Poly (pentadecalactone)-b-poly (l-lactide)(PPDL-b-PLLA) diblock copolymers were prepared via the organic catalyzed ring-opening polymerization (ROP) of l-lactide (l-LA) from PPDL macroinitiators using either 1, 8-diazabicyclo [5.4. 0] undec-7-ene (DBU) or 1, 5, 7-