Thermal Decomposition of RDX Composite Propellants

The thermal decomposition characteristics of RDX, binders, and RDX composite propellants were studied using thermal analytical techniques. Three kinds of binders were tested to elucidate the role of binder on the burning rate of the propellants. There were no apparent correlations between the thermal decomposition rates of binders and the burning rates of propellants, whereas there was a correlation between the decomposition temperature and the burning rate of the propellants. It is found that the major factor which controls the burning rate is the initial thermal-decomposition stage of the binders. Thus, the burning rate of nitramine composite propellants appeared to be largely dependent on the physical and chemical properties of binder.     

Thermal Decomposition of AMMO/AP Composite Propellants

Thermal decomposition of AMMO/AP composite propellants was studied by DTA, TGA and DSC in helium atmosphere. The effects of accelerated aging at 347 K for 370 days on decomposition kinetics were also measured. AMMO/AP propellant showed two different decomposition steps, which were mainly the AMMO binder decomposed region and the reaction of AP dominated region. These regions were separated at around 20 % weight loss point at the condition used in this study. AMMO binder decomposition and AP decomposition were strongly related each other. The heat generated by the AMMO binder decomposition initiated and accelerated the thermal decomposition of AP. Although both Fe₂O₃ and CFe activated the thermal decomposition of AMMO/AP propellants, CFe mainly accelerated the decomposition of AMMO binder and Fe₂O₃ catalyzed the AP reactions which consisted of the AP decomposition and the reaction between decomposed AP and decomposed AMMO binder. AMMO/AP composite propellants were thermally stable even after aging at 347 K for 370 days.     

NEPE推进剂中聚氨酯的热分解行为

采用ＴＧ和ＤＳＣ两种热分析方法研究了ＮＥＰＥ推进剂中各种填料和助剂对聚醚聚氨酯粘结剂热分解行为的影响。     

Thermal Decomposition of BAMO/HMX Propellants

Thermal decomposition of BAMO [bis(azidomethyl)oxetane/tetrahydrofuran copolymer]/HMX composite propellants was studied by isothermal TGA (thermogravimetric analysis) and DSC (differential scanning calorimetry) in helium atmosphere, which was showing overall two steps first-order kinetics. The effects of cross-link ratio on the accelerated aging of the BAMO/HMX propellants were also measured with infrared spectroscopy and gas chromatography. The accelerated aging was conducted at 347 K for several weeks. BAMO/HMX propellants for a very low cross-link ratio made the cavity between HMX and BAMO binder by N₂, CO₂, and H₂O evolutions during accelerated aging. An exotherm, generated by the decomposition of azide binder, initiated and accelerated the thermal decomposition of HMX. The burning rate of BAMO/HMX propellant was larger than those of BAMO binder and HMX, respectively. However, the propellant could not maintain the combustion at low pressure, at which its burning rate was equal to that of BAMO binder.     

DNTF含量对CMDB推进剂热分解特性的影响

通过高压差示扫描量热(PDSC)试验、热重-微分热重(TG-DTG)试验,研究了不同DNTF含量4种配方CMDB推进剂的热分解行为,分析了它们在4种压力条件的热分解特性及分解规律,研究了DNTF对此类推进剂热分解特征量的影响.结果表明,DNTF含量对CMDB推进剂的热分解特征量有明显影响;不同DNTF的加入量改变了推进剂的分解规律,使分解历程变长;压力改变了推进剂的峰形.     

JMZ发射药及其组分的热分解性能

用TG和DTA对含环氧乙烷/四氢呋哺共聚醚(PET)黏结剂的发射药(JMZ发射药)及其相关组分的热分解性能进行了研究.通过Kissinger法计算了一些不同配方热分解反应的活化能.对热分解过程及其影响因素进行了分析.结果表明,该类发射药的DTA曲线呈现两个放热峰.体系中加入了NC后,随着NC含量的增加,其活化能升高.该类发射药的热分解过程主要分为两个阶段:第一阶段为混合硝酸酯和NC的挥发和分解;第二阶段为硝胺的分解以及PET的降解.加入NC后,发射药体系的热稳定性增加.     

An Investigation on Thermal Decomposition of DNTF‐CMDB Propellants

The thermal decomposition of DNTF‐CMDB propellants was investigated by pressure differential scanning calorimetry (PDSC) and thermogravimetry (TG). The results show that there is only one decomposition peak on DSC curves, because the decomposition peak of DNTF cannot be separated from that of the NC/NG binder. The decomposition of DNTF can be obviously accelerated by the decomposition products of the NC/NG binder. The kinetic parameters of thermal decompositions for four DNTF‐CMDB propellants at 6 MPa were obtained by the Kissinger method. It is found that the reaction rate decreases with increasing content of DNTF.     

