Bingham Plastic Behavior Research Articles

Performance of rubber seed oil as an alternative to diesel in oilbased drilling mud formulation

The formulation of an oil-based mud was made possible with the oil extracted from rubber seeds using the famous soxhlet extraction method. The mud was formulated using the API standard of 25 g of bentonite to 350 mL base fluid. The choice of Rubber oil comes as a result of its flash point and aniline point which lies in the range of base oils used for mud formulation. The rheological properties of the rubber OBM were beyond the scope of the viscometer and hence thinner was added to reduce its viscosity and its suitability to compete favorably with diesel OBM was checked. The 10-sec and 10-min gel strength of the Rubber OBM was recorded as 68 lb/100 ft2 and 69 lb/100 ft2 respectively while that of Diesel was 65 lb/100 ft2 and 67 LB/100 ft2 . The plastic viscosity of Rubber OBM was 12 cp while that of Diesel was 17 cp. They both exhibited Bingham Plastic behavior and a similar yield point of 146 lb/100 ft2 . The formulated mud samples were subjected to temperatures of 60 oC and 75 oC and it was discovered that Rubber OBM was likely to retain its rheological property than diesel OBM. Comparison with other rheological properties of diesel OBM showed that the formulated mud could be used alternatively for diesel in drilling operations.

Modelling the cleaning of viscoplastic layers by impinging coherent turbulent water jets

Impinging liquid jets are widely used to clean unwanted soil layers from the walls of structures and vessels. When the soil is a thin layer of an immiscible viscoplastic material, removal involves the growth of a cleared area (which is circular for a jet impinging normally) bounded by a berm of displaced material. Glover et al. [1] presented a semi-empirical model relating the rate of removal to the momentum flow rate in the liquid film. We present a first-order model for cleaning thin layers of these materials based on the rate of viscous dissipation in a shallow wedge of material at the cleaning front. This yields a result of the form of the model in [1], with expressions linking the kinetic parameters to measurable quantities including the rheology of the soil. The fully coupled problem is not solved: the wedge angle and residual layer thickness need to be specified and were obtained here by fitting to the data. The model is compared with experimental results obtained for three soft solids – two petroleum jellies and a soft paraffin – which exhibited Bingham plastic behaviour and creep, for jet Reynolds numbers between 10,000-37,000, and 0.1<h¯/δo<1.5, where h¯ is the average film depth and δo the layer thickness. The data show reasonable agreement with the model.

A new liquid transport model considering complex influencing factors for nano- to micro-sized circular tubes and porous media

A new liquid transport model in wetted nano- to microsized circular tubes is proposed using basic dynamical analyses that comprehensively consider the Lifshitz–van der Waals force (LWF), the electroviscous force, the weak liquid compressibility, and the Bingham-plastic behavior. The model predicts that the average velocity is initially zero and increases nonlinearly with a concave shape before increasing linearly with the pressure gradient (ΔP/L) and is validated using the experimental data. The threshold pressure gradient (TPG) and the lower limit of the movable-fluid radius (Rm) are calculated based on the proposed model, which are mainly determined by the yield stresses from the Bingham plastic behavior and are also affected by the compressibility and LWF. Considering the microstructural complexity of real porous media, the average velocity model is also applicable for tight porous media with a capillary equivalent radius from the permeability. The calculated average velocity is non-Darcy with TPG. The TPG decreases as the permeability increases, and the Rm decreases with the pressure gradient in the low range and remains constant at the higher ranges, which is primarily between 10 and 30 nm. All these results for porous media are compared with the experimental data of core seepage and show good agreement in general. The proposed model has a clear parametric representation compared with previous nonlinear models. It explains the underlying reasons for the nonlinear, low-velocity flow mechanism in nano- to microsized tubes and pores and provides theoretical guidance for liquid transport in porous media and oil recovery from tight oil reservoirs.

