Synthesis functional poly(carbonate-b-ester) copolymers and micellar characterizations

Functional poly(carbonate-b-ester)s were synthesized in buck by ring-opening polymerization of the carbonate (TMC, MBC, or BMC) with tert-butyl N-(2-hydroxyethyl) carbamate as an initiator, and then with epsilon-CL (or epsilon-BCL) comonomer. Subsequently, the PMMC-b-PCL with pendent carboxyl groups and the PTMC-b-PHCL with pendent hydroxyl groups were obtained by catalytic debenzylation. DSC analysis indicated that only one T-g at an intermediate temperature the T(g)s of the two polymer blocks. A decrease T-g was observed when an increase contents of epsilon-CL incorporated into the copolymers. In contrast, two increased T(m)s were observed with increasing PCL content. The block copolymers formed micelle in aqueous phase with critical micelle concentrations (cmcs) in the range of 2.23-14.6 mg/ L and with the mean hydrodynamic diameters in the range of 100-280 nm, depending on the composition of copolymers. The drug entrapment efficiency and hydrolytic degradation behavior of micelle were also evaluated. (c) 2007 Wiley Periodicals, Inc.