Optimized PCL/CNF bio-nanocomposites for medical bio-plotted applications: Rheological, structural, and thermomechanical aspects

The use of bioabsorbable and biodegradable composites in the medical field has experienced significant growth. Cellulose nanofibers (CNF) have been employed to reinforce medical-grade poly[ε-caprolactone], enhancing both its load-bearing capacity and stiffness compared to pure polycaprolactone PCL. The manufacturing process involved a series of steps applied to five different grades of PCL/CNF filaments. Initially, melt extrusion and pelletization were performed on the filament, followed by 3D bioplotting to create the specimens. The influence of CNF reinforcement on poly[ε-caprolactone] was evaluated through a range of tests, including rheological, thermomechanical, and in situ micromechanical assessments. To further characterize the samples, Micro-Computed Tomography and Scanning Electron Microscopy fractography were employed for the microstructural and morphological analyses, respectively. The mechanical properties of poly[ε-caprolactone]/CNF composites with 6 wt % CNF content exhibited a 23.8% increase in tensile strength and a 19.1% increase in flexural strength compared to the pure matrix, while also displaying minimal porosity.