Application Of Zirconium Nanotubes In Biomaterials

In this thesis, ZrO₂ nanotubes were prepared by anodization, nano-hydroxyapatite（n-HAp） with good purity and crystallinity was synthesized by chemical precipitation method. Reinforcement effects of PMMA and HAp bone cement with ZrO₂ nanotubes were studied in detail, the ZrO₂ nanoparticles were also investigated for comparative purposes.Furthermore the preparation and properties of HAp/PMMA biocomposites were investigated.The morphologies, crystal structure, surface and mechanical properties etc. were characterised by scanning electron microscope（SEM）, transmission electron microscope（TEM）, X-ray diffractometer（XRD）, Fourier transform infrared spectroscopy（FTIR） and electro-mechanical universal testing machine.1. In the study of reinforced denture base PMMA with ZrO₂ nanotubes, influence of concentration and surface treatment on the reinforcement effects was investigated. Results indicated that ZrO₂ nanotubes had a better reinforcement effect than ZrO₂ nanoparticles, and surface-treatment would lower the reinforcement effect of the ZrO₂ nanotubes which was itself significantly different from that of the ZrO₂ nanoparticles. Various ZrO₂ concentrations make a great difference in the property, and the flexural strength of the composite was maximised when 2.0 wt% untreated ZrO₂ nanotubes was added.2. Nano-hydroxyapatite（nano-HAp） was prepared by a solution-precipitation method using Ca（NO3）2 and（NH4）2HPO4 as starting materials. Both experiment process and parameters showed great influence on the grain size of final product of hydroxyapatite. Such as, the increased concentration of the raw material, Ca/P ratio, reaction temperature,prolonging reaction time or annealed at a high temperature led to an bigger grain size of hydroxyapatite.3. In the research described, a new method was investigated to prepare hydroxyapatite（HAp） bone cement using nano-hydroxyapatite, CaO and（NH4）2HPO4 as initial raw materials, and reinforcement effects of HAp bone cement with ZrO₂ nanotubes were studied in detail. Results indicated that after solidification the composition of bone cement was hydroxyapatite with good crystallinity and purity. Addition of ZrO₂ nanoparticles or ZrO₂ nanotubes to the bone cement could substantially improve its strength, however, the enhancement effects between ZrO₂ nanoparticles and ZrO₂ nanotubes were slightly different,the optimum addition amount both being 20 wt.%.4. HAp/PMMA biocomposites were prepared through thermal polymerization method taking hydroxylapatite（HAp）, polymethylmethactylaate（PMMA） and methyl methacrylate（MMA） as raw materials. Effects of preparation processes and concentrations on the composites’ morphologies, structure and mechanical properties were investigated. Results indicated that, infiltration of PMMA with MMA would render the formation of big porosity and weak mechanical properties. When the proportion of nano-hydroxyapatite increased, the composite’s porosity decreased and tended to become more uniform, but with a declined flexural strength. The molding process, directly for curing after mixing the initial raw materials, would bestow the composite with low porosity, high strength and flexibility. When the dose of nano-hydroxyapatite was 30 wt%, 40 wt% and 50 wt%, the flexural strength was1.500 N/mm2, 1.439 N/mm2 and 0.709 N/mm2 respectively.