1 research outputs found
Synthesis of Various Branched Ultra-High-Molecular-Weight Polyethylenes Using Sterically Hindered Acenaphthene-Based α‑Diimine Ni(II) Catalysts
A series
of highly sterically hindered acenaphthene-based α-diimine
nickel complexes with the remote R group in 4-position of diarylmethyl
moiety have been synthesized and characterized. Activated with Et<sub>2</sub>AlCl, ethylene polymerization by these nickel complexes is
investigated in detail, involving the remote substituent effect and
influence of polymerization temperature on catalyst activity, thermal
stability, polymer molecular weight, and branching density. These
thermostable nickel catalysts are very active (up to 5.1 × 10<sup>6</sup> g·mol<sup>–1</sup>·h<sup>–1</sup>) for ethylene polymerization and capable of producing various moderate
to highly branched (26–71/1000 C) ultra-high-molecular-weight
polyethylenes (UHMWPEs, <i>M</i><sub>w</sub> up to 4.5 ×
10<sup>6</sup> g·mol<sup>–1</sup>). These polymeric materials
with such unique structure show properties characteristic of thermoplastic
elastomers, i.e., good elastomeric recovery and high strain at break