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Interfacial Tension (interfacial + tension)

Distribution by Scientific Domains

Polymers and Materials Science	47%
Chemistry	41%

Distribution within Polymers and Materials Science

Polymer Science & Technology General	74%
General & Introductory Materials Science	10%

Selected Abstracts

Wettability alteration of caprock minerals by carbon dioxide

GEOFLUIDS (ELECTRONIC), Issue 2 2007
P. CHIQUET
Abstract One of the critical factors that control the efficiency of CO2 geological storage process in aquifers and hydrocarbon reservoirs is the capillary-sealing potential of the caprock. This potential can be expressed in terms of the maximum reservoir overpressure that the brine-saturated caprock can sustain, i.e. of the CO2 capillary entry pressure. It is controlled by the brine/CO2 interfacial tension, the water-wettability of caprock minerals, and the pore size distribution within the caprock. By means of contact angle measurements, experimental evidence was obtained showing that the water-wettability of mica and quartz is altered in the presence of CO2 under pressures typical of geological storage conditions. The alteration is more pronounced in the case of mica. Both minerals are representative of shaly caprocks and are strongly water-wet in the presence of hydrocarbons. A careful analysis of the available literature data on breakthrough pressure measurements in caprock samples confirms the existence of a wettability alteration by dense CO2, both in shaly and in evaporitic caprocks. The consequences of this effect on the maximum CO2 storage pressure and on CO2 storage capacity in the underground reservoir are discussed. For hydrocarbon reservoirs that were initially close to capillary leakage, the maximum allowable CO2 storage pressure is only a fraction of the initial reservoir pressure. [source]

Thermodynamic study of capillary pressure curves based on free energy minimization

GEOFLUIDS (ELECTRONIC), Issue 3 2001
Y. Deng
Abstract This paper presents a new method for pore level network simulation of the distribution of two immiscible phases in a permeable medium. The method requires that the Helmholtz free energy of the system , the medium and the two phases contained within the pore space , be a minimum at all saturation states. We describe the method here and show some typical results from a computer algorithm that implements it. The results include (i) an explanation of the ,scanning' behaviour of capillary pressure curves based wholly on the free energy minimization, (ii) predictions of capillary pressure at arbitrary wetting states, including negative capillary pressures, and (iii) illustrations of how the minimized free energy changes along the scanning curves. The method also predicts the known dependency of the capillary pressure on the pore size distribution and interfacial tension. The current work is restricted to two-dimensional networks, but the free energy minimization appears to be generalizable to three dimensions and to more than two fluid phases. Moreover, functions generated through the minimization, specifically contact areas between the medium surface and the phases, appear to have applications predicting other multiphase petrophysical properties. [source]

Perpendicularly Aligned, Size-and Spacing-Controlled Nanocylinders by Molecular-Weight Adjustment of a Homopolymer Blended in an Asymmetric Triblock Copolymer

ADVANCED FUNCTIONAL MATERIALS, Issue 15 2006
U. Ahn
Abstract Perpendicularly arrayed and size-controlled nanocylinders have been prepared by simply blending an asymmetric polystyrene- block -polyisoprene- block -polystyrene triblock copolymer with polystyrene (the minority component) homopolymers of different molecular weights. The preference for perpendicular orientation or hexagonal ordering of the nanocylinders over a large area in the asymmetric block copolymer can be controlled by adjusting the molecular weight of the blended homopolymer, and the perfection of hexagonal ordering of the perpendicular cylinders can be tuned by using a substrate whose surface tension is much different from that of the majority component of the block copolymer. Such highly controlled nanostructured block-copolymer materials, which have been obtained by a simple method independent of film thickness and interfacial tension between the blocks and the substrates, have wide-ranging commercial potential, e.g., for use in membranes and nanotemplates with size-tunable pores, bandgap-controlled photonic crystals, and other nanotechnological fields demanding a specific nanosize and nanomorphology. [source]

