Synthesis and Characterization of Glycidyl Azide Polymer with Enhanced Azide Content

ABSTRACT

The present study reports the preparation of glycidyl azide polymer with enhanced azide content. This process involves the cationic ring-opening polymerization of epichlorohydrin (ECH) using borontrifluoride etherate (BF₃-etherate) and 2,2-bis(bromomethyl)1,3-propane diol (BMPD) as initiator and co-initiators, respectively, followed by subsequent azidation of the product. For both the products, poly(epichlorohydrin)s (PECHs) and glycidyl azide polymers (GAPs) the substituted 1,3-propane diol units were characterized by spectroscopic as well as thermal analysis. Vapor pressure osmometer studies indicated that as the diol concentration increased in the polymerization the formed PECH molecular weight decreased. The spectral analysis indicates the presence of corresponding diol units in their polymeric chains. The differential scanning calorimetry and elemental analysis of the GAPs developed in this investigation indicated the presence of higher azide content in the polymer.     

Update: An Efficient Synthesis of Poly(ethylene glycol)‐Supported Iron(II) Porphyrin Using a Click Reaction and its Application for the Catalytic Olefination of Aldehydes

The facile synthesis of polyethylene glycol (PEG)‐immobilized iron(II) porphyrin using a copper‐catalyzed azide‐alkyne [3+2] cycloaddition “click” reaction is reported. The prepared complex 5 (PEG‐C₅₁H₃₉FeN₇O) was found to be an efficient catalyst for the selective olefination of aldehydes with ethyl diazoacetate in the presence of triphenylphosphine, and afforded excellent olefin yields with high (E) selectivities. The PEG‐supported catalyst 5 was readily recovered by precipitation and filtration, and was recycled through ten runs without significant activity loss.     

BAMO/GAP无规共聚物/N100/IPDI体系胶片性能研究

采用3,3-双叠氮甲基氧丁环(BAMO)/叠氮缩水甘油醚(GAP)无规共聚物为预聚物,多异氰酸酯(N100)、异佛尔酮二异氰酸酯(IPDI)为固化剂,1,4-丁二醇(BDO)为扩链剂合成了BAMO/GAP无规共聚物/N100/IPDI体系的粘合剂胶片,并对其进行了FT-IR、DSC、TG-DTG表征和力学性能测试。实验表明,所得的粘合剂胶片拉伸强度可达0.87 MPa,断裂延伸率大于106%,玻璃化转变温度在-50℃左右,热分解起始温度为217.0℃,具有较好的热稳定性。     

两种呋咱环叠氮化合物的合成

合成出 5 ,5′ 双 (叠氮甲基 ) 3,3′ 双 (1,2 ,4 口恶二唑 ) (Ⅰ )和双 (叠氮乙酰亚胺基 )氧化偶氮呋咱 (Ⅱ ) ,利用元素分析、红外、核磁共振谱和质谱对两种化合物进行了结构鉴定 .通过将叠氮基引入呋咱衍生物中 ,得到了高氮含量、高生成焓的含能化合物 ,这两种化合物均有较高的密度 ,其中化合物Ⅰ为低熔点叠氮化物 ,可作为含能增塑剂应用     

Thermal characterization of glycidyl azide polymer (GAP) and GAP‐based binders for composite propellants

Differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) were used to investigate the thermal behavior of glycidyl azide polymer (GAP) and GAP‐based binders, which are of potential interest for the development of high‐performance energetic propellants. The glass transition temperature (T_g) and decomposition temperature (T_d) of pure GAP were found to be −45 and 242°C, respectively. The energy released during decomposition (ΔH_d) was measured as 485 cal/g. The effect of the heating rate on these properties was also investigated. Then, to decrease its T_g, GAP was mixed with the plasticizers dioctiladipate (DOA) and bis‐2,2‐dinitropropyl acetal formal (BDNPA/F). The thermal characterization results showed that BDNPA/F is a suitable plasticiser for GAP‐based propellants. Later, GAP was crosslinked by using the curing agent triisocyanate N‐100 and a curing catalyst dibuthyltin dilaurate (DBTDL). The thermal characterization showed that crosslinking increases the T_g and decreases the T_d of GAP. The T_g of cured GAP was decreased to sufficiently low temperatures (−45°C) by using BDNPA/F. The decomposition reaction‐rate constants were calculated. It can be concluded that the binder developed by using GAP/N‐100/BDNPA/F/DBTDL may meet the requirements of the properties that makes it useful for future propellant formulations. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 538–546, 2000     

