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1.
表面活性剂分子在溶液中能够自组装形成多种形式的胶束结构,使溶液呈现出不同的流动特性。表面活性剂分子的自组装行为是其众多实际应用的重要基础,因此也一直是研究热点。表面活性剂分子的自组装行为受溶液条件(质量浓度、温度、流动强度等)影响显著,但目前实验条件下很难直观地、定量地对不同溶液条件下表面活性剂分子自组装行为进行系统监测和研究。本文选取CTAC/Na Sal棒状胶束溶液系统为研究对象,通过介观布朗动力学模拟计算,系统研究了不同质量浓度、温度、剪切强度下CTAC棒状胶束的自组装行为。研究表明,溶液的质量浓度、温度以及对溶液施加的剪切强度对CTAC棒状胶束的自组装能力都具有促进和抑制的两面性影响,即适当的质量浓度、温度及剪切强度有利于CTAC棒状胶束之间的自组装;相反,过高或过低的质量浓度、温度及剪切强度都不利于CTAC棒状胶束之间的自组装。  相似文献   

2.
李钦  陈馥 《日用化学工业》2004,34(3):173-175
介绍了黏弹性表面活性剂溶液的性质,确定黏弹性表面活性剂性质的测试方法和实验手段,以及其内部微观结构和流变特性等方面的研究成果。当黏弹性表面活性剂溶液浓度增加到某一临界浓度时,球形胶束开始向蠕虫状胶束转变,溶液黏度突然增大,随着浓度的进一步增大,蠕虫状胶束快速生长、增长并形成线型柔性棒状胶束,柔性棒状胶束相互缠绕、粘附甚至融合,形成某种超分子三维网状结构,溶液黏度急剧增加,并表现出较强的黏弹性。概述了黏弹性表面活性剂在油田中的应用,特别是在压裂液、酸液、钻井液及提高采收率等方面的应用,指出了黏弹性表面活性剂广泛运用的前景和尚未解决的问题。  相似文献   

3.
谢程程  庞明军  巢建伟 《化工进展》2019,38(5):2441-2450
深入研究表面活性剂的流变特性,对于理解湍流减阻机理和改进制药、化工等领域的产品质量具有重要意义。本文研究了相同升温速率、不同剪切速率以及相同剪切速率、不同升温速率对阳离子表面活性剂十六烷基三甲基氯化铵(CTAC)溶液表观黏度的影响。研究表明:当温度较低时,剪切速率对表面活性剂溶液表观黏度的影响起主导作用;随着温度的升高,高温对胶束的影响增强导致溶液在高温处出现剪切稀化现象。当浓度为0.3125mmol/L时,溶液临界温度随剪切速率的升高保持恒定;但当浓度升高至0.6250~1.2500mmol/L时,在高温和高剪切的作用下,黏度曲线出现“平台”和短暂的增稠现象。对于中等浓度表面活性剂溶液,浓度升高导致蠕虫状胶束出现分支并抑制了“平台”的产生;随着升温速率的增大,胶束结构的响应时间滞后于升温速率,但当γ=150s?1时,滞后效应减弱,高剪切对胶束结构的破坏占主导作用。  相似文献   

4.
采用主链接枝法合成了梳形表面活性剂聚甲基丙烯酸甲酯-g-聚乙二醇单甲醚(PMMA-g-MPEG).利用红外光谱(IR)、核磁共振氢谱(1HNMR)和凝胶渗透色谱(GPC)对其结构进行了表征.分别对PMMA-g-MPEG水溶液的浊点、表面活性及流变性质进行了研究.实验结果表明:其浊点大于90℃;25℃时,其临界胶束浓度为0.4 g/L,临界胶束浓度时的表面张力为48.7 mN/m;稀溶液近似为牛顿型流体,浓溶液具有强烈的剪切变稀的行为和黏弹性.  相似文献   

