聚丙烯酸水溶液及α-A12O3悬浮液的流变性研究

研究了pH、聚丙烯酸(PAA)浓度和分子量对PAA水溶液的粘度的影响,发现溶液的流变行为与溶液中PAA高分子链的离子化程度和构型密切相关,高分子链刚性程度的增加和链的伸展使溶液在pH为7～9时的粘度最大;研究了在PAA溶液中引入陶瓷粉体后悬浮液的粘度变化,发现当陶瓷粉体和PAA的量达到一定比值时悬浮液体系的粘度达到最小值,同时发现陶瓷粉体的粒径大小与这一粘度最小值和悬浮液流变特性也有关.     

高分子稀溶液中偏离Huggins方程式的五种情况

在对高分子溶液的粘度研究中发现,在稀溶液中会出现五种偏离Huggins方程式的情况。本文就这五种情况作了较为详细的介绍,尤其就高分子－高分子和高分子－溶剂分子间的相互作用对二元体系（溶剂－聚合物）和三元体系（溶剂－聚合物A－聚合物B）粘度的影响进行了深入的讨论。     

稀溶液粘度法研究聚合物之间混溶性

介绍了几种粘度法判据，并对溶液中高分子－高分子，高分子－溶剂分子间的相互作用对混合物溶液粘度的影响进行了较为深入的讨论。     

多分散高分子的稀溶液粘度-浓度依赖性

依据最近提出的关于单分散高分子的稀溶液粘度的团簇理论,对多分散高分子的稀溶液粘度的浓度依赖性进行了更新的理论分析。最后得到一个新的多分散高分子的稀溶液粘度与浓度的关系式。实验研究表明,该关系式是与实验数据相一致的。     

聚丙烯酸/聚氧化乙烯高分子复合溶液的结构与粘度

通过溶液折光指数和粘度测定,研究了聚丙烯酸（ＰＡＡ）与聚氧化乙烯（ＰＥＯ）高分子链间在复合溶液中的相互作用和ＰＡＡ／ＰＥＯ高分子氢键复合溶液的结构与粘度,研究了复合溶液粘度随溶液ｐＨ值的变化规律及不同浓度时剪切速率对复合溶液粘度和复合增粘效果的影响。结果表明：ＰＡＡ／ＰＥＯ复合溶液结构不同于ＰＡＡ和ＰＥＯ两组分聚合物溶液结构,ＰＡＡ与ＰＥＯ高分子链间的氢键相互作用形成构象更为伸展、流体力学体积列大     

1,4-丁二醇蒸馏底物解聚溶液组成的分析方法

使用液液萃取法分析溶液中的1,4-丁二醇(BDO)含量,正辛醇作为萃取剂,在30 ℃下测定了水-BDO-正辛醇三元液液相平衡数据。 使用扩展型UNIQUAC模型建立了溶液中水-BDO-正辛醇的活度系数模型,关联该体系的液液平衡数据,通过单纯型法回归获得三元体系组分之间的相互作用能参数。 实验数据以及计算结果表明,通过分析萃取相的组成,能可靠地预测萃余相的组成,进而得到原溶液中BDO的含量。 该法准确、简便,可作为该体系的常规分析方法。     

树状高分子溶液在粘度计毛细管表面的吸附现象

本文测定了树状高分子DAB(PA) n 水溶液和脂肪族超支化聚酯及其硅烷化衍生物溶液性质 .通过粘度测量 ,得到了吸附常数k ,半数吸附浓度ca,分子间缔合常数Km ,特性粘度 [η]等参数 ,解释了特性粘度的反常行为 ,重点研究了吸附现象 .发现树状高分子和超支化高分子溶液在粘度计毛细管表面形成了多层吸附 ,高分子之间的相互作用及高分子与溶剂分子间的氢键作用是形成多层吸附的重要原因     

醇/水介质对PEG大分子单体与BMA分散共聚反应的影响

通过端基反应法合成了苯乙烯单封端的聚乙二醇(St- PEG)大分子单体,使其与甲基丙烯酸丁酯(BMA)在乙醇 水混合介质中进行分散共聚,得到了聚乙二醇接枝的聚甲基丙烯酸丁酯(PBMA- g -PEG)高分子微球.PBMA- g -PEG共聚物的亲溶剂 疏溶剂平衡将影响微球的形成,反应结束时,体系随BMA浓度和介质中水含量的变化呈现出4种不同的状态,透明清液、乳液、伴有沉淀或凝胶的乳液和凝胶.用透射电子显微镜(TEM)和激光光散射(LLS)对乳液体系的粒径及其形态进行了表征,表明所得接枝高分子微球形态规整具有较好的单分散性.通过控制介质中水的含量和BMA的浓度可得粒径在4 0～5 0 0nm范围的PBMA -g -PEG微球.     

