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三种二胺扩链剂浇注聚氨酯弹性体性能比较 总被引:4,自引:0,他引:4
以聚己二酸乙二醇酯二醇(PEA),甲苯二异氰酸酯(TDI)为原料合成聚酯型聚氨酯预聚体,分别用3,3'-二氯-4,4'-二氨基二苯基甲烷(MOCA)、二氨基二甲硫基甲苯(DADMT)和2,4-二氨基-5-巯基甲苯(TX-1)作扩链剂合成聚氨酯弹性体,比较了这3种扩链剂对浇注工艺性能及弹性体的物理机械性能的影响。实验结果表明,DADMT和TX-1两种固化剂得到的聚氨酯弹性体与固化剂(MOCA)得到的聚氨酯弹性体的力学性能相当,TX-1是一种能在常温下与预聚体进行固化反应的扩链剂,可以替代MOCA用于浇注型聚氨酯弹性体。 相似文献
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以聚已二酸乙二醇丙二醇酯(PEPA)、4,4'-二苯基甲烷二异氰酸酯(MDI)为原料,用1,4-丁二醇(BDO)扩链剂或混合扩链剂制备了聚氨酯(PU)弹性体。讨论了预聚体NCO基质量分数、扩链剂和催化剂用量对聚氨酯弹性体力学性能的影响;同时,比较了MDI/BDO体系与2,4-甲基二异氰酸酯/3,3'-二氯-4,4'-二胺基二苯甲烷(TDI/MOCA)体系的性能。结果表明,聚氨酯弹性体的硬度、模量和强度随预聚体NCO基含量增加而增加;提高扩链剂的三元醇含量,弹性体力学性能呈下降趋势;MDI/BDO体系的扯断伸长率和撕裂强度比TDI/MOCA体系高。 相似文献
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以不同结构聚酯(PEA、PEPA、PBA、PCL)为软段,4,4'-二苯基甲烷二异氰酸酯(MDI)和1,4-丁二醇(BDO)为硬段采用预聚体法合成了聚氨酯(PU)弹性体。讨论了MDI/BDO体系中软段种类、相对分子质量、预聚体NC0质量分数及催化剂对聚氨酯弹性体力学性能的影响,并与TDI/MOCA体系进行比较。结果表明,当软段相对分子质量相同时,PBA—PU的硬度最高提高预聚体NCO质量分数可使PU弹性体硬度、撕裂强度和300%模量增加;在制备聚氨酯弹性体中,加入催化剂的弹性体拉伸强度下降16.6%~20.1%;MDI/BDO体系的PU弹性体撕裂强度和冲击弹性较高,TDL/MOCA体系的PU弹性体拉伸强度较好、永久变形较低。 相似文献
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采用2种不同的预聚体合成方法制备聚氨酯浇注弹性体,并对其性能进行了测试。结果表明,分步加入扩链剂乙二醇的预聚体合成工艺所得浇注聚氨酯弹性体的拉伸强度比一次性加入乙二醇的预聚体合成工艺所得浇注聚氨酯弹性体的拉伸强度提高了70%左右,而伸长率变化不大。同时研究了这2种制备工艺对材料动态力学性能的影响。并探讨了不同R值及配方中交联剂用量对聚氨酯浇注弹性体力学性能的影响。 相似文献
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郭智臣 《化学推进剂与高分子材料》2011,(1):17-17
湖南精正设备有限公司拓宽产业链,开发和研制了JZCPU-20聚氨酯弹性体浇注机。该产品用于生产以MOCA等为交联剂的浇注型聚氨酯弹性体制品。机内可合成预聚体及真空脱泡。新的聚氨酯弹性体浇注机市场空间巨大,可广泛用于生产胶辊、密封条、小型轮胎、汽车方向盘、鞋底等制品。 相似文献
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低不饱和度聚醚多元醇制备聚氨酯弹性体 总被引:5,自引:1,他引:4
以甲苯二异氰酸酯、3,3‘-二氯-4,4‘-二氨基二苯基甲烷(MOCA)以及高相对分子质量、低不饱和度聚氧化丙烯多元醇为原料,以预聚体法制备了浇注型聚氨酯弹性体。比较了高相对分子质量、低不饱和度聚醚与普通聚醚在制备浇注型聚氨酯弹性体过程中的加工性能以及弹性体的物理性能。结果表明,与普通聚醚相比,低不饱和度聚醚制得的聚氨酯预聚体粘度较低,流动性较好,釜中寿命长,脱模时间短;制备的硬度为邵A83-95的浇注型聚氨酯弹性体,在硬度相同时,基于低不饱和度聚醚的弹性体的拉伸强度、伸长率、撕裂强度比基于普通聚醚多元醇制备的弹性体高20%-50%。 相似文献
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J. R. Aldrich S. P. Carroll W. R. Lusby M. J. Thompson J. P. Kochansky R. M. Waters 《Journal of chemical ecology》1990,16(1):199-210
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. 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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2008~2009年世界塑料工业进展 总被引:4,自引:1,他引:3
中蓝晨光化工研究院有限公司《塑料工业》编辑部 《塑料工业》2010,38(3)
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。 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