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Distinguishing Linear from Star‐Branched Polystyrene Solutions with Fourier‐Transform Rheology
Author(s) -
Neidhöfer Thorsten,
Sioula Stella,
Hadjichristidis Nikos,
Wilhelm Manfred
Publication year - 2004
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.200400295
Subject(s) - rheology , polystyrene , materials science , viscoelasticity , branching (polymer chemistry) , shear (geology) , composite material , polymer chemistry , polymer
Summary: Fourier‐Transform rheology (FT rheology) was used to study the influence of the degree of branching on the nonlinear relaxation behaviour of polystyrene solutions. The results were compared with those obtained under oscillatory shear and step‐shear conditions. The different topologies could be distinguished using FT rheology where the other rheological measurements failed. Significant differences occurred under large amplitude oscillatory shear (LAOS) conditions as particularly reflected in the phase difference of the third harmonic, Φ 3 , which could be related to strain‐softening and strain‐hardening behaviour. Currently, this work is extended towards different topologies in polyolefins (e.g. long chain branched).Phase difference Φ 3 as a function of the Deborah number De at γ 0 = 2 for the polystyrene solutions measured at temperatures from 295 to 350.5 K.