偶联剂对环氧-铜粉复合导电涂料导电性能的影响

笔者研究了两种硅烷偶联剂KH550、KH570，两种钛酸酯偶联剂CTl36、JSC对环氧-铜粉体系导电涂料导电性能的影响。结果表明，加入KH550、KH570后涂层电阻升高，而CTl36、JSC能降低体系电阻，其中以加入质量分数为2％的JSC效果最好。耐候性实验表明加入JSC可有效防止铜粉的氧化。研究了使用JSC的不同方法对导电性的影响，结果表明，偶联剂、铜粉、环氧同时加入，体系初始电阻最低。对比加入偶联剂JSC的导电体系和不加JSC的体系，SEM照片表明合适的偶联剂能有效分散铜粉，利干形成导电网络．     

镀银铜粉填充型导电硅橡胶的研究

研究了镀银铜粉填充型硅橡胶的导电性能。结果表明 :采用乙烯基三过氧叔丁基硅烷偶联剂对镀银铜粉进行表面处理 ,可改善胶料的混炼工艺性 ,提高镀银铜粉的添加量 ;同时也可提高硫化胶中镀银铜粉与硅橡胶的结合力 ,使表层镀银铜粉颗粒不易脱离 ,相应地提高了硅橡胶的导电稳定性 ;所得镀银铜粉填充型导电橡胶的体积电阻率小于 0 0 1Ω·m。     

紫外光固化法制备漆酚/铜复合导电涂料及其性能的研究

以漆酚为基体,铜为导电填料,利用紫外光固化法制备漆酚/铜复合导电涂料,讨论了涂膜中铜的含量对漆膜导电性能的影响,并测试了漆膜的常规物理机械性能和耐化学腐蚀性能。结果表明,在紫外光辐照下,漆酚/铜混合物涂膜可快速固化。当铜含量达到45%(wt%)时,漆膜的表面电阻率为13.1Ω·cm,耐冲击强度50kg·cm。     

紫外光固化法制备漆酚/石墨复合导电涂料的研究

以漆酚为基体,石墨为导电填料,利用紫外光固化法制备漆酚/石墨复合导电涂料,讨论了涂膜中石墨的含量以及固化方式等对漆膜导电性能的影响,并测试了漆膜的常规物理机械性能。结果表明,在紫外光辐照下,漆酚/石墨混合物涂膜可快速固化。当石墨含量达到25%(wt%)时,漆膜的表面电阻率为442Ω.cm,硬度为6H,附着力2级,冲击强度为45kg.cm。     

镀银铜粉对电磁屏蔽导电胶粘剂性能的影响研究

以α-ω二羟基聚硅氧烷为基胶,以镀银铜粉为导电填料,以硅微粉、白炭黑和硬脂酸锌为体质填料,制备了具有良好粘接性能和电磁屏蔽性能的导电胶粘剂。考察了镀银铜粉的粒径、形貌、银含量及填充量对胶粘剂搭接剪切强度、导电性能、电磁屏蔽性能的影响。研究结果表明：镀银铜粉的银含量与填充量的增加明显提升了导电胶粘剂固化后的导电性能,随着银含量与填充量的增加,体积电阻率先降低、后趋于稳定;胶粘剂的剪切强度则是随着导电粉的粒径与填充量的增加而不断降低。试验中采用银含量为20%（质量分数）的45μm枝状铜导电粉在添加量为70.8%时,制得的导电胶粘剂的综合性能较佳,固化后体积电阻率达到0.007Ω·cm,剪切强度为1.05 MPa,电磁屏蔽性能≥85 dB(300 MHz～10 GHz)。     

片状镀银铜粉/丙烯酸树脂电磁屏蔽复合涂料的研制

以钦酸醋偶联剂改性后的片状镀银铜粉为填料,丙烯酸树脂为黏结剂,制备了一种高性能电磁波屏蔽复合涂料.讨论了片状铜粉含量对涂层导电性能的影响,测试了涂层的主要物理性能及电磁波屏蔽效能.结果表明,电磁波屏蔽复合涂料中片状镀银铜粉与丙烯酸树脂的最佳质量比为3:2,此时制备的涂料具有较好的导电性和电磁波屏蔽性能.涂膜厚度为300...     

