Dresden 2009 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 32: Polymer Physics III
CPP 32.5: Vortrag
Donnerstag, 26. März 2009, 10:30–10:45, ZEU 222
Anisotropy of the dynamic mechanical properties of strongly stretched polymer networks — •Vladimir Toshchevikov1,2, Gert Heinrich1, and Yuli Gotlib2 — 1Leibniz Institut für Polymerforschung, Dresden, Germany — 2Institute of Macromolecular Compounds, Saint-Petersburg, Russia
Superposition of large static and small oscillating strains has been proposed recently as a method for studying the structure of polymer networks [1,2]. The main goal of the present work is to study the anisotropy of the dynamic mechanical properties of strongly stretched polymer networks with respect to the direction of a static strain. This is of importance to understand the crack propagation in rubbers, which is determined by the dynamics of highly stretched network portions near crack tips under pulsed loading conditions (http://www.ipfdd.de/FOR597). We show that a stretched polymer network is characterized by the anisotropy of viscoelastic properties: frequency dependent shear modulus is different for different geometries of applying the shear (parallel or perpendicular to the axis of deformation). For all geometries of the shear, fine structure of the relaxation spectrum leads to the broadening of the frequency dependences of loss moduli which can display several maxima at strong deformations. Theoretically calculated frequency dependences of the loss and storage moduli are in a good agreement with experimental data [2].
This work was supported by the RFBR (08-03-00150).
[1] V.L.Bodneva et al. Polymer Science 2005, 47, 409
[2] E.Munch et al. Polymer 2006, 47, 3477