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采用超声分散-原位聚合工艺制备了聚酰亚胺(PI)/二氧化钛(TiO2)杂化膜。通过傅里叶转换红外光谱、紫外-可见光谱、扫描电子显微镜等对杂化膜进行了表征,探讨了杂化膜中TiO2含量对杂化膜的热性能、吸湿性能和力学性能的影响。结果表明,纳米TiO2粒子均匀分散在PI基体中,TiO2的掺入及与有机基体的杂化提高了材料的热分解温度与玻璃化转变温度,降低了材料的吸湿性能,改善了材料的力学性能。当TiO2含量为6%时,杂化膜的拉伸弹性模量和断裂强度达到最大值,分别为纯PI膜的2.17倍和1.63倍。 相似文献
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采用超声分散-原位聚合的方法,制备了不同纳米二氧化钛(TiO2)含量的聚酰亚胺(PI)/纳米TiO2复合薄膜,通过X射线衍射、紫外可见光谱分析、扫描电子显微镜、红外光谱对薄膜的形态结构及纳米颗粒在复合物中的分散性进行了表征分析.结果表明,纳米TiO2以球状微粒均匀分散在PI基体中,表观粒径约为300 nm(杂化包覆后的粒径),晶形仍为锐钛矿型;纳米TiO2粒子的引入,提高了PI薄膜对可见光的吸收. 相似文献
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TDI/TiO_2有机无机纳米杂化材料的合成与表征 总被引:1,自引:0,他引:1
文章采用有机包覆法对纳米TiO2进行表面改性,制备了2,4-甲苯二异氰酸酯(TDI)/TiO2纳米杂化材料。采用红外光谱(FT-IR)、热质量损失分析(TGA)、静态接触角(CA)、透射电镜(TEM)及分散性实验等手段对纳米TiO2和TDI/TiO2纳米杂化粒子进行分析和表征。红外光谱和热质量损失分析显示,TDI以物理吸附和化学键合的方式存在于纳米TiO2的表面,并形成了有机包覆层。经计算,每nm2约有4.0个羟基参与化学反应,化学包覆率达57.97%。静态接触角数值表明,TDI/TiO2纳米杂化粒子具有很强的疏水性能,与水的接触角达147°。分散性实验显示,TDI/TiO2纳米杂化粒子在基础润滑油中分散稳定,静置20 d未出现分层现象。 相似文献
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《化工进展》2017,(2)
采用硅烷偶联剂(2-氰乙基)三乙氧基硅烷对纳米Al_2O_3粒子进行表面改性,利用热致相变法制备了改性Al_2O_3/PVDF有机无机杂化膜,研究了改性Al_2O_3的添加量对杂化膜性能的影响。经(2-氰乙基)三乙氧基硅烷改性后,纳米Al_2O_3粒子的团聚减少,改性后纳米Al_2O_3的平均最小粒径为52.23nm。与纯PVDF膜比较,改性纳米Al_2O_3的添加改善了PVDF膜的形貌结构,改性Al_2O_3/PVDF杂化膜形成的球晶明显增加,球晶的密度尺寸缩小,杂化膜中形成了大量连通的界面孔,膜的孔隙率升高,改善了PVDF膜的力学性能和亲水性,提高了截留率。当纳米粒子添加量达到5%时,膜的截留率提高了7.2%,膜的纯水通量达到了593.95L/(m~2·h),膜强度达到5.0MPa。 相似文献
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采用反胶束法合成TiO2纳米粒子与感光聚酰亚胺溶液混合制备纳米杂化感光材料,用热台偏光显微镜表征了杂化材料的光刻能力及形貌,用UV光谱表征了杂化材料的TiO2纳米粒子的存在,用椭圆偏振仪测定了杂化材料薄膜的折光指数。 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