Thermodynamics of Nanosystems with a Special View to Charge Carriers

ADVANCED MATERIALS, Issue 25-26 2009
Joachim Maier
Abstract Basic ingredients of interfacial thermodynamics are recapitulated with a special eye on the nanometer-size regime. Questions are then briefly tackled that arise if, in heterogeneous systems, the constituent phases shrink to atomistic dimensions. Particularly helpful in this context are thermodynamic approaches, in which the introduction of interfacial tension is avoided. While the first part addresses ground structure quantities, the second part deals with questions of size and confinement effects on entropy and energy of ionic and electronic defects. These defects represent the respective excitations within this ground structure. The article emphasizes the similarities between ions and electrons manifested in the statistics rather than elaborating on the discrepancies that are primarily reflected by different densities of states and mobilities. It is, therefore, not the intention of the article to address aspects of nanoelectronics that rely on quantum transport for which many reviews are available. Nonetheless all these discussed aspects are directly relevant for both nanoionics and nanoelectronics. [source]

Morphology prediction of ternary polypropylene composites containing elastomer and calcium carbonate nanoparticles filler

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2007
C. G. Ma
Abstract In this work, the morphology was studied in ternary composites of polypropylene (PP) with nanosized calcium carbonate (nano-CaCO3) fillers and elastomer inclusions and the thermodynamic consideration was used to analyze the formation of phase structure of the composites. The wetting coefficient (,a), interfacial tension (,AB), and work of adhesion (WAB) were calculated to predict dispersion state of nano-CaCO3 fillers. A comparison of the prediction and SEM analysis was given. The results show that three types of phase structures were formed: an encapsulation of the filler by elastomer, a separate dispersion of the filler and elastomer, and a particular structure of the filler at the PP/elastomer interface. The predictions by ,a were all successfully supported-up by SEM analysis and the predictions by WAB were however trustless. Both ,AB and WAB can predict a separate dispersion or an encapsulation phase structure, but they were not available for the particular structure of the filler at the PP/elastomer interface. ,a was competent and favored for the prediction of all three types of morphology among the three parameters. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1578,1584, 2007 [source]

Influence of acid treatment on the surface activity and mass transfer inhibition of a splittable surfactant

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 7 2004
Yuh-Lang Lee
Abstract A splittable surfactant, Triton SP-190, was used to evaluate the effects of acid treatment on the mass transfer rate of an extraction process and on the interfacial tension-lowering activity of a system containing this surfactant. Equilibrium and dynamic interfacial tensions at the interface of CCl4 and the aqueous phase containing surfactant were measured by using pendent drop tensiometry enhanced by video digitization. A single-drop extraction apparatus was used to obtain the extraction percentage of acetic acid from the dispersed CCl4 droplets to the aqueous phase. The results indicate that the inorganic acid treatment can inhibit the dynamic and equilibrium interfacial tension-lowering activity of Triton SP-190. The mass transfer resistance induced by the addition of Triton SP-190 can also be reduced by the pre-treatment of acid. The effectiveness of acid treatment on both properties was greater at low pH values, lower surfactant concentrations, and longer treatment times. With HCl treatment, the equilibrium interfacial tension was not able to increase to the value of a surfactant-free system, but approached a maximum value which was independent of the pH value, but dependent on surfactant concentration. On the contrary, the extraction percentage, which has decreased due to the presence of surfactant, can be recovered completely to that of a surfactant-free system by acid treatment. The acid-treatment time required to achieve a significant recovery of mass transfer rate was much longer than that required to recover the interfacial tension. The present results also demonstrate that the constituents contained in an acid-treatment system had different effectiveness in affecting the interfacial tension and mass transfer rate due to the different mechanisms involved. Copyright © 2004 Society of Chemical Industry [source]

Behavior of an organic solvent drop during the supercritical extraction of emulsions

AICHE JOURNAL, Issue 5 2010
Facundo Mattea
Abstract The behavior of a drop of dichloromethane in water in contact with CO2 at high pressure has been investigated with the purpose of analyzing the phenomena that takes place during the supercritical fluid extraction of emulsions process. Experiments have been performed with and without a solute (,-carotene) and a surfactant (n -octenylsuccinic anhydride-modified starch) dissolved in the drop, and the evolution of the drop volume as well as of the interfacial tension between the drop and the aqueous phase has been measured. Additionally, a mathematical model has been developed that allows describing the mass transfer. Results show that the drop undergoes swelling and shrinking processes due to diffusion of CO2 into the drop and dichloromethane out of the drop. CO2 concentration in the drop can be as high as 0.9 (molar fraction). Emulsion drops behave as miniature gas antisolvent precipitators and many particles are formed inside the drop. The interfacial tension between the drop and the aqueous phase increases during the process, therefore destabilizing the emulsion. © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source]