Microscale effects of Bingham-plastic liquid behavior considering electroviscous effects in nano- or microsized circular tubes

Although microscale phenomena are ubiquitous in fluid flow through nano- or microsized channels and pores, the mechanisms remain unclear. To clarify these mechanisms, we investigate herein Bingham-plastic liquids with electroviscous effects (EVEs) in nano- and microsized circular tubes. The constitutive equation and electroviscous forces are introduced into the governing equations, and approximate analytical solutions are obtained. Velocity reduction results from the combined effects of the Bingham characteristics and EVEs. The Bingham behavior reduces the strength of the EVE electric field, and EVEs increase the width of the flow core. The dimensionless average velocity decreases as the tube radius decreases and goes to zero upon approaching the lower limit of the movable fluid radius (Rm). As the pressure gradient decreases, the average velocity first decreases linearly, then decreases nonlinearly in a concave shape, and finally approaches zero as the pressure reaches the threshold pressure gradient (TPG). The Bingham plastic behavior causes both the Rm and the nonlinear flow with TPG, and Rm is still caused by the van der Waals forces under liquid compressibility more obviously. The EVE parameters only affect the degree of nonlinearity when the liquid exhibits Bingham-plastic behavior. These results are consistent with experimentally observed de-ionized water flowing in microscale silica tubes. We infer that the Newtonian fluid displays the Bingham-plastic behavior in nano- or microsized channels in what we call “microscale effects.” These results elucidate the mechanism that leads to nonlinear or low-speed non-Darcy flow in nano- or microsized channels and pores from the liquid characteristic and liquid-solid interaction.

Rheological Characterization of Algal Suspensions for Bioethanol Processing

The paper has aimed at studying the rheology of macroalgae aqueous suspensions in the presence of cellulase enzyme relevant to bioethanol processing by a subsequent fermentation. Rheological measurements of aqueous suspensions of Ceramium virgatum and Cladophora vagabunda macroalgae species were performed using a Couette geometry rotational viscosimeter. The effects of operation temperature (t=25, 50 �C), cellulase/dried algae ratio (R=0, 16 U/mgda), and algal suspension mass concentration (c=5-15%) on rheological behaviour and parameters were evaluated. Algal suspensions behaved as non-Newtonian fluids obeying either a Bingham plastic linear relationship or an Ostwald-de Waele power law corresponding to a pseudoplastic fluid. Characteristic dynamic viscosity of Bingham plastic fluids were in the range 0.045-0.115 Pa�s for C. virgatum suspensions and 0.021-0.114 Pa�s for C. vagabunda ones, whereas apparent viscosity varied from 0.138 Pa�s to 43.551 Pa�s for C. virgatum and from 0.181 Pa�s to 45.417 Pa�s for C. vagabunda. Data obtained in 8 rheological tests corresponding to a Bingham plastic behaviour of C. vagabunda suspensions, which were processed according to a 23 factorial experiment, emphasized an increase in suspension viscosity with all process factors. The results could be useful for optimization of enzymatic hydrolysis process in order to develop efficient and cost effective saccharification and fermentation strategies.

Solvothermal synthesis, characterization, and magnetorheological study of zinc ferrite nanocrystal clusters

In this study, zinc ferrite (ZnFe2O4) nanocrystal clusters were synthesized successfully with a surfactant-assistant solvothermal method and investigated as a potential magnetorheological material. The morphology, structure, and magnetic properties of the obtained ZnFe2O4 nanocrystal clusters were investigated in detail using a scanning electron microscope, transmission electron microscope, X-ray diffraction, and superconducting quantum interference device. It was found that the ZnFe2O4 nanocrystal clusters showed well-defined shape and homogeneous dispersion with narrow size distribution of 276 nm in diameter. The field-dependent magnetization curve indicated superparamagnetic properties of as-prepared ZnFe2O4 nanocrystal clusters with saturation magnetization ( Ms) of 86.6 emu/g at room temperature. The magnetorheological fluid with 25% particle mass fraction was prepared by ZnFe2O4 nanocrystal clusters, and the corresponding magnetorheological properties were also tested using a Physica MCR301 rheometer fitted with a magnetorheological module. The prepared magnetorheological fluid changed from a liquid-like to a solid-like state under an external magnetic field, suggesting typical Bingham plastic behavior. Compared with conventional carbonyl iron particles, ZnFe2O4 nanocrystal clusters–based magnetorheological fluid showed enhanced sedimentation stability. The obtained ZnFe2O4 nanocrystal clusters are considered as an ideal candidate for magnetorheological fluid with typical magnetorheological effect as well as improved sedimentation stability.