Polyacrylate-N-vinyl lactam polymer or copolymer blends as pressure-sensitive adhesives

It has been previously shown that blends of a homopolymer or a copolymer of an N-vinyl lactam with an acrylate or a related copolymer containing a small proportion of acidic groups exhibit macroscale compatibility and a phase separated microstructure. This paper presents an application of this two-phase polymer system for the preparation of melt processable acrylic pressure-sensitive adhesives (PSA). 2-Ethylhexyl acrylate-acrylic acid copolymers, having molecular weights in the range of 50 000 to 115 000 were prepared by free-radical solution polymerization. These copolymers were tacky but possessed insufficient cohesive strength at ambient temperatures to be useful as PSAs. Blending such acrylate copolymers, having some acidic functionality, with minor proportions of a glassy homopolymer or a copolymer of an N-vinyl lactam resulted in materials having a balance of cohesive and adhesive characteristics required of a good PSA. Due to low molecular weights of the components of the polymer blend acrylic PSAs, they are amenable to hot melt processing. Some of the parameters affecting the pressure-sensitive adhesive properties of the polymer blend are: (a) fraction of the glassy polymer in the blend, (b) molecular weights of the polymeric components, (c) acidic functionality of the low molecular weight acrylate copolymer, and (d) N-vinyl lactam functionality of the glassy polymer.     

复合固体推进剂的催化热分解研究

用热分析技术研究复合固体推进剂凝聚相的催化热分解反应，得到大量的热分解参数和有关催化剂的作用规律。     

PET黏合剂及其弹性体热解与推进剂热解相关性研究

采用差示扫描量热/热重(DSC/TG)和裂解气相色谱质谱联用(Py-GC/MS)分析技术研究了PET黏合剂体系、PET/TDI弹性体以及含PET黏合剂体系的简单组分推进剂的热分解特性和热裂解产物状况,探索了PET弹性体的热分解与含PET黏合剂体系的推进剂热解性能之间的相关性.研究结果表明,混合硝酸酯增塑的PET黏合剂体...     

Thermal Decomposition of Ammonium Perchlorate containing a polymeric additive

Thermal decomposition of ammonium perchlorate (AP) containing different concentrations of a polymeric additive such as polyvinyl pyrrolidone (PVP) has been studied by the technique of differential thermal analysis (DTA). The decomposition products have been identified by means of a mass spectrometer. The results of these two experiments suggest strong interaction between AP and PVP in the solid state.     

火药热分解特性与燃烧稳定性间相关性的分析

火药热分解过程的复杂性与其燃烧稳定性之间,存在有某种统计性的增函数关系。火药热分解特性对其燃烧特性的影响,是通过燃烧过程中亚表面热分解表观活化能的变化来实现的,当环境温度和压力较低时,亚表面的热分解特性,与常规条件下该火药的热分析结果相近。对于热分解过程较为复杂的火药,随着环境压力和温度的升高,其亚表面的分期机理和表观分解活化能将发生改变,亚表面分解速率随压力的变化规律也要发生变化,这就导致了燃烧过程的不稳定性,而对于那些热分解过程较为简单的火药,则不会出现这种情况,此外,本文还提出,火药中某些组分的爆燃是导致一些火药燃速压力指数较高的原因。     

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.     

改性双基推进剂主要组分的高压热分解特性

利用高压差示扫描量热仪测试了改性双基推进剂常用的ＮＣ、ＮＧ、ＲＤＸ、ＨＭＸ等几种主要组分在常压及不同压力下的热分解行为,揭示了它们的热分解行为与压力的关系,并进一步分析探讨了各组分对推进剂燃烧性能的影响。     

聚氨酯/三聚氰胺甲醛树脂复合泡沫热降解动力学研究

三聚氰胺甲醛树脂脱水后和多元醇混合,然后用异氰酸酯与混合物进行交联反应,生成聚氨酯/三聚氰胺甲醛树脂复合泡沫.热重分析结果表明,复合泡沫失重分为3个阶段,二苯基甲烷二异氰酸酯(MDI)型三聚氰胺甲醛树脂复合泡沫的第2阶段的失重峰温比甲苯二异氰酸酯(TDI)型三聚氰胺甲醛树脂复合泡沫的高.采用Kissinger法研究了该...     

