Synthesis of Poly(ε-caprolactone)-b-Poly(γ-benzyl-l-glutamic acid) Block Copolymer Using Amino Organic Calcium Catalyst

A biodegradable two block copolymer, poly(ε-caprolactone)-b- poly(γ-benzyl-l-glutamic acid) (PCL−PBLG) was synthesized successfully by ring-opening polymerization of N-carboxyanhydride of γ-benzyl-l-glutamate (BLG−NCA) with aminophenyl-terminated PCL as a macroinitiator. The aminophenethoxyl-terminated PCL was prepared via hydrogenation of a 4-nitrophenethoxyl-teminated PCL, which was novelly obtained from the polymerization of ε-caprolactone (CL) initiated by amino calcium 4-nitrobenzoxide. The structures of the block copolymer and its precursors from the initial step of PCL were confirmed and investigated by 1H NMR, FT-IR, GPC, and FT-ICRMS analyses and DSC measurements.