5.
以3.0代聚酰胺-胺(PAMAM G-3.0)为起始剂,合成了一种新型树枝状非离子表面活性剂。通过表面张力与稳态荧光法研究了其在水溶液和无机盐溶液中的表面性质与聚集行为,并考察了温度对其性质的影响。结果表明,随着温度的升高,表面活性剂的表面张力逐渐降低,但在研究的温度范围内,临界胶束浓度(CMC)的变化不大。当加入质量浓度为1.0%的NaCl、NaBr及Na2SO4时,均使其表面张力增大;而3种无机盐的加入,对表面活性剂CMC的影响不大。  相似文献   

6.
克拉夫点(KP)与cmc,πmax的关系   总被引:6,自引:2,他引:6  
克拉夫点(KP)是表面活性剂的基本属性,在表面活性剂溶液研究中起着重要的作用。本文着重讨论KP与临界胶束浓度(cmc)及降低表面张力的最大效能(π_(max))之间的关系。指出表面活性剂只有在体系温度≥KP的条件下使用时,才能形成胶束和达到降低表面张力的最大效能。  相似文献   

7.
张刚  高彪  韩迎鸽 《当代化工》2021,50(9):2242-2245
双子表面活性剂具有临界胶束浓度低、水溶性好、胶束结构和聚集行为异常、降低油水界面张力效率高、流变性能好等特点,引起了学术界和现场专家的广泛关注.流变特性和界面张力的测定是评价和选择提高采收率(EOR)药剂的两项重要筛选技术.对双子表面活性剂的流变性、润湿性变化、吸附和界面性质做了分析,对双子表面活性剂在提高采收率中的应用研究现状做出总结分析.  相似文献   

8.
将短链二元酸(丁二酸(SA)、戊二酸(GA)、己二酸(AA))和长链N-(3-(二甲基氨基)丙基)硬脂酰胺(C18N3N)以1∶2的摩尔比混合,通过静电相互作用,构筑了三种新型的拟双子表面活性剂。该过程无需复杂的合成。通过表面张力仪和流变仪测试了该系列表面活性剂的表面活性和流变性能。结果发现,2C18N3N/GA拟双子表面活性剂的cmc为4.60×10-5 mol/L,该值远低于传统双子表面活性剂,说明构筑的拟双子表面活性剂2C18N3N/GA具有很强的胶束聚集能力,2C18N3N/SA和2C18N3N/AA体系也具有类似的特征。在浓度超过50 mmol/L时,该系列表面活性剂可形成蠕虫状胶束,溶液表现出黏弹行为,且黏弹溶液具有较好的耐温耐剪切性能。还考查了上述黏弹溶液的pH和温度响应性,发现体系pH为6.1时,溶液黏度很高,pH为4.0或9.3时,黏度下降。随着温度的升高,体系的黏度也会迅速增加。在60℃时,该体系的零剪切黏度可高达11 967.73 Pa·s。该表面活性剂制备简单,性能优良,拓展了新型表面活性剂的制备方法和应用范围。  相似文献   

9.
为确定HCFC?141b水合物生成条件下阴离子表面活性剂十二烷基硫酸钠(SDS)和十二烷基苯磺酸钠(SDBS)的临界胶束浓度(CMC),在0~20℃温度下,通过圆环法实验研究了不同浓度表面活性剂溶液体系的表面张力,考察了表面活性剂对溶液体系表面张力的影响机理并通过C3H8水合物的生成过程实验进行了验证,确定了SDS和SDBS的临界胶束浓度. 结果表明,当SDS和SDBS的质量浓度分别低于500?10?6和100?10?6时,表面活性剂降低水表面张力的效果最明显,二者的CMC分别为1950?10?6和400?10?6,表面活性剂能明显缩短水合反应的诱导时间,提高了其平均生成速率.  相似文献   

10.
双子表面活性剂因其高界面活性、低临界胶束浓度、低浓度时增粘效果明显,在清洁压裂液增稠方面潜力巨大。而溶液胶束结构的形态及变化与溶液粘度密切相关,因此准确表征不同浓度下双子表面活性剂溶液胶束微观结构形态及变化特征具有重要理论指导意义。在大量调研表面活性剂溶液胶束结构形态检测方法与表征的基础上,重点阐述了可用于双子表面活性剂溶液胶束微观结构表征的研究方法及其研究发展现状。  相似文献   

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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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14.
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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17.
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   

18.
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   

19.
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   

20.
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   

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