驱油体系化学剂间相互作用对界面吸附膜的影响

采用界面张力弛豫技术研究了不对称Gemini表面活性剂C12COONa-p-C9SO3Na、部分水解聚丙烯酰胺Mo-4000、疏水缔合水溶性聚丙烯酰胺(HMPAM)等驱油体系化学剂在癸烷/水界面上的扩张流变性质,考察了不同离子强度、不同类型电解质对体系界面流变性质的影响,计算得到界面扩张弹性模量和粘性模量的全频率谱,并通过归一化方法(cole-cole图)探讨了界面吸附膜的弛豫过程。研究发现,界面膜内分子重排和界面与体相间分子扩散交换是影响膜性质的主要弛豫过程。表面活性剂体相浓度增大有利于界面分子重排过程,而低频有利于扩散交换过程;不同结构聚合物以及不同离子强度、不同类型电解质对表面活性剂吸附膜有不同的影响。     

不同结构芳香侧链酰基牛磺酸钠的表面扩张性质

利用悬挂滴方法研究了N-(α-苯氧基)十四酸牛磺酸钠(12+B-T)和N-(α-对乙基苯氧基)十四酸牛磺酸钠(12+2B-T)在空气/水表面上的动态扩张粘弹性质, 考察了时间、扩张频率及摩尔浓度对扩张模量和相角的影响, 测定了不同摩尔浓度条件下的泡沫性能. 研究发现: 低浓度条件下, 表面分子间相互作用决定表面活性剂吸附膜的性质, 膜以弹性为主; 高浓度条件下, 扩散交换过程起主导作用, 吸附膜表现出粘弹特性. 表面活性剂芳环支链上增加一个乙基, 分子间相互作用增强, 扩张模量增大, 泡沫更加稳定.     

不同结构三取代烷基苯磺酸钠表、界面的扩张性质

利用悬挂滴方法研究了两种同分异构体的表面活性剂2-丙基-4,5-二己基苯磺酸钠(366)和2,5-二丙基-4-壬基苯磺酸钠(393)在空气/水表面和癸烷/水界面上的扩张流变性质, 考察了不同表面活性剂浓度下366和393溶液表、界面扩张性质的异同. 实验结果表明, 磺酸根间位的长链烷基对表面扩张模量贡献较大, 表面活性剂分子大小对界面扩张模量影响较大.     

Gemini表面活性剂对疏水缔合聚丙烯酰胺界面吸附膜扩张流变性质的影响

采用小幅低频振荡和界面张力弛豫技术, 考察了疏水缔合水溶性聚丙烯酰胺(HMPAM)在正癸烷-水界面上的扩张黏弹性质, 研究了不对称Gemini表面活性剂C₁₂COONa-p-C₉SO₃Na对其界面扩张性质的影响. 研究发现, 疏水链段的存在, 使HMPAM在界面层中具有较快的弛豫过程, 扩张弹性显示出明显的频率依赖性. 表面活性剂分子可以通过疏水相互作用与聚合物的疏水嵌段在界面上形成类似于混合胶束的特殊聚集体. 表面活性剂分子与界面聚集体之间存在快速交换过程, 可以大大降低聚合物的扩张弹性. 同时, 聚合物分子链能够削弱表面活性剂分子长烷基链之间的强相互作用, 导致混合吸附膜的扩张弹性远低于单独表面活性剂吸附膜.     

表面活性剂对驱油聚合物界面剪切流变性质的影响

利用双锥法研究了表面活性剂十二烷基苯磺酸钠(SDBS)和十六烷基三甲基溴化铵(CTAB)对油田现场用部分水解聚丙烯酰胺(PHPAM)和疏水改性聚丙烯酰胺(HMPAM)溶液的界面剪切流变性质的影响,实验结果表明:HMPAM分子通过疏水作用形成界面网络结构,界面剪切复合模量明显高于PHPAM.SDBS和CTAB通过疏水相互作用与HMPAM分子中的疏水嵌段形成聚集体,破坏界面网络结构,剪切模量随表面活性剂浓度增大明显降低.同时,界面膜从粘性膜向弹性膜转变.低SDBS浓度时,少量SDBS分子与PHPAM形成混合吸附膜,界面膜强度略有升高;SDBS浓度较高时,界面层中PHPAM分子被顶替,吸附膜强度开始减弱.阳离子表面活性剂CTAB通过静电相互作用中和PHPAM分子的负电性,造成聚合物链的部分卷曲,从而降低界面膜强度.弛豫实验结果证实了表面活性剂破坏HMPAM网络结构的机理.     

