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Synthesis of polystyrene microgel with a hyperbranched polyglycerol scaffold as core: Effect of shell congestion

Authors

  • Decheng Wan,

    Corresponding author
    1. Institute of Functional Polymers, School of Materials Science and Engineering, Tongji University, Shanghai 200092, China
    • Institute of Functional Polymers, School of Materials Science and Engineering, Tongji University, Shanghai 200092, China
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  • Hongting Pu

    1. Institute of Functional Polymers, School of Materials Science and Engineering, Tongji University, Shanghai 200092, China
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Abstract

Two hyperbranched polyglycerols (PG) (1a: Mn = 2000, 1b: Mn = 8000), both with 61% of the overall hydroxyl groups being transformed into trithiocarbonates (2a, 2b, with 16 and 65 OH groups being replaced by trithiocarbonates, respectively), can be used as a reversible addition-fragmentation chain transfer (RAFT) agent. Polymerization of styrene mediated by 2a/2b was in a living manner, resulting in star-like, amphiphilic, core-shell structured polymers with 16 arms (3a) and 65 arms (3b), respectively. It was found that for system mediated by 2b, more serious side reaction (radical–radical coupling) occurred than that by 2a, most probably due to their difference in shell congestion. A shell-crosslinked polymer could be prepared in the presence of divinylbenzene via a one-pot route at solid content up to 20%, but analysis proved the crosslinking was incomplete. Furthermore, the 65-arm-star polymer (3b) more tended to undergo macroscopic rather than intramolecular crosslinking than the 16-arm-star polymer (3a) did. The phenomenon might again be attributed to their difference in shell congestion. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007

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