title: Highly efficient synthesis of low polydispersity core cross-linked star polymers by Ru-catalyzed living radical polymerization.
abstract: The efficient formation of low polydispersity core cross-linked star (CCS) polymers via controlled/living radical polymerization (LRP) and the arm-first approach was found to be dependent on the mediating catalyst system. The Ru catalyst, Ru(Ind)Cl(PPh₃)₂ Cat. 1, and tertiary amine co-catalyst were used to synthesize highly living poly(methyl methacrylate) (PMMA) macroinitiators, which were then linked together with ethylene glycol dimethacrylate (EGDMA) to form PMMA(arm)PEGDMA(core) CCS polymers. The quantitative and near-quantitative synthesis of CCS polymers were observed for low to moderate molecular weight macroinitiators (M(n) =  8 and 20 kDa), respectively. Lower conversions were observed for high-molecular weight macroinitiators (M(n)  ≥  60 kDa). Overall, an improvement of between 10 and 20% was observed when comparing the Cat. 1 system to a conventional Cu-catalyzed system. This significant improvement in macroinitiator-to-star conversion is explained in the context of catalyst system selection and CCS polymer formation.
authors: Polymer Science Group, Department of Chemical and Biomolecular Engineering, The University of Melbourne, Victoria 3010, Australia.
authors: Tor Kit
authors: TK
authors: Goh
authors: Satoshi
authors: S
authors: Yamashita
authors: Kotaro
authors: K
authors: Satoh
authors: Anton
authors: A
authors: Blencowe
authors: Masami
authors: M
authors: Kamigaito
authors: Greg G
authors: GG
authors: Qiao
mesh_terms: D002384:Catalysis; D005782:Gels / Q000737:chemistry; D008689:Methacrylates / Q000737:chemistry*; D015394:Molecular Structure; D008970:Molecular Weight; D011092:Polyethylene Glycols / Q000737:chemistry*; D058105:Polymerization; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry*; D019904:Polymethyl Methacrylate / Q000737:chemistry*
chemical_list: D005782:Gels; D008689:Methacrylates; D011108:Polymers; C421283:poly(ethylene glycol)-dimethacrylate; D011092:Polyethylene Glycols; D019904:Polymethyl Methacrylate