Correlation between the Interfacial Tension and Dispersed Phase Morphology in Interfacially Modified Blends of LLDPE and PVC

1999 ◽  
Vol 32 (5) ◽  
pp. 1637-1642 ◽  
Author(s):  
H. Liang ◽  
B. D. Favis ◽  
Y. S. Yu ◽  
A. Eisenberg
Keyword(s):  
Interfacial Tension ◽  
Phase Morphology ◽  
Dispersed Phase

Phase Inversion in Two-Phase Liquid Systems

1992 ◽  
Vol 57 (7) ◽  
pp. 1419-1423
Author(s):  
Jindřich Weiss
Keyword(s):  
Interfacial Tension ◽  
Phase Inversion ◽  
Continuous Phase ◽  
Considerable Effect ◽  
Weak Dependence ◽  
Dispersed Phase ◽  
Two Phase ◽  
Liquid Systems ◽  
Phase Liquid

New data on critical holdups of dispersed phase were measured at which the phase inversion took place. The systems studied differed in the ratio of phase viscosities and interfacial tension. A weak dependence was found of critical holdups on the impeller revolutions and on the material contactor; on the contrary, a considerable effect of viscosity was found out as far as the viscosity of continuous phase exceeded that of dispersed phase.

The role of dispersed phase morphology on toughening of epoxies

Polymer ◽  
1997 ◽  
Vol 38 (1) ◽  
pp. 21-30 ◽  
Author(s):  
Julie Y. Qian ◽  
Raymond A. Pearson ◽  
Victoria L. Dimonie ◽  
Olga L. Shaffer ◽  
Mohamed S. El-Aasser
Keyword(s):  
Phase Morphology ◽  
Dispersed Phase

Effect of Epoxide Group in Thermoplastic Elastomer on the Properties of Polyamide6 and Low-Density Polyethylene Blends

2014 ◽  
Vol 979 ◽  
pp. 143-146 ◽  
Author(s):  
Surakit Tuampoemsab ◽  
Saad Riyajan ◽  
Thritima Sritapunya ◽  
Pornsri Pakeyangkoon
Keyword(s):  
Impact Strength ◽  
Natural Rubber ◽  
Shear Viscosity ◽  
Thermoplastic Elastomer ◽  
Phase Morphology ◽  
Epoxidized Natural Rubber ◽  
Low Density Polyethylene ◽  
Dispersed Phase ◽  
Low Density ◽  
Epoxide Group

Studies on the effect of percentages of epoxide group in thermoplastic elastomer as a compatibilizer on properties of polyamide6 (PA6) and low-density polyethylene (LDPE) blends was successfully carried out in this study. Thermoplastic epoxidized natural rubber (TPENR), made from epoxidized natural rubber (ENR) and LDPE, prepared from 3 types of ENR, i.e., ENR-20, ENR-50 and ENR-70, with the ratio of 90/10 of LDPE/ENR by weight. TPENR was applied as a compatibilizer into the blend of PA6/LDPE/TPENR at the ratio by weight of 80/20/1 by using a twin screw extruder at 235°C. All test specimens were characterized for phase morphology, impact strength and rheological behaviour. Results exhibited that phase morphology of PA6/LDPE blend was incompatible. The addition of TPENR improved the compatibility of PA6/LDPE blends. With inclusion of TPENR-20 as a compatibilizer, the uniformity and the maximum reduction of dispersed phase sized were observed. Moreover, it was revealed that the rheological properties such as shear viscosity increased when compared with PA6/LDPE incompatible blend. In addition, it was found that the highest shear viscosity and also the highest impact strength were obtained for the blend of PA6/LDPE compatibilized by TPENR-20. This result was further supported by SEM images, which showed that the smallest dispersed phase size occurred when a TPENR-20 was used as a compatibilizer. So, it was clearly demonstrated in this study that the suitable type of TPENR, i.e., TPENR-20, has an effect on improving phase morphology and properties of PA6/LDPE blends.

