Flow behavior of symmetrical P (S‐b‐MMA) block copolymers: Rheological problems arising from shear modified morphology

Abstract

SYNOPSISIn this article, symmetrical, narrow distribution P ( S-b-MMA ) block copolymers are characterized rheologically, using a dynamic spectrometer and a stress rheometer. The shear induced morphology changes are investigated by off-line electron microscopy and SAXS. We tried to correlate the results of dynamics and long-time creep experiments with morphological and rheological features. Summarizing, one can point out that the examined block copolymers reveal the well-known low frequency behavior of phase separated blends. Additionally, we observed a significant shear influence on the morphology, i.e. a shear induced structuring and alignment of lamellae. This considerable change in morphology is also reflected by characteristic rheological properties ( retardation time, yield stress). Therefore, problems concerning the validity range of linear viscoelastic behavior arise, which are discussed in brief.

Study of morphology influence on rheological properties of compatibilized TPU/SAN blends

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