Mechanical Properties and In Vitro Degradation Study of Modified-Polylactic Acid Block Copolymers/Polyetheretherketone Biocomposites

Polylactic acid (PLA) plays a crucial role in addressing global environmental concerns, particularly the challenges of achieving carbon peak and neutrality goals. Polyetheretherketone (PEEK) has emerged as a potential orthopedic implant material due to its excellent mechanical properties, elastic modulus similar to human bone, wear resistance, and good biocompatibility. In this study, PEEK/PLA (PEEK/PLA) composites were prepared using a film-casting method. PEEK exhibits a spherical structure and can be dispersed in the PLA matrix, demonstrating good compatibility with PLA. Additionally, PEEK acts as a heterogeneous nucleating agent, reducing the surface free energy barrier for the crystallization nucleation of PLA molecules and promoting PLA crystallization. When the PEEK content is 8%, the tensile strength and Young's modulus of the composite material increase by 15.45% and 91.23%, respectively, compared to pure PLA. Furthermore, the introduction of the copolymer (PC x L y A) not only improves the compatibility between PLA and the blend but also successfully regulates the mechanical properties and in vitro degradation of the composite by adjusting the ratio of ε-caprolactone and L-lactide in the copolymer. This study not only delves into the modification strategies and methods for PLA composites but also provides new insights for developing biomedical materials with excellent properties.