Magnesium ferrite nanocrystal clusters for magnetorheological fluid with enhanced sedimentation stability

In this study, magnesium ferrite (MgFe2O4) nanocrystal clusters were synthesized using an ascorbic acid-assistant solvothermal method and evaluated as a candidate for magnetorheological (MR) fluid. The morphology, microstructure and magnetic properties of the MgFe2O4 nanocrystal clusters were investigated in detail by field emission scanning electron microscopy (FESEM), transmission electron microscope (TEM), thermogravimetric analyzer (TGA), X-ray diffraction (XRD) and superconducting quantum interference device (SQUID). The MgFe2O4 nanocrystal clusters were suspended in silicone oil to prepare MR fluid and the MR properties were tested using a Physica MCR301 rheometer fitted with a magneto-rheological module. The prepared MR fluid showed typical Bingham plastic behavior, changing from a liquid-like to a solid-like structure under an external magnetic field. Compared with the conventional carbonyl iron particles, MgFe2O4 nanocrystal clusters-based MR fluid demonstrated enhanced sedimentation stability due to the reduced mismatch in density between the particles and the carrier medium. In summary, the as-prepared MgFe2O4 nanocrystal clusters are regarded as a promising candidate for MR fluid with enhanced sedimentation stability.

Capillary driven flow in nanochannels – Application to heavy oil rheology studies

Observations of capillary-driven flow of a liquid in a nanochannel can be used to study the liquid’s rheology. Capillary-driven flow of several pure liquids and bitumen diluted in Heptol (80:20) were studied using a nanofluidic chip. Filling speed of water was lower than the theoretical predictions, as expected. However, for methanol and ethanol, experimental values agreed well with theoretical predictions. 5 and 11wt.% bitumen solutions in heptol (80:20) followed the theoretical predictions quite well at the initial times but demonstrated deviation for longer penetration times. However, for 20 and 40wt.% diluted bitumen, experimental observations significantly deviated from the theoretical models. Those deviations were related to the continuous changes in the observed dynamic contact angle of the advancing meniscus. Nanochannel blockage has frequently occurred due to the presence of asphaltenes aggregates when 20wt.% diluted bitumen was used. Theoretical model for capillary filling of Bingham Plastic fluid was developed to probe the possible non-Newtonian behavior of diluted bitumen above the onset of asphaltenes precipitation. Given very small yield stress, it was difficult to precisely distinguish between Newtonian and non-Newtonian Bingham Plastic behavior. Nevertheless, our results show that Bingham Plastic model can describe the rheology of 5wt.% and 11wt.% bitumen at nanoscale more accurately than the Newtonian model. Our study shows nanochannels provide an experimental platform to analyze the flow of petroleum in the nanoporous media.

Mud-coated intraclasts: A criterion for recognizing sandy mass-transport deposits – Deep-lacustrine massive sandstone of the Upper Triassic Yanchang Formation, Ordos Basin, Central China

Numerous examples of sandy mass-transport deposits (SMTDs) in deep-marine and deep-lacustrine environments have been documented by researchers worldwide in recent years. However, it is an enormous challenge that how to distinguish the subaqueous mass-transport processes from the depositional records. After the rigorous examination of several outcrops in the Ordos lacustrine basin in central China, we propose that the “mud-coated intraclasts” in the deep-water thick massive sandstone of the Yanchang Formation are a viable criterion to recognize deposition from sandy debris flows in delta front environments. These so-called “mud-coated intraclasts” are a newly discovered special depositional phenomenon in the massive clean sandstones in China’s lacustrine basins. A mud-coated intraclast generally consists of two components: an inner core and a mud coating. The inner core is generally composed of muddy blobs or sandy lumps. The mud coatings are generally composed of thin shales or mud-rich fine-grained sediments. The inner core, which is generally coated by nearly concentric ring-shaped mud coatings, is embedded in massive deep-water sandstones. Because these features have never been documented in the geological literature, the present authors called them “mud-coated intraclasts” in the present study. The depositional features suggest that the sediments that contain these mud-coated intraclasts were characterized by en masse emplacement (i.e., a Bingham plastic behavior) and were supported by the strength of the plastic medium at all times (i.e., no flow transformations occurred during their transport and deposition). Accordingly, mud-coated intraclasts are one of the most significant criteria that indicate sandy debrites as the origin of the deep-water thick massive sandstones in the Yanchang Formation. This diagnostic feature may be useful to identify analogous SMTDs in other locations.

