The Ligand and Bridge Effect of Metallocene on Producing Polyethylene Wax Under Controlled Hydrogen Partial Pressure

ABSTRACT Polyethylene wax is widely used for its unique physical properties, and metallocene structures are a key focus of research aimed at regulating product properties. In this study, the effects of bridge structures and ligand properties on ethylene polymerization are investigated, with H 2 as the chain‐transfer agent. The results indicate that the bridge and ligands primarily influence ethylene polymerization through electronic and steric effects. The bridge creates a crowded ligand space, increasing resistance to monomer insertion and reducing catalytic activity. The dimethylsilyl bridge, with its electron‐withdrawing effect, inhibits chain transfer, whereas the ethylene bridge, with its electron‐donating effect, does not. Dimethylsilyl bridges also provide greater rigidity, enhance polymer chain regularity, and significantly broaden the molecular weight distribution. For ligands, larger volume effectively prevents chain transfer and results in a broader molecular weight distribution; electron‐donating groups on the ligand can also enhance reactivity, compensating for the loss of reactivity caused by steric hindrance from large ligands. In summary, under identical H 2 pressure conditions, bridged metallocene catalysts with different structures significantly influence catalyst activities and the properties of the synthesized polyethylene wax.