Correlation of phase-separation behavior in polymer blends with thermodynamic measurements in the one-phase region

Higgins, J. S.; Fruitwala, H.; Tomlins, P E

doi:10.1021/ma00199a029

Cited by 44 publications

(35 citation statements)

References 16 publications

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“…Prior to SANS measurements, the binary temperature-composition phase diagram of PαMSAN/dPMMA blends was estimated optically at a relatively low heating rate of 0.5 16,24 The faint, bluish, cloudy appearance of the specimens suggests demixed structures at a fine ( 1µm) lengthscale. We take these as upper estimates of the phase boundaries of the system, given the relative proximity to T g (≈ 120 • C), the limited spatial resolution of optical microscopy, and the finite heating rate employed in the measurement.…”

Section: Resultsmentioning

confidence: 99%

Small Angle Neutron Scattering Study of the Thermodynamics of Highly Interacting PαMSAN/dPMMA Blends

et al. 2019

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Poly(methyl methacrylate) (PMMA) and poly(α-methyl styrene-co-acrylonitrile) (PαMSAN) form partially miscible blends with lower critical solution temperature (LCST) behaviour. We revisit this system using small angle neutron scattering (SANS), examining the effect of molecular weight (M w) of deuterated PMMA (dPMMA), blend composition (φ) and temperature (T) in the homogeneous region. All data are well described by the Random Phase Approximation (RPA) theory, enabling us to determine thermodynamic and structural parameters, including the correlation length ξ, G (the second derivative of the free energy of mixing with respect to composition), and the statistical segment length a of each component. Phase boundaries are computed by extrapolation of G with temperature, to yield the spinodal, and inspection of Kratky plots to yield the binodal. For PαMSAN, a is determined to be 10.1±0.4Å. Unsurprisingly, this system deviates strongly from Flory-Huggins expectations, exhibiting a minimal M w dependence of the phase boundaries and φ-dependence of effective interaction parameter (χ). Comparison of G with values for other blend systems places PαMSAN/dPMMA in a class of highly interacting blends, expected from Cahn-Hilliard theory to yield small initial phase sizes upon spinodal demixing. This is confirmed experimentally, with an illustrative temperature jump resulting in an initial phase size of 30 nm.

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Section: Resultsmentioning

confidence: 99%

Small Angle Neutron Scattering Study of the Thermodynamics of Highly Interacting PαMSAN/dPMMA Blends

et al. 2019

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“…However, Hashimot0 22 and Onuki ss have argued that for binary polymer blends, r q,mol may be the dominant term over the hydrodynamic contribution. In this case the relaxation rate equals (15) where E = IX-XsIIXs> X is the Flory-Huggins interaction parameter, Xs is the X value at spinodal point, and Dc is the self-diffusion coefficient of the constituent polymer. From Eq.…”

Section: B Mode-mode Coupling Analysismentioning

confidence: 99%

Shear stabilization of critical fluctuations in bulk polymer blends studied by small angle neutron scattering

Nakatani

Kim

Takahashi

et al. 1990

The Journal of Chemical Physics

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Smallangle neutron scattering by partially deuterated polymers and their blends J. Chem. Phys. 100, 3905 (1994); 10.1063/1.466325 Timeresolved smallangle neutron scattering study of spinodal decomposition in deuterated and protonated polybutadiene blends. I. Effect of initial thermal fluctuations J. Chem. Phys. 99, 4845 (1993); 10.1063/1.466225 Timeresolved smallangle neutron scattering study of later stage spinodal decomposition of a polymer blend AIP Conf. Proc. 256, 216 (1992); 10.1063/1.42443 Critical fluctuations and relaxation phenomena in the isotopic blend polystyrene/deuteropolystyrene investigated by small angle neutron scattering

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“…This method has a definite advantage over the LS method, since it permits us to investigate the scattering behavior in a wide region of q above the upper bound of the LS method. 18 ,19 Thus as shown below, it has become possible for the first time to see the structure factor S(q,t;T) at such high q and to determine qm(t;T) and Sm(t;T) in the very early stage of SD, where Sm(t;T) is the scattering intensity at the peak of S(q,t;T). The blend chosen is convenient for SANS measurement because it undergoes very slow SD, the typical characteristic time t/ 1 of which was of the order of .…”

Section: Introductionmentioning

confidence: 99%

Time-resolved small-angle neutron scattering study of spinodal decomposition in deuterated and protonated polybutadiene blends. I. Effect of initial thermal fluctuations

Jinnai

Hasegawa

Hashimoto

et al. 1993

The Journal of Chemical Physics

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Articles you may be interested inSmall-angle neutron scattering studies of polybutadiene/polystyrene blends as a function of pressure and microstructure: Comparison of experiment and theory Effect of the Onsager coefficient and internal relaxation modes on spinodal decomposition in the high molecular isotopic blend polystyrene/deuteropolystyrene studied with small angle neutron scattering Smallangle neutron scattering by partially deuterated polymers and their blends J. Chem. Phys. 100, 3905 (1994); 10.1063/1.466325 Timeresolved smallangle neutron scattering study of spinodal decomposition in deuterated and protonated polybutadiene blends. II. Qdependence of Onsager kinetic coefficient J. Chem. Phys. 99, 8154 (1993); 10.1063/1.465642 Timeresolved smallangle neutron scattering study of later stage spinodal decomposition of a polymer blend AIP Conf.Time-resolved small-angle neutron scattering (SANS) experiments have been performed on the self-assembling process of a binary mixture of deuterated polybutadiene and protonated polybutadiene at the critical composition. This mixture has an upper critical solution temperature type of phase diagram with the spinodal temperature at 99.2 ·C. Specimens held in the single-phase state at an initial temperature (T;) were quenched to a point inside the spinodal phase boundary at a final temperature (T f) to induce phase separation via spinodal decomposition (SD). In order to examine the effect that thermal concentration fluctuations have on SD, three different initial temperatures, T;= 102.3 ·C, 123.9 ·C, and 171.6 ·C, were chosen while T f was fixed at -7.5°C. The time-dependent SANS structure factor, S(q,t;T f)' showed clear scattering peaks corresponding to the early and intermediate stages of SD. The time changes in the wave number qm(t;T f) and the intensity Sm(t;T f) at the peak of S(q,t;T f) followed different paths depending on the initial temperature. This fact evidences a definite effect of thermal concentration fluctuations on SD (Le., a significant "memory" effect). A critical test of the linearized Cahn-Hilliard-Cook theory led to the conclusion that this theory can describe satisfactorily the early stage SD in the deep-quench region.

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Correlation of phase-separation behavior in polymer blends with thermodynamic measurements in the one-phase region

Cited by 44 publications

References 16 publications

Small Angle Neutron Scattering Study of the Thermodynamics of Highly Interacting PαMSAN/dPMMA Blends

Small Angle Neutron Scattering Study of the Thermodynamics of Highly Interacting PαMSAN/dPMMA Blends

Shear stabilization of critical fluctuations in bulk polymer blends studied by small angle neutron scattering

Time-resolved small-angle neutron scattering study of spinodal decomposition in deuterated and protonated polybutadiene blends. I. Effect of initial thermal fluctuations

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