DNTF-CMDB推进剂的化学安定性

采用甲基紫法和维也里法研究了DNTF含量、NC与NG的质量比、增塑剂和安定剂的种类及其含量对DNTF-CMDB推进剂化学安定性的影响。结果表明,随着DNTF含量的增加,推进剂的维也里变色时间缩短,甲基紫变色时间增加。NC与NG的质量比对推进剂的化学安定性影响较小。用三乙二醇二硝酸酯(TEGDN)替代增塑剂NG有利于增加推进剂的化学安定性。在N,N′-二甲基-N,N′-二苯脲(C2)、2-硝基二苯胺(2-NDPA)、N-甲基-4-硝基苯胺(MNA)3种安定剂中含C2推进剂的维也里变色时间最长,含MNA推进剂的甲基紫变色时间最长。     

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。     

甲基紫试验在长贮火药安定性检测中的应用

为确定甲基紫在长贮火药安定性检测中的可靠性,对选定的经过85℃老化试验的单基药、双基药、三基药试样,分别进行134．5℃和120℃甲基紫试验。用化学分析法测定了安定剂的含量,用方差检验法分析了甲基紫试验中的试纸变色时间和发射药中安定剂含量随老化时间的变化关系。结果表明,单基发射药、双基发射药、双基改性推进剂的甲基紫试纸变色时间随老化时间的变化显著,双基推进剂和三基发射药甲基紫变色时间随贮存时间的变化不显著。     

含ADN推进剂的能量特性及综合性能

为研究含二硝酰胺铵(ADN)推进剂的能量、安全、贮存及燃烧性能,根据最小自由能原理计算了含ADN推进剂的能量特性参数,采用密闭爆发器及靶线法测试其爆热及燃速,并对其吸湿性及感度进行了研究。结果表明,含ADN/Al/HMX、ADN/Al/CL-20、ADN/AlH3/HMX和ADN/AlH3/CL-20推进剂的标准理论比冲分别为2 675~2 685、2 677~2 686、2 801~2 810和2 803~2 812N·s·kg-1,采用硝酸酯增塑的惰性聚醚黏合剂体系可制备出固化正常、结构致密的含ADN推进剂。随着推进剂配方中ADN含量的增加,推进剂的爆热、吸湿性、燃速和压强指数增大,摩擦感度和撞击撞击提高,密度略有降低。     

BAMO-AMMO黏合剂相对分子质量对推进剂力学性能的影响

ETPE(含能热塑性弹性体)具有力学性能好、能量大和不敏感等特性,因而已成为近年来国内外推进剂用黏合剂的理想基体。以BAMO-AMMO(3,3-二叠氮甲基氧杂环丁烷/3-甲基-3-叠氮甲基氧杂环丁烷嵌段共聚物)作为ETPE,制备了固体推进剂用黏合剂,并着重探讨了BAMO-AMMO黏合剂的Mr(相对分子质量)对推进剂力学性能、动态力学性能和微观结构等影响。研究结果表明:随着黏合剂Mr的增加,推进剂的高温拉伸强度、低温断裂伸长率、储能模量和弹性等均随之增大,而Tg(玻璃化转变温度)降低;然而,当黏合剂Mr过高时,推进剂复合体系中易出现分层现象。     

球形硝基胍粒径对改性单基发射药热安定性和力学性能的影响

为了改善改性单基发射药的安定性和力学性能,制备了含3种不同粒径(50、80和110μm)球形硝基胍(NQ)的改性单基发射药,通过差示扫描量热法、真空安定性试验和甲基紫试验研究了其热分解过程和热安定性,并测试了其抗冲击和抗压缩强度,分析了NQ粒径变化对改性单基发射药热行为和力学性能的影响。结果表明,3种含球形NQ的改性单基发射药试样有两个热分解过程,第一个分解过程对应的是混合硝化棉的分解,第二个分解过程是RDX和NQ的分解,但是第二个分解过程不明显;随着NQ粒径从50μm增至110μm,发射药试样的热分解峰温从176.84℃提高至179.71℃;真空安定性试验中试样48h放气量从0.7558mL/g降至0.5964mL/g,甲基紫试纸变为橙色的时间从44min延长至54min,且加热5h后未发生爆炸;发射药试样的抗冲击强度从4.23kJ/m~2降至3.81kJ/m~2,抗压缩强度从56.93MPa降至53.85MPa。表明球形NQ粒径的增加有利于提高发射药的热安定性,但会降低其力学性能。     