Curing characteristics of glycidyl azide polymer‐based binders

The curing of a glycidyl azide polymer (GAP) with a triisocyanate, Desmodur N‐100, was followed by measuring the hardness and viscosity. The thermal behavior of the cured samples were investigated by a differential scanning calorimeter (DSC) and thermal gravimetric analysis (TGA). Curing causes an increase in the glass transition temperature of GAP. The T_g of gumstocks also increases with an increasing NCO/OH ratio while the decomposition temperature remains practically unchanged. The ultimate hardness of the cured samples increases with an increasing NCO/OH ratio. The binder with a NCO/OH ratio of 0.8 was found to provide the most suitable thermal and physical characteristics for composite propellant applications. The increase in the glass transition temperature of gumstocks upon curing can be compensated by using a 1:1 mixture of bis‐2,2‐dinitropropyl acetal and formal as the plasticizer. The T_g value of gumstocks can be decreased to −46.7°C by adding 25% b.w. of a plasticizer which does not have any significant effect on the decomposition properties of the gumstocks. Furthermore, a remarkable decrease in the ultimate hardness of the gumstocks is achieved upon addition of a plasticizer, while the curing time remains almost unaffected. The addition of dibuthyltin dilaurate as a catalyst reduces the curing time of the gumstocks from 3 weeks to 5–6 days at 60°C. Use of the curing catalyst also results in the hardening of the gumstocks. The decomposition properties of the gumstocks remain practically unchanged while a noticeable increase is observed in the glass transition temperature with an increasing concentration of the catalyst. This can also be compensated by a reverse effect of the plasticizer. The gel time, an important parameter which determines the pot life of a propellant material, can be measured by monitoring the viscosity of the mixture, which shows a sharp increase when gelation starts. The addition of a curing catalyst shortens the gel time remarkably. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 65–70, 2001     

氚气标准源的研制

高性能芯片级原子气室的制备是现阶段芯片级量子传感仪器研制急需解决的关键技术之一。为解决目前芯片级原子气室研制领域存在的碱金属定量填充难、气密性差等问题，开展了高气密性芯片级原子气室制备方法研究，利用微电子机械系统（MEMS）技术实现了芯片级原子气室的批量制备。采用深硅刻蚀技术制备硅气室腔，利用RbN₃的光分解实现碱金属单质的制备及定量填充，采用阳极键合技术对原子气室进行两次硅片/玻璃键合封装，成功获得了以N₂为缓冲气体的Rb碱金属原子气室。对所制备的原子气室进行键合强度、气密性、吸收光谱测试，结果表明原子气室的玻璃/硅片/玻璃键合强度均较高，其中B组原子气室的漏气率平均值为2.2×10^-9 Pa?m³?s^-1，其气密性为目前行业内领先水平。最后从制备工艺上分析了两组原子气室的性能差异原因，为推动量子传感仪器的芯片级集成技术发展奠定重要基础。     

Constructing Highly Reliable and Adaptive Primary Explosive Composites for Micro-Initiator Assisting by a Hybrid Template of Metal–Organic Frameworks and Cross-Linked Polymers

Primary explosive, as a reliable initiator for secondary explosives, is the central component of micro-initiators for modern aerospace systems and military operations. However, they are typically prepared as powders, posing potential safety risks because of the inevitable particles scattering issues in the actual working environments. Here, the fabrication of a highly adaptive bulk material of copper azide (CA)-based safe primary explosive for micro-initiators is demonstrated. This bulk material, as derived by a complete azidation reaction of the carbonized metal–organic framework/cross-linked polymer hybrid template, enables the firm embedding of active CA species in a cross-linked carbon network (denoted as CA-C). Interestingly, this CA-C bulk material demonstrates multifarious mechanical stabilities (e.g., good shock and vibration resistance, and anti-overload capacity) in the simulated working conditions. Meanwhile, the CA contents in the CA-C bulk material reached as high as 70.3%, ensuring its detonation power. As a proof of concept, CA-C bulk material assembling in a micro-detonator can efficiently detonate the secondary explosive of CL-20 under laser irradiation. This work hereby advances the fabrication of safe and powerful primary explosives for the fulfillment of safe micro-initiator in a broad range of applications in aerospace systems.     

有机叠氮化物几何构型和生成热的分子轨道研究

用ＡＭ１、ＰＭ３、ＭＮＤ烽ＭＩＮＤＯ／３四种半经验分子轨道（ＭＯ）方法对５５种有机叠氮化合物的分子可构型进行了全优化计算，与已有的气相实验构型进行比较，发现ＡＭ１法偏差较小，ＰＭ３和ＭＮＤＯ次之。ＡＭ１法计算所得生成热与基团加和法求得的结果最接近，ＭＩＮＤＯ／３计算结果偏差最大。     

三氨基胍叠氮酸盐的非水相合成研究

在非水介质中用游离三氨基胍（ＴＡＧ）与通过离子交换树脂新生成的ＨＮ３进行中和反应，制备了三氨基胍叠氮酸盐（ＴＡＺ）。实验证明，在甲醇中磺酸树脂与ＮａＮ３可定量生成ＨＮ３，且易分离，可避免将无机盐带入ＴＡＺ产品。