PRODUCTION OF BIOACTIVE DENSE
HYDROXYAPATITE USING EGG SHELL DERIVED POWDER
BY
SHARIFAH FATHIN ADLINA BINTI SYED ABDULLAH
A dissertation submitted in fulfillment of the requirement for the degree of Master of Science in Materials
Engineering
Kulliyyah of Engineering International Islamic University
Malaysia
JULY 2012
ABSTRACT
In this work, hydroxyapatite powder is synthesized via a novel hydrothermal process from a biogenic source of calcium phosphate, hen’s eggshell. Dense hydroxyapatite bodies are prepared via uniaxial pressing of circular disc shape of 1:4 height-to- diameter ratio at various compaction pressures. This is followed by a pressureless sintering at various sintering temperatures. The effect of different compaction pressures and sintering temperatures on the phase behaviour of the synthesized powder and mechanical properties of the dense bodies are investigated. Synthesis of hydroxyapatite powder from eggshell as the calcium precursor was proved successful by phase analysis. XRD and FTIR reveals phases of calcium phosphate from pure hydroxyapatite to existence of β-TCP and calcium pyro phosphate (CPP) at elevated temperature, as well as better crystallinity as indicated by narrower peak of XRD. The microstructural development of all sintered hydroxyapatite is found to be affected by compaction pressure and sintering temperature. Density and average grain size increase sharply at sintering temperature of 1100ºC and improve gradually with the increasing compaction pressure. Mechanical properties of dense bodies are measured by a diametrical compression test whereby compressive strength increases almost linearly at increasing temperature until the maximum temperature of 1100oC, where the strength declines at a higher temperature believed to be due to the appearance of second phase in sintered hydroxyapatite. The highest compressive strength achieved is 15.5 MPa. Meanwhile increase of compaction pressure of up to 21 MPa reveals a linear increase of compressive strength. Similarly, Vickers’ hardness test shows the same effect of sintering temperature, obtaining a maximum hardness value of 8.94 GPa at 1100oC before declining rapidly at higher temperatures. In a nutshell, sintering condition can be manipulated to achieve required mechanical strength, with caution taken for the maximum sintering temperature, as exaggerated grain growth accompanied by grain coalescence promotes weak mechanical strength and increases brittleness.
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APPROVAL PAGE
I certify that I have supervised and read this study and in my opinion, it conforms to acceptable standards of scholarly presentation and is fully adequate, in scope and quality, as a dissertation for the degree of Master of Science (Materials Engineering).
……….….
Iis Sopyan Supervisor
………..………
Souad A. Mohamad Co-Supervisor
I certify that I have examined this study and that in my opinion, it conforms to acceptable standards of scholarly presentation and is fully adequate, in scope and quality, as a dissertation for the degree of Master of Science (Materials Engineering).
… … … … ... ……….
Suryanto
Internal Examiner
……….……….
Mujibur Rahman External Examiner
This dissertation submitted to the Department of Manufacturing and Materials and is accepted as a fulfilment of the requirement for the degree of Master of Science (Materials Engineering).
……….………….
Erry Yulian T. Adesta
Head, Department of Manufacturing and Materials Engineering.
This dissertation was submitted to the Kulliyyah of Engineering and is accepted as a fulfillment of the requirement for the degree of Master of Science (Materials
Engineering).
………..………
Amir Akramin Shafie
Dean, Kulliyyah of Engineering.
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DECLARATION
I hereby declare that this dissertation is the result of my own investigation, except where otherwise stated. I also declare that it has not been previously or concurrently submitted as a whole for any other degrees at IIUM or other institutions.
Sharifah Fathin Adlina binti Syed Abdullah
Signature……….. Date……….
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INTERNATIONAL ISLAMIC UNIVERSITY MALAYSIA
DECLARATION OF COPYRIGHT AND
AFFIRMATION OF FAIR USE OF UNPUBLISHED RESEARCH
Copyright © 2012 by International Islamic University Malaysia.
All rights reserved.
PRODUCTION OF BIOACTIVE DENSE HYDROXYAPATITE USING EGG SHELL DERIVED POWDER
I hereby affirm that the International Islamic University Malaysia (IIUM) holds all rights in the copyright of this Work and henceforth any reproduction or use in any form or by any means whatsoever is prohibited without the written consent of IIUM. No part of this unpublished research may be reproduced, stored in retrieval system, or transmitted, in any forms or by any means, electronics, mechanical, photocopying, recording or otherwise without prior written permission of the copyright holder.
