改性聚丙烯酰胺水溶液的疏水缔合性质

合成了一种疏水缔合水溶性聚丙烯酰胺共聚物,使用荧光光谱法并结合紫外及流变性实验,对制备的疏水缔合水溶性聚丙烯酰胺共聚物在水溶液中形成疏水微区、超分子聚集体及空间网络结构进行了研究,并用扫描电子显微镜证实了溶液中网络结构的存在.     

Tensile Mechanical Properties of Hydrophobic Association Hydrogels: Effect of Crosslinking Method,Synthesis Temperature,Mineral Salt and Swelling

Hydrophobic association hydrogels (HA-gels) were prepared through micellar copolymerization of acrylamide (AM) and a small amount of octylphenol polyoxyethylene acrylate (OP-10-AC) in an aqueous solution containing sodium dodecyl sulfate (SDS). For the P(AM/OP-10-AC) HA-gels, the effect of crosslinking method, synthesis temperature, mineral salt (NaCl) and swelling on their tensile mechanical properties was investigated in detail. The experimental results show that crosslinking method, synthesis temperature, NaCl and swelling powerfully influenced tensile mechanical properties of the P(AM/OP-10-AC) HA-gels. In addition, according to the tensile experimental results of the P(AM/OP-10-AC) HA-gels swollen, an effective crosslinking density change model is proposed. The effect of swelling on tensile mechanical properties of the P(AM/OP-10-AC) HA-gels was discussed on the basis of the model.     

疏水改性聚丙烯酰胺对原油组分界面扩张流变性质的影响

利用悬挂滴方法研究了疏水改性聚丙烯酰胺(HMPAM)对胜利采油厂高温高盐油藏采出原油中酸性活性组分和沥青质界面膜扩张流变性质的影响,考察了不同活性组分浓度条件下的界面扩张流变行为.实验结果表明:1750mg·L-1HMPAM能够在界面上形成网络结构,界面扩张模量数值高达100mN·m-1左右;油相中的酸性组分随着老化时间增加吸附到界面上,与HMPAM分子的疏水改性部分形成聚集结构,一方面通过快速的扩散交换过程大大降低扩张模量,另一方面通过与疏水改性部分的相互作用加强HMPAM分子间的缔合强度,增强网络结构的弹性.沥青质分子尺寸相对较大,分子间存在氢键等较强的相互作用,造成沥青质界面聚集体和HMPAM形成的网络结构共同决定界面膜性质,混合膜的扩张模量较单独HMPAM体系仅略有降低.     

疏水缔合聚丙烯酰胺与阳离子双子表面活性剂的相互作用

通过表面张力法和电导率法分别考察了阳离子双子表面活性剂(12-2-12)与非离子疏水缔合聚丙烯酰胺(HMPAM)和普通聚丙烯酰胺(PAM),传统表面活性剂十二烷基三甲基溴化铵(DTAB)与HMPAM和PAM之间的相互作用。结果表明,12-2-12 HMPAM复合体系与12-2-12水溶液体系相比,在w(聚合物含量)CMC时,复合体系的电导率(κ)具有下降的趋势,且κ随着w的增大下降的趋势越明显,说明12-2-12与HMPAM之间存在相互作用。     

环境对水解的疏水改性聚丙烯酰胺的分子行为和性能的影响

以介观模拟耗散颗粒动力学(DPD)方法为主,结合部分实验,研究了环境条件包括p H、盐度以及外加表面活性剂十二烷基磺酸钠(SLS)对疏水改性水解聚丙烯酰胺(HMHPAM)的分子行为和体相及界面性质的影响.将均方根末端距量化表征的聚合物伸展程度与其体相黏度结合起来,通过调整相互作用参数分别讨论了无机盐的水化作用和静电作用对聚电解质HMHPAM分子行为的影响,确定HMHPAM的最佳应用环境.进一步研究了表面活性剂SLS对HMHPAM界面性质和体相性质的影响,提出了作用机制.     

