Design and Characterization of Durable Glass Fibre (GF)-Reinforced PLA and PEEK Biomaterials

Poly(lactic acid) (PLA) and poly(ether-ether ketone) (PEEK) are widely recognized for their biocompatibility and processability in orthopaedic applications. However, PLA suffers from brittleness and limited thermal and mechanical stability, while PEEK, despite its better strength, does not fully replicate the mechanical and tribological performance of natural bone. This study explores the enhancement of structural and tribological properties in PLA- and PEEK-based composites reinforced with short glass fibres (S-GF) via additive manufacturing. Microstructural analysis confirms uniform GF dispersion within both polymer matrices, with no evidence of agglomeration, fibre pull-out, or interfacial debonding, suggesting strong fibre-matrix adhesion. The incorporation of GF significantly improved mechanical performance: microhardness increased by 38.3% in PLA and 36.3% in PEEK composites, while tensile strength increased by 25.1% and 13.4%, respectively, compared to plain polymers. These enhancements are attributed to effective stress transfer enabled by uniform fibre distribution and strong interfacial bonding. Tribological tests further demonstrate enhanced wear resistance, reduce damage propagation, and improved surface integrity under micro-scratching. These findings highlight the potential of GF-reinforced PLA and PEEK composites as high-performance materials for load-bearing biomedical applications, offering a balanced combination of mechanical strength and wear resistance aligned with the functional requirements of bioimplants.