Groups 3 and 4 single-site catalysts for styrene–ethylene and styrene–α-olefin copolymerization

Styrene–ethylene and styrene–α-olefin copolymers are relatively new materials that were developed since the early 1990s thanks to homogeneous single-site catalysts. A wide range of copolymers, differing in their compositions, microstructures and properties have been prepared by using several types of early transition (groups 3 and 4) metal catalysts, which are critically reviewed in this contribution. Structure–activity–control relationships are also discussed.