목차

1. Introduction 1
2. Theoretical background 3
2.1. Self-healing materials 3
2.2. Classification of self-healing polymers 5
2.3. Encapsulation 7
2.3.1. Self-healing systems based on microcapsules 7
2.3.2. Interfacial polymerization 9
2.3.3. Surfactant 10
2.3.4. Polyurethane prepolymer 13
2.3.5. Healing agent 14
3. Experimental 17
3.1. Materials 17
3.2. Synthesis and characterization of urethane prepolymer 19
3.2.1. Synthesis of urethane prepolymer 19
3.2.2. Free-NCO contents 22
3.2.3. FT-IR spectra of urethane prepolymer 23
3.3. Synthesis and characterization of microcapsules 24
3.3.1. Synthesis of microcapsules 24
3.3.2. Optical microscopy and FE-SEM 31
3.3.3. Evaluation of the effects of surfactants 32
3.3.4. FT-IR spectra of microcapsule components 33
3.3.5. Thermogravimetric analysis (TGA) 34
3.3.6. Fracture and release behavior of microcapsules 34
3.4. Microcapsule-embedded self-healing coating 35
3.4.1. Preparation of microcapsule-embedded self-healing coatings 35
3.4.2. Healing behavior of microcapsule-embedded coating 37
3.4.3. Effects of embedded microcapsules on mechanical properties and healing efficiency 39
4. Result and discussion 40
4.1. Analysis prepolymers 40
4.1.1. Free-NCO contents 40
4.1.2. FT-IR spectra of urethane prepolymers 42
4.2. Morphology of microcapsules according to different synthesis conditions 44
4.2.1. Morphology of microcapsules according to different natural gum types 44
4.2.2. Morphology of microcapsules according to different gum contents 48
4.2.3. Morphology of microcapsules according to different prepolymers 51
4.3. Evaluation of the effects of surfactants 53
4.4. Analysis microcapsules 57
4.4.1. FT-IR spectra of microcapsule components 57
4.4.2. Thermal analysis 59
4.4.3. Fracture and release behavior 64
4.5. Evaluation of microcapsule-embedded self-healing coating 69
4.5.1. Healing behavior of coating 69
4.5.2. Mechanical and healing effect of microcapsules 71
4.5.3. Evaluation of healing efficiency 73
5. Conclusions 78
6. References 80