羟基取代烷基苯磺酸盐界面扩张粘弹性质

研究了2-羟基-3,5-二癸基苯磺酸钠(C10C10OHphSO3Na)表面和正癸烷-水界面上的扩张粘弹性质, 考察了平衡时间对界面性质的影响. 研究结果表明, 羟基取代烷基苯磺酸钠具有十分特异的界面性质, 其扩张模量比一般表面活性剂大一个数量级, 达到平衡的时间较长, 形成的界面膜弹性较大. 界面张力弛豫测定结果表明, 平衡时界面上存在特征时间长达103 s的慢过程. 上述实验结果可能是由于羟基间形成氢键造成的.     

疏水缔合共聚物与表面活性剂的界面相互作用

采用界面张力弛豫法研究了疏水缔合聚合物聚丙烯酰胺/2-乙基己基丙烯酸酯[P(AM/2-EHA)]在正辛烷-水界面上的扩张粘弹性质, 考察了不同类型表面活性剂十二烷基硫酸钠(SDS)、聚环氧乙烯醚(Tx-100)和十六烷基三甲基溴化铵(CTAB)对其界面扩张性质的影响. 研究发现, 界面上的表面活性剂分子可以与聚合物的疏水嵌段形成类似混合胶束的聚集体, 表面活性剂分子与聚集体之间存在快速交换. 这种弛豫过程的特征时间远比分子在体相与界面间的扩散交换时短. 当界面面积增大时, 上述混合胶束中的表面活性剂分子能快速释放, 在界面层内原位快速消除界面张力梯度, 从而大大降低界面扩张弹性. 界面上的CTAB分子与聚合物链节上的负电中心通过较强的电荷吸引作用形成复合物. 当界面面积增大时, 上述混合胶束中的CTAB分子释放较慢, 界面张力梯度较大. 非离子表面活性剂Tx-100分子量较大, 扩散速率较慢, 它在界面上与聚集体间的交换比阴离子表面活性剂SDS慢, 其特征时间约为0.9 s.     

正负离子和表面活性剂对水解聚丙烯酰胺分子线团尺寸的影响及其作用机理

采用动态光散射(DLS)方法,研究了无机电解质正离子与负离子对部分水解聚丙烯酰胺(HPAM)分子线团尺寸的影响,也研究了阴离子型表面活性剂与非离子型表面活性剂对HPAM分子线团尺寸的影响.结果表明,无机电解质负离子对HPAM分子尺寸(分子流体力学直径(Dh))影响较小,而无机电解质正离子对Dh的影响较大,且影响程度随正离子浓度增大而减小.Ca2+、Mg2+、K+和Na+对Dh的作用强弱顺序为Mg2+>Ca2+>Na+>K+.当向聚合物溶液中加入阴离子型表面活性剂时,随表面活性剂浓度增大,Dh先减小,后增大,再减小.此外,由于强烈的静电斥力作用,阴离子型表面活性剂分子在聚合物分子表面吸附较弱,难形成"表面活性剂-聚合物"络合物,而非离子型表面活性剂会以类似于胶束聚集体的形式吸附在聚合物分子链上,形成"表面活性剂-聚合物"络合物,结果造成Dh随表面活性剂浓度增加而逐渐增大.     

