Keywords

Nanocrystalline titania, porous scaffolds, sintering additives

Abstract

Titania (Titanium dioxide, TiO2) has been researched as a promising biomaterial due to its excellent biocompatibility. However, the main limitation of titania is its poor mechanical properties which limit its use in many load-bearing applications. In this thesis report, the properties of titania were improved by doping with small quantities of MgO, ZnO and SiO2 as sintering additives. Nanocrystalline powder was selected, as it possesses outstanding properties over conventional coarse-grained powders due to reduced grain size. Nanocrystalline anatase powder of size 5-15 nm was synthesized via a simple sol-gel technique. Small quantities of dopants were introduced into pure titania powder, through homogeneous mixing. The doped powder compositions were compacted uniaxially and sintered at 1300°C and 1500°C, separately, in air. The effects of sintering cycle and temperature on the microstructure, densification and mechanical properties of the sintered structures were studied. Mg doped structures recorded maximum sintered density of 3.87 g.cm-3. Phase analysis was carried out using powder XRD technique using Cu K[alpha] radiation. Microstructural analysis was performed using Scanning electron microscopy. The mechanical properties were assessed by evaluating hardness and biaxial flexural strength (ASTM F-394) of the structures. Results showed 12% increase in hardness and 18% increase in biaxial flexural strength in structures doped with ZnO and SiO2, respectively. Further, simulated body fluid maintained at 36.5°C was used to study the bioactivity and degradation behavior of the structures. The second part of the work aimed in the processing of porous titania scaffolds using polyethylene glycol as the pore-former. The green structures were sintered at 1400°C and 1500°C, separately in air and their properties have been studied. Microstructural analysis was carried out using Scanning electron microscope (SEM). Porosity was evaluated using the immersion technique. Vickers hardness and biaxial flexural tests were used to carry out the mechanical characterization. Further, the biomechanical/biodegradation behavior of the structures was assessed in simulated body fluid (SBF). Biodegradation and change in biomechanical properties as a function of time were studied in terms of weight change, change in Vickers hardness and biaxial flexural strength. The mechanical properties of porous titania scaffolds doped separately with MgO and ZnO have also been studied to investigate the influence of these additives on the properties of porous structures. The Vickers hardness and biaxial flexural strength were seen to improve with the addition of these sintering additives.

Notes

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Graduation Date

2009

Advisor

Kalita, Samar

Degree

Master of Science in Materials Science and Engineering (M.S.M.S.E.)

College

College of Engineering and Computer Science

Department

Mechanical, Materials, and Aerospace Engineering

Degree Program

Materials Science and Engineering

Format

application/pdf

Identifier

CFE0002555

URL

http://purl.fcla.edu/fcla/etd/CFE0002555

Language

English

Release Date

April 2014

Length of Campus-only Access

None

Access Status

Masters Thesis (Open Access)

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