Affirmed by Sharifah Fathin Adlina Syed Abdullah.
Signature Date
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ACKNOWLEDGEMENTS
First and foremost, my gratitude and ash-shukr are, above all, due to Allah s.w.t, the Almighty, for His inspiration and guidance during the research of this work. May He place our good deeds for the betterment of humankind. Insya-Allah.
Deepest appreciation goes to my supervisor, Professor Dr. Iis Sopyan for his never ending advice and guidance in completing this research work. It has been a wonderful journey for me as many valuable experiences and knowledge have been acquired from him to equip me with better understanding in becoming a good researcher in many years to come. This appreciation is also extended to my co- supervisor, Assistant Professor Souad A. Mohamad, for her scholarly guidance, critics and motivation in assisting me in preparing this dissertation.
Without the continuous support and understanding, this work would not have been possible, let alone meaningful. I would like to specially thank my husband, Syed Zulkarnain Shah bin Syed Ahmad Kamal, and my beloved parents Syed Abdullah Syed Abd Rahman and Sharifah Faizah Tuan Hitam. Their infinite words of wisdom, support, and encouragement have driven me to pursue my study to a higher level and for all the sacrifices that they have made for me throughout my life. Not forgetting, to my brother and sisters who each have helped in their own ways with their belief and encouragement.
Special thanks are reserved to my acquaintances at the Polymer Laboratory and Biomaterials Laboratory, Kulliyyah of Engineering particularly Sr. Farah Diana, Sr. Mardziah, Br. A. Sofwan, and Br. Ahmad Fadli. They have been amazing colleagues to work with as they filled me with brilliant ideas to improve my research and dissertation work.
I owe special thanks to all the technical staff especially Br. Syamsul, Br.
Danial, Br. Hairi, Br. Rahimi, Br. Husni, Br. Ibrahim and Br. Razak from the Department of Manufacturing and Materials Engineering, Kulliyyah of Engineering, IIUM for their cooperation and assistance during my studies.
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TABLE OF CONTENT
Abstract……… ii
Abstract in Arabic……….……… iii
Approval Page……… ………. v
Declaration Page………. vii
Copyright Page….……… viii
Acknowledgement……….……….. ix
List of Tables…….……… xi
List of Figures……….……… xii
List of Abbreviations…… ……….. xv
CHAPTER 1:INTRODUCTION……… 1
1.1 Background……… 1
1.2 Problem Statement and its Significance……… 5
1.3 Research Objectives……… 6
1.4 Research Methodology……… 7
1.5 Scope of Research 10 1.6 Dissertation Organization……….….. 11
CHAPTER 2: LITERATURE REVIEW………..……… 12
2.1 Introduction………. 12
2.2 Bone: A Brief Overview………. 14
2.2.1 Composition and Properties of Bone……….. 15
2.2.2 Mechanical Properties of Load Bearing Bone Parts……….…….. 17
2.3 Eggshell Derived Hydroxyapatite Powder ……….. 20
2.4 Dense Hydroxyapatite………...……….. 22
2.4.1 Preparation of Dense HA Bodies…………...………..…... 23
2.4.2 Properties of Dense HA Bodies……….…….. 24
2.4.3 Application of Dense HA Bodies….……… 29
2.4.4 Characteristics Requirements of Dense HA for Bone Implant Application……….……….. 30
2.5 Powder Characterization………. 31