Towards Additive Manufacturing of Tungsten Carbide Using Renewable Resources

We present preliminary experiments leading to novel additive manufacturing of carbides. To this end, we shape and heat treat a biopolymer-metal oxide composite featuring Bingham plastic behavior. Extrusion of such composite at room temperature allows for layer-by-layer fabrication; with the rheology of the composite dictating the scale of fabrication, i.e. thin mixtures for millimetric features, and thicker composites for bigger structures. Upon heat treatment to 900 °C, the biopolymer carbonizes. Further increase in temperature leads to a reaction between this carbon and the metal oxide nanoparticles to form metal carbides1. Such manufacturing process could lead to a more energy-efficient route to complex carbides shapes. Renewable biopolymers replace petroleum-based ones as carbon source; and the temperature needed for carbide formation can be drastically reduced due the colloidal proximity of the reactants. Additive manufacturing of the composite that is precursor to carbides could enable complex shapes, which are challenging or impossible when using powder pressing or machining of bulk carbides. We developed and characterized water-based composites featuring iota-carrageenan (IC) and chitin as mixed with tungsten trioxide (WO3) nanoparticles. The initial target is tungsten carbide (WC). Iota carrageenan powder was mixed with chitin in a weight ratio of 1:4. Thermogravimetric analysis of this mixture yields a 10.85% carbon yield at 900 °C. Thus, WO3 nanoparticles were mixed with this biopolymer powder mixture to achieve a C:WO3molar ratio of 1:8, in accordance to the chemical reaction and providing an excess of carbon. Ultra-pure water was added to the biopolymer-metal oxide nanoparticle mixture and stirred manually to achieve a Bingham plastic composite. The biopolymer composite was loaded in a syringe and manually extruded into 3D spirals shapes of around 10 mm in height. The heat treatment protocol features a ramp of at 5°C/min, nitrogen flow, a dwell of half-hour at 300°C, and a dwell of 3 hours at different temperatures ranging from 750 °C to 1450 °C. Carbonaceous 3D shapes result in all cases. Resultant shapes are of similar geometry to the precursor ones but smaller due to shrinkage. SEM-EDS and XRD analysis were performed on the carbonaceous samples towards characterizing their composition and geometry at different temperatures. The WO3 reduces to different forms of tungsten oxide and finally to tungsten at 900 °C. With further increase of temperature, the reduced tungsten reacts with carbon to form tungsten carbide. It is observed in Figure 1 that tungsten carbide starts to form above 900 °C. Further increase of temperature increases the crystallinity of the tungsten carbide as WC peaks get higher with temperature as seen from the XRD pattern. Figure 2a and 2b show the grain structure before the carbide formation at 750 °C and 900 °C respectively. It can be observed that the grain size increases with temperature. Figure 2c and 2d show that porous carbide was synthesized at 1025 °C and 1150 °C. The carbides synthesized in this process have grain size ranging from tens of nanometers to 2 µm. From elemental analysis using EDS (Table 1), it is observed that the relative amount of tungsten with respect to carbon increases proportional to temperature. This supports the theory of carbonization of the biopolymer as well as the reduction of WO3with the increasing temperature. In EDS analysis, calcium and potassium were also found to be present as the impurities which may come from the water used for composite formation. Ongoing work is 1) investigating the effect of time, heating rate and heating environment on carbide formation and composition; 2) further understanding of shrinkage during heat treatment; and 3) implementing automated fabrication using a fused deposition modeling approach.

Computational methodology for determination of head loss in both laminar and turbulent regimes for the flow of high concentration coal ash slurries through pipeline

ABSTRACTFlow of fine coal ash slurries at high concentrations (60–70% by weight) was analyzed using the commercial computational fluid dynamics (CFD) package FLUENT. Rheological properties of high concentration slurry show that the slurry behaves as a non-Newtonian fluid and exhibits Bingham plastic behavior. The predicted results for pressure drop as a function of flow velocity for the slurry flow at different concentrations are found to be in good agreement with experimental data reported in the literature. The k-ω Shear Stress Transport (SST) model was found to give better results in the turbulent regime and is consistent with the observations reported in literature. The predicted results for pressure drop were used to calculate the friction factor at various Reynolds and Hedstrom numbers. The methodology developed will help the design of high concentration ash slurry disposal systems based on the measured values of rheological parameters of the slurry. The rheological parameters account for the variation of the particle size distribution in the coal ash and thus the effect of particle size distribution on the head loss in the pipe line was established indirectly.

