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氧化钐/热塑性聚氨酯复合材料的防辐射性能及流变性能 总被引:1,自引:0,他引:1
用机械共混法制备了氧化钐/聚氨酯热塑性弹性体(Sm2O3/TPU)复合材料,探讨了Sm2O3/ TPU复合材料的防辐射性能及流变性能.结果表明,在相同的管电压下,复合材料的防辐射性能随Sm2O3用量的增加而提高;在Sm2O3用量相同的情况下,复合材料在管电压为120 kV时的屏蔽性能要优于60 kV下的.Sm2O3/TPU复合材料的防辐射性能优于以天然橡胶(NR)为基质制备的Sm2O3/NR及PbO/NR复合材料的防辐射性能.Sm2O3/TPU复合材料为假塑性流体.当Sm2O3用量为500质量份时,其在基质中的分散达到最佳,此时复合材料具有较好的加工流动性. 相似文献
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采用湿法混炼工艺制备石墨烯/天然橡胶(NR)纳米复合材料和碳纳米管/NR纳米复合材料,研究石墨烯和碳纳米管用量对NR纳米复合材料性能的影响。结果表明:随着石墨烯和碳纳米管用量的增大,NR纳米复合材料的热导率和比热容均先增大后减小;石墨烯/NR纳米复合材料的300%定伸应力先减小后增大,石墨烯用量为2份的石墨烯/NR纳米复合材料的拉断伸长率最大;碳纳米管/NR纳米复合材料的300%定伸应力增大,碳纳米管用量为3份的碳纳米管/NR纳米复合材料的撕裂强度最大。随着温度的升高,石墨烯/NR纳米复合材料的相对介电常数呈先增大后减小的趋势,在110℃时最大;碳纳米管/NR纳米复合材料的相对介电常数呈增大的趋势。 相似文献
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将干冰用于氧化石墨烯(GO)/白炭黑/天然胶乳(NRL)的混合乳液中,利用干冰气化产生的大量气泡破裂而形成的能量对填料聚集体的破碎作用,提高填料在NRL中的分散性,研究干冰用量对GO/白炭黑/天然橡胶(NR)复合材料性能的影响。结果表明:干冰用量较小时,随着干冰用量的增大,复合材料的Payne效应减弱,交联密度增大,物理性能提高,滚动阻力降低;干冰用量较大时,复合材料的Payne效应增强,交联密度减小,物理性能下降,滚动阻力提高;干冰用量为20份时,复合材料的物理性能最佳。 相似文献
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热塑性聚氨酯防辐射复合材料的性能 总被引:1,自引:0,他引:1
通过机械共混法制备了La2(CO3)3,Ce2(CO3)3,Pr2(CO3)3,Nd2(CO3)3/热塑性聚氨酯(TPU)复合材料,研究了镧系碳酸盐/TPU复合材料的防辐射性能,讨论了添加La2(CO3)3/TPU回收料对其力学性能和屏蔽性能的影响.结果表明,在120 kV的入射管电压下,当镧系碳酸盐用量低于400份时,La2(CO3)3/TPU,Ce2(CO3)3/TPU,Pr2(CO3)3/TPU,Nd2(CO3)3/TPU复合材料的防辐射性能基本相当;当镧系碳酸盐用量超过400份时,Nd2(CO3)3/TPU复合材料的防辐射性能最好.在入射管电压为70~120 kV时,4种镧系碳酸盐/TPU复合材料的防辐射性能随着入射管电压的增加先增强后减弱,在85~105 kV出现峰值;除了Ce2(CO3)3/TPU复合材料以外,随着镧系元素原子序数的增加,其他复合材料的最佳防辐射峰值右移,且范围变宽.添加回收La2(CO3)3/TPU对La2(CO3)3/TPU复合材料的防辐射性能影响不大,只是其力学性能有所下降,但仍然能满足使用要求. 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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Cheng-Le Zhao Shane Porzio Alan Smith Haiyan Ge H. T. Davis L. E. Scriven 《Journal of Coatings Technology and Research》2006,3(2):109-115
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. 相似文献
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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. 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