Autor(en)
Franceschini, Fernando C; Tavares, Tatiana T. da R; Greco, Paula P; Galland, Griselda B; dos Santos, João H. Z; Soares, João B. P
Titel
Effects of the type and concentration of alkylaluminum cocatalysts on the molar mass of polypropylene made with in situ supported metallocene catalysts
Teil von
  • Journal of applied polymer science, 2005-03-05, Vol.95 (5), p.1050-1055
Ort / Verlag
Hoboken: Wiley Subscription Services, Inc., A Wiley Company
Links zum Volltext
Quelle
Web of Science
Beschreibungen
Propylene homopolymerizations were carried out with rac‐dimethylsilylenebis(indenyl)zirconium dichloride, methylaluminoxane‐modified silica, and common alkylaluminum cocatalysts. Supported catalysts were prepared by the in situ immobilization technique. The effects of the type and concentration (Al/Zr = 40–1000) of alkylaluminum on the propylene polymerization were evaluated with triethylaluminum (TEA), isoprenylaluminum (IPRA), and triisobutylaluminum (TIBA) as cocatalysts. The polymers were analyzed by gel permeation chromatography, differential scanning calorimetry, and 13C‐NMR. The polypropylene molar mass varied according to the nature of the alkylaluminum in the following order: TIBA > IPRA > TEA > no alkylaluminum. The polymers made with an in situ supported catalyst had lower crystallinities and melting points than the ones produced by homogeneous polymerization. The isotacticity was not affected by the polymerization conditions examined in this investigation. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1050–1055, 2005

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