Complex miscibility behaviour for polymer blends in flow

Fernández, María Luz; Higgins, J. S.; Horst, Roland; Wolf, Bernhard

doi:10.1016/0032-3861(95)90686-v

Cited by 54 publications

(30 citation statements)

References 27 publications

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“…These predictions were confirmed by experiments on blends of ethylene--vinyl acetate (EVAc) with chlorinated polyethylene, CPE, and PS/PVME [240][241][242][243][244]. The shear-induced mixing was also observed in PS blends with polyisobutylene, PIB [245].…”

Section: Influence Of Rheology On Thermodynamicssupporting

confidence: 65%

Rheology of Polymer Blends

Utracki

2011

Encyclopedia of Polymer Blends

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The first polymer blend was patented in 1846 and since then blends have became ubiquitous. Blending may provide a full set of material properties, improving processability and/or specific properties. With the advancement of technology there is the notorious growth of complexity -while in the beginning blending involved two polymers, initially without a compatibilizer, more recent commercial alloys have up to five polymers, three compatibilizers, and frequently are reinforced with macro-or nanoparticles [1].Blends are classified as either thermodynamically miscible or immiscible, with the latter dominating. However, imposition of a flow affects the thermodynamic equi librium and it may enhance the miscibility of immiscible blends or vice-versa -there is an interrelation between rheology and thermodynamics. Similarly, flow affects the degree of deformation of the dispersed phase, thus in immiscible blends there are other interrelations between rheology and morphology, which affect the blend performance. To the complexity of polymer alloys and blends (PAB) behavior one must add the incorporation of solids, either in the form of filler and nanofiller particles or by simple fact of blending two components with widely different transition temperatures.Since the flow of PAB is complex, it is useful to revert to simple models, for example, for miscible blends to solutions or mixtures of polymer fractions, for immiscible blends to emulsions or suspensions, and for compatibilized blends to block copolymers (Table 2.1). It is also advisable to study flow behavior of multiphase systems at constant stress (not at constant deformation rate) [2,3].For miscible blends, the free volume theory predicts a positive deviation from the log-additivity rule (PDB, positively deviating blend). However, depending on the system and method of preparation, these blends may show a positive deviation, negative deviation, or additivity [4]. Upon mixing, the presence of specific interac tions may change the free volume and degree of entanglement, which in turn affect the flow behavior [5,6]. For immiscible blends the flow is similarly affected, but in addition there are at least three contributing phases: of the polymeric matrix, of the First Edition. Edited by Avraam I. Isayev.

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Section: Influence Of Rheology On Thermodynamicssupporting

confidence: 65%

Rheology of Polymer Blends

Utracki

2011

Encyclopedia of Polymer Blends

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“…[12][13][14][15] Katsaros et al [12] reported an increase in the cloud point of PS/PVME blend by as much as 12 8C in a planar stagnation flow. On the other hand, at temperatures as low as 30 8C below the quiescent cloud point, flow induced-phase separation was observed in both shear flow and extensional flow.…”

Section: Introductionmentioning

confidence: 99%

Rheological Investigation of Shear Induced‐Mixing and Shear Induced‐Demixing for Polystyrene/Poly(vinyl methyl ether) Blend

Madbouly

Ougizawa

2004

Macro Chemistry & Physics

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Full Paper: The phase behavior of polystyrene (PS) and poly(vinyl methyl ether) (PVME) blend has been investigated rheologically as a function of temperature, composition and oscillating shear rate as well as different heating rates. An LCST (lower critical solution temperature)‐type phase diagram was detected rheologically from the sudden changes in the slopes of the dynamic temperature ramps of G′ at given heating and shear rate values. The rheological cloud points were dependent on the heating rate, $\dot q$, and oscillating shear rate, $\dot \gamma$. The cloud points shifted a few degrees to higher temperatures with increasing $\dot q$ and reached an equilibrium value (heating rate independent) at $\dot q \geq 2$ °C/min. The phase diagrams of the blends detected at $\dot \gamma$ = 0.1 and 1 rad/s were located in lower temperature ranges than the quiescent phase diagram, i.e., oscillating shear rate induced‐demixing at these two values for the shear rate. On the other hand, at $\dot \gamma$ = 10 rad/s, the phase diagram shifted to higher temperatures, higher than the corresponding values found under quiescent conditions, i.e., shear induced‐mixing took place. Based on these two observations, shear induced‐demixing and shear induced‐mixing can be detected rheologically within a single composition at low and high shear rate values, respectively, and this is in good agreement with the previous investigation using simple shear flow techniques. In addition, the William, Landel and Ferry (WLF)‐superposition principle was found to be applicable only in the single‐phase regime; however, the principle broke‐down at a temperature higher than or equal to the cloud point. Furthermore, different spinodal phase diagrams were estimated at different oscillating shear rates based on the theoretical approach of Ajji and Choplin.Spinodal phase diagrams at different oscillating shear rates.magnified imageSpinodal phase diagrams at different oscillating shear rates.

