油酸衍生物蠕虫状胶束的制备及其刺激响应行为研究

发布时间：2018-05-07 02:38

  本文选题：油酸衍生物 + 刺激响应性　； 参考：《西南石油大学》2017年硕士论文

【摘要】：近年来,环境刺激响应型蠕虫状胶束凭借其独特的微观结构和可调控的流变性质引起了广泛的关注。其中的pH和CO2响应型蠕虫状胶束具有易于制备,性能可逆可控,经济环保等优点,在油气田开发领域中存在着巨大的发展潜力。因此,本论文基于两种油酸衍生物表面活性剂,分别制备了 pH和CO2响应型的蠕虫状胶束,并对两种体系的刺激响应行为及其机理进行了深入的研究,具体研究内容如下:首先,以油酸、N,N-二甲基-1,3-丙二胺为原料合成了油酸酰胺丙基二甲基氧化胺(OAPAO)表面活性剂,并对OAPAO在水溶液中的气/液界面性质和不同pH、温度下的聚集行为进行了系统的研究。由表面张力法和吉布斯等温吸附方程等公式得到了OAPAO溶液在不同pH下的特性参数,对比表明,pH可以调控OAPAO溶液的气/液界面的性质,1H NMR和分子状态分布图证实这是由于OAPAO表面活性剂的分子状态随pH的改变发生了变化。不同pH下的粘度测试证明该体系具有pH响应特性,当PH2.1时,体系为低粘度的粘弹性流体,η0=0.5074 Pa·s,当将pH调节到6.82时,溶液的粘度增大到34.49 Pa·s,实现了三倍数量级的增长,当pH增大到11.88时,溶液的粘度降低为12.0Pa·s;流变和Cryo-TEM研究表明,体系粘度的急剧增大,是因为随着酸性的变弱,OAPAO去质子化程度增大,溶液中质子化的OAPAO和未质子化的OAPAO头基之间可以形成氢键,促进蠕虫状胶束的生长,使溶液中蠕虫状胶束的长度和缠绕的密度变大。不同温度下的粘度测试证明体系还具有温度响应特性,在pH=6.82和pH=11.88时,OAPAO溶液的粘度均随着温度的升高先增大后减小,粘度在35℃时达到最大值,流变测试表明这是温度升高过程中疏水作用和分子热运动相互竞争的结果。其次,利用油酸钠作为主剂,分别引入具有刺激响应的N,N-二甲基环己胺(DMCHA)和N,N-二甲基苄胺(DMBA)制备了两种CO2响应型蠕虫状胶束,并对浓度和摩尔比对体系粘度的影响、体系的流变学性能、CO2的响应特性和响应机理进行了研究。结果表明:两体系的粘度随着摩尔比的增大先增大后减小,随着浓度的增大而增大,同时,相同浓度和摩尔比条件下NaOA-DMBA体系的粘度明显优于NaOA-DMCHA体系,这是由疏水链结构不同引起的。通入CO2前,NaOA-DMCHA和NaOA-DMBA溶液均为水状液体;通入一定时间的CO2后,两体系均变为无色透明的粘弹性流体,且具有剪切稀释特性,符合Maxwell流体模型;加热并通入N2将CO2排出后,两混合溶液再次变回水状液体,如此循环三次,体系粘度几乎没有发生变化,证实了两体系的CO2响应具有循环可逆性。由流变、Cryo-TEM、DLS、分子状态分布图和1H-NMR研究表明,通入CO2前,OA-自组装形成球状胶束;通入CO2后,DMCHA或DMBA被质子化成DMCHA-H+或DMBA·H+通过与OA-的静电屏蔽作用和疏水作用,使得聚集体的微观结构相应的从球状胶束转变成蠕虫状胶束,混合溶液粘度变大。
[Abstract]:In recent years, environmental stimulus-responsive worm-like micelles have attracted wide attention due to their unique microstructure and controllable rheological properties. Among them, pH and CO2 responsive worm micelles have the advantages of easy preparation, reversible and controllable performance, economic and environmental protection, etc., which have great development potential in the field of oil and gas field development. Therefore, based on two kinds of surfactants of oleic acid derivatives, the wormlike micelles of pH and CO2 response were prepared, and the stimuli response behavior and mechanism of the two systems were studied. The specific research contents are as follows: firstly, oleic acid amide propyl dimethyl amine oxide (OAPAO) surfactant was synthesized from oleic acid N-dimethyl-1-methyl-3-propylenediamine. The gas / liquid interface properties of OAPAO in aqueous solution and the aggregation behavior at different pH and temperature were systematically studied. The characteristic parameters of OAPAO solution at different pH were obtained by surface tension method and Gibbs isothermal adsorption equation. The comparison shows that the pH can regulate the properties of the gas-liquid interface of OAPAO solution and the molecular state distribution diagram proves that this is due to the change of molecular state of OAPAO surfactant with the change of pH. The viscosity tests at different pH values show that the system has the characteristics of pH response. When PH2.1, the system is a viscoelastic fluid with low viscosity, 畏 _ 0 ~ (0) 0.5074 Pa / s, and when pH is adjusted to 6.82, the viscosity of the solution increases to 34.49 Pa / s, and the increase of three times order of magnitude is achieved. When pH increased to 11.88, the viscosity of the solution decreased to 12.0Pa s, and the rheological and Cryo-TEM studies showed that the viscosity of the system increased sharply because the degree of deprotonation of OAPAO increased with the weakening of acidity. A hydrogen bond can be formed between the protonated OAPAO and the unprotonated OAPAO head group, which can promote the growth of the wormlike micelles, and increase the length and the winding density of the wormlike micelles in the solution. The viscosity tests at different temperatures show that the system also has the characteristic of temperature response. The viscosity of OAPAO solution increases first and then decreases with the increase of temperature at pH=6.82 and pH = 11.88, and reaches the maximum value at 35 鈩，

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