碳酸钙在聚合物胶束控制下的仿生合成

合成了温敏性的聚(N-异丙基丙烯酰胺)-b-聚(L-谷氨酸)(PNIPAM-b-PLGA)嵌段共聚物,在较高温度下制备了以PNIPAM为核、以PLGA为壳的自组装胶束,研究了胶束对碳酸钙晶体生长的控制作用.使用扫描电镜和X射线衍射表征了碳酸钙晶体的形貌和晶型.当聚合物胶束浓度较高时,得到纤维状的文石;当胶束浓度较低时,...     

带相反电荷高分子和表面活性剂复合物膜在空气/水界面上的特性

利用原子力显微镜技术、表面压松弛法对带相反电荷高分子和表面活性剂在气/水界面形成的界面复合物膜进行了特性研究.原子力显微镜研究结果表明,部分水解聚丙烯酰胺(HPAM)/十六烷基三甲基溴化铵(CTAB)所形成的界面复合物膜呈现出“团”状聚集体形貌.两性聚丙烯酰胺与CTAB形成的界面复合物膜呈现出“纤维丝”的聚集体形貌.亚相中盐的存在对界面复合物的形貌有很大影响.表面压松弛实验则进一步表明界面复合物膜形貌结构的变化对其膜稳定性有直接的影响.     

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.     

新型疏水缔合聚合物P(AM/POEA)与表面活性剂的相互作用

采用粘度法、荧光探针和透射电镜研究了新型疏水缔合聚合物P(AM/POEA)和表面活性剂SDS和CTAB在水溶液中的相互作用. 聚合物P(AM/POEA)结构中, 疏水体(2-苯氧乙基丙烯酸酯)呈嵌段状无序地分布在聚丙烯酰胺主链上. 这类聚合物很容易和表面活性剂相互作用, 通过疏水缔合, 形成混合胶束状聚集体, 导致溶液粘度剧增. 随聚合物溶液中SDS的加入, 溶液粘度发生大幅度起伏变化, 出现最大值. 粘度最大值对应的表面活性剂浓度c_S,max位于表面活性剂CMC附近, 并发现它的位置不随聚合物微结构而变化. 然而它们缔合作用的增粘程度却与聚合物疏水体含量X_H及疏水嵌段尺寸N_H有关. 在实验浓度范围内, X_H和N_H愈大, 溶液的粘度越高. 此外用透射电镜直接观察到聚合物/表面活性剂体系中聚集体的交联结构形貌.     

疏水缔合聚丙烯酰胺与双子表面活性剂的相互作用

制备了一种脂肪酸酯双磺酸盐型双子表面活性剂, 利用粘度法、界面张力法和原子力显微镜研究了疏水缔合聚丙烯酰胺与双子表面活性剂在溶液中的相互作用. 实验结果表明: 疏水缔合聚丙烯酰胺在溶液中能够通过自组装形成疏水微区并发展成网络结构, 疏水微区与表面活性剂在溶液中能形成混合胶束; 当一定量的表面活性剂加入时, 对疏水缔合聚丙烯酰胺的自组装起促进作用, 而过多双子表面活性剂的加入又会对聚合物分子的自组装起抑制作用, 从而显著影响疏水缔合聚丙烯酰胺的溶液性质, 随着表面活性剂浓度的增加, 聚合物溶液粘度先增加、再降低; 同时, 疏水缔合聚丙烯酰胺对双子表面活性剂的界面性能也有较大影响, 聚合物的加入使双子表面活性剂降低油/水界面张力的能力下降, 油/水界面张力达到平衡所需时间延长.     

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.     