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“…[2,3] However, in the case of polymer blends, little work has been done. Horst and Wolf [6] modified the storage-energy term, accounting for disentanglements of polymer networks at high shear rate, and claimed qualitative agreement of their prediction with the experimental results of PS=poly(vinyl methyl ether) of Fernandez et al [7] Lyngaae-Jørgenson and Søndergaard [8,9] derived the stored energy by using polymer network theory and determined a critical stress required to induce mixing for a poly(methyl methacrylate)=poly(styrene-co-acrylonitrile) (PMMA=SAN) blend, while Kammar et al [10] introduced an interaction parameter to the stored energy and evaluated this parameter by fitting the model predictions to the experimental results of the PMMA=SAN blend.…”

Section: Introductionmentioning

confidence: 61%

“…Figure 11 demonstrates the composition dependence of E s calculated from Eqs. (7)(8)(9)(10)(11) at different shear rates. The negative deviation of E s from the linear mixing rule is observed only at the high concentration range of PaMSAN; however, on the other hand, a positive deviation is detected at the lower concentration range.…”

Section: Calculation Of the Stored Energy From The Wolf Modelmentioning

confidence: 99%

Binary Miscible Blends of Poly(Methyl Methacrylate)/Poly(α-Methyl Styrene-co-Acrylonitrile). IV. Relationship Between Shear Flow and Viscoelastic Properties

Madbouly

2003

Journal of Macromolecular Science, Part B

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The effect of simple shear flow on the phase behavior of poly(methyle methacrylate), PMMA, and poly(a-methyl styrene-co-acrylonitrile), PaMSAN, exhibiting an LCST-type phase diagram, has been analyzed on the basis of a generalized Gibbs free energy of mixing, G g _ , modified by a stored energy term, E s . The value of the E s (the energy stored by the polymeric molecules during shear flow) was experimentally determined as a function of composition and shear rate from the viscoelastic material functions of the blend by using two different methods proposed by Marrucci and Wolf. The evaluated E s (proposed by Marrucci) from the entanglement plateau modulus, G 0 N , and dynamic shear viscosity at a given shear rate, Z(g _), were found to well describe the behavior of shear-induced mixing for the present system; i.e., a negative deviation of E s from the linear-mixing rule has been detected, which is a necessary condition for the elevation of the cloud points to higher values under shear flow. However, on the other hand, the calculated E s from the viscoelastic relaxation time, t 0 and zero shear viscosity, Z 0 (Wolf model), predicted both shear-induced mixing and shear-induced demixing for the large and small concentration range of PaMSAN, respectively; i.e., negative and positive deviation of E s from the linear-mixing rule was observed dependent on the concentration of PaMSAN. It is concluded that the viscoelastic material functions of the blend are very helpful for qualitatively anticipating the phase behavior of the blend under the effect of shear flow.

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Complex miscibility behaviour for polymer blends in flow

Cited by 54 publications

References 27 publications

Rheology of Polymer Blends

Rheology of Polymer Blends

Rheological Investigation of Shear Induced‐Mixing and Shear Induced‐Demixing for Polystyrene/Poly(vinyl methyl ether) Blend

Binary Miscible Blends of Poly(Methyl Methacrylate)/Poly(α-Methyl Styrene-co-Acrylonitrile). IV. Relationship Between Shear Flow and Viscoelastic Properties

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