Rheological Properties Of Polymer Solutions Research Articles

The Effect of Surfactant on Performance of Polymer Systems Used During Enhanced Oil Recovery Operations

The combined occurrence of polymers and surfactants has been an intense area of study for many years and has long been recognized to be important in influencing the properties of mixed systems. This article presents the results of an extensive study aimed at describing the effect of surfactant on rheological properties of polymer solutions containing polyacrylamide polymers (FP and AN113) for enhanced oil recovery. Using a homogeneous micro-model and polymer/surfactant solutions with different concentrations, the floods were performed to examine the influence of a surfactant (Hostarex ABSD) on some properties of polymer solutions, such as viscosity and interfacial tension. From the experimental results, it appears that the solutions of FP polymer have obtained better performance on keeping their rheological properties even after being contacted with various concentrations of surfactant.

Study on Laboratory Evaluation of Temperature and Salt Resistance Polymer Solution

At present, China's late stage of oilfield most mining has been reached, there is high water content, and produced low levels problems. Polymer flooding enhanced oil recovery technology is important today, but Pam can't adapt oilfield tertiary oil recovery reservoir with heat resistance and salt. This article examines five kinds of rheological properties of polymer solutions under different salinity, studied under the same mineralized shear viscosity of different polymers. Experimental results show that the shear resistance capacity of 20 million ordinary polymer strong, 8 million and temperature of salt-tolerant associative polymer viscosity retention rates are highest. Less than 5,000 ppm 18 million under NaCl salinity salt resistant polymer viscosity highest salinity between 5,000 ppm NaCl to 15,000 ppm NaCl 8 million and temperature of salt-tolerant hydrophobically associating polymer solution viscosity of the highest.

Near Superhydrophobic Fibrous Scaffold for Endothelialization: Fabrication, Characterization and Cellular Activities

In this work, we have applied an electrospinning method to control wettability and further hydrophobic modification of a hydrophobic polymer mat of poly(vinylidene fluoride-co-hexafluoropropylene). A correlation between the processing parameters, rheological properties of polymer solutions, and electrospinning ability was made using the polymer's critical entanglement concentration, the boundary between the semidilute unentangled regime and the semidilute entangled regime. The wetting behavior, structural and thermal characteristics of electrospun (ES) mats were evaluated and compared with solvent cast sample using advancing and receding contact angle analyses, differential scanning calorimetry, and small-angle X-ray scattering. To demonstrate the feasibility, the best optimized ES samples were examined for their potential and ability to support bone marrow derived endothelial cell seeding efficiency, adhesion and proliferation. Our studies show that, while different processing techniques can effectively modulate physical and morphological changes such as porosity and hydrophobicity, the cellular adhesion and proliferation are highly time-dependent and controlled by chemical factors. As such, these results suggest that it is the interplay of both physical and chemical factors that determine the endothelialization of porous near superhydrophobic scaffolds. The developed electrospun samples demonstrate their feasibility for endothelialization.

In Situ Gelling Gelrite/Alginate Formulations as Vehicles for Ophthalmic Drug Delivery

The objective of this study was to develop an ion-activated in situ gelling vehicle for ophthalmic delivery of matrine. The rheological properties of polymer solutions, including Gelrite, alginate, and Gelrite/alginate solution, were evaluated. In addition, the effect of formulation characteristics on in vitro release and in vivo precorneal drug kinetic of matrine was investigated. It was found that the optimum concentration of Gelrite solution for the in situ gel-forming delivery systems was 0.3% (w/w) and that for alginate solution was 1.4% (w/w). The mixture of 0.2% Gelrite and 0.6% alginate solutions showed a significant enhancement in gel strength at physiological condition. On the basis of the in vitro results, the Gelrite formulations of matrine-containing alginate released the drug most slowly. For each tested polymer solution, the concentration of matrine in the precorneal area was higher than that of matrine-containing simulated tear fluid (STF) almost at each time point (p < 0.05). The area under the curve of formulation 16 (0.2%Gelrite/0.6%alginate) was 4.65 times greater than that of containing matrine STF. Both the in vitro release and in vivo pharmacological studies indicated that the Gelrite/alginate solution had the better ability to retain drug than the Gelrite or alginate solutions alone. The tested formulation was found to be almost non-irritant in the ocular irritancy test. The overall results of this study revealed that the Gelrite/alginate mixture can be used as an in situ gelling vehicle to enhance ocular retention.

