Random Copolymerization of Propene and Norbornene with ansa-Fluorenylamidodimethyltitanium-Based Catalysts

Abstract

Copolymerization of propene and norbornene (P−N) was conducted with (t-BuNSiMe2Flu)TiMe2 (1) activated by Me3Al-free methylaluminoxane (dried MAO), modified methylaluminoxane (MMAO), and Ph3CB(C6F5)4/Oct3Al at 20 °C under atmospheric pressure of propene. The 1−Ph3CB(C6F5)4/Oct3Al system showed the highest activity and gave the copolymer with the lowest molecular weight and broad molecular weight distribution. The 1−dried MAO system produced the copolymer with the narrowest molecular weight distribution. The detailed investigation of this system clarified that the norbornene content in the copolymer was almost proportional to the N/P feed ratio with a narrow polydispersity of 1.1−1.2 and the glass transition temperatures of the P−N copolymers increased linearly against the norbornene content in the copolymers, that is, 53 °C with 17 mol % of norbornene and 249 °C with 71 mol % of norbornene. The 13C NMR spectra also suggested the random distribution of the comonomers in the copolymers obtained.