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

[Display omitted] •All catalysts were found highly active with maximum activity up to 7.04 × 106 g·mol−1·h−1. The activity matches with the activity of high performance early transition metal catalysts.•Thermal stability is a great issue of α-diimine based catalysts, which limits their application at industrial level. So in this perspective, all catalysts retain their considerable activity at elevated high temperature of 140 °C showing their good thermal stability whereas previously reported catalysts of this class usually decompose at 80 °C.•Ultra-high molecular weight polyethylene is an emerging class of advanced materials. All the catalysts generate UHMWPE with maximum Mn up to 333.4 × 104 g·mol−1.•All catalysts maintain generation of UHMWPE even at elevated temperature of 140 °C. Usually catalysts of this class generate high molecular weight polyethylene at low temperature, which limits their application for industrial level.•The t-Bu rich nature and enables their good solubility in non-polar aliphatic hydrocarbons, which are industrially desired polymerization solvent.•The catalysts generate polyethylene thermoplastic elastomers with great mechanical properties and strain recover (SR) values of up to 75%.•Polymerization experiments have been carried out at small and large scale.•The above mentioned properties make these catalysts highly attractive for industrial application. 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, α-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 × 106 g·mol−1·h−1, producing polyethylene with ultra-high molecular weight of up to 333.4 × 104 g·mol−1. More remarkably, these catalysts have thermal stability of up to 140 °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 °C, with great mechanical properties and strain recover (SR) values of up to 75 %. The properties including