2.5.1 X-Ray Diffraction……….. 31
2.5.2 FTIR Analysis……… 34
2.5.3 Field Emisssion Electron Microscopy………... 37
2.6 Compressive Strength Test on Dense Hydroxyapatite Bodies………… 38
2.7 Current and Future Developments……….…… 42
2.8 Summary………. 44
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CHAPTER 3: PREPARATION OF PURE HYDROXYAPATITE POWDERS
FROM EGG SHELL ……….……….. 46
3.1 Introduction……….….……….. 46
3.2 Materials and Methods………..…… 48
3.2.1 Materials……… 48
3.2.2 Experimental Procedure………. 48
3.3 Results and Discussion……… 53
3.3.1 Characterization of Eggshell-derived Hydroxyapatite Powder 53 3.3.1.1 Phase Analysis by X-Ray Diffraction (XRD)……… 53
3.3.1.2 Phase Analysis by FT-IR Spectrum ………….. 56
3.4 Summary……….. 58
CHAPTER 4: PREPARATION OF DENSE HYDROXYAPATITE BODIES VIA UNIAXIAL PRESSING ……… … 59
4.1 Introduction……… 59
4.2 Materials and Methods………..………… 59
4.2.1 Materials………..………..…… 59
4.2.1.1 Hydroxyapatite Powder………..59
4.2.2 Experimental Procedure………. 60
4.2.3 Characterization of Dense Bodies….………..62
4.2.3.1 X-Ray Diffraction……….……… 62
4.2.3.2 Bulk Density Measurement……….……….… 63
4.2.3.3 Porosity………. 64
4.2.3.4 Field Emisssion Electron Microscopy Image………64
4.2.3.5 Compressive Strength Determination …..………..…… 65
4.2.3.6 Vickers’ Hardness Determination……… ………... 66
4.3 Results and Discussion………... 67
4.3.1 Characterization of Dense BCP Bodies……… 67
4.3.1.1 Phase Analysis of BCP Bodies by XRD… 67 4.3.1.2 Relative Density and Porosity 68 4.3.1.3 Microstructure Observation 72 4.3.2 Compressive Strength Test ……… 76
4.3.2.1 Effect of Sintering Temperature 76 4.3.2.2 Effect of Compaction Pressure 78 4.3.3 Vickers Hardness Test ……..…… 80
4.4 Summary……….. 82
CHAPTER 5: CONCLUSION AND RECOMMENDATION..… 83
5.1 Conclusion……….…. 83
5.2 Recommendation………...………...…….. 84
BIBLIOGRAPHY……… 85
LIST OF PUBLICATIONS……….……… 95
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LIST OF TABLES
Table No.
2.1 2.2 2.3
2.4 4.1 4.2 4.3
Mechanical properties of skeletal tissues
Young’s Modulus of bone compared to hydroxyapatite and collagen Mechanical properties of bones in longitudinal and transverse directions
Mechanical properties of bones and HA Disc samples identification
Density Before and After Sintering at Various Compaction Pressure Average Grain Size at Various Sintering Temperature
Page No.
16 20 20
24 61 71 74
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LIST OF FIGURES
Figure No. Page No.
1.1 Flow chart of research methodology 9 2.1 Hierarchical structure of bone 15 2.2 Structure of a long bone in longitudinal section 15
2.3 Sintering process 26 2.4 Illustration of x-ray diffraction theory 31
2.5 Illustration of X-ray diffraction pattern for (a) single crystals 32 (b) polycrystalline powder
2.6 Illustration of IR spectroscopy concept 34 2.7 Illustration of Fourier Transform Infrared spectrospy process 37
2.8 Schematic representation of a failure locus near the shear stress 39 dominant region for pressure-dependent yielding materials
2.9 Fractured specimen during diametrical compression stressing at 41 velocity, v = 1 m/s
2.10 Schematic illustration of Diametrical Tensile Strength 41 3.1 Image of (a) manually crushed eggshell, (b) ballmilled eggshell and 49