An Experimental Determination of the Viscosity of Propylene Glycol/Water Based Nanofluids and Development of New Correlations

Measurements have been carried out for determining the viscosity of several nanofluids, in which different nanoparticles were dispersed in a base fluid of 60% propylene glycol (PG) and 40% water by mass. The nanoparticles were aluminum oxide (Al2O3), copper oxide (CuO), silicon dioxide (SiO2), titanium oxide (TiO2), and zinc oxide (ZnO) with different average particle diameters. Measurements were conducted for particle volume concentrations of up to 6% and over a temperature range of 243 K–363 K. All the nanofluids exhibited a Bingham plastic behavior at lower temperatures of 243 K–273 K and a Newtonian behavior in the temperature range of 273 K–363 K. Comparisons of the experimental data with several existing models show that they do not exhibit good agreement. Therefore, a new model has been developed for the viscosity of nanofluids as a function of temperature, particle volume concentration, particle diameter, the properties of nanoparticles, and those of the base fluid. Measurements were also conducted for single walled, bamboolike structured, and hollow structured multiwalled carbon nanotubes (MWCNT) dispersed in a base fluid of 20% PG and 80% water by mass. Measurements of these carbon nanotubes (CNT) nanofluids were conducted for a particle volume concentration of 0.229% and over a temperature range of 273 K–363 K, which exhibited a non-Newtonian behavior. The effect of ultrasonication time on the viscosity of CNT nanofluids was investigated. From the experimental data of CNT nanofluids, a new correlation was developed which relates the viscosity to temperature and the Péclet number.

Fabrication of spherical Fe3O4 particles with a solvothermal method and their magnetorheological characteristics

Spherical Fe3O4 particles were synthesized with a solvothermal method and assessed as a potential magnetorheological (MR) material. Their morphology, chemical structure, crystal structure, and magnetic properties were measured with scanning electron microscopy and transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and a vibrating sample magnetometer, respectively. The MR characteristics of the Fe3O4 particles were investigated with rotational rheometry under an external magnetic field. When the spherical Fe3O4 particles were dispersed in silicone oil, the MR fluid exhibited typical Bingham plastic behavior, changing from a liquid-like to a solid-like state.

Effects of ripening on rheological properties of avocado pulp (Persea americana mill. Cv. Hass)

Avocado (Persea americana Mill) Hass variety is the most planted in Chile with a greater trade prospect. The aim of this study was to investigate the effect of maturity on rheological properties of Chilean Avocado Hass pulp. Fresh unripe avocados were washed and peeled, cut and stored at 3 different times; a portion was treated at 5°C and the other was treated at 20°C until it reached 2 lb puncture pressure. During maturation changes would develop due to temperature and time, with internal cellular structure changes. Preliminary results of the rheological characteristics of avocado puree show a Bingham plastic behavior.

Molecular and supramolecular characterization of Ni(II)/losartan hydrophobic nanoprecipitate

In this work, a contribution to understanding of the formation of metal(II)/losartan hydrophobic nanoprecipitate is reported. A Ni(II)/Los system was prepared and characterized in solid state and in solution. Solubility studies confirmed the formation of hydrophobic precipitate. Obtained spectroscopic data suggest a sort of coordination between tetrazolic ring as well as OH, and a D4h geometry around the nickel cation. Thermodynamic studies demonstrated that complexation is a stepwise process, with equal enthalpic and entropic contributions for free energy of complexation. DLS and zeta potential titrations indicate the formation of stable nanoparticles of size and charge dependent on the molar ratio. Finally, rheological studies demonstrate a Bingham plastic behavior for Ni(II)/Los suspension.

Optimal design of high damping force engine mount featuring MR valve structure with both annular and radial flow paths

This paper focuses on the optimal design of a compact and high damping force engine mount featuring magnetorheological fluid (MRF). In the mount, a MR valve structure with both annular and radial flows is employed to generate a high damping force. First, the configuration and working principle of the proposed MR mount is introduced. The MRF flows in the mount are then analyzed and the governing equations of the MR mount are derived based on the Bingham plastic behavior of the MRF. An optimal design of the MR mount is then performed to find the optimal structure of the MR valve to generate a maximum damping force with certain design constraints. In addition, the gap size of MRF ducts is empirically chosen considering the ‘lockup’ problem of the mount at high frequency. Performance of the optimized MR mount is then evaluated based on finite element analysis and discussions on performance results of the optimized MR mount are given. The effectiveness of the proposed MR engine mount is demonstrated via computer simulation by presenting damping force and power consumption.