层状硅铝酸盐MAS-20的合成与表征

在水热体系下,通过表面活性剂和分子筛导向剂共同反应制备规则的纳米层状分子筛,实验结果表明,十六烷基三甲基溴化铵在水中达到一定浓度后就会自组装成层状胶束,再加入分子筛导向剂在一定条件下即可合成纳米层状分子筛。通过X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和固体核磁(NMR)表征可以证明所得的样品为20nm左右的层状微孔分子筛,样品具有均匀的层状形貌和规则的微孔结构。     

部分水解聚丙烯酰胺-羟乙基纤维素的水相pH响应性自组装

为考察无规共聚物在全水相环境中的自组装行为, 合成了结构类似于无规共聚物的低相对分子质量的部分水解聚丙烯酰胺(HPAM). 尝试改变水溶液pH值来诱导HPAM与羟乙基纤维素(HEC)发生自组装, 采用透射电子显微镜(TEM)观察到不同pH值时分别获得了100 nm的似正方体胶束, 200 nm×100 nm的类椭球胶束, 100 nm的串珠状胶束以及500 nm×300 nm×50 nm的半月形胶束等pH响应性核壳型聚合物胶束. 建立了金在胶束表面原位还原耦合TEM表征方法, 用于检测低衬度聚合物胶束的纳米细节; 配合电子探针X射线微区分析(EPMA)和扫描电子显微镜(SEM), 证实了半月形聚合物胶束的精致分级构造为亲水性内囊@疏水性连续囊壁@亲水性外壳的多泡囊泡, 并证实pH=0.9时多泡囊泡崩解为疏水性内核@亲水性外壳的10 nm类球体小胶束. 通过分析链节质子化状态的pH响应性, 结合zeta电位和吸光度测定结果, 阐释了不同pH值时组成聚合物胶束的核和壳的链段归属, 获得了全水相中HPAM自组装驱动力和形貌方面的全新知识.     

水溶液中P123对CaCO3微粒形貌的调控

在三嵌段共聚物P123水溶液体系中,合成了特殊形貌的层面光滑的碳酸钙层状聚集体、具有多级结构的碳酸钙层状聚集体和仙人球状的碳酸钙粒子.探讨了反应时间、聚合物浓度和反应温度对碳酸钙粒子形貌和晶型的影响,采用扫描电子显微镜(SEM)、X射线粉末衍射(XRD)及红外吸收光谱对合成样品的形貌、结构进行了表征.结果表明,聚合物浓度和反应温度对碳酸钙粒子形貌和晶型具有重要的影响.利用周期键链(PBC)理论模型解释了层状结构碳酸钙聚集体的形成过程.     

聚对苯二甲酸乙二醇酯/碳酸钙纳米复合材料的制备和表征

以聚乙二醇磷酸酯1000为表面处理剂, 采用碳化法合成了方解石型碳酸钙纳米粒子, 进一步制备了聚对苯二甲酸乙二醇酯/碳酸钙纳米复合材料. 采用透射电子显微镜(TEM)、 X射线衍射(XRD)、 傅里叶变换红外光谱(FTIR), 场发射扫描电子显微镜(FESEM)和热重分析(TGA)对样品进行了分析. 结果表明, 聚乙二醇磷酸酯1000成功地修饰到碳酸钙的表面, 并得到平均直径为60 nm, 形貌为立方体的纳米碳酸钙晶体. 与碳酸钙(空白)样品相比, 表面处理碳酸钙的复合材料表现出更好的分散性和热稳定性. 采用Friedman方法计算了复合材料热分解的活化能. 聚对苯二甲酸乙二醇酯、 聚对苯二甲酸乙二醇酯/空白碳酸钙和聚对苯二甲酸乙二醇酯/表面处理碳酸钙的活化能分别为200.58, 214.86和219.50 kJ/mol, 进一步说明了表面处理碳酸钙更好地改善了聚对苯二甲酸乙二醇酯的热稳定性.     

Enhanced heavy oil recovery by organic alkali combinational flooding solutions

Although alkaline/surfactant/polymer (ASP) flooding is successfully applied in oil fields, some disadvantages such as scales, corrosion effects, and viscosity reductions of polymer solutions appear. Usage of organic alkalis can avoid or decrease these disadvantages. In this paper, the physicochemical properties, including interfacial tension (IFT), and viscosity, of organic alkali combinational flooding solutions and their effectiveness as enhanced oil recovery agents are investigated. Monoethanolamine (MEA) is the optimal one for decreasing the IFT among the three organic alkalis studied in this paper. Although MEA cannot decrease the IFT as low as NaOH does, it has good compatibility with both surfactant and the polymer hydrolyzed polyacrylamide (HPAM). MEA not only helps a surfactant solution or HPAM/surfactant mixture attain ultralow IFT values, but can also promote better viscosity stability for HPAM or HPAM/surfactant solutions compared to NaOH. Moreover, core flood experiments show that adding MEA can obtain additional tertiary oil recovery of 6%–10% original oil in place (OOIP) on the top of HPAM or HPAM/surfactant flooding, although MEA has a lower enhanced oil recovery than NaOH. The experimental results show that MEA is a good choice to replace NaOH in enhancing heavy oil recovery.     

