中低渗透高温高盐油藏驱油共聚物P(AM/AMPSNa/AANa)的合成及性能

在中低渗透高温高盐油藏聚合物驱技术中, 超高相对分子质量聚丙烯酰胺(HPAM)存在不易注入、剪切降粘显著和耐温抗盐性能差等问题。 本文以丙烯酰胺(AM)和2-丙烯酰胺基-2-甲基丙磺酸(AMPS)为单体, 采用过硫酸胺(NH₄)₂S₂O₈和甲基丙烯酸N, N-二甲氨基乙酯(DMAEMA)作为支化结构复合引发体系, 通过共聚后水解工艺, 合成含支化结构耐温抗盐驱油共聚物P(AM/AMPSNa/AANa)。 研究了引发温度、链转移剂用量、引发剂用量对共聚物特性黏数的影响, 并通过红外光谱(IR)和¹³C NMR表征了产物结构。 筛选特性黏数1915 mL/g左右的共聚物, 进行性能评价。 实验结果表明, 共聚物具有优异的耐温抗盐性能、抗剪切性能、抗老化性、注入性和驱油性能, 可应用在中低渗透高温高盐油藏三次采油中。     

Interfacial friction and adhesion of polymer brushes

A bead-probe lateral force microscopy (LFM) technique is used to characterize the interfacial friction and adhesion properties of polymer brushes. Our measurements attempt to relate the physical structure and chemical characteristics of the brush to their properties as thin-film, tethered lubricants. Brushes are synthesized at several chain lengths and surface coverages from polymer chains of polydimethylsiloxane (PDMS), polystyrene (PS), and a poly(propylene glycol)-poly(ethylene glycol) block copolymer (PPG/PEG). At high surface coverage, PDMS brushes manifest friction coefficients (COFs) that are among the lowest recorded for a dry lubricant film (μ ≈ 0.0024) and close to 1 order of magnitude lower than the COF of a bare silicon surface. Brushes synthesized from higher molar mass chains exhibit higher friction forces than those created using lower molar mass polymers. Increased grafting density of chains in the brush significantly reduces the COF by creating a uniform surface of stretched chains with a decreased surface viscosity. Brushes with lower surface tension and interfacial shear stresses manifest the lowest COF. In particular, PDMS chains exhibit COFs lower than PS by a factor of 3.7 and lower than PPG/PEG by a factor of 4.7. A scaling analysis conducted on the surface coverage (σ) in relation to the fraction (ε) of the friction force developing from adhesion predicts a universal relation ε ~ σ(4/3), which is supported by our experimental data.     

一种疏水缔合水溶性聚合物的合成及其溶液性能

粘度;抗盐性;表面活性剂;一种疏水缔合水溶性聚合物的合成及其溶液性能     

耐温抗盐AM-AA-SAS-St四元聚合物驱油剂的合成及性能评价

本文采用乳液聚合方法,以丙烯酰胺、丙烯酸、烯丙基磺酸钠和苯乙烯作为单体,过硫酸铵-亚硫酸氢钠为氧化还原引发剂,合成了一种新型耐温耐盐的四元共聚物,并对其结构进行了红外、核磁共振及元素分析表征。考察了温度、单体浓度、体系pH和引发剂浓度等条件对聚合物表观粘度的影响,并确定了最佳的合成条件,同时对其抗老化、耐温及耐盐性能进行了评价。结果表明,该四元共聚物具有良好的耐温抗盐性能;另外,聚合物的岩心流动实验表明该四元共聚物具有较好的波及效率及出色的驱油效果,可以用作提高采收率的聚合物驱油剂。     

A NOVEL INTERPRETATION OF CONCENTRATION DEPENDENCE OF VISCOSITY OF DILUTE POLYMER SOLUTION*

The concentration dependence of the reduced viscosity of dilute polymer solution is interpreted in the light of anew concept of the self-association of polymer chains in dilute solution. The apparent self-association constant is defined asthe molar association constant divided by the molar mass of individual polymer chain and is numerically interconvertiblewith the Huggins coefficient. The molar association constant is directly proportional to the effective hydrodynamic volume ofthe polymer chain in solution and is irrespective of the chain architecture. The effective hydrodynamic volume accounts forthe non-spherical conformation of a short polymer chain in solution and is a product of a shape factor and hydrodynamicvolume. The observed enhancement of Huggins coefficient for short chain and branched polymer is satisfactorily interpretedby the concept of self-association. The concept of self-association allows us to predict the existence of a boundaryconcentration C_s (dynamic contact concentration) which divides the dilute polymer solution into two regions.     

