Highly Efficient Synthesis of Low Polydispersity Core Cross-Linked Star Polymers by Ru-Catalyzed Living Radical Polymerization
✍ Scribed by Tor Kit Goh; Satoshi Yamashita; Kotaro Satoh; Anton Blencowe; Masami Kamigaito; Greg G. Qiao
- Publisher
- John Wiley and Sons
- Year
- 2011
- Tongue
- English
- Weight
- 359 KB
- Volume
- 32
- Category
- Article
- ISSN
- 1022-1336
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✦ Synopsis
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 dependant on the mediating catalyst system. The Ru catalyst, Ru(Ind)Cl(PPh~3~)~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 ($\overline {M} _{{\rm n}} $ = 8 and 20 kDa), respectively. Lower conversions were observed for high‐molecular weight macroinitiators ($\overline {M} _{{\rm 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. magnified image