Bingham Yield Value Research Articles

Flow ability Enhancement of Waxy Crude Oil Using New Spirocompound based on Aromatic Amine System

This work was focused on an investigating of flow ability of waxy crude oil by nontraditional polymer compound. For this propose, a spirocompound consisted of benzaldehyede and triethanolamine 6,6'-(((phenylmethylene) bis (oxy)) bis (ethane-2,1-diyl)) bis (2-phenyl-1,3,6-dioxazocane) [SB] was synthesized using zeolite as a catalyst. The chemical structure of the [SB] was investigated by FT-IR, TGA,GPC, H1NMR and Mass spectroscopy. The rheological behavior and pour point depression of waxy crude oil were also studied different dosages and temperatures. The results showed a significant reduction in the viscosity at different temperatures and dosages. Moreover, it was noticed a decrease in the apparent viscosity and the Bingham yield value for [SB] 437.7, 367.1, and 307.1 cp and 0.48, 0.39 and 0.31 Pa at 15 oC, 20 oC and 30 oC and concentration 1000 ppm respectively. While the blank experiment displayed 743.1, 694.2 and 607.2 cp and 0.74, 0.69 and 0.60 Pa at the same temperatures. This study included blends between [SB] and the acrylate based polymers abbreviated as (B1, B2, B3 and B4). Furthermore, the rheological behavior and the pour point for these blends exhibited that the blend [B4] shew more reduction in the apparent viscosity than [SB] being alone. The apparent viscosity and yield value for [B4] were; 267.8, 249.2 and 212.7 cp and 0.22, 0.11 and 0.09 Pa at 15oC, 20oC and 30oC and concentration 1000 ppm respectively. The pour point depression (Δpp) of [SB] was 9oC while the blank pour point was 27 o C and the B4 was achieved the maximum depression in the pour point (Δpp= 18 o C) at a concentration of 1000 ppm. This result means that the addition of [SB] to [B4] showed the most positive synergistic effect.

Preparation and investigation of emulsion explosive matrix based on gas oil for mining process

Six emulsifiers derived from polyisobutylene succinic anhydride (PIBSA) were obtained (E1 to E6) with different Hydrophile-Lipophile Balance (HLBs). Interfacial tension measurements were evaluated for the prepared emulsifiers. The emulsifier (E3 and E6) exhibited the lowest interfacial tension value. Two highly concentrated emulsions (HCE) were prepared. And its stability was scanned form point of HLB, rheology and aging. It was found that, the maximum stability was exhibited by E3 and E6 HLBs, Further the rheological measurement was investigated for (E3 and E6). From the rheological measurement, it was found that, the Bingham yield values (σB) were 1244.4 and 1917.7Pa for the E3, E6 and the Herschel Bulkley values (σH) were 432.66 and 699.66Pa for the E3, E6 respectively. Aging indications the changes in the rheological properties and the aged emulsions fits Cross model. Stability of these emulsions was determined.

Synergistic effect between surfactants and polyacrylates-maleicanhydride copolymers to improve the flow properties of waxy crude oil

ABSTRACTFour copolymers were prepared by copolymerization of octadecyl acrylate with maleic anhydride abbreviated as [ODM], the resulted copolymer was reacted with octadecylalcohol [ODMSA], hexadecylamine [ODMCA], benzyl alcohol [ODMBA] and aniline [ODMAn]. Three oil-soluble surfactants were also prepared by esterification of mono, di and tri ethanolamine with oleic acid, abbreviated as [MEAO, DEAO and TEAO]. These compounds were purified and characterized by FTIR, 1H-NMR and GPC. The prepared copolymers were evaluated individually and mixed with the oil-soluble surfactants and evaluated as flow improvers and pour point depressants for waxy crude oil. It was found that, the polymer with aromatic side chain [ODMBA] exhibited the maximum pour point depression ΔPP = 24°C at concentration 1000 ppm, while the minimum pour point depression was obtained by [ODMCA] which pronounced ΔPP = 15°C at 1000 ppm. Furthermore, the blend [B4] between [ODMBA] and oil-soluble surfactant [TEAO] achieved extra depression of pour point (ΔPP = 30°C). The rheological properties of the treated and untreated crude oil with the polymeric additives were also investigated and it was found that Bingham yield value (τB) was decreased from 1.63 Pa at 32°C to 0.3 Pa at the same temperature and 500 ppm concentration of [ODMBA].

