Poly(4‐vinylpyridine)‐supported cationic bis(cyclopentadienyl)zirconocene catalyst: Development of a new simple method to prepare polymer‐supported cationic zirconocene and its application to ethylene polymerization

Bis(cyclopentadienyl)zirconocene dimethyl (Cp₂ZrMe₂) combined with triphenylcarbenium tetrakis(pentafluorophenyl)borate (Ph₃C]B(C₆F₅)₄]) was brought into contact with a suspension of 2% cross‐linked poly(4‐vinylpyridine) to give a new type of polymer‐supported cationic zirconocene catalyst. The resulting polymer‐supported catalyst system combined with Al(i‐Bu₃) showed markedly high activity for ethylene polymerization in even a non‐polar solvent like hexane at 25–60°C and Al]/Zr] molar ratio 40–200. By the analysis of Zr content of the hexane solution, it was found that no Zr was detected in the solution, i. e. no leaching of the cationic catalyst into the hexane medium. The catalytic activity was found to increase with an increase of polymerization temperature and showed the highest at Al]/Zr] = 100. The molecular weight, crystalline melting temperature, crystallinity, and bulk density of polyethylene formed were higher than those of the polymer obtained from the homogeneous system.