Efficient Molecular Weight Control with Trialkylaluminum in Ethylene/Norbornene Copolymerization by [Ph2C(Flu)(3-MeCp)]ZrCl2/Methylaluminoxane Catalyst

• Published in: Macromolecular chemistry and physics Vol. 211; no. 19; pp. 2132 - 2137
• Main Authors: Tada, Tomoyuki, Cai, Zhengguo, Nakayama, Yuushou, Shiono, Takeshi
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.10.2010; WILEY‐VCH Verlag; Wiley
• Subjects: Applied sciences; chain transfer; Copolymerization; ethylene; Exact sciences and technology; metallocene catalysts; norbornene; Organic polymers; Physicochemistry of polymers; polyolefins; Preparation, kinetics, thermodynamics, mechanism and catalysts; synthesis; synthesis; Norbornene copolymer; copolymerization; norbornene; Solution copolymerization; Zirconium complex; Complex catalyst; Experimental study; Complex catalyst copolymerization; ethylene; Saturated copolymer; metallocene catalysts; Sandwich compound; polyolefins; Ethylene copolymer; Alternating copolymer; Alternating copolymerization; Chloro complex; Aluminium Organic compounds; chain transfer; Catalyst activity
• ISSN: 1022-1352; 1521-3935
• DOI: 10.1002/macp.201000172

Ethylene/norbornene copolymerizations were conducted with [Ph2C(Flu)(3‐RCp)]ZrCl2 [R: Me (1) or Me3Si (2)], which give alternating EN copolymers. The activity of 1 in the absence of R3Al was approximately twice that of 2 and increased further upon addition of R3Al. Et3Al increased the activity most effectively, and the $\overline {M} _{{\rm n}} $ of the produced polymer decreased from 100 000 to 25 000 g · mol−1. On the other hand, the $\overline {M} _{{\rm n}} $ value increased upon addition of iBu3Al from 100 000 to 209 000 g · mol−1 accompanied by an ≈2.5‐fold increase of activity. Consequently, 1 was found to be one of the most promising complexes for the synthesis of alternating EN copolymers, of which $\overline {M} _{{\rm n}} $ value was efficiently controlled by the kind and the amount of R3Al added. By choosing the amount of iBu3Al or Et3Al added, the values of alternating ethylene/norbornene (EN) copolymers are widely controlled from 25 000 to 209 000g·mol−1 accompanied with an increase in the polymer yields by the use of [Ph2C(Flu)(3‐MeCp)]ZrCl2 (1) combined with methylaluminoxane (MAO) in toluene.