Synthesis of Ultra-High molecular weight polyethylene elastomers by para-tert-Butyl dibenzhydryl functionalized ?-Diimine nickel catalysts at elevated temperature

The synthesis of polyethylene thermoplastic elastomers directly from ethylene as a feedstock is highly attractive in perception of their diverse applications and low cost. In this contribution, alpha-diimine nickel catalysts (Ni1-Ni4) with sterically bulky para-t-Bu dibenzhydryl moieties at ortho-position as well as different electron-donating and -withdrawing groups at para-position have been synthesized, characterized and applied for ethylene polymerization. These catalysts were found to be highly active with maximum activity up to 7.04 x 106 g center dot mol-1 center dot h-1, producing polyethylene with ultra-high molecular weight of up to 333.4 x 104 g center dot mol-1. More remarkably, these catalysts have thermal stability of up to 140 degrees C. The t-Bu rich nature enables their good solubility in non-polar aliphatic hydrocarbons, which are industrially desired polymerization solvents. Furthermore, these catalysts generate polyethylene thermoplastic elastomers especially at industrially high temperature of 140 degrees C, with great mechanical properties and strain recover (SR) values of up to 75 %. The properties including high thermal stability, polymerization in aliphatic hydrocarbons, and capabilities of yielding elastic ultra-high molecular weight polymers make them highly attractive for potential industrial applications.

Automated summary

This article introduces a method for synthesizing polyethylene thermoplastic elastomers from ethylene, which is highly attractive due to its diverse applications and low cost. By synthesizing alpha-diimine nickel catalysts, polyethylene with high activity and high molecular weight was successfully obtained. These catalysts also exhibited high thermal stability and good solubility, enabling the production of polyethylene thermoplastic elastomers at high temperatures with excellent mechanical properties and strain recovery values.