PLLA-PEG/mPEG Copolymer with Improved Hydrophilicity, Crystallinity, and Biocompatibility: An In-Depth Study on the Crystallization Kinetics.

Poly(lactic acid) (PLA) possesses excellent biocompatibility and biodegradability for the construction of biomaterials. However, its limited crystallinity largely restricts practical application. In this study, four poly(l-lactic acid) (PLLA) copolymers were synthesized by incorporating two different molecular weights of PEG/mPEG (1K and 2K) chains with l-lactide via ring-opening polymerization (ROP). The impact of PEG/mPEG chains on the hydrophilicity and mechanical properties of the resulting copolymers, their crystallization kinetics, and activation energy was also examined. The results demonstrate that introducing PEG/mPEG chains could significantly improve the hydrophilicity, crystallinity, and crystallization rate and reduce the maximum crystallization temperature of the copolymer materials. Among the PLLA copolymers, PLLA-mPEG (2K) exhibits the most remarkable improvements in polymer crystallinity, crystallization rate, and reduction of the maximum crystallization temperature. The advancements in copolymer material properties were anticipated to significantly expand the potential applications for PLLA-based polymer materials, which also greatly improved the applicability as sustainable and controllable biopolymer materials.