<p>Poly(propylene carbonate) (PPC) from propylene oxide and carbon dioxide has remained a subject of considerable research interest owing to its advantageous properties. Recently, the block copolymer approach has been employed to broaden the potential applications of PPC-based materials. In this study, we develop novel PPC-based block copolymers by coupling poly(α-amino acid)s (PAAs) to PPC. The ring-opening polymerization of α-amino acid <i>N</i>-thiocarboxyanhydrides was found to proceed efficiently using the amino-terminated PPC as a macroinitiator and acetic acid as a promotor, yielding the corresponding PPC-<i>block</i>-PAA. The PAA segments were indicated to form α-helix in the resulting block copolymers.</p> Graphical Abstract <p></p>