the particle size and prevent the granules to agglomerating. The coating decreases the impact sensitivity as the H₅₀ of ε-HNIW increases from 15 cm(uncoated) to 37 cm (coated).

Abstract:Carbon nanotubes (CNTs) supporting ferric oxide (Fe₂O₃) nano-particles (CNTs/Fe₂O₃) was prepared by the liquid phase precipitation method, and was determined by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The catalytic properties of Fe₂O₃/CNTs on thermal decomposition of ammonium perchlorate (AP), ammonium dinitramide (ADN) and ammonium nitrate (AN) were investigated. The results show that the surface of CNTs is coated uniformly with nano-particles of α-Fe₂O₃ with average diameter of 22 nm. Primary thermal decomposition temperatures of AP decrease 33.7, 40, 50.8 ℃ respectively, and thermal decomposition peak temperatures decrease 14.7, 22.9, 26.4 ℃ respectively when addition amounts of CNTs/Fe₂O₃ are up to 1%, 3% and 5%. Primary thermal decomposition temperatures of ADN and AN decrease 12.1,3.6 ℃ respectively, thermal decomposition peak temperatures decrease 18.6, 6.6 ℃ respectively when addition amount of CNTs/Fe₂O₃ is up to 1%.

Abstract:A series of thermoplastic polyurethane elastomers (TPU) with different fraction of hard segments based on poly(ethylene-propylene adipate) (PEPA)/ethylene oxide/tetrahydrofurancopolyether(PET）as soft segments were synthesized. The TPUs were characterized by GPC, FTIR and the tensile testing, and were used to coat the hexanitrohexaazaisowurtzitane (CL-20) by water suspension method. The coating effects were assessed by testing impact sensitivity , surface free energy and XPS .The results show that impact sensitivity of CL-20 coated with TPU is lowered and affected by fraction of hard segments of TPU. The coating effects of CL-20 is apparently related to the mechanical properties of TPU. The comprehensive properties of TPU with 50% hard segments content are optimum. The special height H₅₀ of CL-20 coated by this kind of TPU is 46.2 cm, which increase 23.9 cm than that before coating. The coating degree achieved as 68.13%.

Abstract:The modified ammonium nitrate(AN) was prepared by adding more than 20 kinds of inorganic additives with dosage of 0.99%(wt), and the effects of these additives on AN polymorphs were studied by differential scanning calorimetry (DSC) method. The results show that potassic salts prevent the transition of Ⅳ-Ⅲ effectively, while oxide, Cu(NO₃)₂, (NH₄)₂SO₄ and MgSO₄ prevent the transition of Ⅲ-Ⅱ, the composite of KCl and ZnO prevent the transition of Ⅳ-Ⅲ and Ⅲ-Ⅱ simultaneously. The effects of inorganic additives on AN phase transition are the coaction of such factors as anion and cation radius and their matching, ion substitution, the form of solid solutions, adulteration, solubility, charges, ion stereostructure etc.

Abstract:Structures of organic components in a new liquid propellant were identified by the nuclear magnetic resonance spectroscopy (NMR), and validated by the combination of chromatogram and IR (GC/IR). The components of the propellant were confirmed, including organic energetic oxydant, stabilizer and phlegmatizer. The content of every component was quantified by the reference material trans-butenedioic acid, according to the nucleus-carrying mass (NCM) of every component. The result of precision test with NMR is consistent with that with high performance liquid chromatography (HPLC). The relative standard deviation（RSD） obtained is 0.21% for organic energetic oxidant, 0.32% for stabilizing agent, and 0.11% for phlegmatizer, respectively. Results of recovery test are 99.9%, 99.9%, and 99.7% respectively.

Abstract:The research progress of high energy solid propellants was reviewed. Several methods of developing high energy solid propellants were put forward，such as by using energetic binders or high energy density materials，or energetic plasticizers，or new-concept fuel additives，etc.

Abstract:High-density liquid hydrocarbon fuels are important propellants for aircrafts. Recent progress in the synthesis of high-density liquid hydrocarbon fuels and their applications are summarized. The feedstock, synthesis route, property, and cost of fuels under utilization or development are introduced. Molecular design, shape-selective syntheses, and blending technology, are suggested as key points of future work.

Abstract:The green synthesis of nitrate esters using dinitrogen pentoxide (N₂O₅) as nitrating agent was briefly summarized. Three green nitration systems, N₂O₅-organic solvent, N₂O₅-solid support and introduction of blocking group were introduced. The characteristic and prospect of each nitration system were analyzed. The ring-open nitration of propylene oxide compounds was investigated using dinitrogen pentoxide as nitrating agent. The electronic effect and steric effect of substituent on nitration of propylene oxide compounds were discussed.

Abstract:The energy level, ignition, combustion of Al/H₂O and reaction mechanisms of Al with H₂O were reviewed. The applications of nano-aluminum and gelling agent in Al/H₂O propellant were discussed.

Abstract:The application of GAP in energetic thermoplastic elastomers(ETPE), energetic plasticizers and energetic curing agent were reviewed. A view was given on the modification of GAP by co-polymerization, end-capping and use special initiator method. The thermoplastic elastomers based on GAP, the copolymers of GAP, ester group or alkyl group terminal, azide group terminal GAP plasticizers and high molecular GAP has excellent application foreground.

Abstract:The characteristic of boron particle ignition in oxidative system was introduced. According to the analysis of Boron ignition mechanisms and corresponding chemical reactions，the disposals of two different models were explained from two different points, and emphasizes were placed on analysis of the generation and consumption of oxide on the surface of boron particles. Boron particle ignition mathematical models were established and compared finally.

Abstract:The recent development of researches on combustion characteristics of boron-based fuel-rich propellants has been reviewed. The paper summarizes the technical means of adjusting the primary and secondary combustion performance, which include the coating of boron, the adjustment of the formula of propellant, the improvement of the gas nozzle, the quantitative change of air and gas，the appropriate selection of spray regime, the optimization of air inlet mode and the distance between two air inlet, and so on. These efficient measures improve the combustion efficiency of boron-based propellants and reduce the ignition residue.

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