部分水解的疏水改性聚丙烯酰胺分子构型与体相行为的关系

采用介观模拟耗散颗粒动力学(DPD)方法研究分子构型变化对聚电解质疏水改性聚丙烯酰胺(HMHPAM)在水溶液中的行为和性质的影响. 模拟中采用均方根末端距量化表征聚合物的伸展程度, 并通过计算溶液中水分子的扩散系数考察大分子形态和构型变化对体系粘度的影响, 探讨了聚合物的浓度、聚合方式、疏水改性比例及水解程度对聚合物溶液的影响机制, 预测了重复单元的种类和排列方式对聚合物构型和溶液性质的影响规律, 为HMHPAM聚合物的分子设计、合成及应用提供指导.     

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.     

Synthesis,Characterization, and Property Evaluation of a Hydrophobically Modified Polyacrylamide as Enhanced Oil Recovery Chemical

A novel hydrophobically modified polyacrylamide p(AM/NaA/OP-10-AC/BOAM) was successfully synthesized via an aqueous micellar copolymerization method from acrylamide (AM), sodium acrylate (NaA), octylphenol polyoxyethylene acrylate (OP-10-AC), and small amounts of N-benzyl-N-octylacrylamide (BOAM), with the aim of investigating the copolymer's rheological behaviors under various conditions such as polymer concentration, shearing, temperature, and salinity. The copolymer was characterized by infrared spectroscopy, scanning electron microscopy, and atomic force microscope. Scanning electron micrographs show large aggregates in solution formed by the association from the hydrophobic groups of the copolymer. Compared with partially hydrolyzed polyacryamide (HPAM), the copolymer shows a much higher thickening capability and a much greater ability to resist shearing, heat, and salts. This good property of the copolymer is attributed to its three-dimensional dimensional network structure. According to the core flooding test, it can be obtained that oil recovery is enhanced about 4.3% by the copolymer flooding contrasted to the HPAM flooding in mid-low permeability cores under conditions of 1500 mg/L of polymers and 45°C. All the results prove that the copolymer has the capability of increasing oil recovery by improving waterflood sweep efficiency in high-salinity reservoirs.     

疏水改性聚丙烯酰胺溶液的分子模拟

设计了几种不同的非离子型改性聚丙烯酰胺(HM-PAM)和阴离子型改性聚丙烯酰胺(HM-HPAM). 通过分子动力学模拟(MD)方法研究了在聚合物链上加入不同疏水改性单体对提高聚丙烯酰胺耐盐性的影响, 考察了盐浓度对疏水改性聚丙烯酰胺的回旋半径(R_g)、 特性黏数([η])、 径向分布函数(RDF)和均方位移(MSD)的影响以及聚合物的微观结构与特性黏数之间的关系. 研究结果表明, 引入疏水改性单体后, 改性聚丙烯酰胺具有较好的耐盐性. 通过研究非键作用与氢键相互作用可知, 体系中溶质和溶剂间的相互作用及氢键作用越弱, 溶液的特性黏数越大. O-H原子对的RDF结果表明, 聚合物链的伸展与聚合物链及官能团间的相互作用有关. 当RDF峰较弱时, 聚合物链与水的作用越弱, 越有利于聚合物链保持舒展状态, 溶液的特性黏数也就越大. 另外, 从聚合物链的MSD曲线发现, 聚合链的移动性与特性黏数呈负相关.     

疏水化两性离子纤维素接枝共聚物/疏水化聚丙烯酰胺复合溶液的粘性行为

疏水缔合作用;羧甲基纤维素;疏水化两性离子纤维素接枝共聚物/疏水化聚丙烯酰胺复合溶液的粘性行为     

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.     

疏水改性聚丙烯酰胺的增粘机理研究

通过与聚丙烯酰胺（PAM）对比,使用荧光光谱、紫外光谱、原子力显微镜以及流变性实验对疏水改性聚丙烯酰胺(HMPAM)的溶液行为和微观结构进行了研究.通过荧光实验I3/I1值的变化确定了HMPAM的临界缔合浓度.结合荧光、紫外及流变性实验,对HMPAM在溶液中通过疏水缔合形成疏水微区、超分子聚集体及发展到空间网络的结构变化进行了研究.用原子力显微镜证实了HMPAM溶液中网络结构的存在.对HMPAM表现出的特殊流变性从微观上找到了依据,提出了HMPAM的增粘机理.     

