纳米LaCoO3对RDX基混合炸药的热分解特性和感度的影响

用DSC和DTA研究了LaCoO3对含AP的RDX基混合炸药热分解特性的影响。结果表明,纳米LaCoO3对含有AP的RDX基爆炸混合物的热分解具有一定的催化作用;纳米LaCoO3使RDX基混合炸药的撞击感度和热感度降低,摩擦感度增大。     

硝酸脲与RDX共晶炸药研究

为解决RDX生产过程中废硝酸的再利用问题,采用(a)在分离出RDX后,直接加入一定量尿素水溶液,废硝酸与尿素反应制成硝酸脲,(b)RDX和硝酸脲在稀硝酸中共结晶,生成共晶混合炸药(RDX的质量分数60%～70%).经测试,其爆炸性能优于两者直接混合炸药,爆速可达7 500m/s左右,提高了4%;红外光谱分析结果表明,这种混合炸药是一种具有分子间氢键的共晶体.     

溶剂萃取法回收废旧梯黑铝炸药中的RDX和铝粉

利用混合炸药中TNT和RDX在溶剂中溶解度的差异,首先用甲苯萃取出梯黑铝炸药中的TNT,然后分别以丙酮和二甲基亚砜为溶剂,经萃取、冷却结晶,过滤得到RDX。用SEM和DSC对回收RDX进行形貌表征和热分析,用XRD对回收铝粉进行物相分析。结果表明,丙酮和二甲基亚砜中重结晶回收RDX的纯度分别为98.4%和97.8%,撞击感度分别为76%和84%,丙酮重结晶回收RDX晶体质量优于二甲基亚砜重结晶回收的RDX。回收RDX与原料RDX的特征温度基本相同,热安定性良好;回收的铝粉不含炸药,无明显氧化。     

FOX-7和RDX基含铝炸药的冲击起爆特性

为研究FOX-7和RDX基含铝炸药的冲击起爆特性,对其进行了冲击波感度试验和冲击起爆试验,结合冲击波在铝隔板中的衰减特性,确定了FOX-7和RDX基含铝炸药的临界隔板值和临界起爆压力,并通过锰铜压阻传感器记录了起爆至稳定爆轰过程压力历程的变化。结果表明,以Φ40mm×50mm的JH-14为主发装药时,FOX-7和RDX基含铝炸药临界隔板值分别为37.51和34.51mm,对应的临界起爆压力为10.91和11.94GPa;起爆压力为11.58GPa时,FOX-7炸药的到爆轰距离为25.49~30.46mm,稳定爆轰后的爆轰压力为27.68GPa,爆轰速度为8 063m/s;起爆压力为14.18GPa时,RDX基含铝炸药的到爆轰距离为17.27~23.53mm,稳定爆轰后的爆轰压力为17.16GPa,爆轰速度为6 261m/s。     

密度分级法分离废旧梯黑铝炸药中的RDX与铝粉

为了研究分离回收废旧梯黑铝炸药中各成分的高效低成本的物理方法,采用控温离心和控温水洗结晶,回收梯黑铝炸药中的TNT组分;再根据RDX与铝粉的密度差异,使用密度分级法,分离RDX与铝粉,优化了分离条件,对回收物质进行DSC和XRD表征,并测试其撞击感度。结果表明,在密度为2.0g/cm3的溴化锌溶液中,控温30℃、离心转速2500r/min等条件下,回收RDX和铝粉回收率分别为67.6%和86.5%,纯度分别为77.2%和94.6%;回收的RDX热安定性良好,存在少量铝粉和TNT与RDX的共熔物,且基本没有独立存在的TNT组分,其撞击感度为90%;回收铝粉中含有微量氧化铝粉和炸药成分;两种回收物组分中均不含溴化锌。该物理方法可有效实现废旧梯黑铝炸药各组分的高效绿色回收。     

不同约束条件下钝化RDX的烤燃响应特性

以2℃/min的升温速率对带壳的钝化RDX炸药进行慢烤试验,研究了不同约束条件下钝化RDX的烤燃响应特性.结果表明,材料相同时,随着厚度的增加炸药耐烤燃时间随之增长,但反应的剧烈程度逐渐减弱;厚度相同时,耐烤燃特性随材料物理性能的不同发生变化.根据材料力学理论和传热学理论,对所产生的现象进行了分析.结果表明,材料相同时,增加壳体的厚度,可以提高钝化RDX的热安定性;材料不同时,采用热导性低的材料可以提高炸药的热安定性.     