Optimization of Alkyl Methacrylate Terpolymer Properties as Lubricating Oil Rheology Modifier

Solution terpolymerization processes of methyl methacrylate, dodecyl methacrylate, and octadecyl methacrylate using bifunctional 1,1-di(tert-butylperoxy)-3,3,5-trimethylcyclohexane or monofunctional tert-butylperoxy-2-ethylhexanoate initiator were investigated. The first set of terpolymerizations was performed in 2 M xylene solutions, isothermally at 91, 100, 105, and 115 °C. The terpolymerization kineticsconcentrations of molecular species, kinetic chain length, molar mass averages as functions of the reaction timewas modeled by the Villermaux−Blavier tendency kinetic model for radical polymerization. Complete monomer conversions and high molar masses of terpolymers were achieved in a simple batch process with bifunctional initiator. The second set of polymerization reactions was performed in 2 M mineral base oil solutions, under isothermal conditions at 115 and 120 °C, using the bifunctional initiator. By varying the monomer mixture composition and concentrations of the initiator and chain transfer agent, n-dodecyl mercaptan, the terpolymers of different composition and molar mass were obtained. The solution properties of alkyl methacrylate terpolymers as lubricating oil rheology modifierskinematic viscosity, viscosity index, shear stability, and pour pointwere established. A strong correlation between molar mass distribution of synthesized polymers and rheological properties of polymer solutions was revealed by an applied optimization procedure.

高分子流体のディップコーティングにおける膜厚に対する引き上げ速度とレオロジー特性の影響

Dip coating flows of polymer solutions were experimentally studied. A plate was coated with a solution at several withdrawal velocities. The effects of both the withdrawal velocity and rheological properties of polymer solutions on the film thickness were investigated. The film thickness was measured with a CCD laser displacement sensor. In addition, shape of the film surface in a meniscus region was observed. Five fluids were used as test fluids : two Newtonian fluids having different viscosities and three polymeric liquids which have almost the same shear viscosity and are different in elasticity. For every test fluid, the film thickness increased with increasing the withdrawal velocity. The increasing rate of the film thickness was almost constant for Newtonian fluids, while it decreased with increasing the withdrawal velocity for polymer solutions with shear-thinning viscosity. Moreover, the comparison of the results for the three polymer solutions showed that the film became thin for a polymer solution with high elasticity.

Interaction of fluorocarbon and hydrocarbon hydrophobically co-modified PAA with a nonionic surfactant: rheological properties of polymer solutions in the absence of salt

The interaction of a new hydrocarbon (HC) and fluorocarbon (FC) co-modified poly(acrylic acid), SA-1-FX14-1, with a HC nonionic surfactant, Np7.5, was investigated by rheological measurements. Its solution property was compared with HC or FC modified counterpart. It was found that the incompatibility between HC and FC groups in the micellization process was improved in the solution of SA-1-FX14-1. The terpolymer SA-1-FX14-1 associated with Np7.5 more like SA-2 rather than FX14-2. The latter interacted weakly with the HC surfactant due to the lipophobic tendency of the FC hydrophobe. The random distribution of FC and HC hydrophobes along the polyelectrolyte backbone was confirmed to be responsible for the compromised miscibility of HC and FC hydrophobes demonstrated in the system of SA-1-FX14-1 and Np7.5. Several affecting factors, such as backbone rigidity, polymer concentration, surfactant concentration, and FC modifying degree of the terpolymers, were also taken into account. In terms of hybrid surfactants, this type of hybrid polysoap is promising to serve as novel media improving the miscibility of HC and FC groups just as those hybrid small molecule surfactants have done.

FORMATION OF WHEY PROTEIN POLYMERS: EFFECTS OF A TWO‐STEP HEATING PROCESS ON RHEOLOGICAL PROPERTIES

ABSTRACTWhey protein polymers were obtained by two‐step heating of whey protein isolate (WPI) solutions with or without change of pH or protein concentration. Rheological properties of polymer solutions were studied. Viscosity of solutions heated then diluted was about 6 times higher than viscosity of equal concentration solutions heated directly. A second heating at a lower pH resulted in higher viscosity. Solutions were generally thixotropic and pseudoplastic; however, dilatant and rheopectic behavior was also observed. A 4% WPI solution could be converted to a polymer solution with a viscosity comparable to the viscosity of 1% carbohydrate hydrocolloids.

Effect of nonsolvents on properties of spinning solutions and polyethersulfone hollow fiber ultrafiltration membranes

The relationship among the presence of nonsolvent additives, the rheological behavior of spinning solutions and properties of hollow fiber membranes was studied. The additives tested were water, polyvinylpyrrolidone (PVP) and polyethylene glycol (PEG), and the base mixture was polyethersulfone/ N-methyl-2-pyrrolidone (PES–NMP). In addition the effect of combining water and PVP or PEG was also studied. Membranes were prepared using a spinneret having two concentric orifices. The internal coagulant used as well as the nonsolvent from the coagulation bath were both water at 28°C and 30°C, respectively. Rheological properties of polymer solutions were evaluated using a rheometer Haake RV 20. Changes on composition of spin-solutions were also evaluated in terms of membrane water permeability, solute rejection and membrane structure observed using scanning electron microscopy (SEM). Experimental results from this work showed that spinning solutions containing any of the three additives behave as Newtonian fluids in the range of shearing rates tested. The addition of water, PVP or PEG to the base PES–NMP solution increased its viscosity and this effect was independent of the type of additive used. A direct relation between viscosity of casting solutions and membrane thickness was found. However, rheological properties (viscosity and normal stress difference) could not be used to explain differences on membrane water flux (MWF) when using different additives at the same concentration. The addition of any of the three additives generally increased MWF. The extent of this increment seemed to be more related to changes on membrane porosity than changes on pore sizes induced by the nature and concentration of the additive used.

