Synthesis and structural study of an ABA block copolymer consisting of poly(γ‐benzyl l‐glutamate) as the A component and poly(propylene glycol) as the B component

ABA type block copolymers composed of poly(γ‐benzyl L‐glutamate) (PBLG) as the A component and poly(propylene glycol) as the B component were obtained by polymerization of γ‐benzyl L‐glutamate N ‐carboxyanhydride, initiated by amine groups at both ends of poly(propylene glycol). From circular dichroism measurements in ethylene dichloride solution as well as from infrared spectra measurements in the solid state, it was found that the polypeptide block exists in the α‐helical conformation, as in PBLG homopolymer. Wide‐angle X‐ray diffraction patterns for the block copolymers depend on the casting solvent and show basically similar reflections as the PBLG homopolymer.