3D Printing of Bioactive PLA/PA12/WA Composites: Toward High-Performance Bone Implant Materials

Abstract

Bone implantation is among the most performed tissue transplantation procedures globally, particularly in cases involving severe clinical conditions such as bone trauma, tumors, cystic lesions, and high-impact injuries. However, traditional fabrication methods are often associated with several clinical complications, including a heightened risk of infection, excessive intraoperative bleeding, and potential implant failure due to fracture. To overcome these limitations, additive manufacturing techniques, particularly fused deposition modelling (FDM) using polymer-ceramic hybrid composites, have emerged as promising alternatives for fabricating bone grafts. In this study, a composite consisting of polylactic acid (PLA), polyamide 12 (PA12), and wollastonite (WA) in a 60PLA/40Pwt%PA12 with10wt%WA formulation was melt-compounded using a twin-screw extruder at temperatures ranging from 185 to 200 °C. Filaments were successfully fabricated with a consistent diameter of 1.7 ± 0.2 mm under optimized conditions (extrusion temperature: 200–205 °C; screw speed: 3 rpm; cooling fan speed: 50). Cylindrical and cuboid specimens were fabricated via fused deposition modelling (FDM) using printing temperatures ranging from 200 °C to 220 °C, layer heights between 0.1 mm and 0.3 mm, a constant print speed of 50 rpm, and infill densities of 100%. The printed samples were subjected to physical characterization namely density measurement using the Archimedes principle and mechanical evaluation through vickers hardness and compression testing. Finding shows that, vickers hardness of 18.7 HV was recorded at a printing temperature of 200 °C with a layer height of 0.1 mm. This same parameter set also yielded the highest compressive strength of 146.71 MPa, a compressive modulus of 1.52 GPa, and an ultimate strain of 67.94%, demonstrating mechanical characteristics closely aligned with those of natural cancellous bone. These results highlight that lower layer heights, combined with an optimized printing temperature of 200 °C, enhance the printability and mechanical performance of the 60PLA/40PA12/10WA composite filament, suggesting strong potential for future application in bone implant fabrication due to its favourable structural and functional properties.