橡胶材料硫化技术的研究进展

硫化工序是决定橡胶制品质量的关键。文章介绍了橡胶硫化领域的技术演进,其主要包括传统的化学热硫化、新兴的微波硫化及辐射硫化的原理、特点和发展历程,并将它们进行比较,与传统硫化方法相比,微波及辐射硫化技术作为橡胶硫化领域的新兴技术日益得到关注与重视。     

热水硫化橡胶衬里技术

本文概括地叙述了橡胶衬里的硫化及对大型有盖、无盖常压衬胶设备的几种硫化方式,并叙述了热水硫化橡胶的物理、化学性能,比较详细地说明了热水硫化橡胶衬里的施工技术及注意事项。     

热塑性弹性体的反应挤出动态硫化

介绍了制备热塑性动态硫化胶的反应挤出动态硫化技术的发展历史,系统论述了该技术的特点、工艺条件、硫化速率及硫化过程。     

辐射技术在轮胎工业中的应用

辐射技术在轮胎工业中的应用严太玄生产橡胶制品基本工序之一是硫化。传统的硫化技术是在胶料中加入一定比例的硫黄和促进剂，然后再加热。目前橡胶工业仍主要采用这种硫化方法。近年来，随着辐射技术的迅速发展，辐射硫化的方法由于具有节能、降低成本及提高产品质量的优...     

高温快速硫化技术

在橡胶工业中,提高生产率是最重要的关键技术,我们必须对胶料配方和加工技术进行认真的研究。高温快速硫化技术已经在连续硫化和注压工艺中应用。本文将介绍连续硫化技术,其中主要介绍倾斜管道式连续硫化(CCV)、立式连续硫化(VCV)、液体硫化介质硫化(LCM)及其硫化装备。特别介绍了这些硫化技术的特点及其在提高生产率方面的优势。     

新型轮胎加热硫化技术的研究进展

介绍3种新型硫化加热技术,即微波加热硫化技术、辐射加热预硫化技术和电磁感应加热硫化技术在轮胎硫化中的应用研究进展以及3种加热硫化技术的优缺点。指出随着金属内模的不断发展,电磁感应加热硫化技术发展优势明显,两者结合应用有望将我国轮胎硫化技术提升到一个新阶段。     

蒸汽充氮硫化装置开发

介绍了蒸汽充氮硫化装置的研制目的,主要技术特征,工艺流程的组成及确定因素,轮胎硫化的工作原理及工艺流程,在生产使用中取得的经济效益及装置的优点,应用注意事项。该装置已通过技术鉴定,可推广使用。     

微机在胶鞋硫化中的应用及探讨

本文介绍了微机控制应用于橡胶硫化工序的原理及构成、技术经济评价及存在问题。     

橡胶轮胎硫化测温技术

介绍橡胶轮胎硫化测温的原理、设备及数据处理方法和国内橡胶轮胎硫化测温,特别是测温仪器设备的发展历程.国内硫化测温技术早期采用人工平衡电位差计,而现今的测温技术多以计算机为核心进行自动化测温.分析指出硫化测温技术还可在仪器精度及智能、测温与传热过程理论模拟结合方面作进一步研究.     

硫化模拟分析技术在弹性车轮弹性体元件硫化工艺设计中的应用

研究硫化模拟分析技术在弹性车轮弹性体元件硫化工艺设计中的应用。首先采用经验公式计算出弹性车轮弹性体元件硫化时间,在此基础上运用硫化模拟分析技术,通过模型构建、网格划分及过程参数设置,对弹性车轮弹性元件硫化工艺进一步进行模拟分析,将硫化时间缩短16. 7%。弹性车轮弹性体元件溶胀指数、关键尺寸(厚度)和垂向刚度测试结果表明,与经验公式计算结果相比,弹性车轮弹性元件硫化模拟分析结果与实际生产情况更相符,硫化温度和硫化程度预测更准确,所得产品尺寸和性能更佳。实际生产中,该技术应用于橡胶制品硫化工艺设计可以减少试模次数和研发成本,提高产品质量。     

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.