Polyethylene wax has the physical properties of ethylene oligomer, and can be used as lubricant, stabilizer and adhesive. It is widely used in plastics, rubber, ink, cosmetics and other fields. Its preparation technology has been upgraded from the traditional thermal cracking process to catalytic ethylene polymerization technology. In this work, we synthesized three iminopyridyl nickel catalysts Ni1-Ni3 with different steric effects and bulky 2,4,6-tris(4-fluorophenyl)methyl substituents, and investigated their catalytic performance in ethylene chain-walking polymerization processes. Results demonstrated that catalyst structure and polymerization conditions directly influence ethylene catalytic activity, as well as the molecular weight and branching degree of the resulting polyethylene wax. All catalysts successfully produced branched polyethylene waxes with methyl groups and long side chains, exhibiting narrow dispersion. By adjusting polymerization temperature (0-75℃), the branching structure of polyethylene wax could be effectively controlled (15-61/1000C). A solid powder of polyethylene was obtained at lower temperatures, primarily composed of methyl branches. These catalysts exhibited nearly identical superior performance to toluene in industrial solvent n-heptane. The Ph-substituted Ni2 showed high catalytic activity of 4.55 × 10⁶ g·mol^-1·h^-1 in n-heptane versus 4.72 × 10⁶ g·mol^-1·h^-1 in toluene. This technology enables direct synthesis of branched polyethylene wax materials through chain-walk polymerization, featuring simple preparation, cost-effectiveness, high catalytic efficiency, and excellent solvent tolerance. It paves new pathways for high-value production of polyethylene waxes in industrial applications.

Key words: branch polyethylene wax, ethylene polymerization, iminopyridyl nickel, chain-walking, catalyst design