Ballistic Modification of Composite Modified Double-Base Propellants containing ammonium perchlorate

The effect of certain lead and copper salts of organic acids and metallic oxides was studied on the burning rates and heat of explosion of CMDB propellants containing AP. Among lead and copper salts, basic lead salicylate gave increased burning rates, whereas lead methylene disalicylate and basic copper salicylate did not produce catalytic effect. In the case of metallic oxides, ferric oxide and cobalt oxide gave better catalytic activity than copper and chromium oxides. On crosslinking of nitrocellulose with an isocyanate, catalytic activity of ballistic modifiers was reduced. Burning rates obtained in a rocket motor (2-kg propellant) were higher by about 15%-20% than by strand burner (Crawford Bomb) method.     

有机铋铜复盐对DNTF/HMX-CMDB推进剂燃烧性能的影响

研究了有机铋铜复盐(Gal-BiCu)与炭黑、不同芳香族铜盐(Cu1和Cu2)及金属燃烧功能助剂(NB)复配对DNTF/HMX-CMDB推进剂燃烧性能的影响。分析了Gal-BiCu与其他催化剂复配后影响DNTF/HMX-CMDB推进剂燃烧行为的原因。结果表明,Gal-BiCu能有效调节DNTF/HMX-CMDB推进剂的燃烧性能,提高推进剂燃速,显著降低压强指数;当Gal-BiCu与炭黑、Cu1、NB复合时,催化性能更佳;NB质量分数为0.5%时,推进剂在8~20MPa较宽区间内出现平台燃烧,压强指数n≤0.2;8~15MPa区间内压强指数降至0.11。     

Ballistic Modification of Nitramine Propellants with Special Reference to NG‐PE‐PCP‐Based High Energy Propellants

The burning rate pressure relationship is one of the important criteria in the selection of the propellant for particular applications. The pressure exponent (η) plays a significant role in the internal ballistics of rocket motors. Nitramines are known to produce lower burning rates and higher pressure exponent (η) values. Studies on the burning rate and combustion behavior of advanced high‐energy NG/PE‐PCP/AP/Al‐ and NG/PE‐PCP/HMX/AP/Al‐based solid rocket propellants processed by a conventional slurry cast route were carried out. The objective of present study was to understand the effectiveness of various ballistic modifiers viz. iron oxide, copper chromite, lead/copper oxides, and lead salts in combination with carbon black as a catalyst on the burning rate and pressure exponent of these high‐energy propellants. A 7–9 % increase in the burning rates and almost no effect in pressure exponent values of propellant compositions without nitramine were observed. However, in case of nitramine‐based propellants as compared to propellant compositions without nitramines, slight increases of the burning rates were observed. By incorporation of ballistic modifiers, the pressure exponents can be lowered. The changes in the calorimetric values of the formulations by addition of the catalysts were also studied.     

The energy and pressure exponent of composite modified double-base propellant

The paper describes an analysis on the energy and pressure exponents of composite modified double-base (CMDB) propellants. The evaluation of the energy was conducted by means of a thermodynami- cal program. Propellant burning rates were determined by the strand burner method. In the AP-based composition, the energy is enhanced and the pressure exponent reduced with increasing AP content. When AP is partially or entirely replaced by the nitramines HMX or RDX, Isp is improved, and the pressure exponent is inevitably increased. A mixture of lead salicylate or lead o-amino benzoate and copper 2,4- or 3,5-dihydroxy benzoate produces a remarkable effect on the burning nature of the CMDB propellant. It was noted that the pressure exponent decreases from 0.66 to 0.48 with lead and copper salts added at 3.0% in AP-Al, 0.82 to 0.60 at 2.0% in RDX-Al and 0.72 to 0.54 at 2.5% in RDX-AP-Al compositions, respectively.     

Effect of Lead and Copper Methylene Disalicylates on the combustion rates of double-base rocket propellants

The effect of lead and copper methylene disalicylates and their mixtures was studied on the burning rates (35 kg/cm²-140 kg/cm²), heat of explosion, stability and thermal decomposition of double-base propelants. The results indicate that these salts are very effective catalyst and their mixtures produce super-rate burning (140% increase) with a uniform pressure index value in the entire pressure range. These additives lower “n” value to about 0.2–0.3 in some of the pressure regions. Results of DTA study suggest that these additives decompose in an exothermic mode in the temperature range close to the surface temperature of double base propellants.     