三元复合驱碱/表面活性剂/聚合物模拟原油乳状液稳定动力学特性

基于两相分离的乳状液稳定模型,研究了三元复合驱模拟原油乳状液稳定动力学特性;通过液膜强度和油水界面张力探讨了碱/表面活性剂/聚合物对模拟原油乳状液稳定动力学特性的影响机理。 结果表明,乳状液稳定模型可以很好的评价乳状液的稳定性,并得到乳状液的稳定动力学特性;碱浓度小于900 mg/L有利于乳状液的稳定,碱浓度大于900 mg/L不利于乳状液的稳定;表面活性剂和聚合物浓度的增加使得形成的模拟原油乳状液更加稳定;模拟原油乳状液的稳定作用主要是通过碱、表面活性剂降低油水界面张力并增加油水界面膜强度,聚合物通过提高界面膜强度实现的,三者存在协同效应。     

三元复合驱硅垢防垢剂SY-KD的合成及应用

通过分析三元复合驱油体系下硅垢的形成机理,设计合成了新型硅防垢剂SY-KD.SY-KD是由丙烯酸(AA)和对甲基烯丙基氧基苯磺酸(MBS)共聚形成的高分子(CAABS)与2-膦酸丁烷-1,2,4-三羧酸(PBTC)复配的混合物.SY-KD中羧基官能团通过氢键相互作用与原硅酸分子或其二聚体发生键合,由于SY-KD分子链的空间位阻效应,阻止了原硅酸分子或二聚体进一步聚合形成二氧化硅.室内研究结果表明,SY-KD各组分对于硅垢的阻垢能力主要是通过阻聚、吸附分散以及对不溶性SiO2的溶蚀作用来实现的,是一种很好的三元复合驱阻垢剂.SY-KD防垢剂使结垢油井平均检泵周期由50 d左右增加到300 d.     

Effect of Cross Linking Agent on Alkali/Surfactant/Polymer

Alkali/surfactant/polymer (ASP) multisystem flooding technique, which has an expansive application prospect, is one of the enhancing oil recovery (EOR) methods. By adding the organic chromium to the ASP, the molecular structure of polymer was made to change, and the capability of controlling mobility coefficient of ASP was improved. The results showed that multisystem could still keep ultra‐low interfacial tension between the multisystem and crude oil after addition of Cr³⁺. The resistance factor and residual resistance factor, the indicator which describes the capability of controlling mobility, upgraded strikingly. However its storage modulus and loss modulus, the indicator which describes viscoelasticity, increased. The results of physical simulation experiment indicated that this type of improved ASP could increase the recovery ratio by 4.3% compared to common ASP multisystem.     

Phase behavior and structure analysis of the middle mixed layer for ASP flooding system at low surfactant concentration

The phase behavior and interfacial tension of alkali/surfactant/polymer (ASP) flooding system and simulative crude oil were investigated, and the size distribution and structure analysis of the middle mixed layer (MML) were also studied by size analyzer and freeze-fracture TEM. It was found that there were some rules between the volume of MML and the concentration of each component, and the interfacial tension between MML and the oil phase or water phase could reach an ultra-low value. Especially, the freeze-fracture TEM micrographs of MML were firstly obtained, and the new viewpoint was put forward that there coexist the structures of micelle, microemulsions and emulsions in MML and the structure of microemulsion is dominant. This would make an important effect on the research of surfactant theory and ASP flooding mechanism.     

