Adaptable Strategy to Fabricate Self-Healable and Reprocessable Poly(thiourethane-urethane) Elastomers via Reversible Thiol–Isocyanate Click Chemistry

Currently, a variety of elastomers with a self-healing capacity and reprocessability have been developed by dynamic chemistry to extend the service life, increase the reliability of polymeric materials, and reduce the waste. However, it is still a large challenge to seek an appropriate dynamic interaction that may perfectly match the general performance of the target polymeric materials such as polyurethane. Herein, we report a poly(thiourethane-urethane) (PTUU–Nx) elastomer containing dynamic thiourethane bonds prepared via a thiol–isocyanate click reaction, which is stable at room temperature, healable at moderate temperature, and reprocessable at high temperature. Importantly, it exhibits a mechanical strength similar to the polyurethane because of a very similar structure. The dynamic feature of PTUU–Nx is demonstrated theoretically and experimentally to originate from the exchange of thiourethane bonds via the reversible generation of isocyanates and thiols. Most importantly, the thiourethane bond possesses a much lower bond dissociation energy than the urethane bond, which not only makes PTUU–Nx elastomers easier to be reprocessed but also endows them with a desirable self-healing ability under moderate conditions. In addition, the optimized sample PTUU–N2 is utilized to fabricate a conductive device by coating Ag glue on the elastomer surface and inserting the coated elastomer into a circuit, which displays a high self-healing efficiency, as the material recovers to its original mechanical property and conductivity. Therefore, these results not only indicate that the PTUU–Nx elastomers have considerable potential for applications in intelligent electronic devices but also provide new ideas for developing new self-healing materials by applying the adaptable dynamic bond to the target polymers.