Synthesis of phthalimide and succinimide copolymers and their evaluation as flow improvers for an Egyptian waxy crude oil

This paper describes the synthesis, characterization and performance evaluation of three phthalimide and three succinimide copolymers of vinyl acetate, styrene and methyl methacrylate as flow improvers for waxy crude oil. The prepared copolymers were named as; (VA)Ph; (St)Ph; (MMA)Ph; (VA)S; (St)S and (MMA)S. These copolymers were characterized by FTIR and 1H NMR spectroscopy. The molecular weights and nitrogen content of these copolymers were determined by using the GPC technique and the Kjeldhal method, respectively. The rheological properties of crude oil (with and without additives) were studied. From the obtained results, it was remarked that the styrene phthalimide copolymer (St)Ph exhibited the maximum pour point depression (ΔPP500ppm=30). The results of the rheological flow properties showed that the Bingham yield values (τβ) for crude oil without additives at 15, 27 and 39°C were 0.286, 0.131 and 0.075Pa respectively, whereas the τβ for the treated crude oil by the styrene phthalimide (St)Ph copolymer were 0.021, 0.0164 and 0.0081Pa at 500ppm at the same temperatures.

Preparation the Esters of Oleic Acid-Maleic Anhydride Copolymer and Their Evaluation as Flow Improvers for Waxy Crude Oil

Five comb-like copolymers derived from oleic acid-maleic anhydride were prepared and then esterified by long-chain fatty alcohol (POMA Cn), where n = 18, 20, 22. These polymers were characterized by FTIR and 1H NMR analysis. The molecular weight was determined by using gel permeation chromatography (GPC). The prepared copolymers were investigated as flow improvers and pour point depressants (PPD) for crude oil. From the evaluation, it was found that, the maximum depression of PP was obtained by (POMA2 C22) with long-chain alcohol (C22–OH) from 27°C to 15°C (ΔPP3000ppm = −12°C). On the other side, it was remarked that no depression obtained by (POMA2 C18), which esterified by alcohol (C18–OH) at the same condition. The depression of pour point effectiveness was discussed on the light of polymers structure, molecular weights, and their concentrations. By analysis the results of the rheological flow properties, it was found that the POMA2 C22 enhanced the Bingham yield values (τβ). The τβ for crude oil without additives against 15, 27, and 39°C were 0.286, 0.131, and 0.075 Pa respectively, whereas the τβ for the treated crude oil with POMA2 C22 were 0.027, 0.022 and 0.010 Pa at 3000 ppm at the same temperatures. By using the photomicrography analysis, it was found that, the wax morphology was greatly modified to fine dispersed crystals of compact size.

Effect of taurate surfactant and polyvinylpyrrolidone on kaolinite suspension

The adsorption of sodium lauroyl taurate (SLT) onto polyvinylpyrrolidone (PVP) in aqueous solution had the first transition point ( T 1) at 5 mM and the second transition point ( T 2) increased with increasing the concentration of PVP (9 mM for 0.1% PVP, 11 mM for 0.5% PVP and 12 mM for 1.0% PVP). The relative viscosity of the solution (SLT and PVP in water) increased with increasing SLT but reduced viscosity decreased with SLT. The high concentration of a kaolinite suspension (20 g/30 ml-medium) was greatly affected by the presence of SLT and PVP with respect to its flow property. Suspension flow curves at low shear rate (1–15 s −1 by cone-and-plate method) showed a non-Newtonian behavior. Plastic and relative viscosities, along with the Bingham yield, were derived from these flow curves. Characteristic dispersion and fluidity were explained in terms of the Bingham yield value, effective volume fraction and void fraction of the dispersion. The presence of PVP affected the suspension properties as a flocculant at concentration <0.1% and as a dispersant at higher concentrations. The SLT surfactant plays an important role in the Bingham yield value, the suspension viscosity and the effective volume fraction at concentrations above 5 mM. The combination of PVP (≤0.1%) and SLT improves the dispersion ability of kaolinite, but it boosts flocculation with a maximum at 5 mM SLT with PVP greater than 0.1%.