Terminal and transient drop rise velocity of single toluene droplets in water

AICHE JOURNAL, Issue 1 2010
Mirco Wegener
Abstract The knowledge of the drop rise velocity in dispersed systems is of fundamental importance. Especially, the residence time is needed for calculation of mass transfer rates in extraction columns. This work deals with fluid dynamic measurements of toluene droplets rising in water ranging from 1.0 to 7.0 mm, with the premise of high purity of the used chemicals. The toluene/water-system is widely used as a test system with high interfacial tension. A semiempirical correlation for pure systems to predict the terminal velocity of single rising/falling droplets based on experimental data is presented. Results show that a distinction between maximum and characteristic mean values of the drop rise velocity is necessary, especially in the diameter range 2.4,3.0 mm where unexpected velocity fluctuations occur. Two distinct terminal rise velocities were observed for 3 mm droplets. Furthermore, comparisons of the Weber-Reynolds-correlation and the drag coefficient with correlations from literature show good agreement. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source]

Liquid,liquid two-phase flow in pore array microstructured devices for scaling-up of nanoparticle preparation

AICHE JOURNAL, Issue 12 2009
Shaowei Li
Abstract Nanoparticles have been produced by a T-junction microchannel device in our previous work (Li et al., Langmuir. 2008;24:4194-4199). As a scaling-up strategy, pore array microstructured devices were designed to prepare nanoparticles in this article. H2SO4 and BaCl2, respectively, in two phases to form BaSO4 nanoparticles was used as a test system. The characteristics of a well controlled liquid,liquid two-phase flow in the pore array microstructured devices were presented. Nanoparticles with small size and good dispersibility were produced through drop or disk flows in the microstructured devices. The influence of mass transfer and chemical reaction on interfacial tension and flow patterns was discussed based on the experiments. Meanwhile, the effect of the two phase flow patterns on the nanoparticle size was discussed. It was found that the increase of the amount of mass transfer and chemical reaction could change the flow patterns from disk flow to drop flow. The droplet diameter could be changed in a wide range. Flow patterns could be distinguished based on the measured interfacial tension in different concentrations. The prepared nanoparticles were ranged from 10 nm to 30 nm. Apparently the particle size was decreased with the increase of the droplet size in both the drop flow region and the disk flow region whereas it had a reverse trend in the transition region. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source]

Size distributions and stability of toluene diluted heavy oil emulsions

AICHE JOURNAL, Issue 3 2006
Chandra W. Angle
Abstract The sizes and stability of oil droplets created from various concentrations of heavy oil-in-toluene at a fixed oil:water ratio were investigated during turbulent flow in model process water. The Reynolds number (Re) ranged from 17,000 to 34,500 and was obtained by stirred tank mixing with a Rushton turbine. The droplet sizes were monitored using laser light scattering. Results showed that at high Re and low oil concentrations (that is, low drop-surface coverage), breakage of the droplets was the dominant process, but as Re was reduced, coalescence was dominant. Droplets were less prone to breakage as the oil concentrations in toluene increased, and droplet sizes approached a steady state quickly during mixing. Their size distributions broadened and stability increased as heavy oil in toluene increased. Stability was attributed to a surface coverage by asphaltenes and the consequent interfacial elasticity that provided resilience to breakage. Equilibrium interfacial tension ,E was determined by fitting a diffusion-limited kinetic mathematical model to the data. The Gibbs adsorption model gave a monolayer surface coverage of 3 nm2/mol asphaltenes, consistent with other published results. High zeta potential of the droplets also hindered coalescence. © 2005 American Institute of Chemical Engineers AIChE J, 2006 [source]

Calixarene-entrapped nanoemulsion for uranium extraction from contaminated solutions

