High-Performance Olefin Thermoplastic Elastomer Based on Dynamically Cross-Linking Crystalline Macromers and Elastic Backbones

Developing novel olefin thermoplastic elastomers (TPE-Os) that outperform those with well-defined block or grafted chain structures is both highly attractive and challenging. Here, we report the preparation of high-performance TPE-Os in a combinatorial way. Semicrystalline ethylene/1-octene/diene copolymers with pendant vinyl groups and crystalline polyethylene macromers with terminal double bonds are synthesized, and they are dynamically linked with a dithiol-based cross-linker containing a boronic ester bond to form a new TPE-O. Due to the synergy between physical crystallization and dynamic cross-linking, it exhibits a significantly increased Young's modulus (E), elongation at break (ε), ultimate strength (σ), and tensile toughness (UT) of up to 27.2 ± 3.8 MPa, 902 ± 28%, 26.7 ± 1.1 MPa, and 120.1 ± 9.5 MJ·m–3, respectively, which are among the highest levels of the dynamically cross-linked elastomers and traditional well-defined TPE-Os. It also has good elasticity with a 10-cycle elastic recovery ratio of up to 71.4%; a high melting point of nearly 123.8 °C and the σ can even maintain 0.14–0.42 MPa at 200 °C. The new TPE-O also offers high reprocessing performance with a recovery ratio of 113.2% for E, 98.5% for ε, 95.8% for σ, and 92.5% for UT. We believe that our study will facilitate the development of next-generation TPE-Os with higher performance.