Addition of lewis bases and acids. Effect on alfa-olefins polymerization with soluble metallocenes. I- Ethylene

BELELLI, PATRICIA GABRIELA; FERREIRA, MARÍA LUJÁN; DANIEL EDUARDO, DAMIANI

Macromolecular Chemistry and Physics

Wiley

Lugar: Weinheim; Año: 2000 vol. 201 p. 1458 - 1465

1521-3935

In Part 1 of this series the soluble system rac-EtInd2ZrCl2/methylaluminoxane (MAO) was studied in ethylene polymerization with additives. Lewis acids and bases such as AlCl3 and ethyl benzoate (EB) were used to evaluate their effects on polymerization kinetics, catalyst activities, and polymer properties. The results obtained showed a clear trend to improve the performance when AlCl3 was added. The Lewis base might be acting in different ways on the active sites. The activity is strongly decreased with EB. To further elucidate some of the different aspects of metallocene activation, a UV/Visible spectroscopic study was carried out, with toluene as solvent. It was possible to correlate the catalytic activity with AlCl3 as additive to changes in the intensity of the ligand to metal charge transfer (LMCT) bands of EtInd2ZrCl2 when MAO/AlCl3 was the coactivator.