Specific rheology - morphology relationships for some blends containing LCPs

Куличихин, В. Г.; Plotnikova, E. P.; Субботин, А. А.; Platè, N.A.

doi:10.1007/s003970000091

Cited by 18 publications

(7 citation statements)

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“…The particles are localized in the zone of minimal stresses and play the role of a kind of indicator of the normal stress profile. A similar morphological picture was directly observed in strong flows of a two-phase polymer blend [35]. Component separation took place and a low-viscosity LC-polymer created the structure in the form of a regular circular torus.…”

Section: Some Experimental Observationssupporting

confidence: 70%

“…In this section, we will present some experimental observations which illustrate and confirm the results of computer simulation based on the proposed model. These data were obtained in our previous experimental studies devoted to the behaviour of polymer melts, polymer blends, and slightly filled polymer melts in strong shear flows created in deformation between cone and plate or spherical surface and plate [35,36]. In the first case, we were dealing with homogeneous shear flow and in the second one the shear rate varied along the radius.…”

Section: Some Experimental Observationsmentioning

confidence: 93%

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Self-Organization of Polymeric Fluids in Strong Stress Fields

Semakov

Куличихин

Malkin

2015

Advances in Condensed Matter Physics

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Analysis of literature data and our own experimental observations have led to the conclusion that, at high deformation rates, viscoelastic liquids come to behave as rubbery materials, with strong domination by elastic deformations over flow. This can be regarded as a deformation-induced fluid-to-rubbery transition. This transition is accompanied by elastic instability, which can lead to the formation of regular structures. So, a general explanation for these effects requires the treatment of viscoelastic liquids beyond critical deformation rates as rubbery media. Behaviouristic modeling of their behaviour is based on a new concept, which considers the medium as consisting of discrete elastic elements. Such a type of modeling introduces a set of discrete rotators settled on a lattice with two modes of elastic interaction. The first of these is their transformation from spherical to ellipsoidal shapes and orientation in an external field. The second is elastic collisions between rotators. Computer calculations have demonstrated that this discrete model correctly describes the observed structural effects, eventually resulting in a “chaos-to-order” transformation. These predictions correspond to real-world experimental data obtained under different modes of deformation. We presume that the developed concept can play a central role in understanding strong nonlinear effects in the rheology of viscoelastic liquids.

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Section: Some Experimental Observationssupporting

confidence: 70%

Section: Some Experimental Observationsmentioning

confidence: 93%

Self-Organization of Polymeric Fluids in Strong Stress Fields

Semakov

Куличихин

Malkin

2015

Advances in Condensed Matter Physics

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“…We can expect decrease of mechanical energy dissipation and, consequently, decrease of viscosity. Formation of the circle morphology is typical as well for blends of incompatible polymers (Kulichikhin et al, 2001), and in this case drops of disperse phase should have low viscosity and be enough large (more than critical Taylor radius) to be extended in shear field to form closed circles. The viscosity of two-component blend is a sum of inputs stipulated by viscosity of components and their volume fraction.…”

Section: Rheology and Stream Morphologymentioning

confidence: 99%

Rheology-Morphology Interrelationships for Nanocomposites based on Polymer Matrices

Куличихин¹,

Semakov²,

Karbushev³

et al. 2011

Advances in Nanocomposites - Synthesis, Characterization and Industrial Applications

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“…43 Transition through the yield stress also results in the formation of a new material structure. 44 The point of view connecting all these peculiarities of the behavior of multi-component materials was expressed in the following way: ''Shear localization is a generic feature of flows in yield stress fluids and soft glassy materials''. 45 It might be true but the inverse statement is not: shear localization can happen in the flow of fluids not demonstrating yielding (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…This can also take place due to separation of a low viscous component in a polymer blend. 44 Generally speaking, a possibility of appearance of a low viscous thin near-wall layer is still discussible. [49][50][51] Slip with rupture in the velocity profile is also possible at stratified flow if layers are formed by different polymer melts.…”

Section: Introductionmentioning

confidence: 99%

Viscoplasticity and stratified flow of colloid suspensions

et al. 2012

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Investigation of the rheology of concentrated colloid suspensions and direct observation of their flow allowed us to find several effects inherent to these media as typical soft matter. So, at low stress amplitudes, these colloids behave as mild gels with frequency independent elastic modulus and low mechanical losses. Meanwhile, suspensions demonstrate dualism of properties: at a given shear rate, they behave as viscoplastic media with clearly expressed yielding, while at a given low stress the pronounced Newtonian plateau is detected. The increase in shear rates and stresses leads to the sharp drop of the apparent viscosity, which usually is treated as the yielding effect. Transition through the yield stress is of a dynamic nature because the threshold stress depends on time and suspensions are thixotropic yielding materials. In the transient shear rate range, an unstable regime of deformation appears. It manifests itself either as deformation thickening up to jamming, or as the excitation of selfoscillations. The measuring of rheological properties in varying volume-to-surface ratio of a sample proves that flow of a suspension with high velocity at constant shear stress actually proceeds in a narrow layer inside the instrument gap. This conclusion has been confirmed by direct visual observations demonstrating that a flux is separated into three layers. A wide almost motionless layer is seen near a stationary surface. Near a moving surface, a narrow band with linear velocity profile is detected. Between them, a rather wide transient layer is observed and shear rate in this layer exceeds the average (global) shear rate by several times. Approximately, only a half of the total volume of a suspension is involved in flow. So, we observed a three-band flux of a suspension not described before. Shearing leads to an anisotropic structure of a solid phase.

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Specific rheology - morphology relationships for some blends containing LCPs

Cited by 18 publications

References 0 publications

Self-Organization of Polymeric Fluids in Strong Stress Fields

Self-Organization of Polymeric Fluids in Strong Stress Fields

Rheology-Morphology Interrelationships for Nanocomposites based on Polymer Matrices

Viscoplasticity and stratified flow of colloid suspensions

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