氏名　Heidy Visbal
学位の種類　博士（工学）
学位記番号　博甲第334号
学位授与の日付　平成17年03月25日
学位論文題目　Development of an Organic-Inorganic Hybrid Material using Diamond-Modification of Diamond Powder Surface by Ultrasonic and Chemical Treatments-　（ダイヤモンドを用いた有機ー無機ハイブリッド材料の開発-高超音波及び化学処理によるダイヤモンド表面の改質-）
論文審査委員
　主査　教授　石崎　幸三
　副査　教授　小松　高行
　副査　教授　佐藤　一則
　副査　教授　齋藤　秀俊
　副査　助教授　藤原　巧

• 論文目次
• 論文要旨

［平成16（2004）年度博士論文題名一覧］ ［博士論文題名一覧］に戻る．

Contents

Abstract　p.1
List of Figures　p.2
List of Tables　p.3

1. General Introduction　p.1
　1.1　Diamond structure　p.1
　1.1.1 Diamond symmetry　p.3
　1.2　Diamond properties　p.4
　1.3　Diamond types　p.6
　1.3.1 Natural diamond　p.7
　1.3.2 Synthetic industrial diamond　p.10
　1.4　Diamond Surface　p.11
　1.4.1 Surface treatments on diamond surface　p.13
　1.4.1.1 Modifications in vapor phase　p.13
　1.4.1.2 Modification in liquid phase　p.14
　1.5　Methods of surface analysis　p.14
　1.5.1 Diffuse reflectance infrared Fourier transform （DRIFT） spectroscopy　p.14
　1.5.2 X-ray Photoelectron Spectroscopy （XPS）　p.16
　1.6　Purposes and outline of this study　p.19

2. Raw Diamond Powder Characterization
　2.1　Introduction　p.21
　2.2　Industrial preparation of the raw diamond powder　p.21
　2.3　X-ray Diffraction analysis　p.23
　2.4　DRIFT evaluation　p.24
　2.5　Raman analysis　p.25
　2.6　X-ray Photoelectron Spectroscopy（XPS）Analysis　p.27
　2.7　Particle size distribution　p.28
　2.8　Scanning Electron Microscope Images　p.30
　2.9　Specific surface area　p.31

3. Modification of diamond Powder by Ultrasonic Treatment
　3.1　Background　p.32
　3.1.1 Theory of ultrasound　p.32
　3.1.1.1 Cavitation　p.32
　3.1.1.2 Chemical reactions　p.35
　3.1.1.3 Horn　p.35
　3.1.2 Aim of this chapter　p.36
　3.2 Experimental procedure　p.36
　3.2.1 Ultrasonic treatment　p.36
　3.2.2 DRIFT analysis　p.37
　3.2.3 XPS analysis　p.38
　3.2.4 Pretreatment of the powder by acid washing　p.38
　3.2.5 Horn immersion depth　p.38
　3.2.6 Bubbling gas into the liquid　p.39
　3.2.7 Power　p.39
　3.2.8 Ultrasound exposure period　p.39
　3.3 Results and discussion　p.40
　3.3.1 Peaks identification　p.40
　3.3.2 Quantification　p.46
　3.3.3 Pretreatment of the powder by acid washing　p.48
　3.3.4 Horn immersion depth　p.52
　3.3.5 Bubbling gas into the liquid　p.55
　3.3.6 Power　p.61
　3.3.7 Ultrasound exposure period　p.62
　3.4 Conclusions　p.64

4. Surface Modification of Diamond Powder with Formaldehyde Solution
　4.1 Introduction　p.66
　4.2 Experimental　p.66
　4.3 Results and discussion　p.68
　4.3.1 DRIFT Spectral Characteristics　p.68
　4.3.2 Modified surface　p.74
　4.3.3 Reaction mechanism and activation energy　p.75
　4.4 Conclusions　p.77

5. Development of a Diamond-Epoxy Composite
　5.1 Introduction　p.78
　5.2 Experimental　p.78
　5.3 Results and discussion　p.81
　5.3.1 Young's Modulus　p.82
　5.3.2 Damping Capacity　p.82
　5.4 Conclusions　p.84

6. Summary and discussion
　6.1 Modification of diamond powder surface by ultrasonic treatment　p.86
　6.2 Modification of diamond powder surface by chemical treatment　p.87
　6.3 Diamond Epoxy Composite　p.88
Reference　p.89

Acknowledgements

Publications and research activities

A factor that is slowing down a more widespread integration of diamond technologies is that the mechanical and electrical characteristics of interfaces between diamond and other materials are often less than desirable. Such poor interfaces usually have, among their problems, surface energy mismatches which manifest as poor wet ability and adhesion. Fortunately, the properties of the interface between two materials can be significantly altered by changing the surface chemical functionality present on one or both materials and functional materials （organic-inorganic） can be developed combining properties of the bulk and functional properties of the surface layer. Introducing new chemical functionality to diamond surfaces under controlled, mild conditions is not a trivial task. A variety of oxidative, atomic beam, or thermal, chemical modification reactions have been performed previously.
Some reactivity studies have finally begun to use classical organic reactions and chemical principles to devise modification schemes. Modifications of the diamond surface in liquid phase are required for industrial applications, due to easy operation and economy, above others. This work is focused mainly on the modification of diamond powder in liquid phase. Two methods were studied: ultrasonic and chemical treatment. The former one has been already studied by other authors, however the operational parameters and mechanism is still not clear.
In the later one, modification of diamond surface by dissolution of formaldehyde in water is proposed for the first time. Special interest is focused in this method, due to its simplicity and low cost operation. A commercial synthetic powder of 5-12 μm grain size from Matsumoto Yushi-Seiyaku Co., Ltd was used in this study.
In the ultrasonic treatment; the effects of pretreatment with acid, dissolved gases, horn immersion depth, applied voltage, and ultrasound exposure period were studied.
By ultrasonic treatment, oxygen was chemically bonded to the diamond surface as confirmed by XPS analyses. Diffused reflectance infrared Fourier transformed spectroscopy （DRIFT） analyses showed that C-O-C were the main groups produced on the diamond surface. The highest intensity of these groups was obtained by bubbling Ar gas, a horn immersion depth were the node is in contact with the surface of the liquid and using acid pretreated diamond. Acid washing makes the diamond surface more reactive to ultrasonic treatment, increasing the total intensity of oxygen surface groups approximately by a factor of 2.3, compared to the raw diamond. Bubbling gas into the diamond suspension enhances the production of oxygen surface groups compared with no bubbling, and the extent depends on the gas properties. By modifying the surface of the acid washed diamond by ultrasonic treatment, it is possible to obtain an oxygen surface coverage of 13%, meanwhile for the raw diamond is less than 1%. The feasibility of modifying the surface of diamond powder by dissolution of formaldehyde in water was proposed for the first time. The reaction was studied at different temperatures and treatment periods. The products were monitored by DRIFT.
It is showed that methyl formate （HCOOCH 3 ） chemisorbed on the diamond surface and the amount increases by augmenting the reaction temperature. Possible reaction mechanisms were discussed. The activation energies calculated from the experimental data are 34.7 kJ mol -1 , corresponding to a chemisorption process. An organic-inorganic hybrid material using modified diamond was developed. Using the modified diamond powders, the Young's modulus slightly increases while the damping capacity increases by a factor of about two compared to the raw diamond composite. After modification of diamond surface the interface between the matrix and the diamond become more heterogeneous.