原始链模型——一种新的聚合物粘弹性的分子学说

聚合物粘弹性的分子理论,主要是以Rou-se的珠簧模型为基础发展起来的。Rouse模型未曾考虑到分子链之间存在着缠结效应,因此只适用于稀溶液,而无法推广到高分子浓溶液和熔体等稠厚体系。即使象零切粘度与分子     

NPES/AOT反胶束增溶体系及性质研究

该文以壬基酚聚氧乙烯醚硫酸钠(NPES)与琥珀酸二(2-乙基己基)酯磺酸钠(AOT)复配体系为主表面活性剂,正丁醇为助表面活性剂,以柴油为油相,研究了反胶束增溶体系的粘度和电导率等物理化学性质;利用脉冲核磁共振图谱中水的T2弛豫时间分布曲线,研究了反胶束溶液中水的结合状态和分布,采用正规溶液理论计算了NPES/AOT的相互作用参数β值(-7.78),研究结果表明二者存在较强的协同效应,从理论上解释了二者在反胶束溶液中的最佳比例和协同增效作用.     

Thermodynamics of aqueous solutions of polyvinylpyrrolidone

Densities, viscosities and water activities of aqueous solutions of polyvinylpyrrolidone have been determined experimentally at T=(298.15, 308.15, 318.15 and 328.15) K. From the density data, the apparent specific volume of polymer and the partial specific volume of polymer and water have been calculated. From the viscosity data, the viscosity and number average molecular weight of polymer have been calculated. From the water activity data, the vapour pressure of solutions has been calculated. Densities, viscosities and water activities have been correlated successfully with an general equation which takes into account the influence of the polymer concentration and the temperature.     

A New Method for Calculating the Relative Permeability Curve of Polymer Flooding Based on the Viscosity Variation Law of Polymer Transporting in Porous Media

Relative permeability of polymer flooding plays a very important role in oil field development. This paper aimed to measure and calculate the relative permeability curves of polymer flooding more accurately. First, viscosity variation law of polymer in porous media was studied. Rock particles of different diameters and cementing agent were used to make artificial cores and hydrophobically associating polymer solutions were prepared for experiments. Polymer solutions were injected into the cores filled with crude oil and irreducible water. In the process of polymer flooding, produced fluid was collected at different water saturations and locations of the core. Polymer solutions were separated and their viscosities were measured. With the experimental data, the viscosity variation rule of polymer transporting in porous media was explored. The result indicates that the viscosity retention rate of polymer solutions transporting in porous media has power function relationship with the water saturation and the dimensionless distance from the core inlet. Finally, the relative permeability curves of polymer flooding were measured by unsteady state method and the viscosity variation rule was applied to the calculation of the relative permeability curves.     

Solution properties of dendronized poly(hydroxy ethyl methacrylate) polymers

Four generations of dendronized polymers with a methacrylate backbone and hydroxy‐functionalized aliphatic polyester dendrons based on 2,2‐bis(methylol)propionic acid were studied in solutions by rheological measurements, dynamic light scattering, turbidimetry, and ¹H NMR self‐diffusion measurements to reveal the effect of increasing hydrophilicity and molecular size on their solution properties. The studied polymers were interesting new amphiphiles with a hydrophobic main chain and a hydrophilic shell. Evidence of aggregation upon the heating of the first‐generation polymer in an aqueous solution was obtained by dynamic light scattering and turbidimetry, reflecting the effect of the hydrophobic polymer backbone, whereas the higher generation polymers did not show aggregation upon heating. Although the dimensions of the polymers were observed to increase with increasing generation, all the polymers exhibited low viscosities and Newtonian flow behavior in both aqueous and dimethyl sulfoxide solutions. The relative viscosities of the polymers in water and dimethyl sulfoxide showed that the conformation of the polymers was somewhat more open in dimethyl sulfoxide, and this led to higher viscosities than those in water, in agreement with the ¹H NMR diffusion measurements, by which the dimensions were found to be larger for the polymers dissolved in dimethyl sulfoxide. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3674–3683, 2006     