界面扩张流变法研究C_(12)mimBr对Gemini12-2-12在空气/水界面聚集行为的影响

采用界面扩张流变技术研究了季铵盐偶联表面活性剂C12-(CH2)2-C12·2Br(Gemini12-2-12)及其与离子液体表面活性剂溴化1-十二烷基-3-甲基咪唑(C12mim Br)复配体系的动态界面张力、扩张流变性质和界面弛豫过程等,探讨了C12mim Br对C12mim Br/Gemini12-2-12混合体系界面性质的影响及C12mim Br对Gemini12-2-12界面聚集行为影响的机制.结果表明,随着离子液体表面活性剂的不断引入,体系界面吸附达到平衡所需的时间逐渐缩短,扩张模量和相角明显降低,界面吸附膜由粘弹性膜转变为近似纯弹性膜;同时,界面及其附近的弛豫过程也发生显著变化,慢弛豫过程消失,快弛豫过程占主导地位,且离子液体浓度越高,快弛豫的贡献越大.这些界面性质的变化主要归因于离子液体表面活性剂C12mim Br参与界面形成及两表面活性剂在界面竞争吸附的结果.少量离子液体表面活性剂C12mim Br的加入可以填补疏松的Gemini12-2-12界面上的空位,形成混合界面吸附膜.随着C12mim Br含量的增加,嵌入界面的C12mim Br分子数不断增多,导致界面上相互缠绕的Gemini12-2-12烷基链"解缠",在体相和界面分子扩散交换的过程中"解缠"的Gemini12-2-12分子从界面上解吸回到体相,与此同时,C12mim Br分子相对较小的空间位阻及较强的疏水作用促使其优先扩散至界面进而取代Gemini12-2-12分子,最终界面几乎完全被C12mim Br分子所占据.     

新型磺基甜菜碱/聚丙烯酰胺体系表面及界面性能

采用自制的新型磺基甜菜碱两性表面活性剂与相对分子质量2500万的聚丙烯酰胺进行复配,考察了不同温度和矿化度条件下,聚合物对复配溶液表面、界面性能的影响。 采用滴体积法测定了溶液的表面张力,结果表明,加入聚合物使溶液的临界胶束浓度增大,且复配溶液的表面张力大于单独表面活性剂溶液的表面张力。 当聚合物浓度一定,增大溶液矿化度时,体系表面张力增大。 用旋滴型界面张力仪测定了溶液的界面张力,结果表明,增大聚合物浓度,油水界面张力增大,增大溶液矿化度,油水界面张力有所升高。 聚合物质量浓度为1.5 g/L,表面活性剂质量浓度为0.3 g/L时,可使胜利油田孤岛原油和孤东原油的油水界面张力达到超低数量级（10-3 mN/m）。 用分水时间法测定了溶液的乳化性能,结果表明,聚合物浓度增大,分水时间延长,并考察了75、85和95 ℃条件下体系的乳化性能,温度越高,分水时间越短。     

Interfacial dilational properties of partly hydrolyzed polyacrylamide and gemini surfactant at the decane–water interface

The dilational viscoelastic properties of partly hydrolyzed polyacrylamide (HPAM) and surfactant (C₁₂COONa-p-C₉SO₃Na) in the absence or presence of electrolyte were investigated at the decane–water interface by means of longitudinal method and the interfacial tension relaxation method. The polymer plays different roles in influencing the structure of HPAM–surfactant mix-adsorbed layer at different surfactant concentration. At low surfactant concentration, the addition of polymer could sharply decrease the dilational elasticity mainly due to the weakening of the “entanglement” among long alkyl chains in surfactant molecules, while the addition of the polymer may enhance the dilational elasticity due to the slow diffusivity of the polymer chains at higher surfactant concentration. And the added electrolyte, which results in screening of electrostatic interactions between the ionized groups, generally decreases the interfacial dilational elasticity and increases the dilational viscosity. The data obtained on the relaxation processes via interfacial tension relaxation measurement can explain the results from dilational viscoelasticity measurements very well.     

