| 초록 |
Zwitterionic polymerization involves a propagating species with both positively and negatively charged groups. Previous investigations on zwitterionic polymerization concern alternating copolymerization of nucleophilic and electrophilic monomers and polymerization of isolated stable zwitterionic monomers. More recently, the ring-opening polymerization of cyclic monomers using nucleophilic initiators have been studied. Specifically, the zwitterionic polymerization of cyclic esters using N-heterocyclic carbene (NHCs) is the focus of this work. The NHC mediated zwitterionic polymerization of cyclic monomers provides an expedient route to polymers of various architectures such as cyclic polymers, cyclic gradient copolymers and linear telechelic polymers. In this work, the polymerization kinetics of lactide initiated by NHCs and a simple copolymerization protocol to produce cyclic gradient copolymers using the reactivity difference of the monomers towards NHCs are discussed. |
