6533b85dfe1ef96bd12bdc9b

RESEARCH PRODUCT

Soluble Hyperbranched Poly(glycolide) Copolymers

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description

A series of (hyper)branched poly(glycolide) copolymers has been prepared by copolymerization of glycolide (GA) with 2,2-bis(hydroxymethyl)butyric acid (BHB) via combined ROP/AB2-polycondensation. Polymerization was conducted in bulk and catalyzed by stanneous-2-ethyl hexanoate (Sn(Oct)2). The branched topology of the resulting polyesters was studied in detail by 1D- and 2D-NMR spectroscopy and confirmed by the synthesis and characterization of model compounds. The AB2 monomer BHB was incorporated either as a dendritic or focal unit, but hardly in linear or terminal mode. As expected for multifunctional polycondensation, SEC measurements showed polydisperse products with polydispersity index in the range of 1.88 to 3.40. Mn of the copolymers varied from 1100 to 4000 g/mol. MALDI−TOF MS analysis allowed to verify the main polymeric species. Furthermore, MALDI−TOF evidenced incorporation of several BHB units per macromolecule, confirming a successful condensation reaction and the formation of branched copoly...