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

Madbouly, Samy A.

doi:10.1081/mb-120024815

Cited by 6 publications

(3 citation statements)

References 28 publications

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“…This equation is normally used to describe the composition dependence of shear viscosity of miscible polymer blends. Recently, we reported a negative deviation from the additivity rule in miscible polymer blend of poly(methyl methacrylate)/poly(methylstyrene- co -acrylonitrile), and the data were well described by the Lecyar model . It is noteworthy that this is not a general behavior for all miscible polymer mixtures.…”

Section: Resultsmentioning

confidence: 84%

“…Recently, we reported a negative deviation from the additivity rule in miscible polymer blend of poly(methyl methacrylate)/poly(methylstyrene-co-acrylonitrile), and the data were well described by the Lecyar model. 60 It is noteworthy that this is not a general behavior for all miscible polymer mixtures. To our knowledge, there is no generally acceptable and universal valid mixing rule for the viscosity of polymer mixtures.…”

Section: Resultsmentioning

confidence: 99%

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Rheological Behavior of POSS/Polyurethane−Urea Nanocomposite Films Prepared by Homogeneous Solution Polymerization in Aqueous Dispersions

et al. 2007

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Reinforced polyurethane−urea nanocomposite with reactive polyhedral oligomeric silsesquioxanes (POSS) has been prepared via environmentally friendly aqueous dispersion with no organic solvent. Rheological behavior of this important class of materials has been investigated as a function of POSS concentration over a wide range of shear frequency and temperature (−100 to 230 °C). The functionalized diamino-POSS was reacted initially with isophorone diisocyanate (the urethane hard segments) before adding the polyester diol (the soft segments). The complete reaction of diamino-POSS with urethane segments was confirmed rheologically and morphologically (TEM). The molecular relaxations of the hard and soft segments of PU/POSS nanocomposites were investigated using the rectangular torsional mode in the glassy and rubbery states. It was found that the storage elastic modulus increased systematically only in the high-temperature range (i.e., the range of the T g of the urethane segments) while the modulus did not significantly change at low temperatures corresponding to the range of the T g of the polyester soft segments. In addition, the rheological behavior of the pure PU in the melt confirmed the existence of microphase separation of the hard and soft segments at 140 °C. The value of the microphase separation temperature (T MPS) was found to be concentration independent when the POSS concentration is ≤6 wt %. For 10 wt % POSS the T MPS shifted by 20 °C to a higher temperature. The viscoelastic material functions (G‘, G‘ ‘, and η* ) for pure PU film and samples with POSS ≤6 wt % were found to be well described by the time−temperature superposition (or WLF) principle in the low-temperature range studied (i.e., T < T MPS (140 °C)); at higher temperatures the superposition principle failed to describe the experimental data. For 10 wt % POSS film, the validity of WLF principle was extended up to 160 °C due to the shift of T MPS to higher temperature. The incorporation of POSS to the hard segments of PU produced a more homogeneous structure for the 10 wt % POSS as confirmed by TEM. In addition, the viscosity and activation energy of flow were increased dramatically by adding POSS to PU. The thermal stability of PU under a nitrogen atmosphere did not improve by adding POSS, but it improved slightly when tested in an oxygen atmosphere.

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Section: Resultsmentioning

confidence: 84%

Section: Resultsmentioning

confidence: 99%

Rheological Behavior of POSS/Polyurethane−Urea Nanocomposite Films Prepared by Homogeneous Solution Polymerization in Aqueous Dispersions

et al. 2007

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“…In this review a particular interest will be paid for the phase behavior of poly(methyl methacrylate)/poly(a-methyl styrene-co-acrylonitrile) (with 31 wt% AN content) blends under quiescent and shear flow (22,87,88). The effect of phase separation on the linear viscoelastic behavior of this blend will be also considered (75,76).…”

Section: Introductionmentioning

confidence: 99%

Phase Behavior and Morphology of Poly(Methyl Methacrylate)/Poly(α‐Methyl Styrene‐co‐Acrylonitrile) Blends Under Quiescent and Shear Flow

