Dresden 2017 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 5: Polymer Networks and Dynamics I: Elastomers and Magnetic Materials
CPP 5.3: Talk
Monday, March 20, 2017, 11:00–11:15, ZEU 255
Nano-mechanical imaging reveals heterogeneous cross-link distribution in sulfur-vulcanized butadiene-styrene rubber comprising ZnO particles — Yulia Glebova1,2, •Valentin Reiter-Scherer1, Sari Suvanto3, Tarmo Korpela3, Tuula T. Pakkanen3, Nikolai Serverin1, Vladimir Shershnev2, and Jürgen P. Rabe1 — 1Department of Physics and IRIS Adlershof, Humboldt-Universität zu Berlin, Germany — 2Moscow State University of Fine Chemical Technologies, Russia — 3Department of Chemistry, University of Eastern Finnland, Finnland
The addition of zinc oxide (ZnO) to sulfur (S-) vulcanized rubbers is known to accelerate the cross-linking kinetics and to increase the heterogeneity of the cross-link density. However, the spatial distribution of cross-links is hardly known and the mechanism of the activity of ZnO is disputed. We therefore investigated S-vulcanized butadiene-styrene rubber comprising ZnO particles. The samples were fractured and then investigated employing the nano-mechanical mapping mode (NM) of scanning force microscopy (SFM), supported by scanning electron microscopy (SEM). We find that rubber around the ZnO particles exhibits a higher Young's modulus in a shell with a width up to about 200 nm. Furthermore, the extension and retraction curves on these shells exhibit a smaller hysteresis than on the rubber further away from the ZnO particles. We attribute the higher Young's modulus and the smaller hysteresis to a higher cross-link density in rubber surrounding the ZnO particles and we discuss a mechanism of the activity of ZnO in rubbers which can explain this.