Development of High Damping Magneto-Rheological Mount for Ship Engines

In this paper, novel configurations of a compact and high damping force engine mount featuring magnetorheological fluid (MRF) is proposed and analyzed. In the mount, a MR valve structure with both annular and radial flows is employed to generate a high damping force. Firstly, several configurations of the MR mount are proposed. The MRF flows in the mount are then analyzed and the governing equations of the MR mount are then derived based on Bingham plastic behaviour of the MRF. Optimal design of the proposed MR mount is then considered. In the optimization, the objective is to find out the optimal structure of the MR mount that can generate a maximum damping force while the off-state force of the mount is constrained in such a manner that the force ratio of the mount is greater than a required value. Performance of the optimized MR mount is then evaluated based on finite element analysis and validated by experimental results.

선박용 엔진 MR 마운트의 최적설계: 최대 댐핑력

This paper presents optimal design procedures of mount based on a magnetorheological(MR) fluid to isolate the vibration in heavy diesel engine system. At first, frequency response and force-displacement transmissibility methods are used to get required damping force that is necessary for effective vibration isolation. From this result, a new type of high damping force engine mount is proposed and the governing equation of Bingham plastic behavior of MR fluid in flow path is mathematically derived under cylindrical coordinates. Finally, parametric design optimization featuring finite element is performed using ANSYS software to get the required damping force in MR mount system which can be used to reduce engine vibration. Damping force of the MR mount is then determined as an objective function in this analysis based on ANSYS. Furthermore, Magnetic analysis is then applied in this process.

Improving stability of concentrated coal–water slurry using mixture of a natural and synthetic surfactants

The use of a surfactant mixture of natural and synthetic surfactants as additives in stabilizing coal-water slurry (CWS) formed from low rank Indian coals has been explored. The surface activities of the synthetic surfactants, hexadecyltrimethyl ammonium bromide (CTAB, cationic surfactant) and sodium dodecyl sulphate (SDS, anionic surfactant) are found to alter when various concentrations of natural surfactant, saponin (non-ionic surfactant) extracted from the fruits of Sapindous laurifolia are added to them independently. A considerable decrease in viscosity of CWS has been observed on the addition of saponin to the synthetic surfactants, CTAB/SDS (at 50:50 (w/w) for saponin:CTAB; 60:40 (w/w) for saponin:SDS systems). The mixture of anionic-nonionic is however, found to be more effective than the mixture of cationic-nonionic surfactants in reducing the apparent viscosity of the mixtures. The surface tension and contact angle data of the mixtures in solution suggest the high surface activity of the mixtures at these ratios. The rheological behaviors of CWS at weight concentrations varying from 55% to 65%wt.%, the static stability test, effect of pH, temperature, etc. have been studied. The slurries follow Bingham plastic behavior within these ranges of concentrations. A qualitative model of interaction of additive with a coal particle at the interface has been suggested.

Effect of acidity on xylan–montmorillonite bionanocomposites

In this study effect of acidity on polymer/clay nanocomposites was investigated. Bionanocomposites (X–MMT) were obtained using hemicellulosic polysaccharide from corn cob (xylan), and sodium activated smectite-type clay (montmorillonite, NaMMT) in acidic (pH 4), neutral (pH 7), and basic (pH 10) media. Acidity of media was adjusted using identical amounts of appropriate buffer solution in dispersion preparation process. X–MMT dispersions showed a steady zeta potential about −12 mV, regardless of medium pH. NaMMT dispersions did not obey to Bingham's model giving negative yield values. But X–MMT samples showed Bingham plastic behavior mostly. Intercalation by xylan was determined as an expansion in basal spacing (d001) of NaMMT about 1.67 ± 0.05 nm for all pH values. Structural hydroxyl stretching band at 3625 cm−1 disappeared for X–MMT samples, which was a strong evidence of xylan–NaMMT interaction. Rheological and electrokinetic behaviors of X–MMT bionanocomposite dispersions were strongly influenced from the medium acidity, whereas intercalation of clay was identical for all pH values.