Combustion Effects of Nitrofulleropyrrolidine on RDX‐CMDB Propellants

The effect of N‐methyl‐2‐(3‐nitrophenyl)pyrrolidino[3′,4′:1,2]fullerene (mNPF) on the decomposition characteristics of hexogen (RDX) was investigated using differential scanning calorimetry (DSC). The results show that mNPF can accelerate the decomposition of RDX, the peak temperature (T_p) of the exothermal decomposition is reduced by 6.4 K, and the corresponding apparent activation energy (E_a) is decreased by 8.7 kJ mol⁻¹. N‐methyl‐2‐(3‐nitrophenyl)pyrrolidino[3′,4′:1,2]fullerene (mNPF), carbon black (CB), and C₆₀ were used as combustion catalysts to improve the combustion performance of a composite modified double‐base propellant containing RDX (RDX‐CMDB). The burning rate experimental results show that mNPF has a stronger catalytic effect than C₆₀ and CB. The magnitude of the effect of the three carbon substances on the enhancement of the burning rate is as follows: mNPF>C₆₀>CB. The catalytic effects of different contents of mNPF on the burning rates of RDX‐CMDB propellants were also studied, and the results show that the burning rates of RDX‐CMDB propellants are improved with increasing mNPF content. The plateau burning rate of a RDX‐CMDB propellant can be increased to 19.6 mm s⁻¹ when 1.0 % mNPF is added, and the corresponding plateau combustion region occurs at 8–22 MPa.     

复合改性双基推进剂燃烧性能研究

采用近距摄影、扫描电镜、电子能谱、X-射线衍射等多种技术,对CMDB（复合改性双基）、Al-CMDB、Mg／Al-CMDB推进剂燃速和火焰结构进行了研究。结果表明,在CMDB推进剂中添加A1、Mg／A1等金属燃料,改变了火焰结构;Mg／Al合金可提高金属燃料Al粉的燃烧效率。     

双基系推进剂用生态安全的含铋催化剂

综述了生态安全的含铋催化剂对双基和ＲＤＸ－ＣＭＤＢ推进剂燃烧性能的影响,分析比较了铋化物和铅化物的催化作用。分析结果表明,粒度小、分散性好的铋化物能够取代生态安全性差的含铅燃速催化剂用于双基系推进剂中。     

Synthesis,Characterization, and Combustion Catalytic Activities of Copper(II) and Lead(II) Salts of p‐Nitrocalix[n]arenes (n=4, 6, 8)

Six copper(II) and lead(II) salts of p‐nitrocalix[n]arene (n=4, 6, 8) were synthsized and characterized. The DSC curves of all salts showed exothermic decomposition. Sensitivity studies revealed that all the salts with the exception of the lead salt of p‐nitrocalix[6]arene (NCPb6) are relatively insensitive materials. Investigations of the catalytic activities showed that most of the salts displayed high activities in thermal decomposition of NC‐NG and RDX. As evaluated in this work, the salts enhanced the burning rates of both double base (DB) and RDX‐component modified double base propellants. The best catalytic effect was obtained with NCPb6, which increased the burning rate of the DB propellant to the order of about 200 % (2–6 MPa) and 103–198 % (8–20 MPa) while decreasing the pressure index (n) to 0.22 (20–22 MPa).     

AP-CMDB 推进剂稳态燃烧性能计算研究

建立了一个ＡＰ－ＣＭＤＢ推进剂稳态燃烧模型。该模型可用于ＡＰ－ＣＭＤＢ推进剂和经典双基推进剂燃速特性的模拟计算，其计算结果与文献值相符合，说明该模型是合理、可行的。ＡＰ－ＣＭＤＢ推进剂计算结果表明，ＡＰ粒径减小，ＡＰ含量增加，推进剂燃速升高；而含能粘结剂——ＤＢ母体的含能程度越高，即ＮＧ含量增加，或ＮＣ的硝化度加大，都有利于提高推进剂的燃速。     

炭黑粒度对CMDB推进剂燃烧性能的影响

用燃速测试、扫描电子显微镜(SEM)和光电子能谱仪(EDS)研究了炭黑粒度对复合改性双基(CMDB)推进剂燃烧性能和熄火表面的影响.结果表明,将炭黑与铅、铜盐催化剂复配使用能够大幅度提高CMDB推进剂的燃速并降低压强指数,且炭黑粒度越小效果越显著,这可能与炭黑对铅、铜盐凝聚的阻滞作用有关.     