JOURNAL OF PHARMACEUTICAL SCIENCES, Issue 3 2010
Aurélie Spagnul
Abstract Accidental cutaneous contamination by actinides such as uranium occurring to nuclear power plant workers can lead to their dissemination in other tissues and induce severe damages. Until now, no specific emergency treatment for such contamination has been developed. The aim of the present work was to formulate a tricarboxylic calix[6]arene molecule, known to exhibit good affinity and selectivity for complexing uranium, within a topical delivery system for the treatment of skin contamination. Since calixarene was shown to reduce oil/water interfacial tension, we have designed an oil-in-water nanoemulsion, taking advantage of the small droplet size offering a high contact surface with the contaminated aqueous medium. Characterization of the calixarene nanoemulsion was performed by determination of the oily droplet size, zeta potential and pH, measured as a function of the calixarene concentration. The obtained results have confirmed the surface localization of calixarene molecules being potentially available to extract uranyl ions from an aqueous contaminated solution. In a preliminary experiments, the calixarene nanoemulsion was used for the removal of free uranium from an aqueous contaminated solution. Results showed that the calixarene nanoemulsion extracted up to 80,±,5% of uranium, which demonstrates the potential interest of this delivery system for uranium skin decontamination. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99: 1375,1383, 2010 [source]

Thermodynamic micellization model for asphaltene precipitation inhibition

AICHE JOURNAL, Issue 2 2000
Huanquan Pan
Aromatic solvents and oil-soluble amphiphiles are recognized as asphaltene precipitation inhibitors in oil production and transportation. In the absence of the model describing the effect of these inhibitors on asphaltene precipitation from crudes, proposed is a thermodynamic micellization model explaining the inhibition mechanism for both aromatic solvents and oil-soluble amphiphiles. The model shows that aromatic solvents are concentrated in the micellar shell, and the interfacial tension between the asphaltene micellar core and shell is reduced as the micelles becomes stabler. A crude, mixed with a small amount of an oil-soluble amphiphile, achieves a high micellar stability. The amphiphiles behave like resin species of the crude and coadsorb onto the micellar core with resins. The adsorption enthalpy of an amphiphile onto the micellar core is much higher than that of the resin and, therefore, amphiphiles can be very effective inhibitors. The results suggest that the adsorption enthalpy data can be used to screen the amphiphiles for asphaltene precipitation inhibition. For a given oil-soluble amphiphile, this model can predict the amount of the amphiphile required to inhibit the precipitation. [source]

PS/PMMA mixed polymer brushes on the surface of clay layers: Preparation and application in polymer blends

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 22 2007
Jian Zhang
Abstract Polystyrene (PS) and poly(methyl methacrylate) (PMMA) mixed polymer brushes on the surface of clay layers were prepared by using in situ free radical polymerization. Free radical initiator molecules with two quaternary ammonium groups at both ends were intercalated into the interlayer spacing of clay layers. The amount of polymer brushes grafted on the surface of clay layers can be controlled by controlling the polymerization time. Thermogravimetric analysis, X-ray diffraction, and high-resolution transmission electron microscope results indicated successful preparation of the mixed polymer brushes on the surface of clay layers. The kinetics of the grafting of the monomers was also studied. The mixed polymer brushes on the surface of clay layers were used as compatibilizers in blends of PS and PMMA. In the blends, the intercalated clay particles tend to locate at the interface of two phases reducing the interfacial tension. In the meanwhile, PMMA homopolymer chains tend to intercalate into clay layers. The driving force for the intercalation is the compatibility between homo-PMMA chains and PMMA brushes on the surface of clay layers. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5329,5338, 2007 [source]

