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氨法是制备氢氧化镁的主要方法之一,根据氨进入反应体系状态不同分为氨水法和氨气法两种工艺。为了确定氨水与氨气对氢氧化镁颗粒性质的影响,以氯化镁为原料,分别以氨水和氨气为沉淀剂制备氢氧化镁,并利用扫描电镜(SEM)、X射线衍射(XRD)、激光粒度分布仪对产品进行了表征。结果表明:两种沉淀剂制备的氢氧化镁颗粒晶型均随沉淀反应温度的升高趋向完整,颗粒的分散性也随温度的升高得到改善;当反应温度达到75℃以上时,氨气法制备的氢氧化镁呈四方块状(六面体结构),颗粒的规则程度和分散性优于氨水法产品;氨水浓度对氨水法制备的氢氧化镁颗粒粒度及形貌也有较大影响,随氨水浓度的升高,产品粒度及分散性趋向于氨气法产品。本文研究可为氢氧化镁制备中氨法的选择及应用提供参考。 相似文献
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以氯化镁为原料,以氨水为沉淀剂,采用高温沉淀-水热法快速制备了高分散纳米片状氢氧化镁。采用扫描电子显微镜和X射线衍射仪对高分散纳米氢氧化镁的形貌和晶体结构进行了表征;同时将其填充到乙烯-乙酸乙烯酯共聚物(EVA)树脂中,采用转矩流变仪、拉力试验机和氧指数仪对EVA/氢氧化镁混合物的流变性能、力学性能和阻燃性能进行了研究。结果显示,所制备的氢氧化镁产品为六方薄片,分散性高,过滤性好,与EVA的相容性好,且随水热时间的增加而进一步改善。氢氧化镁填充量为50%(质量分数)的EVA混合物的转矩流变性能和力学性能优良,平衡扭矩为17 N.m,拉伸强度为10.9 MPa,断裂伸长率达到470%。 相似文献
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硫酸镁一步法制备氢氧化镁阻燃剂 总被引:9,自引:0,他引:9
实验确定了由硫酸镁一步法制备阻燃型氢氧化镁较适宜的条件为:表面处理剂添加量5~10 mL(以制备5 g氢氧化镁为基准),恒温处理时间3~4 h,陈化时间4~6 h. 此工艺条件下,所制得的氢氧化镁样品XRD分析表明,(001)面对应的衍射峰强度明显高于(101)面,样品(101)方位的扭歪值h<3.0′10-3,比表面积SDET<20 m2/g,颗粒形貌为棒状,直径为25~50 nm,长径比为8~10,且分散性好,样品符合阻燃型氢氧化镁的特殊要求. 该工艺具有流程短、设备简单、操作条件温和(常压、低温操作)、成本低等特点. 相似文献
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利用运城盐湖的卤水和现有产品硫氢化钠为原料,制取高纯氢氧化镁.以合成的高纯氢氧化镁为原料,进一步水热改性处理,得到阻燃型氢氧化镁.水热改性最佳条件:以氢氧化钠为水热改性剂,浓度为4 mol/L;水热改性温度为200 ℃;水热体系中氢氧化镁质量分数为7.5%;水热改性时间为5 h.在最佳条件下制备的氢氧化镁粒度分布范围窄,比表面积小,产品分散性好,形貌为六方形,符合阻燃型氢氧化镁的质量要求. 相似文献
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阻燃剂型氢氧化镁生产新工艺研究 总被引:16,自引:0,他引:16
介绍了以白云石为原料制备阻燃剂用氢氢氧化镁的试验原理及工艺流程,讨论了试验条件对氢氧化镁性能的影响,与卤水,烧碱法比较,该方法具有原料来源方便,生产成本较低等特点。 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