The Direct 3D Printing of Functional PEEK/Hydroxyapatite Composites via a Fused Filament Fabrication Approach

Area of Science:

• Biomaterials Science
• Orthopaedic Engineering
• Additive Manufacturing

Background:

• Polyetheretherketone/hydroxyapatite (PEEK/HA) composites are promising for orthopaedic implants to enhance bone integration.
• Traditional manufacturing methods like Selective Laser Sintering and injection molding have limitations in producing complex, custom implants.

Purpose of the Study:

• To report the direct 3D printing of PEEK/HA composite filaments using Fused Filament Fabrication (FFF).
• To evaluate the material properties and structural integrity of 3D printed PEEK/HA composites for orthopaedic applications.

Main Methods:

• Direct 3D printing of extruded PEEK/HA composite filaments via Fused Filament Fabrication (FFF) using a modified Ultimaker 2+ printer.
• Characterization using Scanning Electron Microscopy with Energy Dispersive X-ray (SEM-EDX), micro-computed tomography (µCT), X-ray Diffraction (XRD), and High-Resolution Transmission Electron Microscopy (HR-TEM).

Main Results:

• HA particles were evenly distributed throughout the PEEK matrix in 3D printed samples.
• XRD analysis revealed up to 50% crystallinity, with crystalline domains observed via SEM and HR-TEM, indicating favorable printing temperatures.
• The yield stress and ultimate tensile strength of the printed composites were comparable to human femoral cortical bone.

Conclusions:

• Fused Filament Fabrication (FFF) is a viable method for 3D printing PEEK/HA composites with up to 30 wt% HA.
• The 3D printed PEEK/HA composites exhibit excellent HA distribution and mechanical properties suitable for custom orthopaedic implants.