Synthesis and interfacial behaviors of amphiphilic poly(oxypropylene) amidoacids

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 1 2006
Kuan-Liang Wei
Abstract A series of hydrophobic poly(oxypropylene) (POP)-backboned and hydrophilic poly(oxyethylene)-backboned amidoacids and imidoacids were prepared through the reaction of poly(oxyalkylene) diamines and trimellitic anhydride (TMA) under mild conditions. The synthesized copolymers were characterized with nuclear magnetic resonance and Fourier transform infrared. Their ability to lower the water surface tension and toluene/water interfacial tension was measured and correlated with the hydrophobic/hydrophilic balance with multiple sodium carboxylate functionalities. The specific POP2000/TMA copolymers, consisting of a 2000 g/mol POP segment and multiple amidoacid functionalities, enabled the demonstration of a strong surfactant tendency and a critical micelle concentration at 0.1 wt %. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 646,652, 2006 [source]

Investigation of the mechanism of lubrication in starch,oil composite dry film lubricants,

LUBRICATION SCIENCE, Issue 1 2007
G. Biresaw
Abstract The boundary coefficient of friction (COF) of starch,oil composite dry film lubricants was investigated as a function of starch type (waxy vs. normal purified food grade corn starch), oil chemistry (hexadecane vs. oleic acid and various vegetable oils), and starch-to-oil ratio. Based on the results, a mechanism of starch,oil interaction in these composites was proposed. According to the proposed mechanism: (a) the oil in the composite is distributed between the bulk and the surface of the starch; and (b) the fraction of the oil trapped in the bulk and that adsorbed on the surface are related to each other by an equilibrium constant, and are functions of the total oil concentration in the composite. In line with the proposed mechanism, an adsorption model was used to quantify the free energy of adsorption (,Gads) of the polar oils onto the starch surface. The analysis gave ,Gads values that were higher than those reported for the adsorption of the same polar oils onto steel surfaces. This result is consistent with the effect of the relative surface energies of steel and starch on the adsorption of polar oils. The adsorption property of the non-polar hexadecane relative to the polar oils was estimated by comparing their interfacial tensions with starch. The result showed a higher interfacial tension for hexadecane,starch than that for the polar oil,starch composites. This result predicts a relatively poorer compatibility with, and, hence, poorer adsorption of hexadecane onto starch leading to higher COF, as was observed in the friction measurements. Published in 2006 by John Wiley & Sons, Ltd. [source]

Design of Blends with an Extremely Low Viscosity Ratio between the Dispersed and Continuous Phases.

MACROMOLECULAR SYMPOSIA, Issue 1 2007
Dependence of the Dispersed Phase Size on the Processing Parameters
Abstract Summary: This work deals with the development of the dispersed phase morphology in immiscible blends of poly(ethylene glycol)/polyamide 66 (PEG/PA) with an extremely low viscosity ratio. The blends were obtained, under different operating conditions, by melt blending in an internal mixer. The objective was to examine the influence of the main processing parameters on the particles size of the minor phase (PEG). A model was elaborated to describe the dependence of the particle size on interfacial tension, PEG concentration, shear rate and viscosity ratio between the two blend components. [source]

Thermodynamic Modeling of Polymer Solution Interface

MACROMOLECULAR THEORY AND SIMULATIONS, Issue 2 2009
Majid Ghiass
Abstract A new method is presented to characterize the interfacial concentration field and interfacial tension between equilibrium polymer solution phases, using readily accessible equilibrium concentration data. The new method is tested and validated using experimental data from different polystyrene solutions and it consists of i) calculation of a universal expression for the concentration gradient coefficient based on the Cahn-Hilliard model and the Wolf interfacial tension master equation, and ii) development of a highly accurate algebraic function (Kappa distribution) that, for a given equilibrium polymer concentration set, yields the essentially exact interfacial profile predicted by the classical gradient theory for polymer solutions. [source]

Interfacial Thermodynamics of Polymeric Mesophases

MACROMOLECULAR THEORY AND SIMULATIONS, Issue 8 2004
Alejandro D. Rey
Abstract Summary: A complete mechanical-thermodynamical formulation for multicomponent nematic polymer-isotropic fluid interfaces is derived, validated, and used to derive the structure and shape equations for these soft anisotropic polymer interfaces. The fundamental role of liquid crystalline order and long range effects in coupling bulk and interfacial effects, and in coupling thermodynamical/liquid crystalline order/geometrical variables is demonstrated, discussed, and validated. The Gibbs-Duhem nemato-thermodynamics equation emerges from an interfacial tension ,,=,,(,, ,, Q, ,sQ, k) that depends on temperature (,), chemical potential (,), nematic tensor order parameter Q, surface gradients of Q, and geometry k, and leads to new couplings in these enhanced phase spaces. The role of entropy and adsorption, and long range effects on interfacial shape and structure selection is revealed. For flat interfaces the preferred structure emerges from a competition between energy, entropy, and adsorption. [source]

