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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 34: Poster: Elastomers and Gels

CPP 34.2: Poster

Wednesday, March 24, 2010, 17:30–19:00, Poster C

Stress relaxation and viscoelasticity of physically crosslinked networks — •Stephan Baeurle¹, Atsushi Hotta², and Andrei Gusev³ — ¹Institut für Physikalische und Theoretische Chemie, Universität Regensburg, Universitätstr. 31, 93053 Regensburg, Germany — ²Department of Mechanical Engineering, Keio University, 3-14-1 Hiyoshi Kohoku-ku, Yokohama 223-8522, Japan — ³Department of Materials, Institute of Polymers, ETH, CH-8093 Zurich, Switzerland

In this presentation we report on a new semi-phenomenological theory, to describe and explain the long-time stress relaxation behavior as well as viscoelasticity of thermoplastic elastomers composed of styrenic-block copolymers. The investigated materials form networks of glassy polystyrene crosslinks, which are physically linked by soft rubbery chain segments made of either polybutadiene or polyisoprene. We demonstrate that the model correctly reproduces the crossover from power-law to stretched-exponential behavior of the stress relaxation at a characteristic crossover temperature, found in recent tensile experiments, and that it provides new insights about the nature of the glassy state in the polystyrene crosslinks.