含N,N-二硝基哌嗪无烟改性双基推进剂的燃烧性能

以CMDB推进剂为基础,用N,N-二硝基哌嗪(DNP)替代推进剂中的RDX,研究了DNP含量、燃烧稳定剂(CaCO3、TiO2、MgO及Al2O3)、燃烧催化剂(铅盐、铅盐/铜盐、铅盐/铜盐/炭黑)对DNP-CMDB推进剂燃烧性能的影响。结果表明,DNP可明显降低无烟CMDB推进剂的燃速,当DNP完全替代RDX时,在18MPa压强下推进剂的燃速降低约68%;铅盐/铜盐/炭黑燃烧催化剂复配体系能够有效降低DNP-CMDB推进剂的燃速压强指数,使其出现平台燃烧效应。     

Combustion Characteristics of a Novel Grain‐Binding High Burning Rate Propellant

The novel grain‐binding high burning rate propellant (NGHP) is prepared via a solventless extrusion process of binder and spherical propellant grains. Compared with the traditional grain‐binding porous propellants, NGHP is compact and has no interior micropores. During the combustion of NGHP, there appear honeycomb‐like burning layers, which increase the burning surface and the burning rate of the propellant. The combustion of NGHP is a limited convective combustion process and apt to achieve stable state. The larger the difference between the burning rate of the binder and that of the spherical granular propellants exists, the higher burning rate NGHP has. The smaller the mass ratio of the binder to the spherical granular propellants is, the higher the burning rate of NGHP is. It shows that the addition of 3 wt.‐% composite catalyst (the mixture of lead/copper complex and copper/chrome oxides at a mass ratio of 1 : 1) into NGHP can enhance the burning rate from 48.78 mm⋅s⁻¹ in the absence of catalyst to 56.66 mm⋅s⁻¹ at P=9.81 MPa and decrease the pressure exponent from 0.686 to 0.576 in the pressure range from 9.81 to 19.62 MPa.     

还原型锡酸铅粒度对Al/HMX/CMDB推进剂燃烧性能及安定性的影响

为研究还原型锡酸铅粒度对Al/HMX/CMDB推进剂燃烧性能及安定性的影响,采用干筛法筛选6种不同粒度的还原型锡酸铅,制备了含不同粒度还原型锡酸铅体系的推进剂;通过燃速靶线试验、甲基紫试验与热加速老化试验得到推进剂的燃速、压强指数、甲基紫变色时间和贮存寿命。结果表明,随还原型锡酸铅粒径由7.0μm减至2.5μm,Pb²⁺及SnO₂的催化活性逐渐增大,活化中心愈多,该体系推进剂在15~20MPa范围内的燃速逐渐增加,压强指数由0.30减至0.17;同时还原型锡酸铅粒度的减小加速了该体系推进剂的自催化作用,造成其安定性下降,当还原型锡酸铅的粒径为2.5~3.5μm时,推进剂的安定性显著降低。     

工艺条件对浇铸 CMDB 推进剂燃烧性能的影响研究

研究了在配方相同情况下,催化剂不同处理工艺及加入方式、烘料时间、配浆时间、固化温度及固化时间等各种工艺条件对浇铸ＣＭＤＢ推进剂燃烧性能的影响。     

1,3,3-三硝基氮杂环丁烷作为增塑剂的无烟CMDB推进剂综合性能研究

对1,3,3-三硝基氮杂环丁烷（TNAZ）作为增塑剂的无烟CMDB推进剂的能量性能、安全性能、燃烧性能和热行为进行了研究,结果表明,TNAZ部分代替NG和DINA应用到无烟CMDB推进剂中,一定程度上提高了推进剂的能量,对推进剂的热稳定性影响不大,推进剂的机械感度和不同压力下推进剂的燃速均有所降低。微量量热实验研究发现,高压下TNAZ作为增塑剂的无烟CMDB推进剂的分解温度为180-235℃,其中TNAZ的分解温度大于220℃,而常压下该推进剂中的TNAZ在70～180℃时即挥发或升华。TNAZ的含量变化对TNAZ—CMDB推进剂火焰结构的影响不明显。     

