Ring-Opening Copolymerization of ε-Caprolactone and L-Lactide Catalyzed by Aluminum Complexes

In recent years, poly(ε-caprolactone) (PCL) and poly (lactic acid) (PLA) have been widely adopted as biodegradable materials, with applications ranging from simple packaging to sophisticated biomedical devices. Although PLA possesses notable advantages such as biocompatibility and high mechanical strength, it suffers from several limitations including brittleness, poor elasticity, low thermal stability, and inadequate permeability. In this study, we synthesized a series of aluminum complexes (Al1−Al6) bearing different substituent structures. These metal complexes were thoroughly characterized by nuclear magnetic resonance (NMR) spectroscopy, elemental analysis, and single-crystal X-ray diffraction. Subsequently, these aluminum complexes (Al1−Al6) were employed as catalysts for the ring-opening polymerization (ROP) of L-lactide (L-LA), followed by the ring-opening copolymerization (ROCOP) of L- LA with ε-caprolactone (ε-CL). Through these polymerization processes, we successfully synthesized a series of high-performance copolymers with excellent properties.