Evaluation of the Interfacial Tension Between a Microemulsion and the Excess Dispersed Phase

1981 ◽  
Vol 21 (05) ◽  
pp. 593-602 ◽  
Author(s):  
E. Ruckenstein
Keyword(s):  
Interfacial Tension ◽  
Oil Recovery ◽  
Phase Inversion ◽  
The Other ◽  
Dispersed Phase ◽  
Middle Phase ◽  
Inversion Point ◽  
Interfacial Tensions ◽  
Dispersed Medium ◽  
Oil Water

Abstract From a consideration of the thermodynamic stability of microemulsions, one can establish a relation between the interfacial tension y at the surface of the globules and the derivative, with respect to their radius re, of the entropy of dispersion of the globules in the continuous medium. Expressions for the entropy of dispersion are used to show that gamma is approximately proportional to kT/r2e, where k is Boltzmann's constant and T is the absolute temperature. Since the environment of the interface between the microemulsion and the excess dispersed medium is expected to be similar to that at the surface of the globules, these expressions are used to evaluate the interfacial tension between microemulsion and excess dispersed medium. Values between 10 and 10 dyne/cm that decrease with increasing radii are obtained, in agreement with the range found experimentally by various authors. The origin of the very small interfacial tensions rests ultimately in the adsorption of surfactant and cosurfactant on the interface between phases. The effect on the interfacial tension of fluctuations from one type of microemulsion to the other, which may occur near the phase inversion point, is discussed. Introduction The system composed of oil, water, surfactant, cosurfactant, and salt exhibits interesting phase equilibria. For sufficiently large concentrations of surfactant, a single phase can be formed either as a microemulsion or as a liquid crystal. In contrast, at moderate surfactant concentrations, two or three phases can coexist. For moderate amounts of salt (NaCl), an oil phase is in equilibrium with a water-continuous microemulsion, whereas for high salinity, an oil-continuous microemulsion coexists with a water phase. At intermediate salinity, a middle phase (probably a microemulsion) composed of oil, water, surfactants, and salt forms between excess water and oil phases. Extremely low interfacial tensions are found between the different phases, with the lowest occurring in the three-phase region. These systems have attracted attention because of their possible application to tertiary oil recovery. It has been shown that the displacement of oil is most effective at very low interfacial tensions.Microemulsions have been investigated with various experimental techniques, such as low-angle X-ray diffraction, light scattering, ultracentrifugation, electron microscopy, and viscosity measurements. These have shown that the dispersed phase consists of spherical droplets almost uniform in size. While it is reasonable to assume that the microemulsions coexisting with excess oil or water contain spherical globules of the dispersed medium, the structure of the middle-phase microemulsion is more complex. Experimental evidence obtained by means of ultracentrifugation indicates, however, that at the lower end of salinity the middle phase contains globules of oil in water, while at the higher end the middle phase is oil continuous. A phase inversion must occur, at an intermediate salinity, from a water-continuous to an oil-continuous microemulsion. The free energies of the two kinds of microemulsions are equal at the inversion point. Since their free energy of formation from the individual components is very small, small fluctuations, either of thermal origin or due to external perturbations, may produce changes from one type to the other in the vicinity of the inversion point. As a consequence, near this point, it is possible that the middle phase is composed of a constantly changing mosaic of regions of both kinds of microemulsions. SPEJ P. 593^

Effect of Fluid Properties on Droplet Generation in a Microfluidic T-Junction

2014 ◽  
Author(s):  
Katerina Loizou ◽  
Voon-Loong Wong ◽  
Wim Thielemans ◽  
Buddhika Hewakandamby
Keyword(s):  
Interfacial Tension ◽  
Scaling Laws ◽  
Viscosity Ratio ◽  
Continuous Phase ◽  
Generation Mechanism ◽  
Droplet Generation ◽  
Dispersed Phase ◽  
Supporting Evidence ◽  
Fluid Properties ◽  
Break Up

