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氮官能化多锂引发合成星形苯乙烯-异戊二烯-丁二烯共聚物的微观结构和玻璃化转变温度 总被引:1,自引:1,他引:0
以六亚甲基亚胺锂(LHMI)与二乙烯基苯(DVB)合成的氮官能化多锂(简称Li)为引发剂,N,N,N′,N′-四甲基乙二胺(TMEDA)为极性调节剂,环己烷为溶剂,制备了带有氮官能化基团的星形无规苯乙烯-异戊二烯-丁二烯共聚物(SIBR),用核磁共振法进行了表征,并分析了TMEDA用量、聚合温度、引发剂浓度及DVB/Li(摩尔比)对SIBR微观结构和玻璃化转变温度(Tg)的影响。结果表明,在DVB/LHMI(摩尔比)为0.8的条件下,SIBR中有C—N存在,并且为臂数不等的星形聚合物;随着TMEDA用量的增加和聚合温度的降低,SIBR中非1,4-结构含量增加,Tg提高;在实验范围内引发剂浓度和DVB/Li对SIBR中非1,4-结构含量和其Tg影响不大。 相似文献
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以自制氮官能化多锂(以下简称Li)为引发剂,N,N,N′,N′-四甲基乙二胺(TMEDA)为极性调节剂,环己烷为溶剂,对苯乙烯(St)、异戊二烯(Ip)、丁二烯(Bd)进行负离子聚合,合成了星形集成橡胶丁二烯-异戊二烯-苯乙烯三元共聚物(SIBR),研究了不同TMEDA/Li(摩尔比)下SIBR的聚合反应动力学。结果表明,在三元共聚合反应中,3种单体的反应速率与其各自浓度均符合一级动力学关系;在SIBR的合成体系中,随着TMEDA/Li的增大,Bd的反应速率常数先升高后降低,St的反应速率常数逐渐增加,Ip的反应速率常数逐渐降低;当TMEDA/Li为1·0、二乙烯基苯(DVB)/Li(摩尔比)为0·8、引发剂浓度为7·69×10-4mol/L时,单体Bd,Ip,St的表观增长反应活化能分别为31·59,47·64,31·76kJ/mol,链增长频率因子分别为1·02×104,1·09×106,5·27×103min-1。 相似文献
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以n-BuLi为引发剂、乙基四氢糠基醚(ETE)和十二烷基苯磺酸钠(SDBS)二元复合调节体系为调节剂、己烷/环己烷为混合溶剂,在聚合温度为50 ℃时采用负离子聚合法进行苯乙烯-异戊二烯-丁二烯(SIBR)三元共聚合,考察了ETE/n-BuLi(摩尔比)和SDBS/n-BuLi(摩尔比)对SIBR微观结构含量和玻璃化转变温度(Tg)的影响。结果表明,当ETE/n-BuLi从0.5增加到2.0、SDBS/n-BuLi为0.1时,SIBR中聚丁二烯的1,2-结构质量分数和聚异戊二烯的3,4-结构质量分数分别增加了5.4和7.6个百分点,Tg上升了28.84 ℃左右;当SDBS/n-BuLi从0.1增加到0.8、ETE/n-BuLi为0.5时,SIBR中聚丁二烯的1,2-结构含量、聚异戊二烯的3,4-结构含量和Tg变化很小;ETE调节SIBR中聚丁二烯的1,2-结构和聚异戊二烯的3,4-结构的能力远远大于SDBS。 相似文献
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以正丁基锂(n—BuLi)为引发剂,N,N,N′,N′-四甲基乙二胺四甲基乙二胺(TMEDA)为调节剂,环己烷为溶剂,通过负离子聚合制备了丁二烯和异戊二烯的共聚物。结果表明,随着TMEDA用量的增加,聚合速度加快,丁二烯单体竞聚率增加,异戊二烯单体竞聚率减少,二者差值逐渐增大,在TMEDA/n—BuLi(摩尔比)不小于0.8时,这种变化趋势变缓,表明共聚物分布不均匀程度增加。 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