Regensburg 2016 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 3: Polymer Networks and Elastomers

CPP 3.2: Vortrag

Montag, 7. März 2016, 10:00–10:15, H40

Development of a new micro-structure based model for the stress-strain response of filler reinforced elastomers including temperature and rate-dependence — •Jan Plagge and Manfred Klüppel — DIK e.V., Hannover, Germany

A newly developed physical material model is presented, which was built on the main assumptions of the Dynamic Flocculation Model (DFM), but includes the stress-softening via the breakdown of highly stressed polymer-filler domains under load. The polymer-response is modeled with the non-affine tube model. Key parameters can be identified with exponents derived from percolation theory describing the cluster size distribution of fillers. Set stress and hysteresis are introduced via a continuous reaggregation mechanism, completely characterized by a critical stress parameter. This is implemented with a convolution-like memory kernel. Modeled stress-strain response is in perfect agreement with experiments. The critical stress parameter was predicted to be dependent of temperature and deformation rate by means of Kramers escape rate. This is confirmed for a wide range of temperatures and speeds by a fit to multihysteresis measurements carried out in a heat chamber. Fitting parameters reveal that the mechanism responsible for hysteresis and set stress takes place on the nanometer scale with energies of roughly 100 kJ/mol, possibly rearrangement of primary filler particles. To conclude, the newly developed model reproduces all major rubber characteristics with a small set of physically motivated parameters, making it a promising option to further understand the complex polymer-filler interplay.