Copolymerization of ethylene with higher a-olefins, such as 4-methyl-1-pentene, 1-hexene, 1-octene and 1-dodecene, was carried out with both aspecific and isospecific bridged metallocene complexes, comparing the catalytic behaviour Ž . following metallocene supportation on methylalumoxane-pretreated
ZSM-5 acid zeolite supported metallocene catalysts for ethylene polymerization
✍ Scribed by Maria de Fátima V. Marques; Simone C. Moreira
- Publisher
- Elsevier Science
- Year
- 2003
- Tongue
- English
- Weight
- 497 KB
- Volume
- 192
- Category
- Article
- ISSN
- 1381-1169
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✦ Synopsis
Zeolite H-ZSM-5 was used as support for the impregnation of Cp 2 ZrCl 2 catalyst in the synthesis of polyethylene. The catalyst preparation conditions were varied and the statistic program was employed with the purpose of evaluating the best catalyst preparation method.
In order to utilize zeolite as support material it was necessary to perform a thermal treatment, which is composed by a pre-drying at 120 • C and afterwards a calcination at 300 • C under heating rate of 2 • C/min before treatment with methylaluminoxane (MAO) and bis(cyclopentadienyl) zirconium dichloride.
It was observed that high amounts of zirconium fixed on the support surface did not lead to catalysts with higher activities, but in general the molecular weights of the obtained polyethylenes were very high. Furthermore, the supported catalyst was submitted to a longer MAO pre-contact before starting the polymerization by feeding the monomer, causing a sharp increase in the catalyst activity.
📜 SIMILAR VOLUMES
## Abstract Summary: Supports of type MgCl~2~/AlR~__n__~(OEt)~3−__n__~, obtained by reaction of AlR~3~ with adducts of MgCl~2~ and ethanol, have been shown to be effective for the immobilization and activation of [Cp~2~TiCl~2~] and other single‐site olefin polymerization catalysts without the use o