A correlation of the limiting viscosity number, molecular mass and composition of statistical linear styrene-methyl methacrylate copolymers

Statistical copolymers of styrene and methyl methacrylate of different compositions were synthesized by the radical solution copolymerization in a batch isothermal reactor. Copolymers were characterized by the size exclusion chromatography (SEC), elemental analysis and dilute solution viscometry. Experimental limiting viscosity numbers were described by the Mark-Houwink-Kuhn-Sakurada correlation as the function of the molar mass and by the Mendelson correlation as the function of both the molar mass and copolymer composition. A new correlation of the intrinsic viscosity number, molar mass and composition was developed, based on semiempirical considerations. The correlation takes into consideration all the effects which affect the dimensions of random linear copolymer coils in solvents. The new equation was found to be superior to the Mendelson’s one in correlating the experimentally obtained intrinsic viscosities.     

Polymer complexes stabilized through hydrogen bonds. Influence of “structure defects” on complex formation: Viscometry and fluorescence polarization measurements

The structure of polymer complexes stabilized through hydrogen bonds can be much influenced by the presence of nonactive groups (structure defects) on the polymer chains. In this paper two very simple homopolymer/copolymer systems are studied: the homopolymer is a polybase, polyoxyethylene (PEO) or polyvinylpyrrolidone (PVP), and the copolymer a partially neutralized poly(acrylic acid) (PAA). The acrylate groups on PAA chain behave as structure defects. Viscometry provides information about macroscopic structure of polymer complex in solution while fluorescence polarization is especially adapted for the study of the local mobility of polymer chains. Two kinds of structure are found: the first one is compact and implies a low viscosity of the mixture, eventually precipitation occurs, the second one is a highly branched structure, close to a gel, which leads to a very high increase in viscosity. For instance, the viscosity of the mixture may be several hundred times higher than the sum of the viscosities of the two individual polymer solutions. Such mixtures are especially adapted to be used like thickening agents.     

Preparation and Solution Characteristics of a Novel Hydrophobically Associating Terpolymer for Enhanced Oil Recovery

Hydrophobically associating terpolymers were prepared by the micellar copolymerization technique using acrylamide (AM), 2-trimethylammonium ethyl methacrylate chloride (TMAEMC) as a cationic monomer, and small amounts of 5,5,5-triphenyl-1-pentene (TP<0.5 mol-%) as the hydrophobe. The structure of the copolymer was characterized by FT-IR and ¹H-NMR. The aqueous solution properties of the terpolymers were also investigated as functions of polymer concentration, salinity, temperature and shear rate. The results showed that the thickening behavior of these terpolymers are remarkably dependent on both the number and length of hydrophobic segments in the copolymer chains. As expected, the terpolymers exhibited improved viscosity enhancement properties as the concentration exceeded 0.25 g⋅dL⁻¹, due to intermolecular hydrophobic association. Additional evidence for hydrophobic microdomains was obtained utilizing pyrene-probe fluorescence. Additionally, the ternary copolymers showed favorable salt tolerance, temperature resistance, and recoverable viscosity after shearing.     