极低剪切速率下聚丙烯酰胺溶液在毛细管中的流变特性 Ⅱ.毛细管尺寸和盐浓度对流变性能的影响

流变性能;流变行为;极低剪切速率下聚丙烯酰胺溶液在毛细管中的流变特性 Ⅱ.毛细管尺寸和盐浓度对流变性能的影响     

疏水缔合聚丙烯酰胺在盐水中的自组装行为

使用静态光散射、动态光散射以及原子力显微镜(AFM)研究了疏水缔合聚丙烯酰胺(HAPAM)在盐水溶液中的自组装行为.研究了聚合物分子在不同盐浓度中的表观重均分子量(Mw,a),均方根回转半径(),流体力学半径(),第二维里系数(A2)的变化,并根据/的比值得出聚合物分子的聚集形态.实验结果表明:随着盐浓度的增强,聚合物溶液的分子链由舒展变得卷曲.     

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.     

Studies on Interaction of Hydrophobically Modified Polyacrylamide of a New Family with Cationic Gemini Surfactant

A new family of hydrophobically modified polyacrylamides (HMPAM) was synthesized via homogeneous copolymerization of acrylamide (AM) and anionic surface-active monomer of acrylamide-type, sodium 2-acrylamido-tetradecane sulfonate (NaAMC₁₄S) in aqueous solution. The copolymers NaAMC₁₄S/AM with microblock structures and with different chain microstructures were obtained by varying the copolymerization factors, such as the feed ratio of NaAMC₁₄S to AM and the amount of added electrolyte NaCl and initiator. The interaction between copolymers NaAMC₁₄S/AM and cationic gemini surfactants, C₁₂C₃C₁₂Br₂ and C₁₂C₆C₁₂Br₂, was studied by using viscosimetry and fluorescent probe technique. The results show this new family of HMPAM, NaAMC₁₄S/AM, has very strong interaction with gemini surfactants, and their aqueous solutions exhibit unique rheological properties.     

水溶性β-环糊精聚合物和疏水改性聚丙烯酰胺的主客体相互作用

主体环糊精聚合物(β-CDE)与客体疏水改性丙烯酰胺共聚物P(AM/POEA)构成超分子结构的高分子识别体系. 这种客体聚合物是含有少量疏水体(x_POEA＜0.01)的水溶性聚合物, NMR测定结果表明β-CDE和P(AM/POEA)的主客体相互作用是通过环糊精空腔和疏水体POEA形成包结络合物进行的. 在P(AM/POEA)聚合物水溶液中加入β-CDE, 由于主客体聚合物相互作用出现粘度的大幅上升, 增粘的幅度可通过改变聚合物浓度和疏水体含量来调节, 同时对盐浓度和温度的影响也进行了研究. 通过透射电镜直观观察的结果表明, 此类缔合聚合物体系的主客体相互作用生成实心球状多分子聚集体.     

氟碳改性聚丙烯酰胺共聚物的溶液性质

研究了氟碳链改性的聚丙烯酰胺水溶液性质及其对盐浓度的依赖性，重点考察 了氟碳疏水组分含量、盐浓度对特性粘数的影响，以及粘度随剪切速率和温度的变 化关系。结果表明聚合物溶液的粘度随盐的引入而增大，但在两种溶液中最小值对 应的共聚单体含量一致。随温度的增加，共聚物溶液粘度依次出现了最小和最大值 。所有实验结果均归于溶液中存在的疏水和氢键两种相反作用的综合结果。     

荧光探针法研究疏水改性聚丙烯酰胺溶液的疏水缔合行为

采用胶束共聚 共水解方法合成疏水改性水溶性聚合物聚(丙烯酰胺/丙烯酸钠/N 辛基丙烯酰胺)[P(AM/NaAA/C8AM)],并以芘为荧光探针,应用稳态荧光光谱法研究了它的疏水缔合行为。结果表明,随聚合物浓度、疏水单体摩尔分数、疏水侧链长和温度的增加,疏水缔合作用增强;不同疏水单体含量的P(AM/NaAA/C8AM)的临界缔合浓度为1.5~3.0 g/L;表面活性剂十二烷基硫酸钠(SDS)与P(AM/NaAA/C8AM)发生了强烈的疏水相互作用,形成混合胶束,得到SDS的临界胶束浓度(CMC)为8×10-3 mol/L;由于聚合物链上羧基的存在,使其具有良好的 pH敏感性,随 pH值的增大,P(AM/NaAA/C8AM)的疏水缔合作用呈现先减弱后恒定再增强的变化。