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以聚乙烯醇(PVA)、明胶和壳聚糖为原料,以戊二醛为交联剂,在醋酸溶液中通过共混交联反应合成了壳聚糖/明胶/聚乙烯醇复合水凝胶,考察了聚乙烯醇/壳聚糖/明胶的质量比、交联剂用量、反应温度、反应时间对复合水凝胶溶胀性能的影响。通过正交实验,确定制备复合水凝胶的优化条件如下:交联剂用量为6 mL、反应温度为75℃、反应时间为70 min、聚乙烯醇/壳聚糖/明胶的质量比为1∶2∶2,在此优化条件下合成的壳聚糖/明胶/聚乙烯醇复合水凝胶溶胀性能良好,对水的平衡溶胀度达到985%。 相似文献
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《应用化工》2022,(5):983-987
以天然可降解高分子壳聚糖为载体,选择温度敏感单体N-异丙基丙烯酰胺以及pH敏感单体2-丙烯酰胺基-2-甲基丙磺酸,以偶氮二异丁腈为引发剂,N,N-亚甲基双丙烯酰胺为交联剂,通过自由基接枝共聚反应制备壳聚糖水凝胶。通过红外(IR)、扫描电镜(SEM)对其结构及形貌进行了表征,并探讨了影响水凝胶溶胀率的因素。结果表明,当单体配比NIPAM∶AMPS为6∶4、引发剂用量为单体总质量4%、交联剂用量为单体总质量的4%、反应温度为45℃形成的水凝胶在水中溶胀率可达95%左右。该水凝胶具有一定的温度和pH敏感性,预计在药物控释、组织工程、抗凝血材料等领域拥有广阔的应用前景。 相似文献
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以天然可降解高分子壳聚糖为载体,选择温度敏感单体N-异丙基丙烯酰胺以及pH敏感单体2-丙烯酰胺基-2-甲基丙磺酸,以偶氮二异丁腈为引发剂,N,N-亚甲基双丙烯酰胺为交联剂,通过自由基接枝共聚反应制备壳聚糖水凝胶。通过红外(IR)、扫描电镜(SEM)对其结构及形貌进行了表征,并探讨了影响水凝胶溶胀率的因素。结果表明,当单体配比NIPAM∶AMPS为6∶4、引发剂用量为单体总质量4%、交联剂用量为单体总质量的4%、反应温度为45℃形成的水凝胶在水中溶胀率可达95%左右。该水凝胶具有一定的温度和pH敏感性,预计在药物控释、组织工程、抗凝血材料等领域拥有广阔的应用前景。 相似文献
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以丙烯酸钠(AANa)、丙烯酰胺(AM)为原料,过硫酸胺((NH)4S2O8)为引发剂,N,N'-亚甲基双丙烯酰胺(MBA)为交联剂,采用水溶液聚合法制备了聚合物P(AM-AANa)。利用红外光谱对P(AM-AANa)的结构进行了表征,并考察了丙烯酸(AA)中和度、AM和AANa物质的量比、(NH)4S2O8用量、MBA用量、反应时间、反应温度等因素对聚合物溶胀性能的影响。结果表明,当nAM∶nAA=2∶1、AA中和度为70%、引发剂用量为单体用量的0. 4%、交联剂用量为单体用量的0. 8%、反应温度为65℃、反应时间为8 h时,所制备的P(AM-AANa)水凝胶具有最佳溶胀性能。 相似文献
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为了实现餐厨垃圾中含碳组分的回收与增值化利用,以自制纳米CaO2作为氧化剂激发餐厨垃圾中的碳组分释放,尿素作为改性剂,丙烯酰胺作为单体,N,N′-亚甲基双丙烯酰胺作为交联剂,过硫酸钠作为引发剂,通过自由基聚合交联反应合成水凝胶,并对制得的水凝胶进行了溶胀性能的分析。研究通过单因素实验考察了水凝胶制备的影响因素,结果表明在氧化剂用量为0.70g、改性剂用量为4.60g、单体用量为2.80g、交联剂用量为0.14g、引发剂用量为0.38g时,水凝胶的溶胀率可以达到1429.78%。水凝胶在去离子水中0~12h的溶胀行为符合Fickian的Case I扩散模型,12~84h的溶胀行为符合Schott溶胀动力学的二级模型,微观表征结果证明溶胀性与水凝胶的网状结构有关,热重分析证明餐厨垃圾制备得到的水凝胶具有良好的热稳定性。 相似文献
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温度和pH值对智能水凝胶溶胀行为的影响 总被引:1,自引:0,他引:1
以N-马来酰化壳聚糖(N-MACH)为交联剂,N-异丙基丙烯酰胺(NIPAAm)为单体,羧甲基纤维素钠(CMC)为半互穿材料,分别合成了PNIPAAm和PNIPAAm/CMC半互穿网络智能水凝胶,研究了两种水凝胶在不同温度的去离子水和不同pH值的缓冲溶液中的溶胀现象,结果表明介质温度和pH值对水凝胶的溶胀行为有显著影响。在温度和pH值一定时,水凝胶的溶胀率随着交联剂用量的增加而下降,随着CMC用量的增加而上升。 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