Studies on rheological behaviour of hydrophobically associating polyacrylamide with strong positive salinity sensitivity

Hydrophobically associating polymer has been obtained by homogeneous copolymerization of acrylamide and an anionic surface-active monomers (surfmer) of acrylamide-type, sodium 2-acrylamido-tetradecane sulfonate (NaAMC₁₄S) in aqueous solution, and under different concentration conditions of NaAMC₁₄S above its critical micellar concentration (CMC) and below CMC, two structure types of copolymers P (AM–NaAMC₁₄S) were prepared in which main chains NaAMC₁₄S were distributed in microblock and in random manner, respectively. The hydrophobically associating property and rheological behaviour of the copolymers were studied with viscosimetry and then by fluorescence probe method. It was found that the apparent viscosity of the aqueous solution of the copolymers with microblock structures exhibits strong positive salinity sensitivity, whereas the positive salinity sensitivity of the apparent viscosity of the aqueous solution of the copolymers with random structure only appears generally and the apparent viscosity was diminutively increased because of salinity-promoting hydrophobic association. For those copolymers with microblock structures, the apparent viscosities of their brine solution are much higher than that of their pure water solution. In CaCl₂ solution (2 wt%), as the copolymer concentration attains 0.2 wt%, the apparent viscosity enhances dramatically with the increase in concentrations, and as the copolymer concentration was 0.3 wt%, the apparent viscosity can enhance by almost two orders of magnitude (from 32 to 1,000 mPa·s) as compared with in pure water solution. Thus, for copolymer P (AM–NaAMC₁₄S) with microblock structure, the peculiar positive salinity sensitivity, i.e. salinity thickening, is displayed distinctly. The unusual positive salinity sensitivity of copolymers P (AM–NaAMC₁₄S) with microblock structure was also revealed by fluorescence probe method, and the value I ₁/I ₃ of pyrene in the brine solution of the copolymers was smaller than that in pure water solution of the copolymers. This unique salinity sensitivity is a reflection of the unusual microstructure of the copolymers. The experiment results are interpreted in terms of the effects of the surfmer distribution manner in the copolymer main chain and bonding way of the ionic surfmer to the copolymer main chain on the forming intermolecular association.     

一种水溶性荧光示踪共聚物(AM-AMCO)的合成及性能研究

本文采用乳液聚合方法,以丙烯酰胺和7-烯丙基氧-4-甲基香豆素作为单体,过硫酸铵-亚硫酸氢钠为氧化还原引发剂,合成了一种水溶性荧光示踪二元聚合物。考察了温度、单体浓度、体系pH和引发剂浓度等条件对聚合物表观粘度的影响,确定了最佳合成条件,并对聚合物结构进行了红外表征。紫外、荧光及耐温抗盐性研究结果表明了该二元聚合物可作为潜在的油田示踪剂,并具有良好的耐温抗盐性能。     

甲基丙烯酸3-磺酸丙酯钾盐苯乙烯共聚物负离子与N,N,N-三甲基十六烷基溴化铵相互作用研究

聚电解质与表面活性剂相互作用研究已有很多报道[1～4],由于在很多方面与生物膜中脂质体-蛋白质间相互作用相似,从而近年来备受关注[5～6].作为带电荷的水溶性高分子,聚电解质与带相反电荷的表面活性剂分子可以形成规整性非常好的聚电解质表面活性剂复合物.Ａｎｔｏｎｉｅｔｔｔｉ等报道聚丙烯酸与十六烷基三甲基溴化铵(ＣＴＡＢ)形成规整的介规相(Ｍｅｓｏｐｈａｓｅ)聚电解质表面活性剂复合物结构[7],漆宗能等在同一体系既观察到了热致液晶也观察到了溶致液晶[8].在研究甲基丙烯酸3磺酸丙酯钾盐(ＳＰＭＳ)的苯乙烯(Ｓｔ)共聚物(Ｐ(ＳＰＭ…     

Capillary electrochromatography with polymeric continuous beds synthesized via free radical polymerization in aqueous media using derivatized cyclodextrins as solubilizing agents

