Controlling polyethylene branching via surface confinement of Ni complexes

The heterogeneous surface support can play a key role in determining polymer microstructure, as we show for novel variant of Ni-catalyst from the family late-transition metal complexes; this extends toolbox catalytic solutions industrial processes. Novel variants single-atom catalysts (Ni-FO-Al@SiO2, Ni-FO-Si@SiO2, Ni-O-Al@SiO2, and Ni-O-Si@SiO2) were prepared form unsymmetrical a-diimine Ni complexes (Ni-OH Ni-FOH) then characterized by inductively coupled plasma - optical emission spectrometry (ICP-OES) X-ray photoelectron spectroscopy (XPS) analysis. Ethylene slurry-phase polymerization was performed both via self-supporting covalent-tethering strategies to systematically study confinement effects. High activity maintained under (as high 3.9 × 106 g PE (mol Ni)−1 h−1). crucial features molecular weight (>106 mol−1) branching density 180.1BD/1000C) found among samples produced polymerization. A detailed investigation suggested that functional groups, such OH Cl, coordinate with active species their lone pairs terminate ethylene Microstructure analysis confirm supporting substrate provides chance modulate chain-walking behavior these catalysts. Systematic high-temperature 1H 13C NMR indicated could significantly decrease solid substrate. Until now, microstructure control has been mainly realized laborious synthesis bulky ligands.