Light scattering characterization of tetramethyl polycarbonate blends with polystyrene and with styrene–pentabromobenzyl acrylate copolymers

Merfeld, G. D.; Paul, Donald R

doi:10.1016/s0032-3861(99)00162-7

Cited by 20 publications

(28 citation statements)

References 33 publications

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“…Figure 7c shows LS data for the same system reported by Merfeld and Paul [71] (albeit PS is hydrogenous and with slightly higher MW) for a 50/50 blend annealed at 250 °C, or T=9°C inside the spinodal. As above, in Fig 7b, the peak position appears initially "invariant" in q within the first 200 s and the authors do employ Cahn-Hilliard analysis.…”

Section: The Need For Contrast and Common Artefactsmentioning

confidence: 67%

“…The shaded area corresponds to the q range probed by light scattering, in panel (b) where for a time window up to s, the scattering data could be misinterpreted as corresponding to the early stages of demixing. (c) SALS data for TMPC/PS330k 50/50 (Mw(TMPC)≈ 38 kgmol -1 , Mw(PSd)≈330 kgmol -1 , adapted from[71]) of similar to the system shown in (a,b) and TS=241°C, quenched at 250°C, thus also T=9 °C; the data were interpreted according to the early stage Cahn-Hilliard formalism, yielding inconsistent results in terms of the lengthscale  dependence on quench depth T; for instance, the authors find to remain 'stubbornly' between 1.0 and 1.1 m for quench depths varying from T=1-14 °C. Panel (c)[71], Copyright 2000.…”

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confidence: 99%

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Spinodal nanostructures in polymer blends: On the validity of the Cahn-Hilliard length scale prediction

Cabral

Higgins

2018

Progress in Polymer Science

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Section: The Need For Contrast and Common Artefactsmentioning

confidence: 67%

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confidence: 99%

Spinodal nanostructures in polymer blends: On the validity of the Cahn-Hilliard length scale prediction

Cabral

Higgins

2018

Progress in Polymer Science

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“…Many techniques have been extensively used to investigate the miscibility, molecular dynamics and phase separation kinetics of polymer blends, such as, differential scanning calorimetry (DSC), [1,2] NMR, [3][4][5][6] dielectric spectroscopy, [7][8][9][10][11][12] dynamic mechanical measurements, [13][14][15][16][17] and time-resolved light scattering. [18][19][20][21][22][23] We have recently investigated the miscibility, dielectric spectroscopy, viscoelastic properties and morphology under Summary: The phase separation kinetics of a poly(methyl methacrylate), PMMA, and poly(a-methylstyrene-co-acrylonitrile), PaMSAN, blend exhibiting a LCST-type phase diagram have been investigated as functions of temperature and demixing time for the near critical composition (PaMSAN/PMMA ¼ 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.…”

Section: Introductionmentioning

confidence: 99%

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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“…Their kinetics results indicated that all three copolymers were able to slow the phase‐separation rates in these systems. These results were interesting because in previous studies5–9 in which copolymer additives were observed to stabilize a blend system, the phase‐separation kinetics were also slowed. This slowdown is usually attributed to the copolymer additive migrating to the interface and thus lowering the interfacial energy between phases.…”

Section: Introductionmentioning

confidence: 74%

Effect of random and block copolymer additives on a homopolymer blend studied by small‐angle neutron scattering

Voge

Fosser

Waldow

et al. 2004

J Polym Sci B Polym Phys

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Small-angle neutron scattering (SANS) has been employed to study a blend of polystyrene and polybutadiene modified by copolymer additives. SANS data from the one-phase region approaching the phase boundary has been acquired for blends modified by random and diblock copolymers that have equal amounts of styrene and butadiene monomers as well as a random copolymer with an unequal monomer composition. The binary blend is near the critical composition, and the copolymer concentrations are low at 2.5% (w/w). The data have been fitted with the random-phase approximation model (binary and multicomponent versions) to obtain Flory-Huggins interaction parameters () for the various monomer interactions. These results are considered in the context of previous light scattering data for the same blend systems. The SANS cloud points are in good agreement with previous results from light scattering. The shifts in the phase boundary are due to the effects of the additives on the parameter at the spinodal. All the additives appear to lower the parameter between the homopolymers; this is in conflict with the predicted Flory-Huggins behavior.

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Light scattering characterization of tetramethyl polycarbonate blends with polystyrene and with styrene–pentabromobenzyl acrylate copolymers

Cited by 20 publications

References 33 publications

Spinodal nanostructures in polymer blends: On the validity of the Cahn-Hilliard length scale prediction

Spinodal nanostructures in polymer blends: On the validity of the Cahn-Hilliard length scale prediction

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

Effect of random and block copolymer additives on a homopolymer blend studied by small‐angle neutron scattering

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