Efficient control of ethylene–norbornene copolymerization behavior of a fluorenylamido-ligated titanium complex: substituent effects of the amido ligand and copolymer properties

Copolymerization behavior is the most critical factor in the properties of polymeric materials. Highly active copolymerization of ethylene and norbornene was explored using (fluorenyl)(amido)titanium complexes bearing substituted amido ligands. The norbornene content and norbornene sequence distribution of the copolymers were controllable by changing the comonomer feed ratio and the polymerization temperature, respectively. The evaluation of the monomer reactivity ratios indicated that the copolymerization behavior of the (fluorenyl)(amido)titanium complex was tunable from alternating to random nature. The thermal and mechanical properties of the resulting copolymers depended on the sequence distribution of norbornene.