Mechanical Analysis and Biodegradation of Oxides-Based Magneto-Responsive Shape Memory Polymers for Material Extrusion 3D Printing of Biomedical Scaffolds

The development of advanced smart polymers, characterized by superior strength, exceptional quality, biodegradability, and lightweight structures, stands as a paramount concern in the context of biomedical implant materials. Aiming at the requirements of a tracheal scaffold, this research focuses on developing magnetic shape memory polymers using solvent evaporation method and characterizing their morphology, viscoelastic, thermodynamic, mechanical and shape memory properties. Furthermore, an assessment of degradation is conducted, along with an evaluation of tensile strength both pre- and post-degradation. The findings reveal that the dispersion of Fe3O4 nanoparticles exhibits homogeneity at a 15wt% concentration but tends to aggregate at high proportions. The glass transition temperature increases with the addition of Fe3O4, while less than 10% ratio of the Fe3O4 cannot activate the magnetic actuation. Notably, the tensile and elastic modulus for the 15wt% Fe3O4 composition measure at 59.70MPa and 24.68MPa, respectively, and exhibit a diminishing trend with higher nanofiller content. Subsequently, it demonstrates favorable thermal and magnetic shape memory behavior, yielding reasonable shape recovery ratios. Over a degradation period of 120 days, a reduction in average weight loss was observed for 15wt% concentration, while higher for higher concentrations due to their non-uniform dispersion. Post-degradation, the tensile strength experiences a decline with proportional reduction of 41.15%, 37.61%, 47.13%, 42.46%, and 54.77%, respectively. Based on the finite element analysis, the multi-objective optimization of the structural parameters of the tracheal stent was carried out, and manufactured by material extrusion 3D printing. Finally, the stability, flexibility and compression properties of the scaffold were tested by relevant experimental tests, which ensured the suitability (foldability) of scaffolds. In conclusion, the developed magnetic shape memory polymers showed promising potential for biomedical scaffolds preparation.