镀银铜粉导电填料对复合型导电涂料性能影响的研究

研究了镀银铜粉作为导电填料,聚氨酯树脂作为基料树脂配制复合型导电涂料时,镀银铜粉含量及其形貌,以及不同形状导电填料配用对涂膜导电性能的影响,并通过涂膜的导电机理,探讨造成这些影响的原因。     

树枝状镀银铜粉的制备及在导电橡胶中的应用

采用置换还原法制备树枝状镀银铜粉,通过扫描电镜、能谱分析以及高温氧化试验,研究了沉积过程、粉末性能以及用镀银铜粉为填充材料的导电橡胶性能。结果表明,络合剂YH-10对银离子有较强的络合作用,树枝状铜粉表面镀覆一层均匀致密的银层,电阻率达到0.0001Ω·cm,表面未见氧化物出现。在150℃保温1.5 h条件下,镀银铜粉未被氧化,表明粉末具有抗高温氧化性。制备的镀银铜粉和进口镀银铜粉为导电填料制备导电橡胶,其各项性能参数相当。     

醇酸树脂铜粉复合导电涂料的研制

研制了一种以醇酸树脂为基料的铜系复合导电涂料,讨论了导电填料的含量、粒径大小、偶联剂的含量以及固化工艺对涂料导电性能的影响规律,并用渗滤模型与隧道效应理论分析了这些影响规律。结果表明,加入200目55％-60％铜粉,偶联剂含量5％,在50℃固化15 min后室温完全固化,导电涂料的综合性能较好,涂层表面电阻率为100Ω·cm。     

复合导电填料导电胶的研究(英文)

在铜粉表面进行化学镀银,获得银铜导电粉。把镀银铜粉与1%的TiFeCoNi纳米合金粉混合,制成复合导电填料。用环氧树脂、复合导电填料和固化剂混合制成导电胶粘剂。对导电胶的性能进行了测试。结果表明,当导电填料占导电胶重量比的70%时,导电率可达0.005Ω·cm。最佳的固化条件是130℃、保温3 h。把导电胶放在85℃条件下保温600 h,导电胶的电阻率和剪切强度变化量不超过20%。导电胶的电阻随使用温度的变化类似于金属电阻的变化规律。     

Sapindaceae,cyanolipids, and bugs

Scentless plant bugs (Heteroptera: Rhopalidae) are so named because adults of the Serinethinae have vestigial metathoracic scent glands. Serinethines are seed predators of Sapindales, especially Sapindaceae that produce toxic cyanolipids. In two serinethine species whose ranges extend into the southern United States,Jadera haematoloma andJ. sanguinolenta, sequestration of host cyanolipids as glucosides renders these gregarious, aposematic insects unpalatable to a variety of predators. The blood glucoside profile and cyanogenesis ofJadera varies depending on the cyanolipid chemistry of hosts, and adults and larvae fed golden rain tree seeds (Koelreuteria paniculata) excrete the volatile lactone, 4-methyl-2(5H)-furanone, to which they are attracted.Jadera fed balloon vine seeds (Cardiospermum spp.) do not excrete the attractive lactone. Loss of the usual heteropteran defensive glands in serinethines may have coevolved with host specificity on toxic plants, and the orientation ofJadera to a volatile excretory product could be an adaptive response to save time.Mention of a commercial product does not consititute an endorsement by the USDA.     

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.     

2008～2009年世界塑料工业进展

收集了2008年7月～2009年6月世界塑料工业的相关资料,介绍了2008～2009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、环氧树脂、不饱和聚酯树脂)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。     

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.     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.