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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 43: Nanoparticles and Composite Materials I
CPP 43.2: Talk
Thursday, March 17, 2011, 14:30–14:45, ZEU 222
Modelling of stress and strain amplification effects in filled polymer melts — •Jan Domurath, Marina Saphiannikova, and Gert Heinrich — Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Strasse 6, 01069 Dresden
When hard filler particles are added to a polymer melt, it is usually assumed
that it’s zero-shear viscosity and therefore the stress increase according to
Einstein’s or a similar formula. In some papers one finds an alternative
approach in which the local strain field is increased according to these formulas.
Although both approaches provide the same increase of the shear stress in the
linear limit, it can be shown that the second approach violates the energy
conservation law as the macroscopic and microscopic dissipated energies are not
equal anymore. In this contribution we propose a new stress and strain
amplification approach in which both the stress and strain tensors are modified
to describe the behaviour of filled polymer melts in the non-linear shearing
regime. The new approach is tested using relatively simple constitutive models
for description of nonlinear viscoelastic behaviour in polymer melts. The stress
and strain amplification approach enables us to explain the peculiar behaviour
of the overshoot peak observed recently in filled LDPE melts [1].
F.R. Costa et al. Adv. Polym. Sci. 210, 101 (2008)