The effect of a solid wall on polymer chain behavior under shear flow

Molecular dynamics computer simulations are used to investigate the properties of isolated bead–rod chains with excluded volume effects under a simple shear flow. With the help of the collisional dynamics technique, the simulations are performed with both the chains end grafted to an impenetrable wall and the isolated free-space chains immersed in a solvent. The comparison of these chains shows up the effect of the wall presence. We have calculated both the microscopic properties (such as end-to-end distance of polymer chain, the deformation ratio) and the macroscopic rheological properties of the model polymer solution (such as shear viscosity, first normal stress difference). A comparative analysis of the chains dynamics shows that the response of the grafted chains to simple shear flow is much different from that of the free chains. It was demonstrated that the grafting of polymer chains also gives rise to the distinctive rheological properties of the polymer solutions. For example, the effective viscosity of the grafted chains is an order of magnitude higher then the viscosity of the free chains.

Magnet enhanced optical falling needle/sphere rheometer

A magnet enhanced falling needle/sphere rheometer equipped with a precision optical monitor and signal feedback system has been developed. The instrument which utilized the basic features of a magnetic sphere/needle rheometer could be controlled using a PC/AT(286) computer. The important advantages of this instrument over existing falling needle/sphere viscometers are as follows: (1) An extremely large viscosity range from the usual solvent viscosity (say, ∼1.0 cP) to that of polymer melts (say, 1010 cP) is available with an experimental precision of ≲1%. (2) The measurement time could be reduced by about 4 orders of magnitude (e.g., from hours to seconds) for a high viscosity fluid. (3) One single needle/sphere could cover a few orders of the viscosity range and two needles with appropriate densities could cover the whole viscosity range (1 cP≲η≲1010 cP). (4) Only a small amount (∼4 mL with the present setup) of sample is needed. (5) The sample chamber can be sealed hermetically and is suitable for toxic fluids. (6) The instrument permits measurements of the shear rate dependence of viscosity using a single needle/sphere. (7) For nonNewtonian fluids, the viscoelastic behavior could be measured. A set of viscosity standards was used to calibrate the device. Linear calibration curves of viscosity against the reciprocal of the falling needle velocity under both natural gravity field and fixed artificial magnetic fields were obtained. A flow curve was determined for a random copolymer solution using a single needle but varying the magnetic field, showing the applicability of the device for measuring the rheological properties of polymer solutions and melts.

Prediction of the non-linear rheological properties of polymer solutions by means of the Rouse-Zimm model with slippage

The non-affine deformation of macromolecules and the slippage function are discussed. In case of polymer solutions with moderate concentration the slippage function is determined by means of the Cox-Merz rule. The non-linear viscoelasticity of these solutions is described with the aid of the Rouse-Zimm model with slippage function. The theoretical predictions show good agreement with published experimental data.

Production of an Extracellular Polysaccharide by Haloferax mediterranei

The extremely halophilic archaebacterium Haloferax mediterranei produces an exocellular polymeric substance that gives the colonies a typical mucous character and is responsible for the appearance of a superficial layer in unshaken liquid medium. This exocellular polymeric substance can be obtained from the supernatant of shaken liquid cultures by cold ethanol precipitation, and yields as high as 3 mg/ml have been detected. The substance was produced under all the conditions tested and with all substrates assayed, although higher yields were obtained with sugars, particularly glucose, as carbon and energy source. The total exocellular polymeric substance produced was proportional to the total biomass. The polymer is a heteropolysaccharide containing mannose as the major component. Glucose, galactose, and another unidentified sugar were also present, as well as amino sugars, uronic acids, and a considerable amount of sulfate, which accounts for the acidic nature of the polymer. The infrared spectrum and specific assays showed the absence of acyl groups. The rheological properties of polymer solutions were studied, showing a pseudoplastic behavior and a high apparent viscosity at relatively low concentrations. Viscosity was remarkably resistant to extremes of pH, temperature, or salinity. These characteristics make this polymer interesting for enhanced oil recovery and other applications for which a very resistant thickening agent is required.

