ABSTRACT
The biocompatible polymer polyetheretherketone (PEEK) is a suitable candidate to be part of potential all-polymer total joint replacements, provided its use is associated with better osseointegration, mechanical performance, and wear resistance. Seeking to meet the aforementioned requirements, respectively, we have manufactured a PEEK composite with different fillers: carbon fibers (CF), hydroxyapatite particles (HA) and graphene platelets (GNP). The mechanical outcomes of the composites with combinations of 0, 1.5, 3.0 wt% GNP, 5 and 15 wt% HA and 30% of wt% CF concentrations pointed out that one of the best filler combinations to achieve the previous objectives was 30 wt% CF, 8 wt% HA and 2 wt% of GNP. The study compares the bioactivity of human osteoblasts on this composite prepared by injection molding with that on the material manufactured by the Fused Filament Fabrication 3D additive technique. The results indicate that the surface adhesion and proliferation of human osteoblasts over time are better with the composite obtained by injection molding than that obtained by 3D printing. This result is more closely correlated with morphological parameters of the composite surface than its wettability behavior.
ABSTRACT
New proton conducting membranes based on sulfonated polysulfone (sPSU) reinforced with TiO2(B) nanowires (1, 2, 5 and 10 wt.%) were synthesized and characterized. TiO2(B) nanowires were synthesized by means of a hydrothermal method by mixing TiO2 precursor in aqueous solution of NaOH as solvent. The presence of the TiO2(B) nanowires into the polymer were confirmed by means of Field Emission Scanning Electron Microscopy, Fourier transform infrared and X-ray diffraction. The thermal study showed an increase of almost 20 °C in the maximum temperature of sPSU backbone decomposition due to the presence of 10 wt.% TiO2(B) nanowires. Water uptake also is improved with the presence of hydrophilic TiO2(B) nanowires. Proton conductivity of sPSU with 10 wt.% TiO2(B) nanowires was 21 mS cm-1 (at 85 °C and 100% RH). Under these experimental conditions the power density was 350 mW cm-2 similar to the value obtained for Nafion 117. Considering all these obtained results, the composite membrane doped with 10 wt.% TiO2(B) nanowires is a promising candidate as proton exchange electrolyte in fuel cells (PEMFCs), especially those operating at high temperatures.