主体炸药RDX对CH-6炸药药柱特性的影响

用药柱特性试验和X射线探伤测定了分别由压煮RDX与丙精RDX制成的两种CH-6混合炸药的药柱特性。结果表明．由压煮RDX制成的CH-6混合炸药．其药柱特性优于由丙精RDX制成的CH-6混合炸药。确定了造成这种结果的原因。     

Preparation of lithium niobate optical thin film and patterned microstructure via chemical modification

In this paper, a stable lithium niobate (LN) sol was prepared using niobium pentachloride, niobium ethoxide, lithium acetate, anhydrous ethanol, and benzoylacetone (BzAcH) as a chemical modifier. The effects of different starting materials and organic solvents on the obtained gel film quality of the sols were studied and the optimization mechanism of BzAcH on the film quality was analyzed in detail. The effects of heat treatment temperature on the structure and performance of the LN thin films were also studied. X-ray diffraction (XRD) spectra showed that LN was more highly crystalline in the heat treatment temperature range of 600–800 °C. The refractive index of the LN thin films first increased and then decreased with increasing heat treatment temperature, and the LN thin film prepared at 700 °C had the largest refractive index. Light transmittance tests showed that as the heat treatment temperature increased, light transmittance decreased. Finally, it was determined that LN gel films modified with BzAcH were more highly sensitive to UV light and that after UV irradiation, it was difficult to dissolve LN gel films in organic solvent. The UV-sensitive property was utilized to realize microstructure processing of the LN thin films. The results indicated that a high-quality, non-destructive, and photoresist-free micro-fabrication method was realized. This method was used to fabricate microscale LN fine patterns with smooth sidewalls while avoiding lateral corrosion. These results are of great significance for LN thin film applications and the development of LN-based optoelectronic devices prepared by chemical methods.     

High-oleic safflower oil. Stability and chemical modification

High-oleic acid safflower oil has been shown to have high-temperature oxidative stability comparable with that of hydrogenated vegetable oils. This stability, added to the ease of handling at low temperatures, should make the oil attractive as a commercial cooking oil. Epoxidation of the new safflower oil led to a product similar to epoxidized olive oil but lighter in color.     

Effect of chemical modification on FTIR spectra. I. Physical and chemical behavior of coir

Coir fibers were chemically modified through alkali treatment, and crosslinking with formaldehyde, para-phenylene diamine, phthalic anhydride, and combined crosslinking-cyanoethylation reactions in appropriate solvent and catalyst. The parent and chemically modified coir were characterized by FTIR spectra. The percent moisture regain, tensile strength, and behavior toward some chemical reagents (solubility %) of parent and chemically modified fibers have also been evaluated. The modified fibers showed significant hydrophobicity, improved tensile strength, and good chemical resistance. © 1995 John Wiley & Sons, Inc.     

Deoxycholate‐chitosan nanospheres fabricated by γ‐irradiation and chemical modification: Nanoscale synthesis and controlled studies

A systematic protocol to fabricate self‐assembly deoxycholate‐chitosan nanospheres (DC‐CsNS) by γ‐ray pre‐irradiation and chemical modification was studied. Hydrophobic deoxycholic acid moieties were chemically conjugated to pre‐irradiated chitosan. The influences of chitosan physical forms (i.e., colloid and flake) during irradiation, radiation doses, and the reaction system (heterogeneous or homogeneous) on the chemical modification and the particle shape and size were investigated. Pre‐irradiation of chitosan in colloidal form produced smaller DC‐CsNS particle size than that of flake form. In the heterogeneous reaction, the pre‐irradiated dose influenced the DC‐CsNS particle size, whereas in the homogeneous reaction all pre‐irradiation doses gave an identical average size range of 30–50 nm. By pre‐irradiation (10 kGy) of chitosan in colloidal form before heterogeneous chemical conjugation, it is possible to obtain DC‐CsNS with an average size of 46 nm. DC‐CsNS of about 50 nm in size could also be synthesized using homogeneous chemical conjugation onto non‐irradiated chitosan with the addition of N‐hydroxysuccinimide (NHS). © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Degradation of TNT,RDX, and HMX Explosive Wastewaters Using Zero‐Valent Iron Nanoparticles

The high‐energy explosives 2,4,6‐trinitrotoluene (TNT), hexahydro‐1,3,5‐trinitro‐1,3,5‐triazine (RDX), and the high melting explosive octahydro‐1,3,5,7‐tetranitro‐1,3,5,7‐tetrazocine (HMX) are common groundwater contaminants at active and abandoned munitions production facilities causing serious environmental problems. A highly efficient and environmentally friendly method was developed for the treatment of the explosives‐contaminated wastewaters using zero‐valent iron nanoparticles (ZVINs). ZVINs with diameters of 20–50 nm and specific surface areas of 42.56 m² g⁻¹ were synthesized by the co‐precipitation method. The explosives degradation reaction is expressed to be of pseudo first‐order and the kinetic reaction parameters are calculated based on different initial concentrations of TNT, RDX, and HMX. In addition, by comparison of the field emission scanning electron microscopy (FE‐SEM) images for the fresh and reacted ZVINs, it was apparent that the ZVINs were oxidized and aggregated to form Fe₃O₄ nanoparticles as a result of the chemical reaction. The X‐ray diffraction (XRD) and X‐ray absorption near edge structure (XANES) measurements confirmed that the ZVINs corrosion primarily occurred due to the formation of Fe₃O₄. Furthermore, the postulated reaction kinetics in different concentrations of TNT, RDX, and HMX, showed that the rate of TNT removal was higher than RDX and HMX. Furthermore, by‐products obtained after degradation of TNT (long‐chain alkanes/methylamine) and RDX/HMX (formaldehyde/methanol/hydrazine/dimethyl hydrazine) were determined by LC/MS/MS, respectively. The high reaction rate and significant removal efficiencies suggest that ZVINs might be suitable and powerful materials for an in‐situ degradation of explosive polluted wastewaters.     

