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。     

降感RDX的制备及晶形控制

采用溶剂-非溶剂重结晶方法制备了降感RDX,研究了温度、溶剂、非溶剂、搅拌强度、表面活性剂和加料方式等工艺条件对双重结晶的影响.采用光学显微镜和扫描电镜分析了所得晶体的形貌,测定了其撞击感度.结果表明,采用最佳工艺条件:70℃,二甲基亚砜(DMSO)为溶剂,甲醇为非溶剂,糊精为表面活性剂,搅拌强度1 000 r/min,改善了RDX的晶貌和内部质量,降低了撞击感度.通过控制溶液的初始浓度可制得不同粒度的RDX,粒径为100～120 μm晶体的撞击感度比原料降低了34%.     

重结晶工艺对太安撞击感度的影响

用溶剂-非溶剂法重结晶粗制太安,研究了溶剂-非溶剂体系、重结晶温度、搅拌速度和非溶剂滴加速度4个因素对重结晶太安撞击感度的影响.测定了不同工艺条件下重结晶太安的特性落高,通过金相显微镜和偏光显微镜分析了不同结晶工艺所得太安晶体的形貌及表观缺陷,讨论了重结晶工艺对太安晶体撞击感度的影响.结果表明,以乙酸乙酯为溶剂,三氯甲烷为非溶剂,温度50℃, 非溶剂稀释速度0.05 mL/min,搅拌速度100 r/min条件下制备的重结晶太安的特性落高为14.6 cm,比常用的丙酮-水重结晶太安的撞击感度显著降低.     

超细ε-HNIW的制备工艺

采用溶剂-非溶剂重结晶法研究了六硝基六氮杂异伍兹烷(HNIW)的超细化制备工艺.通过改变溶剂与非溶剂的体积比、溶液温度、进料速度、超声波振荡频率等影响因素,研究了超细ε-HNIW的粒度及粒度分布,确定的最佳工艺条件为:溶剂为乙酸乙酯,非溶剂为石油醚,溶剂与非溶剂的体积比为1∶5,50 ℃下的ε-HNIW饱和溶液体系,超声波振动频率为60 kHz,所得ε-HNIW的粒度约1 μm.     

HMX熔点与所含杂质RDX含量的估测

为了确定影响HMX熔点的因素, 采用毛细管数字熔点仪和差示扫描量热仪进行了纯品RDX和HMX试样的熔点实验.通过在丙酮中重结晶的方式,制备了含有RDX的HMX试样,并不断增大RDX含量,测试了该系列重结晶试样的熔点.结果表明,影响熔点的主要因素是试样中的有机杂质含量和重结晶情况.RDX在HMX中的质量分数为0～25%和94%～100%时,有机杂质含量与相应的熔点呈线性关系,说明根据熔点可大致判断HMX中杂质RDX的含量.     

重结晶降低RDX感度研究

采用N-甲基吡咯烷酮、二甲基甲酰胺、二甲基亚砜作溶剂,对普通RDX进行重结晶.研究了不同溶剂对RDX晶体形貌、晶体内空穴、位错、残存溶剂的影响,通过扫描电镜和光学显微镜,分析了重结晶RDX晶体的结晶形貌和内部质量,用密度瓶法测试了晶体密度,用10kg落锤测定了撞击感度.结果表明,用二甲基亚砜重结晶制备的RDX有较好的晶体质量,撞击感度最低(54%),晶体密度达1.823g/cm3.     

真空蒸馏法细化NTO及其晶型控制的研究

采用真空蒸馏法,以丙酮为溶剂,通过改变蒸馏温度、溶液初始质量浓度、系统真空度等参数,探讨了各因素对NTO重结晶的粒度分布及晶型的影响.对实验结果进行理论分析,确定了最佳重结晶细化NTO的工艺参数.结果表明,晶型主要受蒸馏温度的影响,其次是系统真空度.在蒸馏温度60 ℃左右、系统真空度0.05 MPa～0.06 MPa、溶液初始质量浓度不低于0.2 g/12 mL时,通过真空蒸馏法可以得到比较规则的立方晶型,颗粒粒度在1 靘左右,且分布范围窄.     

喷雾干燥法制备球形RDX的工艺优化

以丙酮为溶剂,采用喷雾干燥法制备了微米级球形RDX,研究了入口温度、进料速率、喷雾气体流速和溶液浓度对所得RDX颗粒形貌的影响。通过扫描电镜(SEM)分析了不同工艺条件下制备的RDX的球形化效果,用DSC分析了其热分解特性,并测试了其撞击感度。结果表明,制备球形RDX的最佳工艺条件为:入口温度为60℃,进料速率为1.5mL/min,喷雾气体流速为357L/h,原料RDX质量分数为1.9%,抽气流速为40m3/h。在此工艺条件下,获得了中值粒径为2.82μm、表面较光滑的球形RDX颗粒。与原料RDX相比,球形RDX的热分解表观活化能降低了2.33kJ/mol,特性落高从19.98cm升至54.70cm,表明球形RDX的撞击感度明显降低。     

重结晶法制备纳米RDX

用一种新型重结晶方法,获得了几十纳米到若干微米的RDX微晶。用TEM和DLS研究了溶剂相中PRDX浓度对颗粒粒径的影响和陈化时间对颗粒生长的影响。通过控制溶剂中RDX的浓度可制得所需尺寸的RDX微晶。建立了结晶动力学模型。用该模型阐明了溶剂中RDX的浓度与颗粒大小的关系,实验结果符合该模型。     

非溶剂体系温度对细化RDX影响的分子动力学模拟及实验研究

利用自行研制能定量控制的喷射重结晶装置,以二甲基亚砜为溶剂、水为非溶剂细化得到RDX,同时结合分子动力学方法探讨了喷射重结晶RDX过程中最佳非溶剂体系温度,以及不同温度对制备RDX晶体的影响;采用扫描电子显微镜(SEM)、X射线粉末衍射仪(P-XRD)、差式扫描量热法(DSC)对其进行性能表征和热分析;并测试了其撞击感度。结果表明,分子动力学模拟制备RDX的最佳非溶剂体系温度与实验结果一致,即最佳温度为30℃,在此条件下可获得中值粒径为836nm、粒径分布均匀、形貌趋于球形且表面光滑的RDX;与原料RDX相比,细化后的RDX表观活化能升高了46.85kJ/mol,具有较好的热安定性,指前因子(lg(A/min))提高了4.87,热爆炸临界温度增加1.14℃,撞击感度(H_(50))最大提高至40.07cm。     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料,介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。按通用热塑性树脂（聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂）、工程塑料（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。