Preparation of Conductive Epoxy Composite Using Bisphenol-Type Epoxy and Copper-Deposited Carbon Materials

다국어 초록 (Multilingual Abstract)

Thermally conductive materials have received attention due to the miniaturization of electronic devices and development of aerospace technology. Thermal dissipation from inside of devices to outside is crucial technique for preventing problems such as overheating or even explosion. Polymer material can be excellent candidate for thermal issue in terms of basic property, process ability and economics etc. However polymer resins have decisive weakness to be used as conductive material, which is very low electrical and thermal conductivity. Therefore polymer usually applied to conductive material by being mixed with conductive filler such as nitride chemicals, metal, metal oxide and carbon-based materials. These materials are referred to as conductive polymer composite. Among a number of polymer resins, epoxy resin has outstanding mechanical, chemical and thermal properties. Especially bisphenol-type epoxy commonly has an advantage of loading filler because of flexible chemical structure.
In this study, curing reaction of three kinds of bisphenol-type epoxy was analyzed using differential scanning calorimeter (DSC) kinetically. And three kinds of epoxy monomer and six kinds of curing agents were reviewed through measuring thermal conductivity using laser flash apparatus (LFA) method. Actually, thermal conductivity of epoxy composite is mainly under the control of conductivity of filler. However, thermal conductive path between filler and epoxy resin is also important because filler was surrounded by epoxy resins in composite. This is why many researchers have studied developing crystalline epoxy such as liquid crystalline epoxy resins. Meanwhile, copper nanoparticles were deposited on carbon black and graphite to increase thermal conductivity of carbon black and graphite which are very common conductive filler in diverse fields. Synthesis was examined by transmission electron microscope (SEM) and X-ray diffraction (XRD). The particles synthesized were mixed with epoxy selected above and the morphological, electrical, thermal and mechanical properties of epoxy composite were measured by SEM, 4-point probe, LFA and universal testing machine (UTM).

목차 (Table of Contents)

• 1. Introduction 1
• 1.1. Objectives 1
• 1.2. Epoxy resin 3
• 1.3. Curing agents and curing mechanism 5
• 1.4. Percolation theory 10
• 1.4.1. Principle of percolation theory 10
• 1.4.2. Percolation theory in polymer matrix composite 12
• 1.4.3. Percolation theory in carbon black system 13
• 1.5. Fundamentals of carbon black 14
• 1.5.1. Basic of carbon black 14
• 1.5.2. Structure of carbon black 15
• 1.6. Electroless deposition 18
• 1.6.1. Basic of metal deposition 18
• 1.6.2. Electroplating 18
• 1.6.3. Electroless deposition 20
• 1.6.4. Electroless Cu deposition 21
• 1.7. References 23
• 2. Analysis of Heat Kinetics by Chemical Structure of Bisphenol-Epoxy Resins and Its Effect on Thermal Conductivity 27
• 2.1. Introduction 27
• 2.1.1. Overview 27
• 2.1.2. Measuring thermal conductivity 29
• 2.2. Experimental 31
• 2.2.1. Materials 31
• 2.2.2. Determination of curing process 33
• 2.2.3. Measurement of thermal conductivity 33
• 2.2.4. Characterization 34
• 2.3. Results and discussion 34
• 2.3.1. Determination of curing process 34
• 2.3.2. Analysis of heat curing kinetics by different bisphenol-epoxy monomers 40
• 2.3.3. Effect of chemical structure of epoxy resins on thermal conductivity 59
• 2.4. Conclusions 65
• 2.5. References 66
• 3. Synthesis of Copper Nanoparticles-Deposited Carbon Black and Its Application to Electrically Conductive Substrate 68
• 3.1. Introduction 68
• 3.2. Experimental 70
• 3.2.1. Materials 70
• 3.2.2. Cu deposition on carbon black 70
• 3.2.3. Fabrication of electrically conductive substrates 71
• 3.2.4. Characterization 71
• 3.3. Results and discussion 72
• 3.3.1. Confirmation of Cu deposition on carbon black 72
• 3.3.2. Morphology of Cu-deposited carbon black 77
• 3.3.3. Conductive properties of Cu-deposited carbon black 79
• 3.3.4. Morphology of electrically conductive substrate 83
• 3.3.5. Electrical properties of conductive substrate 86
• 3.4. Conclusions 89
• 3.5. References 90
• 4. The Effect of Copper Deposition at Surface of Carbon Black on Thermal Conductivity of Epoxy Composite 94
• 4.1. Introduction 94
• 4.2. Experimental 96
• 4.2.1. Materials 96
• 4.2.2. Cu deposition on carbon black 96
• 4.2.3. Fabrication of conductive epoxy composite 98
• 4.2.4. Characterization 98
• 4.3. Results and discussion 99
• 4.3.1. Deposition of copper nanoparticles on graphite 99
• 4.3.2. Fracture morphology of epoxy composite 99
• 4.3.3. Electrical volume resistivity of epoxy composite 103
• 4.3.4. Thermal conductivity of epoxy composite 105
• 4.3.5. Mechanical properties of epoxy composite 108
• 4.4. Conclusions 110
• 4.5. References 111
• 5. Synthesis of Copper Nanoparticles-Deposited Graphite and Its Properties with Different Ratio 116
• 5.1. Introduction 116
• 5.2. Experimental 118
• 5.2.1. Materials 118
• 5.2.2. Deposition of copper on graphite 118
• 5.2.3. Characterization 119
• 5.3. Results and discussion 120
• 5.3.1. Confirmation of Cu deposition on graphite 120
• 5.3.2. Morphology of Cu-deposited graphite 124
• 5.3.3. Conductive properties of Cu-deposited graphite 126
• 5.4. Conclusions 130
• 5.5. References 130
• 6. The Effect of Copper Deposition at Surface of Graphite on Thermal conductivity of Epoxy Composite 134
• 6.1. Introduction 134
• 6.2. Experimental 136
• 6.2.1. Materials 136
• 6.2.2. Cu deposition on graphite 136
• 6.2.3. Fabrication of conductive epoxy composite 138
• 6.2.4. Characterization 138
• 6.3. Results and discussion 139
• 6.3.1. Deposition of copper nanoparticles on graphite 139
• 6.3.2. Fracture morphology of epoxy composite 139
• 6.3.3. Electrical volume resistivity of epoxy composite 143
• 6.3.4. Thermal conductivity of epoxy composite 145
• 6.3.5. Mechanical properties of epoxy composite 147
• 6.4. Conclusions 148
• 6.5. References 149