Synthesis and Characterization of Polyrotaxane-based Polyurethane with Improved Mechanical Strength and Elongation = 기계적 강도와 연신율이 향상된 폴리로탁산 기반 폴리우레탄의 합성 및 특성 연구

다국어 초록 (Multilingual Abstract)

Highly stretchable polymers have gotten much attention due to a wide range of applications including biomedical materials, automobiles, etc. Because of slide-ring structure, polyrotaxane has been frequently used to endow polymers with stretchability. In this study, polyrotaxane was used as a chain extender of polyurethane to improve both tensile strength and elongation. Highly stretchable polymer synthesized by crosslinking polyurethane with pre-synthesized polyrotaxane consists of polypropylene glycol (PPG) with low-covered cyclodextrin (CD) which acts as chain extender and crosslinker, respectively. Polyrotaxane was synthesized by threading beta cyclodextrin (β-CD) along the axis of PPG-diamine polymer backbone, followed by end-capped with 2,4,6-trinitrobenzene sulfonic acid (TNBS). The synthesized polyurethane and polyrotaxane were characterized by 1H-NMR and FT-IR spectroscopies. The coverage of cyclodextrin on polyrotaxane was adjusted by the mole ratio of PPG and β-CD. DSC and TGA were used to characterize thermal properties of polyurethane. A tensile test was also conducted to measure tensile strength and elongation. DMA was used to characterize elasticity and crosslink density. As a result, an increase in the tensile strength and elongation of the polyrotaxane as the content of polyrotaxane increased was confirmed. This study suggests that polyurethane containing polyrotaxane can be used as a new class of highly stretchable polymers.

목차 (Table of Contents)

• ABSTRACT 1
• CHAPTER 1. INTRODUCTION 2
• CHAPTER 2. THEORETICAL BACKGROUND 3
• 2-1. Cyclodextrin 3
• 2-1-1. History of cyclodextrin 4
• 2-1-2. Properties of cyclodextrin 5
• 2-2. Poly(propylene glycol) 7
• 2-3. Inclusion complex 7
• 2-4. Polyrotaxane 9
• 2-4-1. Polymer topology 9
• 2-4-2. Polyrotaxane 10
• 2-4-3. Pulley effect of slide-ring structure 13
• 2-5. Polyurethane 14
• 2-5-1. side reaction of polyurethane 15
• 2-5-1-1. Polyurea 15
• 2-5-1-2. allophanate and biuret reaction 16
• 2-6. Polyols 17
• 2-7. Isocyanates 18
• 2-8. Chain extender and crosslinkers 19
• CHAPTER 3. EXPERIMENTAL 20
• 3-1. Materials 20
• 3-2. Experimental 22
• 3-2-1. Synthesis of Pseudorotaxane 22
• 3-2-2. Synthesis of Polyrotaxane 24
• 3-2-3. Synthesis of polyurethane with 1,4-BD chain extender 25
• 3-2-4. Synthesis of polyurethane with polyrotaxane chain extender 26
• 3-3. Measurement 28
• 3-3-1. Spectroscopic measurement 28
• 3-3-2. Thermal analysis 28
• 3-3-3. Mechanical property 28
• CHAPTER 4. RESULTS AND DISCUSSION 30
• 4-1. Characterization of cyclodextrin derivatives 30
• 4-1-1. Pseudorotaxane 30
• 4-1-2. Polyrotaxane 34
• 4-2. Characterization of Polyurethane 38
• CHAPTER 5. CONCLUSIONS 50
• REFERENCES 51
• ABSTRACT (KOREAN) 54