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The rheological properties of aqueous solutions of a series of hydrophobically modified alkali‐soluble emulsion (HASE) polymers containing hydrophobic macromonomer with varying number of ethylene oxide (EO) units were examined. The viscosity of a 3 wt% HASE solution increased from 0.06 to 300 Pa s when the number of EO units changed from 0 to 30, and then decreased to 4 Pa s for 40 EO units. The formation of a network structure in the HASE polymer systems is caused by association of hydrophobic moieties in the solution rather than by physical chain entanglements. Two different associating mechanisms, namely the backbone and the multiple center associative mechanisms, are proposed for the HASE polymer with varying number of EO units. The backbone associative mechanism is applicable to HASE polymers with short EO spacer where the hydrophobic association is hindered by electrostatic repulsion on the backbone. In contrast, with longer EO spacer, hydrophobes from different polymer chains are able to associate, leading to the formation of multiple center associative junctions. The drastic reduction in the viscosity for 40 EO units in both dilute and semi‐dilute concentrations is attributed to the formation of a higher proportion of intramolecular associative junctions. Copyright © 2006 Society of Chemical Industry 相似文献
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W. Hreczuch B. Trathnigg E. Dziwiński K. Pyzalski 《Journal of surfactants and detergents》2001,4(2):167-173
2-Ethylhexyl laurate, as an exemplary longer-chain aliphatic ester, was subjected to direct ethoxylation. The synthesis was described and the obtained products were analyzed qualitatively by means of the mass spectrometry and chromatographic methods. Solubility of the obtained ethoxylates was studied by determination of their cloud points in selected model solutions. It was shown that longer-chain aliphatic esters are feasible as raw materials for ethoxylation in the presence of an appropriate catalyst. They undergo effective and selective reaction with ethylene oxide without formation of excessive amounts of by-products. The obtained products exhibit typical properties of ethoxylate-type nonionic surfactants. Their solubility in water and butyldiglycol solution was relatively lower compared to their methyl ester equivalents. 相似文献
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通过微波加热的方法,将质量分数为20%的硼酸镧分散在Y分子筛上,得到负载型La2(B2O7)3-NaY分子筛催化剂。k(B2O7)3-NaY用于催化正辛醇乙氧基化反应。结果表明:k(B2O7)3-Nay的催化活性与b2(B2O7)3及Y分子筛相比均有较大程度的提高。正交实验结果表明:La2(B2O7)3-NaY催化剂的用量为正辛醇质量的5%,反应温度为140℃,初始压力为0.4MPa-0.5MPa,当环氧乙烷(EO)平均加成数为2.2时,EO加成数为1、2和3的3种组分之和占产物中醇醚总质量的73.2%,正辛醇转化率为85%,产品的分子质量分布指数E=2888,具有较好的窄分布效果,且催化剂可重复使用,重复使用3次催化速率没有改变。 相似文献
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丙烯酸β-羟乙酯的合成研究 总被引:2,自引:0,他引:2
研究了以乙酸铬、丙烯酸铬为催化剂,对羟基苯甲醚为阻聚剂,丙烯酸与环氧乙烷合成丙烯酸β-羟乙酯的工艺条件,得到了高收率、高质量的产品。 相似文献
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近年来,由于国内市场环氧乙烷供应量的剧增,导致中国乙氧基化生产工艺的蓬勃发展。介绍了国内企业乙氧基化生产工艺现状,对其特点及发展进行了详细地分析和阐述。最后,指出了乙氧基化生产工艺的发展趋势。 相似文献
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以菜籽油为原料,通过酯交换、环氧化和环氧化开环反应,合成了羟化乙氧基化双重改性菜籽油。最佳合成条件如下。(1)环氧化反应:以强酸性阳离子交换树脂为催化剂,以冰乙酸为活性氧载体,催化剂用量为酯交换菜籽油质量的5%、双氧水用量为酯交换菜籽油质量的40%、反应温度50℃、反应时间6h,(2)开环反应:环氧化油脂与聚乙二醇(PEG)的质量比为1.67:1、KOH用量为环氧化油脂质量的1%、反应时间4h、反应温度55℃。最终得到以羟化乙氧基化双重改性菜籽油为主的加脂剂,具有极好的乳化性、稳定性,经加脂的成革柔软、丰满、有弹性,手感滑爽,加脂效果优良。 相似文献
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介绍了环氧乙烷产能和乙氧基化项目的快速增长情况。简述了国内乙氧基化技术的进步、存在问题和工艺特点,对国内不同类型的乙氧基化技术的工艺性能和适用情况进行了对比分析。从生产事故、政府监管以及工程设计方面阐述了乙氧基化项目建设和运行的严峻形势,分析了环氧乙烷爆聚给乙氧基化生产带来的严重危害并提出解决思路。 相似文献
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利用连续管式反应器 ,对以KOH为催化剂的十二醇液相乙氧基化反应进行了动力学研究 ,获得了动力学模型d [EO] /dt =k [EO] [cat]和速度常数k =exp (2 2 14 -82 810 /RT) ,并用带夹套的静态混合器作为乙氧基化反应的放大反应器。对其特性进行了研究 :反应器的压降在操作范围内小于 0 1MPa ;物料在反应器中的停留时间分布试验表明 ,物料在反应器内的流动为理想活塞流 ;传热特性的研究结果证明其效率至少比空管高 4倍。同时以苯酚为起始剂进行了放大试验。 3 6MPa的反应压力使液化的环氧乙烷与起始剂反应 ,很好地解决了反应过程中物料的混合与反应热的传递问题 相似文献
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《国际聚合物材料杂志》2012,61(9):860-877
Schiff base prepared from salicylaldehyde and diethylene triamine was ethoxylated by poly (ethylene glycol) of different molecular weights, namely 200, 600, 1000 and 2000, by using β,β-dichlorodiethyl ether as a linking agent. The ethoxylation reaction took place at both ends of the base upon using poly(ethylene glycol) (PEG) 200 and 600, whereas at one end when PEG 1000 and 2000 were used. The chemical structure of the prepared compounds was confirmed by using IR and 1HNMR spectroscopy. Thermodynamic parameters for micellization and adsorption or the prepared compounds were measured based on the surface tension of their solutions at different temperatures. Then, the compounds under investigation were tested as oil spill dispersants according to different standard test methods. It was found that the compounds with lower molecular weights of PEG showed the best dispersancy. 相似文献
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总结了\"十二五\"期间中国乙氧基化产业发展情况、产业布局及产品结构,阐述了乙氧基化产业的技术创新亮点及产业目前存在的问题,提出了中国乙氧基化产业及技术未来发展方向的建议。 相似文献
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聚氧乙烯醚的物化性能应用及乙氧基反应技术的现状 总被引:2,自引:0,他引:2
详细介绍了聚氧乙烯醚的物化性能,包括水溶性,润湿性,分散性,洗涤性,乳化性,生物降解等及其在纺织,洗漆印染,油墨,涂料,金属清洗等行业中的应用,并概述了国内外乙氧基反应工艺路线的现状进行比较。 相似文献