Effects of chemical composition and thermal stability of finishes on the compatibility between glass fiber and high melting temperature thermoplastics

POLYMER COMPOSITES, Issue 2 2000
P. Gao
Experimental studies were made on the surface characteristics of glass fibers with two different finishes. The effects of the chemical composition and thermal stability of the finishes on the compatibility between glass fibers and high melting temperature thermoplastics were investigated. Thermogravimetric Analysis (TGA) was used to characterize the composition of surface finishes and their thermal stability. The chemical composition of surface finishes was investigated using a combination of X-ray photoelectron spectroscopy (XPS) and Time-of-Flight secondary ion mass spectrometry (ToF SIMS). Static contact angle measurements were performed at room temperature to characterize the interfacial tension between the glass fibers and thermoplastics. The study provides a fundamental understanding on some important compatibility issues between thermoplastic resins and glass fiber related to composite fabrication and application. [source]

Compatibilization of PP/PAE blends by means of the addition of an ionomer

POLYMER ENGINEERING & SCIENCE, Issue 8 2010
A. Granado
Minor amounts of poly(ethylene- co -methacrylic acid) ionomer neutralized with Zn (PEMA-Zn) were added in the melt state to blends of polypropylene (PP) with up to 40% of poly(amino ether) (PAE) resin. Given the good barrier characteristics of PAE, it is a good candidate to improve the poor barrier properties of PP. However, PP/PAE blends were found to be almost fully immiscible, with a large dispersed phase size and a brittle mechanical behavior. Upon PEMA-Zn addition, the dispersed particle size clearly decreased from diameters of several microns to diameters mostly below 0.5 ,m, indicating that compatibilization occurred. This compatibilization was due to the presence of PEMA-Zn in the two phases of the blends and was additionally proven by the large decrease observed in the interfacial tension. Further, the fine morphology led to an enhancement in the unnotched impact strength of the ternary blends and of their ductile behavior (elongation at break 30- to 40-fold that of the corresponding binary blends). POLYM. ENG. SCI., 50:1512,1519, 2010. © 2010 Society of Plastics Engineers [source]

Improved toughness in HIPS obtained from different styrene/butadiene-graded block copolymers through modification of the polydispersity index of the PS block,

POLYMER ENGINEERING & SCIENCE, Issue 10 2006
Graciela Morales
The polymerization of styrene in the presence of graded block copolymers with a polystyrene/polybutadiene composition of 40/60, 30/70, and 20/80 and with a polydispersity index (Mw/Mn) in the polystyrene block varying from 1.1 to 1.6 was studied. As the polydispersity index of the polystyrene block increases, an improvement of up to 50% in the Izod impact toughness of the produced high-impact polystyrene was achieved. The rubber particle morphology type, the size, and the volume fraction of the rubber phase particles could be modified through changes in the composition of the graded block copolymer. The changes that occurred in the rubber phase were mainly generated by the variation in the interfacial tension between the phases, and this variation was principally attributed to an increase in the polydispersity index of the polystyrene block in the precursor copolymer. POLYM. ENG. SCI., 46:1333,1341, 2006. © 2006 Society of Plastics Engineers [source]

Morphology and rheological properties of polypropylene/reactive elastomer blends

POLYMER ENGINEERING & SCIENCE, Issue 10 2002
Frédérique Marguerat
The relation of morphology to the linear viscoelastic properties for polymer blends consisting of an inert polypropylene and an elastomeric dispersed phase, made of two miscible copolymers, EVA and EMA, was investigated. The rheological properties of the elastomeric phase were modified by crosslinking in presence of an organometallic catalyst. The activation energy for the transesterification reaction taking place between EVA and EMA has been determined by following the increases of the complex viscosity with time and temperature. The Palierne model has been used to describe the linear viscoelastic behavior of the blends, and to estimate the interfacial tension between the immiscible components. The model was shown to describe relatively well the linear viscoelastic properties of reactive and nonreactive blends containing 30% or less elastomer. In parallel, the morphology of reactive and nonreactive blends (i.e. without catalyst in the elastomeric phase), before and after rheological experiments, has been determined using scanning electron microscopy. The size of the dispersed elastomeric particles for reactive blends prepared using an internal mixer was found to be, in most cases, much smaller than that for nonreactive blends. [source]