Influence of Oleic Acid and Electrolyte on the Interfacial Dilational Properties of Surfactant/Polymer Systems at the Decane-Water Interface

The dilational properties of partly hydrolyzed polyacrylamide (HPAM) and 4,5-diheptyl-2-propylbenzene sulfonate (377) mixed systems in the absence or presence of electrolyte or oleic acid at the oil-water interface have been described by means of the oscillating barriers method and the interfacial tension relaxation method. The polymer plays different roles in influencing the nature of polymer-surfactant adsorbed layers at different surfactant concentrations. At low surfactant concentration, the addition of polymer perhaps weakens the “entanglement” of long alkyl chains, which decreases strikingly the dilational modulus of the adsorbed layer. At high surfactant concentration, the addition of the polymer increases the dilational modulus due to the hydrophobic interactions between polymer and surfactant molecules. On the case of adding electrolyte, the frequency dependence of dilational modulus increases due to the enhancement of exchange process of surfactant molecules and bivalent cation has more obvious effect than Na ion. Oleic acid plays dual roles in controlling interfacial dilational properties of mixed adsorption films: a small quantity of oleic acid increases the dilational modulus by forming densely packed mixed adsorption layer with surfactant molecules, while the superfluous addition of oleic acid could decrease the dilational modulus mainly due to the weakening of the “entanglement” among long alkyl chains in surfactant molecules.     

Interfacial Dilational Properties of Hydrophobically Modified Partly Hydrolyzed Polyacrylamide and Anionic Surfactants at the Water-Decane Interface

The dilational viscoelastic properties of hydrophobically modified partly hydrolyzed polyacrylamide and anionic surfactants (4,5-diheptyl-2-propylbenzene sulfonate and gemini surfactant C₁₂COONa-p-C₉SO₃Na) in the absence or presence of electrolyte have been investigated at the decane–water interface by means of longitudinal method and the interfacial tension relaxation method. Experimental results show that at low surfactant concentration, the increase of the dilational modulus by the addition of surfactant molecules at low frequency might be explained by the mix-adsorption of the polymer chains and surfactant molecules. At the same time, polymer chain could sharply decrease the dilational modulus of surfactant film mainly due to the weakening of the strong interactions among long alkyl chains in surfactant molecules. At high surfactant concentration, the addition of surfactant molecules can decrease the dilational modulus of polymer solution due to the fast process involving in the exchange of surfactant molecules between the interface and the mixed complex formed by surfactant molecules and hydrophobic micro-domains. The added electrolyte, which results in screening of electrostatic interactions between the ionized groups, generally increases the frequency dependence of the interfacial dilational modulus. The data obtained on the relaxation processes via interfacial tension relaxation measurements can explain the results from oscillating barriers measurements very well.     

不同电性Gemini表面活性剂界面扩张性质

利用Langmuir槽法研究了含聚氧乙烯醚链中间链的两性Gemini表面活性剂C8E4NC12、阳离子Gemini表面活性剂C12NE3NC12和阴离子Gemini表面活性剂C8E4C8在空气/水表面和癸烷/水界面上的扩张性质,考察浓度对3种Gemini表面活性剂溶液表、界面扩张性质的影响.结果表明,由于分子间存在库仑引力,两性Gemini分子表现出较高的扩张弹性和粘性,且界面扩张性质类似于表面.对于有相同电荷Gemini分子,C8E4C8分子中的刚性苯环导致其疏水长链在表面上的取向不同于C12NE3NC12分子,两者表现出不同的表面扩张性质;而油分子能改变同电荷Gemini分子中长链烷基的取向,造成其界面扩张弹性和粘性远低于表面.提出了不同电性Gemini分子在界面排布的示意图,并利用弛豫过程的特征参数进行了验证.     

A Surface Rheological Study of Polyoxyethylene Alkyl Ether Carboxylic Salts and the Stability of Corresponding Foam

The dynamic dilational viscoelastic properties of polyoxyethylene alkyl ether carboxylic salts at the air-water interface were investigated by drop shape analysis method and their foam stability were measured by Bikerman Method. The influences of time, dilational frequency, and bulk concentration on surface dilational modulus and phase angle were expounded. The results show that the surfactant with the longest straight-chain shows the highest dilational modulus, which in agreement with the best foam stability. However, the foam stability of branched-alkyl chain surfactant cannot be explained in terms of film elasticity alone.     

