Publication Date

2020

Document Type

Dissertation/Thesis

First Advisor

Vahabzadeh, Sahar

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Mechanical Engineering

Abstract

Calcium phosphate (CaP) ceramics have become popular as bone substitutes due to their biocompatibility and similarity to natural bone. Although they are widely used, the mechanical and biological properties of these CaP ceramics can be improved by various methods such as combining them with polymers or ionic substitution in their crystal structure. In current research, we have used carboxymethyl cellulose (CMC) and magnesium (Mg) to modify the physical and mechanical properties of CaP. CMC is a derivative of cellulose which is hydrophilic, biodegradable, and biocompatible. Presence of Mg, a trace element naturally found in the body, is linked to bone mass density, bone metabolism, and improved bone formation.Results showed that Mg presence and its concentration alters the ratio of the two main phases in BrC samples. The initial and final setting time of Mg-BrC increased in a dose-dependent manner with increase in Mg content and reached final setting times of >4 hrs in concentrations beyond 1wt% Mg. On the other hand, compressive strength decreased in a dose-dependent manner, reducing from 8.04 ± 2.04 MPa for pure to 0.45 ± 0.09 MPa for 2.50wt% Mg. For CMC-HA, centrifugation was successfully utilized to optimize the synthesis and neutralization of the samples. CMC-HA composites with Mg showed less intense and broader peaks in X-ray diffraction (XRD) patterns, suggesting decrease in crystallinity and crystallite size due to the presence of Mg. Compositions without Mg also showed some slight broadening indicating the effect of CMC on HA crystallization. Fourier Transform Infrared Spectroscopy (FTIR) results showed a crosslinking effect between CMC and HA molecules demonstrating the HA particles are not only embedded in the CMC matrix, but also formed bonds between the CMC and HA molecules. To summarize, we have produced BrC with Mg of varying concentrations and characterized by XRD, setting time, and compressive testing. CMC-HA nanocomposites of varying CMC concentrations were made and the effects of Mg incorporation were observed by XRD and FTIR.

Extent

71 pages

Language

eng

Publisher

Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

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