Thermoplastic vulcanizates dynamically cross-linked by a tailored small molecule

Thermoplastic vulcanizates (TPVs) with more features and functions are able to find broader applications, which is increasingly desired in our daily lives. However, great challenges were facing to develop novel TPVs with integrated properties such as reinforcement, recycling, and shape memory. Herein, we report a simple and effective route to prepare mechanically robust, recyclable and shape memory-epoxidized natural rubber (ENR)/polylactic acid (PLA) TPVs by employing a tailored cross-linker (FDP) containing triple dynamic covalent bonds instead of conventional cross-linkers. The ENR phase in ENR/PLA TPVs evolved into a regular continuous phase and PLA was grafted onto ENR chain segments through FDP. The TPVs exhibited a tensile behavior of classical elastomers rather than that of plastics, with a tensile strength of 7.8 MPa and elongation at break of 174%, increased by 1.5 times and 2.9 times, respectively as compared to the traditional TPVs vulcanized by peroxide. The topology rearrangement of the cross-linked ENR networks in the TPVs can be accomplished at high temperatures. Furthermore, its regular phase structure also bestowed an excellent shape memory ability on the TPVs. This work is promising to provide a new design idea for the development of high-performance TPVs using readily available raw materials.