(c) calcium oxide
3.2 Image of (a) hydrothermal synthesis on stirring plate (b) oven dried 50 hydroxyapatite compound
3.3 Image of (a) wet hydroxyapatite compound after ball milling, 51 (b) drying hydroxyapatite compound on hot plate, and
(c) dried hydroxyapatite powder
3.4 Flow chart of preparation of hydroxyapatite powder via 52 hydrothermal method.
3.5 XRD patterns of BCP powder calcined at temperature ranging from 54 300oC to 900oC
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3.6 FTIR spectra of BCP at various calcinations temperature 57
4.1 Flowchart of preparation of dense pure BCP 59
4.2 Sintering cycle of dense BCP 61 4.3 (a) Illustration of Material Testing Machine - Twin Column 65
Bench Mounted (Lloyd Instruments) (b) BCP dense body mounted on the machine before compression test
4.4 BCP dense bodies subjected to sputter coating 66 4.5 XRD patterns of (a) HA powder calcined at 600oC 67
(b) HA powder calcined at 600oC, followed by sintering of HA bodies at 1200oC (c) HA powder calcined at 800oC (d) HA powder calcined at 800oC, followed by sintering of HA bodies at 1200oC
4.6 BCP dense bodies (a) before sintering (b) after sintering 68 4.7 The effect of sintering temperature on the sintered BCP samples 70
4.8 The effect of compaction pressure on the sintered BCP samples 71 sintered at 1100oC
4.9 SEM of dense BCP compacted with 20 MPa at (a) 1100oC 73 (c) 1250oC(e) 1400oC; magnified x5000 (b) 1100oC
(d) 1250oC (f) 1400oC
4.10 SEM of dense BCP sintered at 1100oC compacted with (a) 1 kpsi 75 (c) 5 kpsi (d) 7 kpsi; magnified x5000 (b) 1 kpsi (d) 5 kpsi (f) 7 kpsi
4.11 Some samples of BCP bodies after diametrical tensile strength tests 76 4.12 Effect of sintering temperature to the compressive strength at 77
compacting pressure 0-1 kpsi, 3-4 kpsi, and 5-6 kpsi
4.13 Effect of compaction pressure to the compressive strength at sintering 79 temperature of 900oC to 1100oC
4.14 BCP dense bodies (a) before coating (b) after coating 80 4.15 Effect of sintering temperature on the Vickers hardness of BCP 81
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LIST OF ABBREVIATIONS
BCP
CO3 2 -
FESEM FTIR HA Hv OH- P2O7 PO4 3 -
TCP α-TCP β-TCP TEM XRD
Biphasic calcium phosphate Carbonate ion
Field emission scanning electron microscope Fourier transform infrared spectroscopy Hydroxyapatite
Vicker’s hardness Hydroxide ion Pyrophosphate Phosphate ion
Tricalcium phosphate Alpha-tricalcium phosphate Beta-tricalcium phosphate
Transmission Electron Microscope X-ray diffraction
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CHAPTER ONE INTRODUCTION
1.1 BACKGROUND
Bone is a living material composed of cells and a blood supply encased in a strong, interwoven composite structure. Its composition of inorganic and organic hybrid consists of 70 percent apatitic calcium phosphate, embedded among the remaining 30 percent inorganic collagen fibre constituents, providing strength and elasticity. Bone mass is typically at its highest at a person’s age of mid-twenties, after which the gradual reduction in bone mass is not replenished as quickly as it is resorbed.
Decrease in body mass occurs as body grows older, leading to an increased vulnerability to fractures. In postmenopausal women, the production of estrogen, a hormone that helps to maintain the levels of calcium and other minerals necessary for normal bone regeneration, drops off dramatically resulting in an accelerated loss of bone mass of up to 3 percent per year over a period of five to seven years. Hence during recent decades, the need to restore the functions of bone loss due to an ageing population or traumatic events have led researchers to research on various materials either synthetic or natural to be used as bone implants (Sivakumar, 1999).
Hydroxyapatite (HA) is the major mineral component of hard tissues of bone and dental enamel. Because of the biological compatibility of HA with these tissues, various studies of preparation, compaction and sintering of HA have been reported in the literature. These efforts have been directed towards development of a strong polycrystalline ceramic implant material from pure hydroxyapatite. It is known that clinical success requires the simultaneous achievement of a stable interface with
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connective tissue and a match of the mechanical behaviour of the implant with the tissue to be replaced (Hench, 1991).
Among various phases of calcium phosphate, hydroxyapatite [Ca10(PO4)6(OH)2, HA] and beta-tricalcium phosphate [Ca3(PO4)2, β-TCP] are the two most commonly used calcium phosphate ceramics used for medical purposes. These materials are used in a variety of physical forms such as porous, granular and dense forms. Hydroyapatite (HA) has a stoichiometry similar to bone mineral, whereas tricalcium phosphate (TCP) has a stoichiometry similar to amorphous bone precursor.
Both HA and TCP ceramics are biocompatible material. As they are by definition materials that assume the functions of tissue in natural organs or organ parts, therefore they must imitate the properties of such tissues in natural organs or organ parts.
However, they show different biological response at the host site. TCP ceramics is resorbable after implantation while HA is more permanent. Implants of HA were observed to take on average of two months for bone ingrowth to reach 75%
whereas TCP ceramics had 79% of bone ingrowth after only one month following implantation (Galois et al., 2004). Termed Bi-phasic calcium phosphate (BCP) bioceramics, this combination of hydroxyapatite (HA) and tri-calcium phosphate (TCP) phases have attracted attention as an ideal bone graft substitute. BCP consists of well controlled mixtures of non-resorbable hydroxyapatite, and other resorbable calcium phosphate phases, exhibiting a combination of enhanced bioactivity and mechanical stability that is difficult to achieve in a single phase (Kim et al., 2005).