Over the last decade, significant work has been performed in an attempt to quantify the effect of different parameters such as flowrate, geometrical and fluid characteristics on the droplet break up mechanism in microfluidic T-Junctions. This demand is dictated by the need of tight control of the size and dispersity of the droplets generated in such geometries. Even though several researchers have investigated the effect of viscosity ratio on both the droplet break up mechanism as well as on the regime transition, fluid properties have not been included in most scaling laws. It is therefore evident that the contribution of fluid properties has not been quantified thoroughly. In the present work, the effect of fluid properties on the volume of droplets generated in a microfluidic T-junction is investigated. The main aim of this work is to examine the influence of viscosity of both the dispersed and continuous phase as well as the effect of interfacial tension on the size of droplet generated along with the break up mechanism. Three different oils have been utilised as continuous phase in this work to enable investigation of the effect of viscosity of the continuous phase with experiments performed at constant Capillary numbers. Various glycerol weight percentages have been employed to vary the viscosity of the dispersed phase fluid (water). Lastly, the effect of interfacial tension has been explored using two of the oils at constant μcUc (viscous force term). High speed imaging has been utilised to visualise and measure the volume of the resulting droplets. The viscosity ratio (viscosity of dispersed phase over viscosity of continuous phase) between the two phases appears to affect the droplet generation mechanism, especially for the highest viscosity ratio employed (mineral oil-water system) where the system behaves in a noticeably different way. Influence of interfacial tension is also noticeable even though less evident. In terms of the effect of viscosity of dispersed phase on the droplet generation a small difference on the volume of the droplets generated in olive oil glycerol systems is also reported. In an attempt to enumerate the effect of fluid properties on the droplet generation mechanism in a microfluidic T-junction, this paper will present supporting evidence in detail on the above and a comparison of the findings with the existing theories.

Relationship between interfacial tension and dispersed-phase particle size in polymer blends. I. PP/EPDM

2002 ◽  
Vol 86 (12) ◽  
pp. 3148-3159 ◽  
Author(s):  
H. Shariatpanahi ◽  
H. Nazokdast ◽  
B. Dabir ◽  
K. Sadaghiani ◽  
M. Hemmati
Keyword(s):  
Particle Size ◽  
Interfacial Tension ◽  
Polymer Blends ◽  
Phase Particle ◽  
Dispersed Phase

scholarly journals Drop formation in microfluidic cross-junction: jetting to dripping to jetting transition

2019 ◽  
Vol 23 (8) ◽  
Author(s):  
Nina M. Kovalchuk ◽  
Masanobu Sagisaka ◽  
Kasparas Steponavicius ◽  
Daniele Vigolo ◽  
Mark J. H. Simmons
Keyword(s):  
Interfacial Tension ◽  
Capillary Number ◽  
Continuous Phase ◽  
Flow Rate Ratio ◽  
Dispersed Phase ◽  
Flow Focusing ◽  
Jet Formation ◽  
Relative Contribution ◽  
Power Law Function ◽  
Dispersed Phases

AbstractThe regimes of drop generation were studied in a Dolomite microfluidic device which combined both hydrodynamic and geometrical flow focusing over a broad range of flow rates. A series of aqueous dispersed phases were used with a viscosity ratio between continuous and dispersed phases of close to unity. Surfactants were added to alter the interfacial tension. It was shown that the transition from dripping to jetting is well described by the capillary numbers of both the dispersed and continuous phases. Only the jetting regime was observed if the capillary number of the dispersed phase was above a critical value, whereas at smaller values of this parameter a jetting → dripping → jetting transition was observed by increasing the capillary number of the continuous phase. The analysis performed has shown that the conditions for a dripping to jetting transition at moderate and large values of the capillary number of the continuous phase can be predicted theoretically by comparison of the characteristic time scales for drop pinch-off and jet growth, whereas the transition at small values cannot. It is suggested that this transition is geometry mediated and is a result of the interplay of jet confinement in the focusing part and a decrease of confinement following entry into the main channel. The flow fields inside the jet of the dispersed phase were qualitatively different for small and large values of the capillary number of the continuous phase revealing the relative contribution of the dispersed phase flow in jet formation. The volume of the drops formed in the jetting regime increased as a power law function of the flow rate ratio of the dispersed to continuous phase, independent of the interfacial tension.

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