Carbon black filled PET/PMMA blends: Electrical and morphological studies

POLYMER ENGINEERING & SCIENCE, Issue 10 2000
J. G. Mallette
In this work, the electrical and morphological properties of blends of poly(ethylene terephthalate) (PET), poly(methyl methacrylate) (PMMA), and carbon black (CB) were analyzed. Resistivity decreases similarly in both PET and PMMA with CB concentration. Similarly in the PET/PMMA blend, extensive modification to this behavior occurs, since resistivity becomes a function of morphology and specific location of CB in the polymers. A minimum in the resistivity of the blend with 5% CB (PET basis) is observed at 100% PET, whereas with an increase in the CB content to 20%, the minimum in the resistivity shifts to 60% PET. High conductivity is observed when PET is the continuous phase (having the larger viscosity). Large stresses lead to a large dispersion of CB and a high deformation and rupture of the dispersed PMMA phase. This situation itself promotes an increase of surface area of droplets and high CB concentrations at the interface. Consideration is given to models that predict a selective location of conductive particles in the PET matrix based on its lower interfacial tension with CB. [source]

HLD concept as a tool for the characterization of cosmetic hydrocarbon oils,

POLYMER INTERNATIONAL, Issue 4 2003
Véronique Nardello
Abstract The HLD (hydrophilic lipophilic deviation) concept was applied to several water/i -C13En/2-propanol/hydrocarbon oil systems. For each oil, the optimum formulation, corresponding to HLD,=,0, was determined by systematically changing the formulation as a monotonic variation of the surfactant ethylene oxide number (EON) scanned variable. The optimum value for EON (symbolized as EON*) was accurately pinpointed both by estimating the solubilization and by measuring the interfacial tension with a spinning-drop tensiometer. This method allowed the classification of cosmetic hydrocarbon oils such as isohexadecane, paraffin oil, squalane, squalene and hydrogenated polydecenes in C30, C40, C40,C50, on an equivalent alkane carbon number (EACN) calibration scale based on five linear alkanes covering the liquid range (C5 to C16). © 2003 Society of Chemical Industry [source]

The effect of surfactants on deformation of falling non-Newtonian drops in a Newtonian liquid

THE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 1 2008
Denis RodrigueArticle first published online: 4 MAR 200
Abstract Deformation of settling non-Newtonian ellipsoidal drops in a Newtonian liquid was experimentally observed. Corn oil was used as the Newtonian phase and solutions of polyacrylamide in aqueous glycerine as the non-Newtonian phase. The shear-thinning behaviour of the drops fluid was controlled by the amount of polymer dissolved, while the effect of interfacial tension was examined using different concentrations of sodium dodecyl sulphate (SDS). In the range of 1,<,E,<,2.9, 0.2,<,Eo,,<,23, and 0,<,Ma,<,17.2, drop eccentricity increased linearly with a modified Eötvös number taking into account the effect of surfactants. For the range of experimental conditions tested, drop deformation was mainly controlled by viscous and interfacial tension forces, while shear-thinning and inertia effects were negligible. On a observé expérimentalement la déformation de gouttelettes ellipsödales non newtoniennes sédimentant dans un liquide newtonien. Del'huile de mäs a été utilisée comme phase newtonienne et des solutions de polyacrylamide dans de la glycérine aqueuse comme phase non newtonienne. Le comportement rhéofluidifant du fluide des gouttes est contrôlé par la quantité de polymères dissous, tandis que l'effet de la tension interfaciale est examiné avec différentes concentrations de sulfate de dodécyle de sodium. Dans la gamme de 1,<,E,<,2,9, 0,2,<,Eo 23 and 0,<,Ma,<,17,2, l'eccentricité des gouttelettes augmente linéairement avec le nombre d'Eötvös modifié en tenant compte de l'effet des surfactants. Pour la gamme des conditions expérimentales testées, la déformation des gouttelettes est principalement contrôlée par les forces de tension visqueuse et interfaciale, tandis que les effets de rhéofluidifiance et d'inertie sont négligeables. [source]