Dense ceramics have been used as scaffolds in some load-bearing cases due to its high mechanical strength. Dense hydroxyapatite is described as having porosity of less than 5% by volume. It may also be described as microporous; the maximum pore size should be less than 1 μm in diameter. The microporosity is dependent on
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temperature and sintering condition and it is undeliberately introduced. This is a contrast to porous hydroxyapatite whose microporosity can be purposely introduced by mixing the hydroxyapatite powder with a volatile component before evaporating it at a low temperature prior to sintering. Dense ceramics have better mechanical performance than porous ceramics, thereby making it a desirable substitute for some load-bearing cases. Traditionally, dense HA has been made by sintering HA powders at high temperature. However, formation of dense HA is controlled by many factors, such as Ca/P molar ratio, sintering temperature and properties of the synthesized powders (Ramesh, et al., 2008).
Hydroxyapatite powders can be synthesized via numerous production routes, using a range of different reactants. Generally the common methods can be categorized under wet (chemical) and dry method, whereby wet chemical method includes hydrothermal synthesis, precipitation and hydrolysis. Of these methods, hydrothermal method scores over other processes by virtue of being simple, cheap, and easy application in industrial production. Moreover, hydroxyapatite prepared by hydrothermal also has the feature of small size, low crystallinity and high surfacial activation, which can meet different demands (Castner, et al., 2002). This method also means having the ability to control the crystal face, pore structures, and its chemical composition, since sintering process is crucial in giving shape to the ceramics.
Several methods of chemical synthesis have been developed to prepare hydroxyapatite powder using various types of calcium and phosphorous sources. In this research work, a natural source is used as the calcium source. Hen’s eggshell, due to its large calcium composition, is used to synthesize pure and biocompatible hydroxyapatite powder. The main ingredient, which is about 95 percent of eggshell, is calcium carbonate (CaCO3). The remaining 5 percent consists of calcium phosphate,
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magnesium carbonate and soluble and insoluble proteins. In this research work, a novel, straightforward technique is used to convert calcium carbonate obtained from eggshells into highly pure and crystalline hydroxyapatite via hydrothermal method.
The method developed is inexpensive and simple to be executed.
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1.2 PROBLEM STATEMENT AND ITS SIGNIFICANCE
Calcium phosphate bioceramics have been widely used in biomedical applications due to their excellent biocompatibility, bioactivity and osteoconduction characteristics.
HA is known for its low resorbability whilst β-TCP is known to a have rapid resorption rate. However β-TCP is difficult to sinter, exhibits poor mechanical strength and low resistance to crack-growth propagation (Cai, et al., 2007). To control the biodegradation rate and compensating the non-biodegrability of HA, biphasic calcium phosphates (BCP), which consist of HA and β-TCP combined, have been studied by many researchers. The resorption rate of BCP depends on the molar ratio of β-TCP/HA in the mixture; the higher the ratio, the faster the resorption.
Ideally the resorption rate should match the rate of the new bone formation, so the β- TCP/HA phase content ratio is a critical parameter to control during synthesis (Nilen, 2008).
The production of BCP involves synthesizing hydroxyapatite and sintering of the powder to achieve certain phase. In this work, hydroxyapatite powder is prepared using hen’s eggshell as the calcium source. The eggshell contributes 11 percent of the total weight of egg. The major constituent present in the shell is calcium carbonate (CaCO3), which accounts around 95 percent of the total weight, or about 5.5 g. Food and Agriculture Organization of the United Nations projected that poultry production in Asia will reach about 34.2 million tons, accounting for 36 percent of the world's total. In Malaysia, egg production grew 50% in 10 years and reaches 8.3 x 109 units in 2010. By taking 11 percent of the weight, it comes to nearly 5 million kg of eggshell waste a year. This material goes as waste and lead to pollution since it favors microbial action.
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Dense HA is described as HA with porosity of less than 5 volume percent with micropores size diameter less than 1µm. The microporosity is unintentionally introduced and is dependent on the temperature and duration of sintering. Vast research and development efforts have been carried out in identifying the parameters that effect the sintering process and its influence on the mechanical properties of the produced dense bodies. Large particle size along with hard agglomerates exhibits lower densification in HA (Murray, et al., 1995). Difference in shrinkage between the agglomerates is also responsible to produce small cracks in the sintered HA (Ruys et al., 1995). Therefore, synthesis of nanostructured HA is an important step to achieve good mechanical properties for dense nanostructure.