橡胶的物理与化学改性

该文综述了近十年来橡胶的物理改性与化学改性的状况。     

高聚物黏结剂对RDX基含铝炸药性能影响的数值计算及实验验证

为研究乙烯-醋酸乙烯酯共聚物(EVA)对RDX基含铝炸药性能的影响,在A-IX-II炸药中添加EVA制备了含铝PBX炸药。用分子动力学(MD)方法计算了黏结剂EVA与A-IX-II炸药各组分的结合能以及作用方式、AIX-II炸药及含铝PBX炸药的力学性能。计算结果表明,EVA与A-IX-II炸药各组分的结合能均大于0,相互作用力以范德华力为主;EVA能够显著提升A-IX-II炸药的力学性能,使其弹性模量从20.58GPa升至33.27GPa。对A-IX-II炸药和含铝PBX炸药进行了静态力学性能试验,计算结果与试验结果一致性较好。     

Isotope studies of detonation mechanisms of TNT,RDX, and HMX

An analysis is performed of experimental data from isotopic tracer studies of the detonation mechanism and formation of the diamond phase of carbon in the detonation products of TNT, RDX, HMX, and their mixtures. Dependences of the relative yield and phase composition of carbon in the detonation products of components of composite explosives on the particle sizes of the explosives are given. __________ Translated from Fizika Goreniya i Vzryva, Vol. 43, No. 5, pp. 96–103, September–October, 2007.     

Multifunctional coupling agents. II. Chain extension and terminal group modification of polyamides

New bifunctional coupling agents possessing one 2‐oxazoline group and one 2‐oxazinone group were converted in a Haake melt mixer or extruder with PA6 and PA12. It was shown by means of NMR spectroscopic investigations that the 2‐oxazoline group reacted mainly with carboxylic groups whereas the oxazinone group reacted preferably with the amino groups. Both reactions proceeded with high selectivity and independent from each other. In the case of carboxy/amino group terminated polyamides, the conversions resulted in increased molecular weights since both reactive terminal groups of the polyamides were addressed simultaneously by the coupling agent. In the case of amino group terminated polyamides, the conversion with the bifunctional coupling agent resulted in oxazoline terminated polymer chains. Unlike PA6, it was possible to convert PA12 in two steps. At lower temperatures (210°C) and short reaction times (2 min), the reaction of the oxazinone group with the amino groups was predominant, whereas the reaction of the oxazoline group with the carboxylic groups proceeded to a sufficient extent only after longer reaction times or at higher temperatures. In the case of PA6, processing temperatures of about 250°C were necessary. Here, a side reaction was observed that resulted in the formation of cyclic quinoxaline structures under evolution of water. This side reaction did not disturb the chain extension significantly. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2170–2177, 2004     

The Effect of RDX Crystal Defect Structure on Mechanical Response of a Polymer‐Bonded Explosive

An explosive composition, derived from AFX‐757, was systematically varied by using three different qualities of Class I RDX. The effect of internal defect structure of the RDX crystal on the shock sensitivity of a polymer bonded explosive is generally accepted (Doherty and Watt, 2008). Here the response to a mechanical non‐shock stimulus is studied using an explosion‐driven deformation test as well as the ballistic impact chamber. No correlation between RDX crystal quality and deformation sensitivity is observed. The DDT behavior (Deflagration to Detonation Transition) of the three plastic bonded explosives, although similar in composition, is distinct regarding the rate of diameter increase in the explosion‐driven deformation test. Recovered polymer bonded explosive from the explosion‐driven deformation test responds equally fast or slower in the ballistic impact chamber. Based on our experimental results the shear rate threshold as a single parameter describing mechanical sensitivity is challenged, and preference is given to the development of an ignition criterion based on inter‐granular sliding friction under the action of a normal pressure.     

蛋白质的化学修饰研究进展

蛋白质的化学修饰作为改善蛋白质的物理化学和生物学特性的有效手段,已经得到了越来越多的研究和开发.评述了蛋白质化学修饰领域的研究现状与水平,涉及化学修饰剂的种类和选择、化学修饰反应方法与条件以及修饰蛋白在生物医学和生物技术方面的应用等.