Styrene-Maleic Anhydride Copolymer Esters as Flow Improvers of Waxy Crude Oil

Four comb-like copolymers derived from styrene-maleic anhydride copolymer were prepared and characterized by FTIR, 1H-NMR and elemental analysis. The molecular weight was determined using GPC and their intrinsic viscosity was measured. The prepared polymers were investigated as pour point depressants and flow improvers for waxy crude oil and it was found that, the maximum depression was obtained by the sample that has long branch chain (PPD4) from 27°C to −3°C (ΔPP = 30°C, at 10000 ppm). While, the minimum depression was exhibited by short branch chain, PPD1 (ΔPP = 21°C) at the same conditions. The effect of these polymers on the rheology and flow properties of Qarun waxy crude oil was investigated. It was found that the Bingham yield value (τβ) decreased from 6.0 pa.s. to 0.5 pa.s. for PPD4 at 27°C and 10,000 ppm. The dynamic viscosity also decreased from 110 m pa.s. to 24 m pa.s. for the same sample and the same conditions.

Styrene-maleic anhydride copolymer esters as flow improvers of waxy crude oil

Four comb-like copolymers derived from styrene-maleic anhydride copolymer were prepared and characterized by FTIR, 1H-NMR and elemental analysis. The molecular weight was determined using GPC and their intrinsic viscosity was measured. The prepared polymers were investigated as pour point depressants and flow improvers for waxy crude oil and it was found that, the maximum depression was obtained by the sample that has long branch chain (PPD4) from 27 °C to − 3 °C (ΔPP = 30 °C, at 10,000 ppm), while the minimum depression was exhibited by short branch chain, PPD1 (ΔPP = 21 °C) at the same conditions. The effect of these polymers on the rheology and flow properties of Qarun waxy crude oil was investigated. It was found that the Bingham yield value (τ β) decreased from 6.0 Pa s to 0.5 Pa s for PPD4 at 27 °C and 10,000 ppm. The dynamic viscosity also decreased from 110 mPa s to 24 mPa s for the same sample and the same conditions.

Electrokinetic sonic amplitude measurement of concentrated alumina suspensions: Effect of electrosteric stabilization

This paper describes a convenient and rapid colloidal measuring process of electrokinetic (ζ-potential, ESA signal) properties of the relatively concentrated aqueous suspensions of a submicron α-Al2O3 powder with the anionic polyelectrolyte (Dolapix CE64) dispersant by applying of an advanced electrokinetic sonic amplitude "ESA" technique without dilution. In addition to ESA measurement, the following measurements were also applied: the viscosity, sedimentation, Bingham yield value and prticle size distribution. Very good agreement is observed from the relationship between the electrokinetic (ζ, ESA) values, the viscosity and its pH dependence for each concentrated α-Al2O3 suspension with different amounts of dispersant. The results indicate that the amount of 0.4 mass% Dolapix CE64 is the optimum amount of dispersant that can cause electrosteric effect and decreases mean (d50) particle size of different concentrated (2 vol% and 45.68 vol%) α-Al2O3 suspensions near to the original size. Finally, the study illustrates that Dolapix CE64 is an effective dispersant at all solid loading conditions.

Interaction between humic acid and montmorillonite in the presence of calcium ions II. Colloidal interactions: Charge state, dispersing and/or aggregation of particles in suspension

Charge state and particle network formation were studied at pH 6–6.5 in model systems containing montmorillonite, humic acid (HA) and calcium ions (Ca 2+), which are responsible for microaggregate formation in soils. Since dispersing and aggregation of particles are governed by the composition of the coating layer on particle surfaces, the interfacial equilibria for the same systems were studied in Part I. Here, the composition of the systems was based on the HA and Ca 2+ adsorption results using a meaningful HA concentration unit related to the molar amount of its acidic functional groups. Approaching real conditions, the effect of Ca loading was also studied at low and high HA content, representing the colloid fractions of soil poor (∼0.5%) and rich (∼5%) in organic matter. The zeta potential was measured and the structure of dense suspensions was characterized using rheology. HA addition breaks down the shear-tolerant structure of the particle network forming in montmorillonite suspensions at pH ∼6.5. Suspensions become liquefied due to the dispersing effect of the HA. However, a much stronger structure can build up, if both HA and Ca 2+ are present in optimal ratio, which can be readily estimated from the charge balance between negative charges (cation exchange sites on montmorillonite and acidic groups of HA) and positive charges of Ca 2+. On the other hand, zeta potential determination did not support these changes, except the dispersing effect of HA. The strengthening of the particle network was quantified using the Bingham yield values. With increasing Ca loading, an almost fivefold increase in shear tolerance could be attained in HA-rich suspensions vs. those without HA or with low HA content. The aggregation of mineral particles is enhanced by the joint effect of HA and Ca 2+. The higher the OM content, the more the Ca loading is expected to reach optimal aggregation.

