Polymer-supported zirconocene catalyst for ethylene polymerization

The use of crosslinked poly(styrene-co-4-vinylpyridine) having functional g roups as the support for zirconocene catalysts in ethylene polymerization w as studied. Several factors affecting the activity of the catalysts were ex amined. Conditions like time, temperature, Al/N (molar ratio), Al/Zr (molar ratio), and the mode of feeding were found having no significant influence on the activity of the catalysts, while the state of the supports had a gr eat effect on the catalytic behavior. The activity of the catalysts sharply increased with either the degree of crosslinking or the content of 4-vinyl pyridine in the support. Via aluminum compounds, AlR3 or methylaluminoxane (MAO), zirconocene was attached on the surface of the support. IR spectra s howed an intensified and shifted absorption bands of C-N in the pyridine ri ng, and a new absorption band appeared at about 730 cm(-1) indicating a sta ble bond Al-N formed in the polymer-supported catalysts. The formation of c ationic active centers was hypothesized and the performance of the polymer- supported zirconocene was discussed as well. (C) 1999 John Wiley & Sons, In c. J Polym Sci A: Polym Chem 37: 37-46, 1999.