FUSED FILAMENT FABRICATION (FFF) OF POLYMER/MAGNESIUM COMPOSITES FOR BIOMEDICAL IMPLANTS: SYNTHESIS, CHARACTERIZATION, AND OPTIMIZATION

Abstract

Metallic implants are widely used in orthopedic procedures due to their excellent mechanical strength and biocompatibility. However, they pose several limitations, including poor tissue integration, potential ion toxicity, and the necessity for secondary surgeries. Magnesium (Mg) and its alloys have emerged as promising alternatives, offering biodegradability, biocompatibility, and a favorable strength-to-weight ratio, making them suitable for orthopedic and cardiovascular applications. Meanwhile, biodegradable polymers such as PLA and PCL are commonly used in scaffold fabrication but are hindered by slow degradation rates and limited mechanical strength. Integrating Mg particles into these polymers can enhance their performance by improving mechanical properties, enabling controlled degradation, and potentially eliminating the need for implant removal. This dissertation presents a comprehensive investigation into polymer/Mg composites, beginning with an extensive literature review that establishes the role of Mg as a bioactive material and highlights the importance of polymers in regulating Mg degradation. Experimental studies were carried out to develop 3D-printable polymer/Mg composite filaments, focusing on how different concentrations of magnesium affect their thermal, mechanical, and biological characteristics. The 10% Mg composition demonstrated a good balance of mechanical strength, bioactivity, and controlled degradation, making it a promising formulation for bone tissue engineering. Optimization of 3D printing parameters showed that a nozzle temperature of 180°C, a layer height of 0.3 mm, and a speed of 130 mm/s yielded the highest mechanical strength (24.29 MPa) and strain (8.27%). The Life Cycle Assessment (LCA) findings revealed that FDM-based production offers a substantially reduced environmental footprint relative to traditional casting processes, especially when solvent recovery measures are applied. Incorporating trichloromethane recycling notably decreased both Global Warming Potential (GWP) and Fossil Fuel Depletion (FFD), demonstrating enhanced sustainability of the process. This dissertation provides a strong foundation for developing polymer/Mg composite scaffolds, demonstrating their potential in biomedical implant applications. This research paves the way for the next generation of biodegradable orthopedic implants by integrating advanced manufacturing techniques with sustainable processing strategies.

Date of Award	2025
Original language	American English
Awarding Institution	HBKU College of Science and Engineering