Investigation on the influence of different block ratios on the properties of biodegradable ABA–type block copolymer PTMC–b–PCL–b–PTMC

In this study, a series of ABA–type block copolymers, PTMC–b–PCL–b–PTMC, with varying block ratios were synthesized via sequential ring–opening polymerization. A systematic investigation was conducted to assess the mechanical properties, thermal behavior, crystallization characteristics, enzymatic degradation under lipase–rich conditions, and biological performance of the copolymers with different compositions. The results demonstrated that increasing the PTMC block content significantly influenced the physicochemical properties of the copolymers. Specifically, a higher proportion of PTMC blocks resulted in decreased crystallinity and enhanced toughness. Furthermore, lipase degradation studies revealed that during the early stages, all polymer compositions exhibited the characteristic surface erosion behavior of polyesters. However, in the later stages, PCL–OH exhibited more pronounced collapse degradation, whereas the block copolymers PTCT6040 and PTCT7030, with higher crystallinity, maintained surface erosion–dominated degradation while preserving their macroscopic structure and mechanical stability. Additionally, biocompatibility assays confirmed the non–cytotoxicity of these materials, highlighting their potential for applications in tissue engineering.