含CL-20的NEPE推进剂能量水平分析

用电算法对含有CL－20的NEPE固体推进剂配方的能量特性进行了对分析，并研究了在一这固含量下，配方中不同组分含量对体系能量示性参数的影响，研究结果表明：（1）与含HMX的原基础配方相比，CL－20引入和替代对高能固体推进剂NEPE体系的量能作用具有两重性，即提高能量密度和改善体系氧平衡条件。（2）无论是多铝还是少铝配方，CL－20／Al体系氧平衡值应保在0．52以上，CL－20与Al对体系的能量水平提高具有正加和作用。（3）在高铝含量的原基础配方中，单纯用CL－20替代HMX（体系氧平衡值＞0．51），发动机总得以提高。（4）在低铝含量的基础配方中，用CL－20替代HMX和减少那部分铝后，不仅使得少铝含量（Al≤8％）推进剂体系的能量水平得以显著提高，而且在某种程度上缓解了降低特征信号和提高能量及其他综合性能之间的矛盾。     

18-冠-6/ADN含能共晶氧化剂对BAMO-THF推进剂能量特性的影响

采用X射线单晶衍射表征了新型18-冠-6/二硝酰胺铵含能共晶(18-Crown-6/ADN)氧化剂晶体的结构;采用氧弹式量热计测定了其燃烧热并获得其标准摩尔生成焓(Δ_fH_m~θ);采用最小自由能法计算了18-Crown-6/ADN对3,3-二叠氮甲基氧丁环与四氢呋喃共聚醚(BAMO-THF)推进剂能量性能的影响。结果表明,18-Crown-6/ADN晶体属于单斜晶系,C2/c空间群,晶胞参数:a=2.393 5nm、b=0.863 27nm、c=2.032 4nm;α=90°、β=112.874°、γ=90°;18-Crown-6/AND的Δ_fH_m~θ为-(833.57±4.89)kJ/mol,其取代配方中的AP、HMX、ADN或CL-20后推进剂的理论比冲(I_(sp))最低;含18-Crown-6/ADN的BAMO-THF推进剂中加入部分高能组分(如CL-20、HMX)可提高其能量性能;能量计算表明,BAMO-THF/A3、Al、AP、(18-Crown-6/ADN)/CL-20/HMX的质量分数分别为25%、18%、15%、42%,18-Crown-6/ADN、CL-20和HMX的质量比约3∶4∶3时,配方的I_(sp)约2 550N·s/kg,燃烧室温度约2 900K,燃气平均相对分子质量约24.50,特征速度约1 540m/s。     

DAATO3.5对改性双基推进剂安全性能的影响

设计了一种含N–氧化–3, 3'–偶氮双(6–氨基–1, 2, 4, 5–四嗪)(DAATO_(3.5))的改性双基推进剂,通过DSC(差示扫描量热)、撞击感度和静电火花测试,分别研究了其全分解范围的热稳定性、机械感度和静电感度的变化;借助真空安定性、甲基紫、5 s爆发点试验,研究了该推进剂的热安定性。结果表明:DAATO_(3.5)不改变推进剂的分解峰型,可小幅降低推进剂的主分解峰温,但降低幅度对DAATO_(3.5)含量不敏感;随DAATO_(3.5)含量增加,推进剂撞击感度的引发距离H_(50)、静电感度的引发电压V_(50)及引发能E_(50)线性降低,甲基紫试验变色时间、5 s爆发点温度小幅下降,真空安定性试验放气量有所增加。     

CL-20基交联改性双基推进剂的燃烧性能

设计了以CL-20、HMX、RDX及其混合物为氧化剂的XLDB推进剂,研究了其燃烧性能。结果表明,用CL-20替代XLDB推进剂中的HMX、RDX可大幅提高其燃速,压强指数略有提高。5～20MPa的压强指数为0.48。用CL-20替代50%(质量分数)HMX、RDX后,推进剂的燃速变化趋势不同。在低于12MPa时,CL-20/HMX-XLDB推进剂的燃速低于HMX-XLDB推进剂,且在5～20MPa范围内压强指数较高。     

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。