Flexible, Reconfigurable, and Self-healing TPU/Vitrimer Polymer Blend with Copolymerization Triggered by Bond Exchange Reaction.

In recent decades, flexible, reconfigurable and fast-response self-healing polymers have attracted considerable concentration for both industrial field and scientific research. Mechanical blending remains as the most mature, economical, effective, and the simplest approach to produce polymer blends, which can combine several distinctive advantages from different thermoplastic materials. However, such a process cannot be simply applied to thermosetting materials due to their permanent molecular structures. The synthesis of high performance polymer blends connected by covalent crosslinks remains a big challenge for the present industrial system. In this paper, we proposed a novel approach to synthesize polymer blends via blending thermosetting vitrimer containing dynamic covalent networks with thermoplastic polymers. It is demonstrated that the intrinsic relationship could be established by controlling the bond exchange reactions between the thermoset and the thermoplastic, thus trigger copolymerization. Due to the highly controlled processing conditions, the synthesized polymer is highly flexible, recyclable, reprocessable and possesses self-healing behavior at the same time. In addition, they show potential applications in adhesive film and wearable electronics. This new technology opens a new way to reprocess thermoset in a fashion similar to the thermoplastic in the current polymer industry.