Effect of Polyvinylpyrrolidone and Sodium Lauroyl Isethionate on Kaolinite Suspension in an Aqueous Phase

Suspension of concentrated kaolinite (20 g/30 ml-medium) in the presence of polyvinylpyrrolidone (PVP) and sodium lauroyl isethionate (SLI) was allowed to evaluate its degree of dispersion based on their rheological studies. Flow curves at low shear rate, measured by means of cone-plate method, showed a non-Newtonian flow. Plastic viscosity and Bingham yield value were derived from the flow curves. Relative viscosity, effective volume fraction and void fraction of secondary particle were also obtained. Results of dispersity and fluidity of the suspension were explained. PVP acted as a flocculant at a concentration lower than 0.1% but as a dispersant at a higher concentration. The presence of SLI could decrease both the Bingham yield value and suspension viscosity. Cooperative and competitive effects of PVP and SLI were found. Results indicated that SLI enhanced the degree of dispersion of kaolinite when PVP was less than 0.1%. The suspension, however, showed a maximum flocculation (i.e., aggregation) at 4 mM SLI when the concentration of PVP was higher than 0.1%.

The rheology of concentrated suspensions of depletion-flocculated latex particles

The effect of adding non-adsorbing polymer, poly(acrylic acid) (PAA), on the rheological properties of concentrated electrostatically-stabilised polystyrene latex suspensions was investigated. The extrapolated yield stress of the depletion-flocculated suspensions was studied as a function of the concentration and the molecular weight of the free polymer. Specifically, the Bingham yield value was observed to increase with either an increase in the weight fraction of the polymer or through the use of a longer chain polyacid. Unlike the sterically stabilised colloidal suspensions studied in the literature, at high polymer concentrations these charge-stabilised latex particles exhibited plateauing in the yield stress for each polyacid. The energy of separating particles within an aggregate into single units was calculated using the yield stress and average particle co-ordination number. In contrast to what was commonly done in the literature, the latter was not assumed to be constant but estimated from the aggregate mass fractal dimension as obtained from static light scattering techniques. It was found that the separation energy showed similar trends to those in the yield stress with both varying the polymer concentration and molecular weight. These trends also bear remarkable similarities to those in the depth of the secondary potential energy well as measured using atomic force microscopy (AFM).

Rheological Properties of Aqueous Suspensions of Palygorskite

The rheology of aqueous suspensions of six palygorskites with different particle morphologies has been investigated as a function of clay concentration, adsorbed ion, pH, and electrolyte concentration, using a rotary viscometer. Rheological parameters (plastic viscosity, Bingham yield value, and apparent viscosity) increase with the length/width ratio of individual palygorskite fibers. The plastic viscosity increases linearly with clay concentration within the range investigated (up to 5% w/v). The rheological parameters are higher for clays saturated with divalent ions than those for clays saturated with monovalent ions. For ions of the same valency the rheological parameters tend to increase with decreasing radius of the hydrated ion. The flow of suspensions is pseudoplastic regardless of the nature of the adsorbed ion. Measurements of electrophoretic mobility in very dilute suspensions suggest that the point of zero charge of the palygorskite surface is at pH 4 to 4.5. Scanning electron microscopy indicates significant differences in fiber arrangement between low and high pH values. Face‐to‐face particle association occurs at low pH values, giving rise to close‐packed domains of fibers, while at high pH values the fibers adopt a random orientation. The flow of suspensions is pseudoplastic at pH ≤ 7 and changes to Newtonian at pH ≥ 9. At pH ≤ 7 the rheological parameters remain relatively constant even at high electrolyte concentrations, but at pH ≥ 9 they are influenced significantly by electrolyte addition. Electrolyte‐free palygorskite suspensions at pH 7 are antithixotropic. When the pH falls below 7 or when electrolyte is added, the suspensions coagulate and become thixotropic. Some rheological properties of palygorskite are similar to those of platy clay minerals such as kaolinite and montmorillonite, while other rheological properties deviate considerably. The models developed to explain the rheological behavior of platy clay minerals do not always account for the behavior of palygorskite, because of differences in particle morphology and surface structure.

