| 초록 |
Dendrimer-like star-branched polymers have recently appeared as a new class of hyperbranched polymer. These polymers resemble dendrimers in branched architecture, but comprise of polymer chains instead of small spacers. Therefore, they are much bigger in molecular weight and size than dendrimers. A promising methodology has been developed for the synthesis of such polymers by Hirao et al. It involves only two reactions: (1) a coupling reaction of α-functionalized living PMMA with chain-end-functionalized PMMA with two or more benzyl bromide (BnBr) moieties, and (2) a transformation reaction to BnBr. By repeating the two reactions, well-defined dendrimer-like star-branched (PMMA)s up to the 7th-generation have been successfully synthesized. The resulting PMMA reaches to 2 x 106 in Mn value and possesses 508 polymer segments and 512 BnBr moieties at the chain end. Herein, the synthesis of various dendrimer-like star-branched polymers with different polymer segments, branch densities, and end-functionalities will be reported. Their solution behaviors are also discussed with respect to size, intrinsic viscosity, and branching factor “g’”. |
