Platinum Metals Rev., 2001, 45, (2), 82
Ruthenium-Initiated Star Polymers
Star-shaped polymers are attracting interest as polymeric materials because of their unusual structures. Such structures can be made by living polymerisation processes, one of which involves a Unking reaction using living linear polymers and divinyl compounds.
Researchers at Kyoto University in Japan now report a multi-arm star-shaped polymer with a cross-linked microgel core (K.-Y. Baek, M. Kamigaito and M. Sawamoto, Macromolecules, 2001, 34, (2), 215–221). Using in-situ polymerisation of methyl methacrylate (MMA), a halide initiator and RuCl2(PPh3)3, in the presence of Al(Oi-Pr)3 a living poly(MMA) was formed which on reaction with a divinyl compound resulted in star-shaped polymers.
The yield depended on the structures of the initiators, divinyl compounds, monomers and other reaction conditions. The best system gave a polymer of about 20 poly(MMA) arms per molecule.