Highly Efficient Ti-Based Catalyst Systems for Vinyl Addition Polymerization of Norbornene

Norbornene polymerization via “vinyl addition” proceeded with (t-BuNSiMe2Flu)TiMe2 (1) in the presence of various cocatalysts [methylaluminoxane (MAO), modified methylaluminoxane (MMAO), and Ph3CB(C6F5)4/Oct3Al] at wide range of temperatures (20−80 °C) with high activity. The 1−Ph3CB(C6F5)4/Oct3Al system produced 4.8 × 103 kg of polymer per mole of Ti per hour at 20 °C. All the catalyst systems produced high molecular weight (Mn) polymers. In the 1−MMAO system, the yield and Mn values increased linearly keeping narrow molecular weight distribution against the Al/Ti ratio, suggesting that MMAO should take part not only in the initiation but also in the propagation reaction. The rate enhancement with higher Al/Ti ratio was also observed in the Ph3CB(C6F5)4/Oct3Al system. The activity of the 1−dried MAO and 1−MMAO systems increased with raising reaction temperature up to 60 °C, whereas that of 1−Ph3CB(C6F5)4/Oct3Al decreased. The polynorbornenes obtained with 1 were amorphous, soluble in halogenated aromatic...