Laboratory Study on Low Gas/Liquid Ratio Foam Flooding for Zhuangxi Heavy Oil

Considering the high cost and injection pressure of conventional foam flooding, foam flooding with low gas/liquid ratio was proposed to enhance the heavy oil recovery. A foamer containing 0.2 wt% α -olefin sulfonate, 0.1 wt% HPAM and 0.5 wt% Na₂CO₃ was selected for Zhuangxi heavy oil. Then the foam stability and low gas/liquid ratio foam flooding were studied via micro model and sand pack experiments. The results indicate that the foam is much more stable in heavy oil than in diesel; in flooding tests, this foamer with gas/liquid ratio of 0.2:1 increases the oil recovery by 39.8%, which is nearly 11% higher than ASP solution in terms of the same injection volume (0.3PV) and agents.     

What is the Criterion for Selecting Alkaline/Surfactaint/Polymer Flooding Formulation: Phase Behavior or Interfacial Tension

An experimental study on determination of alkaline, surfactant, polymer (ASP) flooding systems using natural mixed carboxylate was conducted to examine the decisive factor for ASP flooding, phase behavior or interfacial tension. The volume and color of middle phase liquid were observed, the transient interfacial tension at different salt and alkaline concentrations were measured and, finally, coreflood test in laboratory were made. The results showed the flooding system with larger volume and brown color of middle phase emulsion sometimes not to obtain better oil recovery efficiency. The primary and more important phenomenon affecting the oil recovery is a lower or ultralow minimum interfacial tension value at the crude oil/soluble phase interface.     

重烷基苯磺酸盐的界面性质和驱油机理

重烷基苯磺酸盐是在三次采油中广泛采用的表面活性剂之一，但重烷基苯原料组成复杂导致最终磺化产物的驱油效果差异很大.实验通过柱层析的方法将重烷基苯分离成6个族组分，并对其中的二烷基苯、单烷基苯和二烷基茚萘满、烷基萘、多苯烷进行磺化，中和提纯后对各磺酸盐进行界面张力测定.通过对比不同矿化度下界面张力以及各组分复配后的界面张力，对原油等效烷烃数(EACN)以及各组分碳数最低值(nmin)测定，得出各组分之间协同效应的规律和复配机理，从而阐明了重烷基苯磺酸盐的驱油机理.通过研究十二烷基苯磺酸钠(LAS)与各组分之间的复配作用对上述规律和机理进行了进一步验证.     

Adsorption,wetting, foaming,and emulsification properties of mixtures of nonylphenol dodecyl sulfonate based on linear alpha-olefin and heavy alkyl benzene sulfonate

Nonylphenol dodecyl sulfonate (C₁₂NPAS) has been synthesized, and mixed with heavy alkyl benzene sulfonates (HABS) in different proportions. The effects of different mixing ratios on properties such as adsorption, wetting, foaming, and emulsification, of the C₁₂NPAS/HABS surfactant mixtures have been systematically investigated. Experimental results have shown that, after mixing, the wetting and foaming properties of C₁₂NPAS/HABS are improved remarkably. Compared with C₁₂NPAS and HABS alone, the adsorption and emulsifying properties of C₁₂NPAS/HABS are far superior, which we attribute to a synergistic effect between these surfactants.     

Interaction Between the Hydrophobically Modified Polyacrylamide and HPAM-Flooding Produced Liquid

In order to utilize the produced liquid of hydrolyzed polyacrylamide (HPAM) flooding to enhance oil recovery, the interaction between hydrophobically modified polyacrylamide (HMPAM) and the produced liquid of HPAM flooding was investigated. The viscous characteristic of HMPAM in aqueous solution was investigated by Ubbelohde viscometer. The results show the intrinsic viscosity of HMPAM in aqueous solution is higher than that of HPAM, indicating that HMPAM has better effect on increasing the viscosity of aqueous solution. The viscosity of the complex system consisted of HMPAM and the produced liquid from HPAM flooding is lower than that of the HMPAM system, but higher than that of the HMPAM/HPAM complex system in mineralized water. In order to investigate the major factor of the influence on the viscosity of the HMPAM/produced liquid complex system, the viscosities of HMPAM/HPAM (and hydrolyzed HPAM with different hydrolysis degree) in distilled water and in mineralized water were studied. The fluorescence spectrum and transmission electron microscopy measurements were carried out to investigate the interaction between HPMAM and produced liquid from a microscopic perspective. These results are useful for farther enhancing oil recovery after HPAM flooding.