STRUCTURE AND DYNAMICS OF IRREGULAR MULTIARM STAR POLYMERS
Author(s): D.Vlassopoulos (Foundation for Research and Technology-Hellas (FO.R.T.H.), Institute of Electronic Structure and Laser, 71110 Heraklion, Crete, Greece), T.Pakula (Max-Planck Institute for Polymer Research, Postfach 3148, 55021 Mainz, Germany), J.Roovers (National Research Council, Institute for Chemical Process and Environmental Technology, Ottawa, Ontario K1A0R6, Canada)
Melt properties of highly branched star polymers consisting of a 1,2-polybutadiene core and nearly 270 arms of 1,4-polybutadiene with varying sizes have been investigated using small angle X-ray scattering (SAXS) and dynamic rheological measurements in the linear viscoelastic limit. Despite their difference in internal structure compared to the regular stars with 128 arms and spherical dendritic core, these polymers exhibit the same features: a liquid-like ordering resulting from their specific intramolecular monomer density distribution. This leads to a dual terminal viscoelastic relaxation, consisting of a fast arm relaxation and a slow structural relaxation mechanisms. Both modes conform quantitatively to the generic behaviour of multiarm star polymers, suggesting a universality of the behaviour of highly branched macromolecular objects.
Key words: star polymers, structure, rheology, linear viscoelasticity,
relxation processes, dynamics
PACS: 61.25.Hq, 83.10.Nn, 81.05.Lg
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