Direct Synthesis of Thermoplastic Polyolefin Elastomers from Nickel-Catalyzed Ethylene Polymerization

TLDR

Thermoplastic elastomers are prized for their processability, reusability, and recyclability, yet their synthesis usually requires long‑chain α‑olefins, multiple steps, and several catalysts, making single‑step ethylene‑based routes highly desirable but challenging. This study reports the synthesis of polyethylene‑based thermoplastic elastomers through α‑diimine nickel‑catalyzed ethylene polymerization. The authors use α‑diimine nickel catalysts to polymerize ethylene in a single step, varying catalyst structures and polymerization conditions to produce polyethylene with elastomeric properties. By tuning catalyst and conditions, the stress‑at‑break and strain‑at‑break of the polyethylene products were adjustable over a wide range, and some variants exhibited excellent elastic properties.

Abstract

As a promising alternative to thermoset elastomers, thermoplastic elastomers (TPEs) have attracted much attention because of their unique properties, including processability, reusability and recyclability. The synthesis of TPEs based on olefinic building blocks usually requires the use of long chain α-olefins, multiple steps, and/or multiple catalysts. The concept of using only ethylene as feedstock in a single step is fascinating but also very challenging. In this contribution, we report the synthesis of polyethylene-based TPEs through α-diimine nickel-catalyzed ethylene polymerization. The stress-at-break and strain-at-break values of these polyethylene products could be tuned over a very wide range using different nickel catalysts and different polymerization conditions. Most importantly, products with excellent elastic properties could be generated in the screening process.