Rheology and Morphology of Phase-Separating Polymer Blends

Abstract

Simulations of phase separation under oscillatory shear flow have been performed based on the time-dependent Ginzburg-Landau (TDGL) equation. To calculate the stress tensor, the expression proposed by Kawasaki was used. The results of the simulations have been confronted directly with experimental results on a LCST blend of PRMSAN/PMMA to evaluate the potential of the simulations. The effect of quench depth, shear amplitude, and shear frequency on the morphology development as well as on the corresponding rheological properties has been investigated. The results show that the characteristic rheological behavior of phase-separating systems can be attributed to the interfacial relaxation, which is changing during the process of phase separation. The strength of the concentration fluctuations and the interfacial volume fraction are key factors determining the contribution of interfacial relaxation to the global rheological behavior of the blend. In the low frequency range, the oscillatory shear cannot affect the critical point, but it can accelerate the coagulation and growth of the blend morphology. The simulations qualitatively agree with the experimental findings.

Creep Behavior of a Polymer Blend Melt and 3D Observation of the Deformed Bicontinuous Structure by a High-contrast X-ray CT

“…In other case, the structure is declared as cocontinuous only It has been reported that the frequency dependence of the loss modulus G" of the blend with the bicontinuous structure is also expressed by the power law G" ~ w m with the exponent m somewhat smaller than n. [25][26][27][28] The same result is obtained in the present study, although the reason for m < n is not known.…”

“…[25][26][27][28][29] The reported exponent n is in the rage of 0.5 < n ≤ 1. However, in all these reports, detailed study on the phase separated structure is missing.…”

Dispersion State of Zirconium Oxide Particles in Polymer Blends and Viscoelastic Behavior of the Composites

“…[18][19][20][21] The behavior similar to the percolation threshold, G' ∼G" ∼ω n with tanδ = tan(nπ/2), was also observed 22) . However, these behaviors are somewhat vague due to the coarsening of bicontinuous structure during rheological measurement and to possible acceleration of domain growth (or break up) affected by small (or large) amplitude oscillation.…”

Rheological and mechanical properties of poly(α-methylstyrene-co-acrylonitrile)/ poly[(methyl acrylate-co-methyl methacrylate)] blends in miscible and phase separated regimes of various morphologies. Part IV: Influence of the morphology on the mechanical properties (IUPAC Technical Report)

“…Representative Institution number [1] V. Altstädt Until 1995: BASF, Ludwigshafen, Germany; 1995-2000: TU Hamburg-Harburg, Hamburg, Germany; Since 2000: University Bayreuth, Bayreuth, Germany [2] L. Glas Shell, Ottignies Lovain la Neuve, Belgium [3] B. Pukánszky TU Budapest, Budapest, Hungary [4] D. W. Schubert GKSS, Geesthacht, Germany [5] G. H. Michler University Halle-Wittenberg, Merseburg, Germany J. Laatsch [6] R. Moore ICI Technology, Middlesbrough Cleveland, England [7] J. G. Williams Imperial College, London, UK [8] F. Ramsteiner BASF, Ludwigshafen, Germany…”

“…In a paper by V. Schytt and J. Lyngaae-Jørgensen [2], the limits of miscibility in the quiescent state and during flow has been discussed. I. Vinckier and H. M. Laun reported the manifestation of the interface in oscillatory shear measurements [3,4], and Z. I. Zang, Y. L. Yang, I. Vinckier, and H. M. Laun compared, measured, and simulated morphologies under oscillatory shear [5]. D. W. Schubert investigated the χ-parameter and the phase diagram of PαΜSAN/PMMA blends by cloudpoint and neutron-scattering techniques [6].…”