Microemulsion polymerization of styrene using developed redox initiation system and study of rheological properties of obtained latices

Microemulsion polymerization of styrene was kinetically studied using a potassium persulfate (KPS)/P-methyl benzaldehyde sodium bisulfite (MeBSBS) adduct as the developed redox pair initiation system. The rate of microemulsion polymerization of styrene was found to be dependent on the initiator, emulsifier, and monomer to the powers of 1.4, −0.77, and 0.83, respectively. The apparent Arrhenius activation energy (Ea) estimated for the microemulsion polymerization system was 6.5 × 104 J/mol. Also, the morphological parameters were studied at different initiator concentrations. The rheological measurements for the prepared microemulsions were carried out to investigate the effect of the preparation parameters on the rheological behavior of the polystyrene microemulsions. The rheological flow curves of the polystyrene microemulsion latices prepared at different temperatures were carried out, and we found that the plastic viscosity and Bingham yield values of the flow curves increased with an increasing reaction temperature. That may be due to the cage effect of the prepared polymer particles, which trapped the medium molecules. The plastic viscosity increased with increasing emulsifier concentration while the Bingham yield value decreased. For the polystyrene microemulsion prepared in the presence of different initiator concentrations, the plastic viscosity and Bingham yield increased with increasing initiator concentration. This trend was found to be the same for the microemulsion latices prepared in the presence of different monomer concentrations. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1240–1249, 2000

Interactions between zinc sulphide particles under flotation-related conditions

Rheological investigations of dispersions of spherical synthetic zinc sulphide particles have been conducted under flotation-related conditions and correlated with interparticle force-distance measurements using “colloid probe” atomic force microscopy. The interparticle interactions observed are discussed in terms of zinc sulphide surface chemistry; the latter was characterised by electrokinetic and X-ray photoelectron spectroscopic measurements. At pH < pHiep of zinc sulphide there is clear evidence of a hydrophobic attraction, in addition to electrostatic and van der Waals forces, affecting interparticle interactions. The presence of copper(II) ions at pH 4 resulted in increased Bingham yield values and interparticle cohesive forces, whereas at pH 10 no such attractive interactions were observed. These findings are discussed in the context of copper(II) ion activation of sphalerite in flotation practice.

Correlation between flow properties of silica‐PVA aqueous slurries and spray‐dried granules

The correlation between rheological behavior of a slurry, composed of silica microspheres and poly (vinylalcohol) (PVA), and microstructure and also the disintegration behavior of spray‐dried granules were studied. Pseudoplastic flow behavior was analyzed under the Bingham approximation to obtain the Bingham yield value, τB, plastic viscosity, ηpl, and bulkiness of the flow unit, CFP. CFP is the ratio of the effective volume fraction of flocs, φF, to that of dry solid, φP. The dispersion of silica in the slurries was dominated by PVA adsorption at low pH and the electrostatic repulsion at high pH. The granules prepared from the slurry at pH=7 had the smallest apparent density and disintegrated under the smallest applied load. It is concluded that the microstructure and disintegration behavior of the granules are greatly affected by pH values at which the slurries are prepared, in spite of the similar flow behavior.

The flow characteristics of halloysite suspensions

AbstractThe rheology of aqueous suspensions of Na halloysites with different particle shape has been investigated using a Haake rotary viscometer. Three halloysites from New Zealand were used: Matauri Bay (MB), Te Akatea (TA) and Opotiki (Op) which are mainly composed of thick long tubules, short thin laths, and spherules, respectively. Suspensions of the materials subsequently prepared from the MB and TA samples show a pseudoplastic consistency under shear, characterized by a steep initial rise in shear stress as shear rate increases, followed by a linear increase in stress when a certain shear rate is exceeded. The Op halloysite, on the other hand, shows Newtonian flow behaviour for which shear stress increases linearly with shear rate throughout. For MB and TA, the shear stress developed during rotor acceleration is larger than that produced during deceleration, and the corresponding flow curves enclose a hysteresis loop. As suspension pH increases, the pseudoplastic character decreases as does the amount of hysteresis. Above pH 7.5, flow approaches Newtonian and hysteresis is absent. Plots of Bingham yield value against pH at different ionic strengths (0.003, 0.03 and 0.3 M NaCl) intersect at pH 6.0 for MB and at pH 7.1 for TA. These values are identified with the point of zero charge (PZC) of the particle edge surface. The flow characteristics of halloysites may be explained in terms of the influence of particle shape, pH, electrolyte concentrations, and layer composition on particle interactions.