羟基磺基甜菜碱氟碳表面活性剂在油水界面的扩张粘弹性

氟碳表面活性剂是目前表面活性最高的特种表面活性剂,在三次采油等领域具有良好的应用前景。 用小幅周期振荡法研究了羟基磺基甜菜碱型氟碳表面活性剂(FS)在油-水界面的扩张粘弹性能,考察了振荡频率、FS质量分数、无机盐(NaCl、CaCl₂、MgCl₂)对FS在油-水界面的扩张粘弹性能的影响。 结果表明,FS溶液在油水界面的扩张模量、扩张弹性和扩张粘度随着FS质量分数的增加而出现最大值,随着频率的增大而略有增加。 加入无机盐时,扩张模量、扩张弹性随NaCl质量分数增大而出现最大值,而随着CaCl₂或者MgCl₂质量分数的增加,FS溶液的扩张模量、扩张弹性和扩张粘度减小,而当CaCl₂或者MgCl₂质量分数分别为0.05%、0.1%时,tanθ达到最大值。     

界面张力弛豫法研究芳香侧链酰基牛磺酸钠的界面相互作用

采用界面张力弛豫方法研究了表面活性剂N-(α-苯氧基)十四酸牛磺酸钠(12+B-T),N-(α-乙基苯氧基)十四酸牛磺酸钠(12 +2B-T)和N-(α-己基苯氧基)十四酸牛磺酸钠(12+6B-T)在空气-水表面和癸烷-水界面上的扩张流变性质,考察了芳环支链链长变化对分子界面行为的影响,获得了表面活性剂结构对极限扩张弹...     

Interpretation of surface dilational elasticity data based on an intrinsic two-dimensional interfacial compressibility model

The present analysis shows that the introduction of intrinsic two-dimensional compressibility of a surfactant adsorption layer allows a much better interpretation of experimental data on the limiting (high-frequency) elasticity and characteristic frequency of diffusional relaxation than models using Frumkin's or other adsorption isotherms. The proposed model describes experimental data on surface dilational elasticity, as well as on surface pressure, sufficiently well at low and high surfactant concentrations, assuming the Lucassen and van den Tempel model of surface dilational elasticity is realized.     

The interfacial dilational properties of hydrophobically modified associating polyacrylamide studied by the interfacial tension relaxation method at an oil-water interface

The interfacial dilational viscoelastic properties of hydrophobically associating block copolymer composed of acrylamide (AM) and a low amount of 2-phenoxylethyl acrylate (POEA) (<1.0 mol%) at the octane-water interfaces were studied by means of the interfacial tension relaxation method. The dependencies of interfacial dilational elasticity and viscous component on the dilational frequency were investigated. The interaction of hydrophobically associating block copolymer [P(AM/POEA)] with sodium dodecyl sulfate (SDS) has been explored. The results show that at lower frequency, the dilational elasticity for different concentration copolymer is close to zero; at higher frequency, the dilational elasticity shows no change with increased frequency; At moderate frequency (10(-3)-1 Hz), the dilational elasticity decreased with a decrease in the dilational frequency. The results show that the hydrophobic groups of [P(AM/POEA)] chains can be associated by inter- or intrachain liaisons in water solution. The dilational viscous component for P(AM/POEA) comes forth a different maximum value at different frequencies when the polymer concentration is different. It is generally believed that the dilational viscous component reflects the summation of the various microscopic relaxation processes at and near the interface and different relaxation processes have different characteristic frequencies. The spectrum of dilational viscous component may appear more than once maximum values at different frequencies. The influence of SDS on the limiting dilational elasticity and viscous component for polymer solution was elucidated. For 5000 ppm polymer solution, the limiting dilational elasticity decreased with an increase in SDS concentration. The dilational viscous component passed through a maximum value with a rise in the dilational frequency, which appeared at different frequency when SDS concentration is different; and the higher is the concentration, the lower is the dilational frequency. It can be explained that macromolecules may be substituted by SDS molecules in the interface and the interaction of molecules decrease, which makes the limiting dilational elasticity decrease. For 200 ppm polymer solution, the limiting dilational elasticity increased firstly and then decreased with SDS concentration increasing. This may be explained that the interfacial polymer concentration is so low that SDS molecules absorbed in the interface dominate dilational properties of the interfacial film even at very low SDS concentration. However, SDS molecules can gradually substitute the polymer molecules in the interface with a rise in SDS concentration, which results in the decrease in the limiting dilational elasticity.