1.3 RESEARCH OBJECTIVES
The current research is carried out with the objective to produce bioactive dense hydroxyapatite using eggshell derived powder. In achieving the main objective, several sub-objectives are addressed. The sub-objectives outlined in this thesis are as follows:
a) To synthesize hydroxyapatite powder using eggshell via hydrothermal method.
b) To characterize the chemical properties of the synthesized pure hydroxyapatite powder.
c) To fabricate hydroxyapatite dense bodies via uniaxial pressing.
d) To examine the effects of compaction pressure and calcination temperature on the physical and mechanical properties of the prepared dense hydroxyapatite bodies.
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1.4 RESEARCH METHODOLOGY
A well planned methodology has been set up in order to fulfil all the goals of this research as presented in Figure 1.1.
1. Experimental design on how to synthesize hydroxyapatite powders from eggshell using hydrothermal technique, and production of dense hydroxyapatite bodies via uniaxial pressing.
2. Synthesis of pure hydroxyapatite powders which include:
a. Selection of suitable raw materials and its composition to produce pure hydroxyapatite powders.
b. Pure hydroxyapatite powder preparation using hydrothermal method.
c. Determination of suitable calcination temperature of pure hydroxyapatite powder before densification into green bodies.
d. Chemical characterization of synthesized powders using XRD, and FTIR.
3. Compaction of hydroxyapatite dense bodies from the synthesized powders, which include:
a. Determination of suitable pressure range to be applied during compaction.
b. Compaction of dense hydroxyapatite bodies using hardened steel mould and die set.
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c. Determination of the heat treatment temperature and heating and cooling rate for densification.
d. Physical, chemical and mechanical characterization of dense bodies via XRD, FESEM, densitometer, diametrical tensile strength (DTS) tester and Vickers hardness tester.
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Experimental Design
Powder Synthesis
Compaction
Physical/Chemical/Mechanical Characterization
Sintering
Thesis Report
Figure 1.1: Flow chart of research methodology
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1.5 SCOPE OF RESEARCH
The initial phase of the research was the preparation of hydroxyapatite powder from eggshell as the calcium source. These powders were synthesized via a novel, straightforward technique of converting calcium carbonate obtained from eggshell into highly pure and crystalline hydroxyapatite powder via hydrothermal method.
Subsequently, dense bodies were prepared from the hydroxyapatite powder.
The powders were directly compacted into circular shape disks of height-to-diameter ratio of 1:4 via uniaxial pressing, with compacting pressure varied from 1 kpsi (7 MPa) to 6 kpsi (42 MPa). The green bodies were then heat treated to obtain the dense phase. The sintering process, which is an essential step in the ceramic materials production, resulted in obtaining materials with different phase compositions and properties. The study of sintering behavior of the synthesized hydroxyapatite was carried out at a temperature ranging from 900ºC to 1400ºC using a standard heating and cooling rate of 2ºC/min, and a holding time of 2 hours. The study was based on several physical, chemical and mechanical aspects of the prepared dense bodies such as the hydroxyapatite phase stability, relative density, hardness, compressive strength and also the grain size.
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1.6 DISSERTATION ORGANIZATION
The current research work is presented over four chapters of the dissertation with Chapter One discussing brief idea, philosophy, and the objectives of the study and approach used in the research. In Chapter Two, an overview of the human skeletal system with detail description on functions, composition and properties of bone is discussed. The chapter also details out the development of hydroxyapatite synthesis from natural source (hen’s eggshell), progress on dense hydroxyapatite, and the mechanism of a mechanical test which is the compressive strength test. Chapter Three presents the description of the preparation of pure hydroxyapatite powder from crushed eggshell using different predetermined calcinations temperature. It also discusses the characterization work on the synthesized powder, namely phase analysis by X-Ray Diffraction and Fourier Transform Infrared (FTIR) spectrum. Chapters Four engages in the preparation of dense bodies using the synthesized powders via uniaxial pressing with a variety of compaction pressure of the tool-and-die set, prior to sintering of the dense bodies at different sintering temperature ranging from 900oC to 1400oC. Throughout this chapter, physical, chemical and mechanical properties of the dense bodies are discussed in detail, with regards to the effect of compacting pressure and sintering temperature on the phase behavior and mechanical properties of the dense bodies. General conclusions of this research and recommendation for further work are summarized in Chapter Five.
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