A Study on the Effect of Additives on Temperature Sensitivityin Composite Propellants

The hydroxy‐terminated polybutadiene (HTPB) based composite propellants without any metal additive and with varying concentration of metal additives such as iron oxide, copperchromite, strontium carbonate and lithium fluoride have been cast and cured. These propellants have been characterized for density and calorimetric value (cal‐val). Further, their temperature sensitivity has also been determined from the burning rates calculated from the P‐t profiles obtained on static evaluation of Ballistic Evaluation Motor (BEM) after conditioning at different temperatures. The data indicate that iron oxide is best to enhance burning rates and at the same time, to reduce temperature sensitivity.     

聚苯乙烯热分解反应动力学研究

采用热重法对聚苯乙烯(PS进)行了热分解动力学研究。结果表明:PS呈两段热解,主要发生在340~520℃区间,在该范围内,PS在400~444℃达到最大热解速率;随着升温速率的增加,其最大热解速率对应的峰温有所升高,热解起始、终止温度也相应提高,但最终质量分数基本一致,为4.4%~4.8%。采用等转化率法和比较法求解得到PS热解过程的动力学三因子,其活化能为136.76kJ/mol,指前因子lnA为26~28,动力学机理函数的积分形式为。用反应模型对实验数据进行了模拟,模拟准确度很高,标准偏差为0.048。     

杯［4］芳烃的热分解动力学研究

通过热失重分析法（TG）研究了杯［4］芳烃与对叔丁基杯［4］芳烃在氮气氛围下的热稳定性,利用Kissinger方法和Flynn?Wall?Ozawa方法分析计算二者的热解表观活化能,通过Coats?Redfern方法确定了热分解动力学机理与模型,并分别求出了材料主降解阶段的非等温动力学方程。结果表明,Kissinger和Flynn?Wall?Ozawa方法求得的杯［4］芳烃的表观活化能分别为166.64 kJ/mol和175.79 kJ/mol,求得的对叔丁基杯［4］芳烃脱叔丁基过程的表观活化能分别为153.97 kJ/mol和166.81 kJ/mol,其自身苯环热分解过程的表观活化能分别为248.38 kJ/mol和252.92 kJ/mol,两物质的热性能在氮气氛围下都表现得较为稳定,且分解温度对于高分子材料的适应性较强;杯［4］芳烃热分解机理函数为g（α）=［-ln（1-α）］^3/2,反应级数n=3/2,其非等温热分解机理属于随机成核和随后生长反应,对叔丁基杯［4］芳烃脱叔丁基过程的热分解机理函数为g（α）=［-ln（1-α）］^2/3,反应级数n=2/3,其非等温热分解机理属于随机成核和随后增长反应,自身苯环热分解过程的热分解机理函数为g（α）=α²,反应级数n=2,其非等温热分解机理属于一维扩散反应。     

纳米粒子的热分解动力学模型

研究了纳米粒子热分解反应的动力学规律,首次提出了纳米粒子热分解的通用的微分速率方程,导出了纳米粒子热分解通用的动力学微分机理函数；并且用纳米碳酸钙、纳米碳酸锌和纳米氢氧化铜的热分解数据考察了机理函数的适用性.研究结果表明3种纳米粒子热分解过程具有相似的动力学规律和相同的机理函数,其速率方程与纳米粒子瞬时表而积分数的幂成正比,其机型函数为纳米粒子剩余质量分数的2n/3次方.     

Synthesis of a selenium and germanium containing random copolymer as an acceptor for all‐polymer solar cells

For the need of electron‐transporting and electron‐affinity materials, n‐type polymers (as acceptor) have gained a lot of attention recently. We have synthesized a selenium and germanium containing copolymer as the acceptor for all‐polymer solar cells (all‐PSCs). The copolymer has larger p‐orbital selenium and germanium atoms for more electron transition from pi to pi* to enlarge light harvest of polymer. To prepare the copolymer, a monomer containing d‐orbital atom, selenium, was first synthesized from low‐cost starting materials. A random copolymer was prepared from the monomer with a commercial germanium containing monomer via palladium catalyzed Stille coupling reaction. Taking the side‐chain effect into account, we incorporated dodecyloxy group to increase the solubility of the polymer and also increase the coplanarity by oxygen–sulfur (S–O) interaction. Despite the low short‐circuit current density (Jsc) value, the random copolymer with 3d‐orbital electrons has the potential to be the candidate for n‐type material. In comparison, we also fabricated P3HT/PffBT4T‐2OD all‐PSCs, acquiring PCE of about 0.5% without any additive. POLYM. ENG. SCI., 58:387–394, 2018. © 2017 Society of Plastics Engineers