Ideal self-healing polymeric materials are characterized by the ability to spontaneously repair the damage inflicted on them leading to prolonged life-time and enhanced reliability of the products made thereof (e.g. dynamic seals). A particular useful approach for the design of self-healing materials is the introduction of hydrogen bonds. These supramolecular bonds provide a stress-relieve mechanism since they open up under external stress and secure the covalent bonds from breaking. Upon stress release the hydrogen bonds recombine, and the material physical-mechanical properties are restored.To protect covalent polymer networks on a macroscopic level we aim at the synthesis of transient-covalent dual networks. The additional hydrogen bonding groups built up the transient network and provide microscopic self-healing ability. Therefore, monodispersed polybutadienes and polyisoprenes were synthesized by anionic polymerization. The synthesis of the corresponding dual networks can be realized in a two-step procedure. First, urazole groups as supramolecular stickers were incorporated into the polydiene backbones via ene reaction. Thereafter, the permanent crosslinking is performed either by hydrosilylation or peroxide radicals.  The microscopic structure of transient and dual networks on the chain level was investigated via small angle neutron scattering. Also an insight into the dynamic behaviour was achieved by quasielastic neutron scattering experiments, dynamical rheological analysis, and dielectric spectroscopy. A significant influence caused by the dissipation mechanism of the hydrogen bonds was observed.

Development of intrinsically protected supramolecular elastomers for dynamic-mechanical and neutron scattering investigations

248th National Meeting (2014)

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