The Rheological and Colloidal Properties of Bentonite Dispersions in the Presence of Organic Compounds V. Bentonite and Sodium Montmorillonite and Surfactants

AbstractThe influence of surfactants on the flow behavior of sodium montmorillonite dispersions (2% w/w) was studied for a cationic (cetylpyridinium chloride, CPCl) and an anionic surfactant (sodium dodecylsulfate, SDS). When the dispersion pHs were &gt;3.5 and &lt;7, CPCl concentrations &gt;10−4 M increased the shear stress but the Bingham yield value remained virtually unchanged (τo ≈ 100 mPa). At pH ≈ 7, the shear stress and yield point decreased with increasing CPCl concentration (τo from 430 to 100 mPa). The flow properties of sodium calcium bentonite dispersions were independent of pH and CPCl concentrations ≤ 10−4 M; they increased modestly at higher concentrations. At pH &lt; 4, SDS addition to the sodium montmorillonite dispersions increased the shear stress and yield value to a maximum value (τo = 2100 mPa) at 10−3 M SDS; higher SDS concentrations reduced the shear stress and yield value. At pH &gt; 4, the flow values decreased to a minimum value at 10−2 M SDS (τo from 430 to 50 mPa). The flow of the sodium calcium bentonite dispersions at pH &gt; 4 was independent of SDS concentrations ≤ 10−3 mole/liter; at higher SDS concentrations, the flow values increased more strongly in sodium calcium bentonite than in sodium montmorillonite dispersions.Surfactants influence the flow behavior of sodium montmorillonite dispersions by their action on the card-house networks in strongly acidic medium and, at higher pH, by the electroviscous effect. At the highest surfactant concentrations without flocculation, the shear stress and yield value are increased by interacting chains of opposed particles.Addition of the surfactants increases the salt (NaCl) stability of the dispersions because the adsorbed surface active agents influence the counterion distribution between the Stern and the diffuse ionic layer.

Changes of Rheological Properties of Finely Particulated In&lt;SUB&gt;2&lt;/SUB&gt;O&lt;SUB&gt;3&lt;/SUB&gt;/SnO&lt;SUB&gt;2&lt;/SUB&gt; Sol Complex Suspensions in Mechanically Dispersing and Aging Processes

Flow properties and aging mechanism were analyzed at three different pH, under simple Bingham approximation of steady flow, for complex suspensions containing finely powdered In2O3and SnO2 sol that was in situ precipitated during gridding processes. At pH 5, near isoelectric points of both oxides, gelation was mainly attributed to crosslinking of the pre-existing flocs. In contrast, increase in the viscosity during aging at pH 2 and 9.5 was mainly due to increase in effective floc volume. The total pore volume, median pore size, and Vickers hardness of slip cast body were found to be closely related with the change in the Bingham yield value during aging.

Flow Properties of Montmorillonite Suspended in Water with Surfactant

Abstract The flow properties of montmorillonite, one of the main clay components in coal, were studied in water suspensions to clarify the origins of the Bingham flow properties of coal water slurry (CWM) in the presence of a surfactant. The addition of anionic surfactants, such as sodium poly(isoprenesulfonate) and sodium polycarbonate, significantly decreased the apparent viscosity and Bingham yield value of the montmorillonite suspension, although the latter value never became zero, even when a large quantity of surfactant was added. The amount of water bound to montmorillonite particles, measured using 1H NMR, was found to increase with the addition of a surfactant. The Bingham yield value and the relative viscosity of the montmorillonite suspension were described by Michaels’ equation, τB = A(Sφ − Sφ0)3 (Eq. 6), and by the modified Brinkman’s equation, ηr = (1 − Sφ)−k (Eq. 8), respectively. In both equations, the sum volume of montmorillonite particles and its bound water (Sφ) is correlated to the flow properties through constants A and k. A reduction of both A and k suggests two different actions of the anionic surfactants in the montmorillonite suspension. A decrease in the A value indicates a reduction of the strength of the aggregate networks of montmorillonite at a low shear rate, while a decrease in the k value shows that the shape of the effective montmorillonite particle becomes more spherical due to an increase of bound water.