The Effects of Adding Multi-Walled Carbon Nanotubes (MWCNT) on the Mechanical Properties and Biocompatibility of The Ultra-High Molecular Weight Polyethylene Polymer Matrix (UHMWPE) in Joint Replacements

Ultra high molecular weight polyethylene (UHMWPE) has been used as the material of choice in joint replacement prosthesis as an articular component for several years. Despite its distinct physical and chemical characteristics, the lifespan of this polymer is limited. One approach to increase the lifespan and mechanical properties is the use of multi-walled carbon nanotubes (MWCNT). Multi-walled carbon nanotubes are promising candidates for use as a filler phase in polymers due to their excellent mechanical properties and excellent surface-to-volume ratio. In this research, the addition of 0.1% by weight of multi-walled carbon nanotubes functionalized with carboxyl groups was investigated on the mechanical properties and biocompatibility of the UHMWPE base matrix and its comparison with the pure UHMWPE sample. Fourier transform infrared spectroscopy (FTIR) confirmed the presence of characteristic peaks of UHMWPE and carbon nanoparticle in the matrix. X-ray diffraction (XRD) showed an increase in the intensity of the characteristic peaks of the composite compared to the pure sample. The differential scanning calorimetry test (DSC) showed an increase of about 10% in the crystallinity of the composite containing carbon nanotubes (PE/MWCNT). The dynamic mechanical thermal analysis (DMTA) showed an increase of about 22% in the storage modulus compared to the control sample, and finally, the cell viability through the cell culture test in the PE/MWCNT composite showed a 15 % increase in cell viability. According to mechanical and biocompatibility results, the composite sample can perform better in terms of mechanical loads in bearing surfaces compared to pure UHMWPE.