Consistently averaged hydrodynamic interaction beyond the Oseen approximation for Rouse–Zimm–Bueche dumbbells in steady shear flow

The effect of including corrections to the Oseen hydrodynamic interaction in the rheological properties of polymer solutions is investigated. The case of a dilute suspension of Rouse–Zimm–Bueche dumbbells in steady shear flow is examined within the consistent averaging approximation due to Öttinger [J. Chem. Phys. 83, 6535 (1985)]. A reduction of the values of the material functions as compared to the results obtained in the Oseen approximation is observed. The effect is most important at zero shear rate and the highest allowed value of the hydrodynamic interaction parameter. It decreases when either the shear rate is increased or the hydrodynamic interaction parameter is lowered. The ratio of the second to the first normal stress coefficients is always a small positive quantity.

Apparatus to Measure Small-Angle Light Scattering Profiles of Polymers under Shear Flow

The apparatus and the principle to measure flow small-angle light scattering (“flow-SALS”) are presented as one of the rheo-optical techniques. The flow-SALS technique presented here enables one to investigate small-angle light scattering profiles and rheological properties of polymer solutions, liquids, and mixtures, as well as polymer liquid crystals under various types of shearing, i.e., steady-state shear flow, oscillatory shear flow, and shear recovery after the cessation of steady-state flow. This technique may be useful to investigate the flow-induced formation, dissolution, and deformation of supermolecular structure with spatial correlation length of a few microns, and also their effect on rheological properties. In order to demonstrate the prospect of its use, some preliminary results on flow-SALS from the lyotropic polymer liquid crystal [20 wt% poly(γ-methyl-d-glutamate) in m-cresol] are presented.

Assembly to automatic determination of the rheological properties of polymer solutions and melts

Assembly to automatic determination of the rheological properties of polymer solutions and melts

Effect of solvent, concentration, and molecular weight on the rheological properties of polymer solutions

The zero-shear viscosity η0 of polychloroprene samples of different molecular weights over a wide range of concentration in good and poor solvents has been studied. Butanone and cyclohexane were used as θ solvents and benzene at two different temperatures (25 and 45.5°C) was used as two good solvents. The zero shear specific viscosity η in θ solvents, at the high concentration region is found to be higher compared to the values obtained in good solvents. whereas in a moderately concentrated region the values are just opposite in θ and good solvents. The high values of specific viscosity in poor solvent at the concentrated region have been explained as due to the fact that the efficiency of entanglements is much bigger in θ solvent than in good solvent. There are indications from our data that, at the crossover point concentration, the onset of entanglements begins, and from this concentration the entanglement begins to play a role in the viscosity. The superposition of viscosity data for each solvent was carried out by shifting vertically the curve along log η0 axis at constant concentration by a factor (M/M0)3.4, where M0 is the molecular weight of the reference sample. The shift factor was found to be exactly proportional to M3.4 in the range of higher concentration (beyond the crossover point concentration) and approximately to M in the lower concentration range (below the crossover point concentration). This showed that the relation η0 ∝ M3.4 was obeyed by the present data. To correlate the viscosity data obtained at good and θ solvents, the method as given by Graessley has been employed, which has taken into account the contraction of dimensions of chains with concentration in good solvents. It has been observed that, though this approximate correction for variation of chain dimensions on correlating variable, C[η], has moved the correlations for θ and good solvents closer to a common curve, complete superposition of data has not been effected by this correction. On the other hand, the correlation of the data by the method given by Dreval and co-workers showed the plot of log{η/(C[η])} vs. C[η] produced a single curve for solutions of polychloroprene samples in two different θ solvents (butanone and cyclohexane) over the entire concentration range. But in the case of good solvents (benzene at 25°C and benzene at 45.5°C) the similar plots yielded, instead of one, two curves. However, the normalization of the correlating variable, C[η], by the Martin constant KM, which is related to the flexibility of macromolecular chain and polymer-solvent interaction, reduced all data of the polymer samples to a common curve. This zero-shear viscosity master curve is valid for the entire range of concentration independent of molecular weight and the nature of solvents.

Solvent Effects on Rheological Properties of Polymer Solutions

Solvent Effects on Rheological Properties of Polymer Solutions

Influence of Rheological Properties of Polymer Solutions upon Mixing and Circulation Times

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInfluence of Rheological Properties of Polymer Solutions upon Mixing and Circulation TimesD. E. Ford and J. UlbrechtCite this: Ind. Eng. Chem. Process Des. Dev. 1976, 15, 2, 321–326Publication Date (Print):April 1, 1976Publication History Published online1 May 2002Published inissue 1 April 1976https://doi.org/10.1021/i260058a018RIGHTS & PERMISSIONSArticle Views108Altmetric-Citations9LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (646 KB) Get e-Alerts

Rheological properties of polymer solutions over a wide range of the velocity gradient

Rheological properties of polymer solutions over a wide range of the velocity gradient