Effect of the alkylaluminum cocatalyst on ethylene polymerization by a nickel–diimine complex

✍ Scribed by Leonardo C. Simon; Raquel S. Mauler; Roberto F. De Souza

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 151 KB
• Volume: 37
• Category: Article
• ISSN: 0887-624X
• DOI: 10.1002/(sici)1099-0518(19991215)37:24<4656::aid-pola24>3.0.co;2-g

✦ Synopsis

Different chlorine-free alkylaluminum compounds were active cocatalysts for ethylene polymerization in the presence of 1,4-bis(2,6-diisopropylphenyl)-acenaphthenediimine-dichloronickel (II) (1). The combination of 1 with trimethylaluminum or triisobutylaluminum produced catalytically active species that polymerized ethylene with productivities up to 469 kg polymer /(mol Ni ⅐ h). The activity of the catalytic system and the properties of the polymeric materials were influenced strongly by the reaction temperature. The polymers had a high molecular weight (up to 642 ϫ 10 3 g ⅐ mol Ϫ1 ), and the molecular weight increased with the reaction time. The polyethylenes were branched, and the branching could be modulated by the proper choice of reaction parameters.