单壁纳米碳管的纯化及其储氢特性

针对半连续氢电弧法制备的单壁纳米碳管提出了一种纯化方法。采用HNO3和H2O2回流水煮的方法对单壁纳米碳管进行了纯化处理，透射电镜观察及热重分析表明样品中的无定形炭、纳米碳颗粒及金属催化剂颗粒等杂质可被有效去除，提纯后单壁纳米碳管的收率约为35％，纯度在95％以上；研究发现该纯化方法对单壁纳米碳管的孔径分布和比表面积有较大影响。采用体积法测定了纯化前后单壁纳米碳管样品的储氢容量，结果表明纯化样品的储氢量为1．65％，比未提纯样品（0．56％）有较大提高。     

用炭黑生成多壁纳米碳管的机理

在没有催化剂的情况下，通过固态转换，于改型高温电弧炉的阳极上，用炭黑生成了多壁纳米碳管。提出了炭黑通过固态转换变成纳米碳管的机理。存在于炭黑中的五角形缺陷和七角形缺陷转移到高拉伸应变畴，是生成机理的关键。该生成机理可分为两个阶段。两个阶段的根本机理是相同的，只是促使纳米碳管生长的拉伸应力源不同而已。在生长的第一阶段，炭黑粒子问颈形部位被热力拉伸为粗短的纳米管，高温电弧炉内存在于等离子体中的静电力促使粗短纳米碳管延伸成各种微米长度。     

催化化学气相沉积法合成单壁纳米碳管的研究进展

介绍了合成单壁纳米碳管的三种主要方法,总结了国内外催化化学气相沉积法合成单壁纳米碳管的研究现状,着重介绍了催化剂对合成单壁纳米碳管影响的研究情况,并分析了反应工艺条件对合成单壁纳米碳管的影响.     

国外有关塑料助剂研究的期刊文摘(纳米碳管)

纳米碳管(Carbon Nanotube)是1991年日本的Ijima首先发现的一种直径在小于100nm,长度可达到微米量级的具有单层壁或多层壁的空心、管状的碳的存在形式。这一发现将纳米结构的研究推向了一个高潮。在高分子中,纳米碳管及具有类似结构的纳米碳纤维因其纳米、纤维状的结构而具有了潜在的增强、增韧等特性,因而成为最近几年来高分子研究领域中的一个热点。--译者     

纳米碳管/高密度聚乙烯复合材料性能的研究

应用熔融共混法制备纳米碳管／高密度聚乙烯复合材料。考查了纳米碳管含量及制备工艺对材料电性能和力学性能的影响。结果表明加入纳米碳管可以显著提高高密度聚乙烯的导电性，电阻率变化呈现渗流现象。渗流阈值在20％～25％之间，其电阻率下降8个数量级。随纳米碳管含量的增加复合材料的模量提高，断裂伸长率下降。经过对纳米碳管进行溶液浸润预处理，复合材料的导电性和力学性能均得到改善。     

PE-UHMW／PE-HD／CNTs摩擦复合材料的制备及其摩擦学研究

主要研究了超高相对分子质量聚乙烯和高密度聚乙烯以及纳米碳管复合材料的制备工艺及其抗磨损性能，并系统地研究了复合材料中纳米碳管的质量份数、预处理方法以及摩擦对偶材料对复合材料摩擦性能的影响。结果表明，高密度聚乙烯的加入可以提高复合材料的流动性能；纳米碳管可以显著提高复合材料的抗磨损性能，其比磨损率随纳米碳管质量份数的增加而减小；对偶材料100Cr6对复合材料的比磨损率大于X5CrNil8—10；纳米碳管可以分散在复合材料中，但团聚现象仍然存在。     

多壁碳纳米管的改性研究

采用蒸发酸纯化法处理多壁碳纳米管以去除管体表面无定形碳等杂质和改善管体之间相互缠绕团聚的现象,利用X射线衍射(XRD)、扫描电镜(SEM)和透射电镜(TEM)对未纯化碳纳米管和纯化之后碳纳米管的结构和形貌进行表征。结果表明:与纯化处理前的多壁碳纳米管相比,在维持原有结构的情况下,纯化后的多壁碳纳米管管体表面的无定形碳等杂质去除干净,管体缺陷处断裂出现更多的端口,使得多壁碳纳米管的长度变短,比表面积增大,且在管体断裂处形成很多的亲水性基团,使管体的分散性提高从而明显改善了管体之间的缠绕团聚现象。     

超声作用联合纳米腐植酸处理苯酚废水

采用静态吸附法研究了超声联合纳米腐植酸处理苯酚废水;用红外光谱(FT-IR)、扫描电镜(SEM)、比表面积测试仪(BET)对纳米腐植酸的粒径大小、形貌、比表面积及孔径等进行表征,结果表明:纳米腐植酸粒度分布均匀,平均粒径为50 nm,比表面积为110.31 m2/g,孔径为6.56 nm;考察了苯酚初始浓度、纳米腐植酸用量、超声声强及频率等因素对纳米腐植酸和超声作用协同处理苯酚废水的最佳工艺条件。实验结果表明:超声频率为20 kHz,超声声强0.2 W/cm2,苯酚初始质量浓度为100 mg/L,pH值为6.0,溶液体积100 mL,吸附温度40℃,吸附时间120min,纳米腐植酸用量为40 g/L的条件下,纳米腐植酸与超声作用协同处理苯酚废水吸附率可以达到95.7%;吸附剂纳米腐植酸对苯酚的吸附主要受颗粒内扩散所控,其再生循环使用5次后,苯酚的吸附容量仅减少18.9%。     

纳米碳管的分散对其增强环氧树脂强度的影响

以纳米碳管增强环氧树脂复合材料为研究对象,研究了纳米碳管在环氧树脂中的分散效果及碳管含量、分散剂的用量和碳管的分散时间对环氧树脂弯曲性能和热性能的影响,并用扫描电子显微镜(SEM)观察其微观结构.结果表明,纳米碳管的分散对环氧树脂的弯曲性能影响很大,而加入纳米碳管能够显著提高环氧树脂的耐热性.     

不同碱和酸处理对碳纳米管结构和形貌的影响

研究了不同碱和酸处理对碳纳米管的微观结构和形貌的影响,采用TEM、SEM和XRD对其进行了表征。K_2CO_3、NaOH和KOH在750℃处理多壁碳纳米管时发现:NaOH的氧化刻蚀能力最强,K_2CO_3的氧化刻蚀能力最弱;强碱能够强烈地刻蚀碳纳米管的管壁,使碳纳米管的管壁变薄,变粗糙,并且有孔洞结构形成,同时造成内径扩大。硝酸处理碳纳米管时发现:随着处理时间的延长碳纳米管管壁变薄,内径变大,但是当处理时间超过16 h后,碳纳米管的管径变化不是很明显,但有大量的碳纳米管被短切。碱处理与酸处理对碳纳米管的微观结构和形貌的影响有很大差异,这是由于碱和酸对碳纳米管的氧化刻蚀的反应环境和刻蚀机理不同。     

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.     

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。     

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.