Effect of Porosity and Post-Processing on the Mechanical Performance of Additively Manufactured PEEK Osteoconductive Scaffolds

Additive manufacturing enables the fabrication of porous polyetheretherketone (PEEK) structures with controlled architectures for biomedical applications. In particular, porous PEEK scaffolds have attracted significant attention due to their potential to enhance osteoconductivity while maintaining mechanical compatibility with bone. However, the relationship between porosity, post-processing conditions, and mechanical performance remains insufficiently understood, especially at high porosity levels. In this study, the effects of porosity (49–81%) and post-processing heat treatment (4 and 6 h at 300 °C) on the mechanical performance of additively manufactured PEEK osteoconductive scaffolds were experimentally investigated. Compression and three-point bending tests were conducted to evaluate strength and elastic modulus. Results demonstrated a strong inverse relationship between porosity and mechanical properties, with significant reductions observed beyond critical thresholds of approximately 66% in compression and 59% in bending. Heat treatment improved mechanical performance at lower porosity levels, likely due to enhanced crystallinity and interlayer bonding, while its effect diminished at higher porosities due to reduced load-bearing material and ligament thinning. These findings highlight the importance of optimizing porosity and post-processing conditions to achieve a balance between mechanical integrity and osteoconductive potential in PEEK scaffolds. The results provide practical design guidelines for the development of additively manufactured PEEK structures for load-bearing orthopedic applications.