Enhanced processability and mechanical properties of poly-ether-ether-ketone/nano-silicon nitride composite scaffolds fabricated by laser powder bed fusion

Abstract

Poly-ether-ether-ketone/nano-silicon nitride (PEEK/nSN) composite scaffolds, fabricated by laser powder bed fusion (LPBF), show great potential for orthopedic applications due to their excellent biological performance and mechanical adaptability. However, the effect of nSN on LPBF processability and scaffold properties remains unclear. This study systematically investigates the processability and mechanical performance of PEEK/nSN composites to enable reliable clinical fabrication. The results show that adding nSN improves powder flowability and inhibits crystallization, enhancing LPBF processability. The introduction of nSN reduces PEEK's non-isothermal crystallization Avrami exponent from 3.04 to 2.01, suggesting a transformation from a three-dimensional spherulitic to a two-dimensional lamellar crystal structure. Tensile tests reveal that the presence of nSN alters the optimal process parameters, reducing the optimal laser power from 25 W to 22 W due to increased energy absorption efficiency, as shown by an increase in absorbance at 843 cm⁻¹ from 0.27 to 0.35 as the nSN content increases to 2 wt%. Porous diamond-structured scaffolds were fabricated using optimal parameters for pure PEEK, PEEK/1 wt% nSN, and PEEK/2 wt% nSN. Diamond-structured scaffolds fabricated with 1 wt% nSN showed a 12.2 % increase in elastic modulus compared to pure PEEK, highlighting the enhanced mechanical performance. Overall, this study offers key insights into the stable and customizable LPBF fabrication of PEEK/nSN porous scaffolds, providing a foundation for future research on their bioactivity and antibacterial properties for orthopedic applications.