Degradable star polymers with high "click" functionality

Abstract

Degradable polyester-based star polymers with a high level of functionality in the arms were synthe sized via the "arms first" approach using an acetylene-functional block copolymer macroinitiator. This was achieved by using 2-hydroxy-ethyl 2′-methyl-2′-bromopropionate to initiate the ring-opening polymerization (BOP) of caprolactone monomer followed by an atom transfer radical polymerization (ATRP) of a protected acetylene monomer, (trimethylsilyl)propargyl methacrylate. The hydroxyl end-group of the resulting block copolymer macroinitiator was subsequently crosslinked under ROP conditions using a bislactone monomer, 4,4′-bioxepanyl-7,7′-dione, to generate a degradable core crosslinked star..