Autonomous Movement of Silica and Glass Micro-Objects Based on a Catalytic Molecular Propulsion System

CHEMISTRY - A EUROPEAN JOURNAL, Issue 10 2008
Christoph Stock Dr.
Abstract A general approach for the easy functionalization of bare silica and glass surfaces with a synthetic manganese catalyst is reported. Decomposition of H2O2 by this dinuclear metallic center into H2O and O2 induced autonomous movement of silica microparticles and glass micro-sized fibers. Although several mechanisms have been proposed to rationalise movement of particles driven by H2O2 decomposition to O2 and water (recoil from O2 bubbles,36,,45 interfacial tension gradient37,42), it is apparent in the present system that ballistic movement is due to the growth of O2 bubbles. [source]

Effect of Cross Linking Agent on Alkali/Surfactant/Polymer

CHINESE JOURNAL OF CHEMISTRY, Issue 1 2008
Ke ZHANG
Abstract Alkali/surfactant/polymer (ASP) multisystem flooding technique, which has an expansive application prospect, is one of the enhancing oil recovery (EOR) methods. By adding the organic chromium to the ASP, the molecular structure of polymer was made to change, and the capability of controlling mobility coefficient of ASP was improved. The results showed that multisystem could still keep ultra-low interfacial tension between the multisystem and crude oil after addition of Cr3+. The resistance factor and residual resistance factor, the indicator which describes the capability of controlling mobility, upgraded strikingly. However its storage modulus and loss modulus, the indicator which describes viscoelasticity, increased. The results of physical simulation experiment indicated that this type of improved ASP could increase the recovery ratio by 4.3% compared to common ASP multisystem. [source]

Influence of acid treatment on the surface activity and mass transfer inhibition of a splittable surfactant

A descriptive force-balance model for droplet formation at microfluidic Y-junctions

AICHE JOURNAL, Issue 10 2010
Maartje L. J. Steegmans
Abstract In a previous article, we studied the basics of emulsification in microfluidic Y-junctions, however, without considering the effect of viscosity of the disperse phase. As it is known from investigations on many different microstructures that viscosity and viscosity ratio are governing parameters for droplet size, we here investigate whether this is also the case for microfluidic Y-junctions and do so for a wide range of process conditions. The investigated Y-junctions have a width of 19.9 or 12.8 ,m and a depth of 5.0 ,m, and the formed monodisperse droplets (CV < 1%) are between 3 and 20 ,m. We varied the disperse-phase viscosity using different oils (1,105 mPa s), and continuous-phase viscosity using glycerol,water and ethanol,water mixtures (1.0,6.2 mPa s), which corresponds to disperse-to-continuous-phase viscosity ratios from 0.4 to 105.0. Through the variation of the liquids, also a range in interfacial tensions (12,55 mN m,1) is assessed. The disperse-phase flow rate is varied from 0.039 to 18.0 ,L h,1, the continuous-phase flow rate from 1.39 ,L h,1 to 0.41 mL h,1, and this corresponds to flow rate ratios from 1.1 × 10,3 to 0.14, which is once again based on wide range of conditions. For all these conditions, in which droplets are formed in the dripping and jetting regime, the droplet size could be described with a model based on the existing force-balance model, but now extended to incorporate the cross-sectional area of the droplet and the resistance with the wall. Surprisingly enough, it was found that the droplet size is not influenced by the disperse-phase viscosity, or the viscosity ratio, but it is dominated by the resistance with the wall and the continuous-phase properties. Because of this, emulsification with Y-junctions is intrinsically simpler than any other shear-based method as droplet size is only determined by the continuous phase. © 2010 American Institute of Chemical Engineers AIChE J, 2010 [source]