Regensburg 2016 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 35: Activated and Glassy Dynamics of Soft Matter (joint session CPP/DY, organized by CPP)

CPP 35.7: Talk

Wednesday, March 9, 2016, 11:30–11:45, H51

Tayloring the properties of polydiene elastomers via associating hydrogen bonding groups: A micro- and macroscopic approach — •Barbara J. Gold, Claas H. Hövelmann, Wim Pyckhout-Hintzen, Andreas Wischnewski, and Dieter Richter — Forschungszentrum Jülich, JCNS-1 & ICS-1, 52425 Jülich, Germany

Nature uses a combination of dynamic hydrogen and static covalent bonds e.g. in the muscle protein TITIN [Wojtecki et al., Nature Materials 2011] to achieve toughness in otherwise elastic materials. We transferred this mechanism into conventional elastomers by introducing associating hydrogen bonds into covalent crosslinked polydiene networks. Since the associating behaviour of these functional groups can be triggered by temperature or mechanical stimulation this new generation of elastomers serves as key actor for the design of novel knowledge-based materials.

The influence of the hydrogen bonding groups on the dynamics of linear polymer chains has been studied by oscillatory shear rheology, dielectric and neutron spin echo spectroscopy. We observe a clear influence on the relaxation time spectra resulting in a longer disentanglement time, higher segmental friction as well as a second relaxation process related to the lifetime of the associating groups. Furthermore the Gaussian chain structure, observed via small angle neutron scattering, remains unaffected which excludes phase separation within the material. Stress-strain investigations show a significant increase of the mechanical resistance due to the additional functional groups compared to conventional elastomers.