CL-20含量及其粒度级配对NEPE推进剂燃烧性能的影响

采用静态与水下声发射法测试了CL-20含量及其粒度级配对NEPE推进剂燃速与压强指数的影响;采用DSC与TG-IR联用研究了CL-20对NEPE推进剂热分解行为的影响。结果表明,随着CL-20质量分数由42%增至50%,推进剂燃速与压强指数上升,燃烧效率提高,表明CL-20氧化能力高于GAP/硝酸酯含能黏合剂体系;随着CL-20/HMX、CL-20/Al质量比增高,推进剂燃速上升,燃烧效率上升;CL-20对推进剂燃速和压强指数的贡献高于HMX;随着CL-20/AP质量比增高,CL-20/AP混合体系分解产物氧化能力降低,燃烧反应速率降低,燃速降低;CL-20粒度级配对NEPE推进剂燃烧行为影响显著,当CL-20的粒径(d50)在5~50μm时,随着细粒度CL-20含量增高,推进剂燃速与燃速压强指数下降;当体系中存在超细粒度CL-20(d50=500nm)时,推进剂燃速与燃速压强指数随着超细粒度CL-20含量的增加而有所增加,4种粒度CL-20对NEPE推进剂燃速的贡献顺序为:粗粒度>中粒度>超细粒度>细粒度。     

含能复合催化剂对微烟推进剂燃烧性能的影响

为研究含能催化剂对微烟推进剂燃烧性能的影响,制备了多种含复合含能催化剂的RDX-CMDB推进剂,利用靶线法测定了推进剂在不同压力下的燃速,并对测试结果进行了线性回归.结果表明,在研究的含能催化剂中,2HDNPPb/2HDNPCu和4HDNPPb/2HDNPCu复合催化剂对推进剂有更好的催化效率和降低压力指数的能力.将含能复合催化剂与单一含能催化剂的催化作用进行比较得出,当催化剂加入量一定时,羟基吡啶铅盐、铜盐复合使用比单一的铅盐或铜盐有更好的催化效果.     

Evaluation of various stabilizers for Stability and Increased Life of CMDB Propellants

This study establishes superiority of resorcinol as stabilizer for CMDB propellants followed by RDME (resorcinol dimethylethcr) as compared to other resorcinol derivatives and that of CdO amongst metal oxides. The use of resorcinol and CdO combination in CMDB formulation results in higher E of 33 kca/mol and shelf life of 203 years as compared to E of 31 kcal/mol and life of 70–73 years for resorcinol or CdO based composition suggesting their synergistic stabilization effect. Results of the present investigation bring out that aging mechanism of CMDB involves cleavage of RO-NO₂ bond like DBP, however, AP-based CMDB are strongly autocatalytic. Thus stabilizers used in DBP (Carbamite and 2-NDPA) do not take care of CMDB propellant aging. Suitability of resorcinol may be explained on the basis of its activated aromatic ring for scavenging of oxides of nitrogen.     

On the Burning Rate Characteristics of CMDB Propellants

The object of this paper is to obtain expressions for the burning rate pressure exponent and the temperature sensitivity of AP-based and HMX-based CMDB propellants in terms of the respective physical constants on the basis of a recently developed model of combustion for CMDB propellants and to examine the effects, if any, on these two parameters, of the changes in propellant composition, AP particle size and pressure. Computer programs were developed for this purpose and the results obtained for typical sets of input data presented in the paper. While the results of the calculation indicate a markedly strong dependence of the pressure exponent and the temperature sensitivity on pressure and composition for both AP-based and HMX-based CMDB propellants, the parameters are characterized by far lesser dependence on AP particle size for the AP-based propellant.