Poly(propene-co-norbornene)s with high molar masses and tunable norbornene contents and properties, obtained in high yields using ketimide-modified half-titanocene catalysts†

The ketimide-modified half-titanocene catalysts, Cp′TiCl₂(NC^tBu₂) [Cp′ = C₅H₅ (), C₅Me₅ (), Me₃SiC₅H₄ ()], afford high molecular weight copolymers of propene (P) and norbornene (N) with efficient N incorporation in the presence of MAO. The poly(P-co-N)s obtained were studied in detail by determining the microstructure and comonomer contents using ¹³C-NMR spectra, molar masses, and thermal and mechanical properties. The ketimide Cp′TiCl₂(NC^tBu₂) catalysts and exhibited higher catalytic activities and yielded the copolymers with higher N contents and molar masses than the ketimide-modified Cp*TiCl₂(NC^tBu₂) (); the resultant copolymer using catalyst contained 61.7 mol% of N and M_w equal to 657 kg mol⁻¹ possessing uniform composition. The copolymers show very different tensile behaviours passing from ductile and tough materials to stiff and fragile ones as the N content increases.