Effects of shear on miscible polymer blends: in situ fluorescence studies

Mani, Suresh; Malone, Michael F.; Winter, H. Henning; Halary, Jean Louis; Monnerie, L.

doi:10.1021/ma00019a036

Cited by 66 publications

(40 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Changes in the phase behavior of the polymer blend, which occur as a consequence of the stresses associated with melt flow, are likely to significantly influence the ultimate morphology of the processed and solidified materials. Flow field was found to exert a marked influence on the phase behavior of polymer blends, [1][2][3][4][5][6][7][8][9][10][11] and it is obvious that this effect must be considered, in particular, when trying to understand the state of polymer blends during processing. From a scientific perspective, the increased use of polymer blends has emphasized the need to understand i) the underlying thermodynamics that drive 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.…”

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

View full text Add to dashboard Cite

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.

show abstract

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

View full text Add to dashboard Cite

show abstract

“…In the late stage of the phase separation, R x l t 1. 4 and R x l t 0.3 , respectively. These observed features agree with the theoretical analysis given in the last section, i. e., R (x) l t 5/4 and R (y) l t 1/4 .…”

Section: Domain Growth Under Shear Flowmentioning

confidence: 96%

“…As well as shear-induced mixing, [3] application of shear flow may also induce composition heterogeneity or demixing. [4] Recent experiments have revealed that a string-like phase of thin domains oriented parallel to the flow direction can be formed in strong shear flow, [5] although very recent experiments showed that this string-like phase can eventually break up in strong shear. [6] According to their computer simulation results, Qiu et al [7] argued that the chain-stretching effect may be responsible for the stringlike structure.…”

Section: Introductionmentioning

confidence: 99%

The Morphology and Corresponding Rheological Properties of Phase-Separating Polymer Blends Subject to a Simple Shear Flow

Luo

Yu²

2002

Macromol. Theory Simul.

View full text Add to dashboard Cite

“…[2] In addition, the shear flow competes with the phase separation process, which influences the morphology and stability of the domain. [3,4] Recent experiments have revealed that, in the velocity-vorticity plane, a string-like phase of thin domains oriented parallel to the flow direction can be formed under strong shear Summary: The spinodal decomposition of a binary mixture subjected to simple shear flow is investigated in the framework of the modified time-dependent Ginzburg-Landau (TDGL) equation with an external velocity term. The domain growth and related rheological properties of a binary mixture under shear flow are simulated in three dimensions by means of the cell dynamics scheme (CDS).…”

Section: Introductionmentioning

confidence: 99%

The Chain Stretching Effect on the Morphology and Rheological Properties of Phase‐Separating Polymer Blends Subjected to Simple Shear Flow

Luo

Zhang

Yang

2004

Macro Theory & Simulations

View full text Add to dashboard Cite

Summary: The spinodal decomposition of a binary mixture subjected to simple shear flow is investigated in the framework of the modified time‐dependent Ginzburg‐Landau (TDGL) equation with an external velocity term. The domain growth and related rheological properties of a binary mixture under shear flow are simulated in three dimensions by means of the cell dynamics scheme (CDS). The simulation results show that the domain growth is anistropic and depends on the terminal relaxation time of the polymer chain. It is found that lamellae‐like domains with the normal parallel to the velocity gradient direction are observed when the terminal relaxation time is long enough. This result has also been confirmed by carefully checking the scattering functions in different incident light directions and the evolution of the domain size in different directions. In addition, when the chain stretching effect is strong, the transients of the excess shear viscosity are much higher than the case without the chain stretching effect. The terminal relaxation time of the chain also has an important effect on the first and second normal stress differences.The time evolution of the morphology for the case with strong chain stretching effect.imageThe time evolution of the morphology for the case with strong chain stretching effect.

show abstract

Effects of shear on miscible polymer blends: in situ fluorescence studies

Cited by 66 publications

References 9 publications

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

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

The Morphology and Corresponding Rheological Properties of Phase-Separating Polymer Blends Subject to a Simple Shear Flow

The Chain Stretching Effect on the Morphology and Rheological Properties of Phase‐Separating Polymer Blends Subjected to Simple Shear Flow

Contact Info

Product

Resources

About