Madbouly

Ougizawa

2005

Journal of Macromolecular Science, Part C: Polymer Reviews

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The kinetics of spinodal decomposition (SD) for the binary blend poly(methyl methacrylate), PMMA, and Poly(a-methylstyrene-co-acrylonitrile), PaMSAN, with 31 wt% AN content (LCST-type phase diagram) has been thoroughly studied using a timeresolved light scattering technique. The early stage SD was dominated by a diffusion process and can be well described within the framework of the linearized CahnHilliard theory. The spinodal temperature could be evaluated from the analysis of the early stage SD based on the Cahn theory. In addition, viscoelastic properties of this system have been systematically investigated at temperatures below and above the LCST phase diagram. The linear viscoelastic properties of the blends were found to be greatly changed by phase separation in the two-phase regime. This change in the linear viscoelastic properties attributed to an additional contribution of concentration fluctuations to the material functions at the phase separation temperatures. The phase diagram of the blends was also estimated rheologically through the dynamic temperature ramps of G 0 , G 00 and h Ã . Furthermore, the phase behavior and morphology of this system has been studied under different shear rates using simple shear apparatus and transmission electron microscopy (TEM), respectively.

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Spinodal Decomposition in Binary Blend of Poly(methyl methacrylate)/Poly(α‐methyl styrene‐co‐acrylonitrile): Analysis of Early and Late Stage Demixing

Madbouly

Ougizawa

2004

Macro Chemistry & Physics

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Summary: The phase separation kinetics of a poly(methyl methacrylate), PMMA, and poly(α‐methylstyrene‐co‐acrylonitrile), PαMSAN, blend exhibiting a LCST‐type phase diagram have been investigated as functions of temperature and demixing time for the near critical composition (PαMSAN/PMMA = 25:75) using a time‐resolved light scattering technique. We found that the scattering data in the early stage spinodal decomposition (SD) can be well described by the linearized Cahn–Hilliard theory. Spinodal temperature Ts ∼ 171 °C was determined from Dapp versus T and q versus T based on the analysis of Cahn theory in the early stage SD, where Dapp is the apparent diffusion coefficient and qm is the scattering vector at the maximum scattering intensity. The value of Ts obtained from the analysis of light scattering data was in good agreement with the phase diagram obtained visually at the equilibrium condition. The LCST‐type phase diagram of this blend was also calculated using the Flory–Huggen theory. The estimated interaction parameter used for the calculation of the phase diagram was found to be composition and temperature dependent. The coarsening behavior of the blend at the late stage SD was also studied by analyzing the magnitudes of qm and Im at various demixing times and temperatures based on the nonlinear statistical theories. Both of qm and Im obtained at different times and temperatures can be superposed and reduced to the respective master curves by horizontal shifting when they are plotted against log (t/aT) at a given reference temperature, where aT is the temperature‐dependent shift factor. The shape of the phase separation domain structures as a function of time during the SD was also considered. The scaling structure function F(x,t;T) = qm(t;T)3I(q,t;T) versus q/qm was found to be time independent and falls onto a universal curve in the late stage SD as a result of the dynamical self‐similarity accompanying with the phase separation process.Optical microscopy pictures for the structure development of spinodal decomposition for PαMSAN/PMMA = 25:75 blend at 180 °C for different demixing times.imageOptical microscopy pictures for the structure development of spinodal decomposition for PαMSAN/PMMA = 25:75 blend at 180 °C for different demixing times.

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

Cited by 6 publications

References 28 publications

Rheological Behavior of POSS/Polyurethane−Urea Nanocomposite Films Prepared by Homogeneous Solution Polymerization in Aqueous Dispersions

Rheological Behavior of POSS/Polyurethane−Urea Nanocomposite Films Prepared by Homogeneous Solution Polymerization in Aqueous Dispersions

Phase Behavior and Morphology of Poly(Methyl Methacrylate)/Poly(α‐Methyl Styrene‐co‐Acrylonitrile) Blends Under Quiescent and Shear Flow

Spinodal Decomposition in Binary Blend of Poly(methyl methacrylate)/Poly(α‐methyl styrene‐co‐acrylonitrile): Analysis of Early and Late Stage Demixing

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