A novel synthetic route to amphiphilic acrylamide-based monolithic stationary phases for capillary electrochromatography (CEC) employing water-soluble cyclodextrins as solubilizing agents was explored. N,N'-Octamethylenebisacryamide and N,N'-dodecamethylenebisacryamide were synthesized and their solubilization in aqueous solution with derivatized and underivatized cyclodextrins of different cavity size was studied. Amphiphilic stationary phases were synthesized by free radical copolymerization of the bisacrylamide-cyclodextrin host-guest complexes with hydrophilic monomers and an additional hydrophilic cross-linker in aqueous solution. Complex formation in solution and removal of the complexed cyclodextrin from the polymer during synthesis was studied with 1H-NMR and solid state 13C-NMR spectroscopy and cyclodextrin-modified micellar electrokinetic chromatography. The impact of the incorporated alkylene groups in the acrylamide-based macroporous polymer on retention was studied with neutral solutes by CEC in the normal-phase elution mode and in the reversed-phase elution mode. Batch-to-batch reproducibility of the synthesis procedure and day-to-day repeatability of the separations achieved were investigated. With these capillaries, a sufficiently high electroosmotic flow velocity, a high reproducibility and repeatability of separation parameters and high plate numbers (up to 200,000 m(-1) were obtained.     

丙烯酰胺-苯乙烯双亲嵌段共聚物水溶液的粘度性能

通过改变丙烯酰胺 (AM)与苯乙烯 (St)两单体的投料比 ,在微乳液介质中制备了分子组成系列变化的丙烯酰胺 苯乙烯双亲嵌段共聚物 (PAM b PSt) ,使用旋转粘度计测定了共聚物水溶液的表观粘度 ,详细考察了共聚物浓度、共聚物链结构、剪切速率、盐度及温度等因素对共聚物水溶液表观粘度的影响规律 .研究结果表明 ,由于PAM b PSt分子链中的PSt疏水嵌段链段之间具有强的疏水缔合作用 ,导致其具有独特的流变性能 .当共聚物水溶液的浓度高于某一临界值后 ,疏水缔合作用以分子间的缔合为主 ,大分子链之间会形成动态物理交联网络 ,增大了流体力学体积 ,使PAM b PSt水溶液可产生良好的增稠性能 ;疏水缔合作用是一吸热过程 ,升高温度有利于分子间的缔合 ,因此PAM b PSt水溶液具有良好的耐温性 ;聚合物水溶液中盐类物质的存在 ,会增强溶剂的极性 ,有利于分子间的缔合 ,使PAM b PSt水溶液具有良好的耐盐性 .     

聚(丙烯酰胺-丙烯酸)/聚(丙烯酰胺-二甲基二烯丙基氯化铵)分子复合型聚合物驱油剂的增粘作用

通过Brookfield粘度测定及室内岩心驱油试验评定,研究了聚(丙烯酰胺－丙烯酸)/聚(丙烯酸胺－二甲基二烯丙基氯化铵)[P(AM－AA)/P(AM－DMDAAC)]分子复合型聚合物驱油剂的增粘、抗温、抗盐性及其驱油效果.结果表明：聚合物组成一定时,其复合比影响溶液复合增粘效果;复合型聚合物溶液的抗盐性明显优于P(AM－AA)溶液的抗盐性;多价金属离子的加入是提高溶液抗盐性的有效途径.该驱油剂的最终采收率达61.91％.     

自组装效应对AM/NVP共聚的影响

研究了丙烯酰胺(AM)与N-乙烯基吡咯烷酮(NVP)在水/四氢呋喃(THF)溶液中的自由基共聚。发现,当水溶液中含THF,AM的聚合速率下降,NVP的聚合速率提高。黏度测定发现,在THF质量分数为28%,AM/NVP物质的量比为5∶1的水/THF体系中,共聚物的黏度达到最大值,与该体系中NVP的聚合速率达到最大值相一致。溶液中加入氯化钠,AM的聚合速率提高,但随THF的含量增加而降低。加入尿素,在含水率达到较大值,NVP聚合速率最大。用透射电子显微镜(TEM)和核磁共振谱(NMR)对聚合物结构进行了表征。在水/THF中,共聚物链自组装形成"核―壳"状微聚体。NVP上的五元环聚集成"核"状,共聚物链的酰胺基团尽量舒展,形成"壳"状。溶剂的组成变化伴随"核―壳"状微聚体半径的改变,影响AM和NVP的聚合速率。     

