POLYMERIZATION OF ETHYLENE OVER METALLOCENES CONFINED INSIDE THE SUPERCAGE OF A NAY ZEOLITE

Abstract

Metallocene catalysts entrapped inside the supercages of NaY zeolite were prepared by reacting NaY with methylaluminoxane (MAO) or trimethylaluminium (TMA) and then with Cp(2)ZrCl(2) (Cp: cyclopentadienyl) or Cp(2)TiCl(2). NaY/MAO/Cp(2)ZrCl(2) and NaY/MAO/ Cp(2)TiCl(2) catalysts could polymerize ethylene. The amount of additional MAO for the polymerization was lowered to a mole ratio of Al/Zr of 186. Molecular weights and melting points of polyethylene polymerized with NaY-supported catalysts were higher than those of polyethylene obtained with homogeneous metallocene catalysts. It could be confirmed by extraction experiments that the metallocene catalyst was confined securely inside the supercage of the NaY zeolite.