Urethanes as reversible covalent moieties in self-healing polymers

For the first time, reversible covalent urethane units are used for the design of new self-healing polymers. For this purpose, an electron-poor diol was synthesized and utilized as a cross linker to create a self-healing polymer. Therefore, the diol, butyl methacrylate and 2-isocyanato ethyl methacrylate are intermixed and photo-polymerized in a bone-shaped Teflon mold. The resulting test specimens are characterized by DSC, TGA and DMTA and the self-healing behavior is studied using tensile tests. Thereby, healing efficiencies of up to 85 % could be reached while the material exhibits good mechanical properties with high E-moduli. Additionally, the self-healing mechanism, which is based on exchange reactions, is investigated by Raman as well as temperature dependent IR measurements.