Thesis (M.Sc.) - Cairo University - Faculty of Engineering - Department of Mechanical Design and Production

The goal of this research is to find the best quality that arises after hip joint replacement, such as strength, wear, and the coefficient of friction between the joints. TiO2 nanoparticles of various concentrations were employed in this study with different weight ratios (5 %, 10%, 15%, and 20%) will be used to improve the mechanical characteristics of HDPE, which is the most frequently used polymer in biomedical applications. It is utilized as a matrix in composite nanoparticles because of its outstanding characteristics, such as high flexibility and durability. The composite nanoparticles are fabricated by using dispersion technique (extrude twin screw (brabender machine)). And then they pressed in a hot molded die. The test specimen are cut from the samples with standard shapes and sizes. The morphology, crystal structure, and mechanical properties are characterized by different techniques. Scanning electron microscopy (SEM) showed the variations of particle diameters. X-ray diffraction (XRD) studied the effect of TiO2 on the HDPE crystal structure and the tensile test showed the mechanical properties of the composite. Finally, a wear test was performed to determine the tribological behavior. The composite tensile strength and young's modulus have been improved by 10% and 5%, respectively while the wear rate has been reduced by 40% compared with pure HDPE. This results are due to the fine nano grain size which are obtain from grinding processes which are showed in the TEM and SEM test. Also the reason of the enhancement of tensile strength, Hardness and wear rate are due to strong bonding between the particle and the matrix

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