Introduction of a Reliable Method for Determination ofIntrinsic Viscosity for Any Polymer with High Precision简

Intrinsic viscosities for a given polyelectrolyte in salt free and low-salt solvents reported in literatures are normally not comparable, because of inadequate valuation procedures. This article describes a theoretically justified reliable method, which is free of any model assumptions： The so called Wolf plot （logarithm of the relative viscosity as a function of polymer concentration） enables the unequivocal determination of intrinsic viscosities for all kinds of macromolecules, irrespective of whether they are chain molecules of different architecture or globular polymers, whether they are charged or uncharged. The validation of the method was examined by evaluation of the viscosities of a polyelectrolyte, some uncharged polymers of different architectures, uncharged polymer blends, and some literature data.     

Concentrated solution viscosities of polymeric associates

Reasons have been advanced why in some cases concentrated-polymer-solution viscosity measurements are not a suitable method for determining the degree of association of groups attached to polymer chains. These are based on the finite lifetimes of associates compared with the finite lifetimes of the entanglements, which are the major contributors to concentrated-polymer-solution viscosities. The validity of these reasons has been checked in a system where the degree of association of polymer chains can be measured spectroscopically. It was found that the viscosity of these solutions was considerably less than that calculated by the concentrated-solution viscosity equation for solutions of polymers of the average molecular weight expected from the spectroscopically found degree of association.     

EFFECT OF ADSORPTION ON THE VISCOSITY OF DILUTE POLYMER SOLUTION*

Careful measurements of the dilute solution viscosities of polyethylene glycol and polyvinylalcohol in water were carried out. The reduced viscosities of both polymer solutions plot upward curves atextremely dilute concentration levels similar to the phenomena observed for many polymer solutions in theearly 1950's. Upon observation of the changes of the flow times of pure water in and the wall surfacewettability of the viscometer after measuring solution viscosity, a view was formed that the observed viscosityabnormality at extremely dilute concentration regions is solely due to the effect of adsorption of polymerchains onto the wall surface of viscometer. A theory of adsorption effect based on the Langmuir isothermswas proposed and a mathematical analysis for data treatment was performed. The theory could adequatelydescribe the existing viscosity data. It seems necessary to correct the viscosity result of dilute polymersolutions measured by glass capillary viscometer by taking into account the effect of adsorption in all cases.     

An Eluent Pressure Detector for Aqueous Size Exclusion Chrohatography

Abstract

An on-line viscometer which measures the eluent pressure drop across a long capillary was developed for use in aqueous size exclusion chromatography (SEC). Intrinsic viscosities of several polymer standards were calculated from data collected by the viscometer. These viscosities agree well with the measurements made with a Ubbelohde four-bulb shear dilution viscometer. The on-line viscometer becomes more sensitive as polymer hydro-dynamic volume increases. Therefore, it can be more effective than a refractive index detector for SEC analysis of high molecular weight, water soluble polymers.     

Universal calibration in GPC: A new approach for the calculation of molecular weights

A method has been developed for determining simultaneously the molecular weight of a broad-distribution polymer and the Mark-Houwink coefficients for that polymer type by using only GPC and intrinsic viscosity data. Standardized samples of poly(vinyl chloride), polystyrene, polybutadiene, and an experimental cycloolefin polymer were analyzed by this method. Shear-corrected intrinsic viscosities were used in all cases because of the high molecular weights involved. Molecular weight data for all samples were found to be in good agreement with molecular weight data obtained by membrane osmometry and from other GPC techniques. The proposed technique provides a means for calculating the molecular weight of a single polymer sample through universal calibration of GPC without knowledge of the Mark-Houwink coefficients for that polymer type.     

DIESEL FUEL-AQUEOUS ETHANOL MICROEMULSIONS

Two-phase mixtures of diesel fuel and aqueous ethanol were microemulsified and data were collected on rheological properties, densities, water tolerance and critical solution temperatures. For the detergentless system of diesel fuel, aqueous ethanol and butanol it was found that the relative viscosity varied directly with the volume percent of the dispersed water phase and approximates Einstein's formula. With ionic systems it was found that relative viscosities varied with increasing volume percent of dispersed water by values greater than those predicted by Brinkman and Roscoe for suspensions of diverse particle size. Water tolerances for ionic systems were greater than those observed with 1-butanol. The nature of the surfactant and its concentration determine to a large degree the microemulsion's physical properties.