Size-based separation of synthetic polyelectrolytes in entangled polymer solution capillary electrophoresis: the effect of binary mixtures of separating polymers differing in molecular mass

The influence on the electrophoretic behavior of polystyrenesulfonates of the percentage of high-molecular-mass chains in an entangled poly(ethylene oxide) solution having a bimodal molecular mass distribution has been investigated and compared with the results obtained for similar solutions of unimodal molecular mass distribution. The comparisons between the different separating polymer solutions were made at a constant total mass concentration, so as to keep constant the mesh size and to highlight the sole effect of the network dynamics. The use of binary polymer mixtures of two different molecular masses but of same nature can be a convenient alternative to modulate the dynamics of the network and the viscosity of the separating medium. A 20-30% content of high-molecular-mass chains in an entangled poly(ethylene oxide) solution having a binary molecular mass distribution appears to be a good compromise for a moderate viscosity and a good separation selectivity in comparison with a solution containing only chains of high molecular mass at the same concentration.     

Synthesis and aqueous solution properties of a well-defined thermo-responsive schizophrenic diblock copolymer

We report only the second example of a thermo-responsive 'schizophrenic' diblock copolymer surfactant: unlike the original (meth)acrylamide-based example reported by Laschewsky and co-workers (J. Am. Chem. Soc., 2002, 124, 3787), this new methacrylate-based diblock copolymer is near-monodisperse, readily synthesized in high yield and exhibits a broad temperature range between the two micelle transitions.     

Formation of antifouling functional coating from deposition of a zwitterionic-co-nonionic polymer via “grafting to” approach

We develop a new process for the preparation of synergistic antifouling functional coatings on gold surfaces via a “grafting to” approach. The strategy includes a synthetic step of polymer brushes that consist of poly (ethylene glycol) (PEG) and zwitterionic side chains via a typical reversible-addition fragmentation chain transfer (RAFT) polymerization process, and a subsequent deposition of the polymer brushes onto a gold substrate. The presence of PEG and zwitterion chains on these polymer brush-coated gold surfaces has been proved to have a synergistic effect on the final antifouling property of the coating. PEG chains lower the electrostatic repulsion between zwitterionic polymer chains and increase their graft density on gold surfaces, while zwitterionic polymer effectively improves the antifouling property that is offered by PEG chains alone. Protein adsorption and cell attachment assays tests are conducted to confirm that this copolymer layer on gold surface has a pronounced resistance against proteins such as Bovine serum albumin and Lysozyme. Importantly, the antifouling property can be systematically adjusted by varying the molar ratio of PEG to zwitterionic chains in the final coating copolymer.     

P(AM-NVP-DMDA)疏水缔合水溶性共聚物的研究

采用自由基水溶液共聚合法制备了Ｐ（ＡＭ－ＮＶＰ－ＤＭＤＡ）疏水缔合水溶性共聚物。对共聚物的溶液性能进行了研究,包括盐效应、粘温关系、流变性能、热稳定性、与碱、表面活性剂的相互作用、稀溶液性质等。共聚物分子中由于引入了较多的疏水基团而具有较强的疏水缔合效应,在聚合物浓度较低时具有较高粘度。ＮＶＰ结构单元的引入可适当提高共聚物溶液的热稳定性。对共聚物溶液的电镜分析结果表明,在其水溶液中存在着微相分离结构,它对共聚物溶液的增粘起着重要作用。     

Solution Behavior of an Alternating Anionic-Zwitterionic Copolymer

In this paper the dilute solution properties of a novel alternating anionic-zwitterionic copolymer are discussed. The copolymer, synthesized through a spontaneous route, exhibited contrasting poly-ampholytic and polyelectrolytic behavior in aqueous salt solution. Intrinsic viscosity and light-scattering studies as a function of simple electrolyte added are presented to illustrate the unique solution characteristics. An explanation of the effect of salt on the molecular dimensions of the polymer is offered.