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本文研究了六种不同超细粉末橡胶对丁苯橡胶SBR1502的力学性能、滚动阻力、耐磨性和动态力学性能的影响。结果表明,与丁苯橡胶配合体系相比,含超细粉末橡胶的丁苯橡胶配合体系硫化胶的主要力学性能基本不变,硫化胶的滚动阻力变化不大、耐磨性和0℃损耗因子提高。特别是含超细粉末丁腈橡胶和超细粉末丁苯(30%结合苯乙烯含量)的丁苯橡胶配合体系,其0℃损耗因子提高幅度达到了20%~29%,显示超细粉末橡胶可明显提高丁苯橡胶的抗湿滑性。 相似文献
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采用动态硫化法制备了丁腈橡胶/尼龙6热塑性弹性体(NBR/PA 6 TPV),考察了硫化体系、羧基丁腈橡胶(XNBR)以及增塑剂高密度氧化聚乙烯蜡(AC-316 A)和正丁基苯磺酰胺(BBSA)对TPV硫化特性、力学性能和微观形貌的影响。结果表明,以促进剂HVA-2/促进剂DM为硫化体系,动态硫化过程体系黏度的变化比以酚醛树脂/SnCl2为硫化体系时更平稳;但用后者制备TPV,其撕裂强度和扯断伸长率等力学性能更优,PA 6的结晶度更低。XNBR能对NBR和PA 6起到增容作用,当XNBR与NBR的质量比为10/90时,TPV的力学性能最好,NBR在PA 6中分散得最均匀。AC-316 A和BBSA都能对TPV起到增塑作用,随其用量的增加,体系黏度降低。 相似文献
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以超细全硫化粉末丁腈橡胶(UFPNBR,型号VP-401、VP-501、VP-550)与HPVC为原料制备HPVC/UFPNBR全硫化热塑性弹性体,研究了橡塑比对热塑性弹性体的力学性能、流变性能、耐油性能及耐增塑剂迁移性能的影响。结果表明,随着橡塑比的增加,热塑性弹性体的拉伸强度先增加后降低;断裂伸长率和断裂永久变形逐渐降低;橡塑比的增加有利于共混物的塑化,但降低了共混物的加工性能;UFPNBR的加入能有效地抑制增塑剂的析出,提高了热塑性弹性体的耐油性能及耐增塑剂迁移性能。 相似文献
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以超细全硫化粉末丁腈橡胶(UFPNBR,型号VP-401、VP-501、VP-550)与HPVC为原料制备HPVC/UFPNBR全硫化热塑性弹性体,研究了橡塑比对热塑性弹性体的力学性能、流变性能、耐油性能及耐增塑剂迁移性能的影响.结果表明,随着橡塑比的增加,热塑性弹性体的拉伸强度先增加后降低;断裂伸长率和断裂永久变形逐渐降低;橡塑比的增加有利于共混物的塑化,但降低了共混物的加工性能;UFPNBR的加入能有效地抑制增塑剂的析出,提高了热塑性弹性体的耐油性能及耐增塑剂迁移性能. 相似文献
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PA6/POE-g-MAH体系的结构与性能研究 总被引:5,自引:0,他引:5
以动态硫化及非动态硫化方法制备了马来酸酐接枝乙烯-辛烯共聚物(POE-g-MAH)增韧的聚酰胺6(PA6) 共混物,研究了PA6/POE-g-MAH体系的力学性能以及POE-g-MAH在PA6中的分散状况。结果表明动态硫化 PA6/POE-g-MAH共混物的屈服强度、冲击强度、断裂伸长率及弯曲模量均高于非动态硫化方法制备的PA6/POE-g- MAH共混物,动态硫化的PA6/POE-g-MAH共混物可以在材料的刚性与韧性之间达到良好的平衡。扫描电子显微镜图像的统计分析表明,非动态硫化PA6/POE-g-MAH共混物中分散的橡胶相数均颗粒尺寸随组成中POE-g-MAH 的含量增大而不断增大,动态硫化的PA6/POE-g-MAH共混物中分散的橡胶相数均颗粒尺寸随POE-g-MAH含量的增大变化不大。 相似文献
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M. S. J. Simmonds W. M. Blaney F. Delle Monache M. Marquina Mac-Quhae G. B. Marini Bettolo 《Journal of chemical ecology》1985,11(12):1593-1599
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. 相似文献
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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. 相似文献
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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. 相似文献
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中蓝晨光化工研究院有限公司《塑料工业》编辑部 《塑料工业》2009,37(3)
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. 相似文献
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中蓝晨光化工研究院《塑料工业》编辑部 《塑料工业》2007,35(3):1-25,67
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。 相似文献
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Inorganic/organic hybrid materials have considerable promise and are beginning to become a major area of research for many
coating usages, including abrasion and corrosion resistance. Our primary approach is to prepare the inorganic phase in situ
within the film formation process of the organic phase. The inorganic phase is introduced via sol-gel chemistry into a thermosetting
organic phase. By this method, the size, periodicity, spatial positioning, and density of the inorganic phase can be controlled.
An important aspect of the inorganic/organic hybrid materials is the coupling agent. The initial task of the coupling agent
is to provide uniform mixing of the oligomeric organic phase with the sol-gel precursors, which are otherwise immiscible.
UV-curable inorganic/organic hybrid systems have the advantages of a rapid cure and the ability to be used on heat sensitive
substrates such as molded plastics. Also, it is possible to have better control of the growth of the inorganic phase using
UV curing. It is our ultimate goal to completely separate the curing of inorganic and organic phases to gain complete control
over the morphology, and hence optimization of “all” the coating properties. Thus far, it has been found that concomitant
UV curing of the inorganic and organic phases using titanium sol-gel precursors afforded nanocomposite coatings which completely
block the substrate from UV light while maintaining a transparent to visible light. Also, it has been found that the morphology
of the inorganic phase is highly dependent on the concentration and reactivity of the coupling agent.
Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004, in Chicago,
IL. 相似文献