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Synthesis and Dynamic Properties of Ultra-Small-Branched Star Poly(ε-caprolactone)s and Their Application to Alternative Plasticizers : 초단가지 성형구조 폴리(입실론-카프로락톤)의 합성과 동역학적 특성 분석 및 이들의 대체가소제 응용
DC Field | Value | Language |
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dc.contributor.advisor | 곽승엽 | - |
dc.contributor.author | 최우혁 | - |
dc.date.accessioned | 2017-10-27T16:39:54Z | - |
dc.date.available | 2017-10-27T16:39:54Z | - |
dc.date.issued | 2017-08 | - |
dc.identifier.other | 000000144993 | - |
dc.identifier.uri | https://hdl.handle.net/10371/136779 | - |
dc.description | 학위논문 (박사)-- 서울대학교 대학원 공과대학 재료공학부, 2017. 8. 곽승엽. | - |
dc.description.abstract | In this study, we develop ultra-small-branched star poly(ɛ-caprolactone)s (USB-SPCLs) as nontoxic alternative plasticizers for flexible poly(vinyl chloride) (PVC) and investigate the interplay of dynamic properties with plasticization.
We successfully synthesize the three- and six-branched SPCLs with extremely small branched segments using a facile pseudo-one-pot process in a pilot scale and investigate the effect of ultra-small branches on their crystallization behaviors. The number of branched segments and the individual branched segment lengths for USB-SPCLs are precisely controlled via manipulating monomer-to-core ratio, adjusting monomer-to-polymer conversion, end-capping the terminal hydroxyl groups, and vacuum purification, which results in USB-SPCLs having the branched segments below five degree of polymerization with a high yield exceeding 93%. The molecular weights obtained from 1H NMR spectroscopy are consistent with that obtained from MALDI-TOF-MS and the molecular weight distributions are narrow with Mw/Mn ≤ 1.2, indicating that USB-SPCLs have mono-dispersed branches. USB-SPCLs have low melting temperatures and broad double-melting peaks attributed to their extremely small branches, and the crystallization behaviors for USB-SPCLs depend on the end group concentration. On the other hand, the glass transitions for USB-SPCLs depend on the total molecular weights, regardless of the number and length of branched segments. The extremely small branched effects on molecular dynamics are investigated using USB-SPCLs. USB-SPCLs interestingly show total-molecular-weight-dependent glass transitions regardless of the molecular architecture parameters, such as the number and length of branches, whereas typical star polymers with polymeric large branches show the end-group-concentration-dependent glass transitions. The viscoelasticity of USB-SPCLs does not depend exponentially on the individual branched molecular weight, as observed in typical star polymers, and instead follows the Mark–Houwink power law and the Bueche-modified Rouse model for unentangled linear polymers. The flow activation energy and the longest Rouse relaxation time of USB-SPCLs show that the individual branches of USB-SPCL are dynamically equivalent and that a whole USB-SPCL molecule moves with a simple uni-motion. These results suggest that a whole USB-SPCL molecule presumably acts as a dynamically-equivalent single coarse-grain unit because of the extremely small branches on the scale of 20‒40 atoms. USB-SPCL is used as a nontoxic plasticizer for the production of phthalate-free flexible PVC. USB-SPCL is a transparent liquid at room temperature and exhibits unentangled Newtonian behavior due to its extremely short branched segments. USB-SPCL is biologically safe without producing an acute toxicity response. Torque analysis measurements reveals that USB-SPCL offers a faster fusion rate and a higher miscibility with PVC compared to a typical plasticizer, DEHP. The solid-state 1H NMR spectrum reveals that PVC and USB-SPCL are miscible with an average domain size of less than 8 nm. The flexibility and transparency of the PVC/USB-SPCL mixture are comparable to the corresponding properties of the PVC/DEHP mixture, and the stretchability and fracture toughness of PVC/USB-SPCL are superior to the corresponding properties of the PVC/DEHP system. Most of all, PVC/USB-SPCL shows excellent migration resistance with a weight loss of less than 0.6% in a liquid phase, whereas DEHP migrated out of PVC/DEHP into a liquid phase with a weight loss of about 10%. The dynamic effects of unentangled star-shaped polymers with extremely small branches on the plasticization of miscible polymer blends are investigated using USB-SPCLs, PVC, and their blends. Photon correlation dynamics of USB-SPCLs supports our previous suggestion that a whole USB-SPCL molecule acts as a single coarse-grain unit with dynamically-equivalent branches because of the extremely small branches, resulting in the total-molecular-weight-dependent Rouse dynamic behaviors of USB-SPCLs, regardless of the molecular architectures. The dynamic light scattering intensity autocorrelation curves of miscible PVC/USB-SPCL blends reveal that strong intermolecular interactions between PVC and USB-SPCL molecules determine the dynamic homogeneous behaviors of the blends despite their significantly different mobilities. The molecular motions of the blends depend on the total-molecular-weight-dependent Rouse dynamic behaviors of USB-SPCLs. These dynamic results clearly show the plasticization of the entangled neat linear PVC matrix by distinctive and rapid molecular mobility of USB-SPCLs. Free-volume-dependent dynamic behaviors of the pyrene-labeled and -doped PVC blends with different amount of USB-SPCL are analyzed using temperature-dependent FS techniques, to investigate the correlation between the dynamic behaviors of individual polymer chains and the controlled free-volume changes. The individual PVC component in the PVC/USB-SPCL blends interestingly exhibited broad thermal glass transition range from the glass transition of the whole blend system to the glass transition of original PVC, differ from a typical glass transition dynamics of miscible polymer blend with single glass transition temperature, indicating the heterogeneous glass transition dynamic behaviors of the miscible PVC/USB-SPCL blend system. These results suggest that the motion of individual PVC component in PVC/USB-SPCL blends depends on both the enlarged free volume by fast-moved USB-SPCL molecules and the dynamic constraint by entangled PVC chains while general glass transition dynamics is sufficiently described by free-volume of the whole blend system. | - |
dc.description.tableofcontents | CHAPTER I INTRODUCTION 1
I-1. Ultra-Small-Branched Poly(ε-caprolactone) 1 I-1-1. Poly(ε-caprolactone) 4 I-1-2. Star-shaped poly(ε-caprolactone) 4 I-1-3. Extremely small branches in SPCL 4 I-2. Alternative Plasticizer 7 I-2-1. Phthalate plasticizer for poly(vinyl chloride) 7 I-2-2. PCL plasticizer 11 I-3. Polymer Dynamics 14 I-4. Research Objectives 18 References and Notes 22 CHAPTER II SYNTHESIS OF ULTRA-SMALL-BRANCHED STAR POLY(ε-CAPROLACTONE)S AND THEIR HIGH END GROUP CONCENTRATION EFFECTS ON CRYSTALLIZATION 28 II-1. Introduction 28 II-2. Experimental Section 30 II-2-1. Materials 30 II-2-2. Synthesis of USB-SPCLs 30 II-2-3. Characterization 32 II-3. Results and Discussion 34 II-3-1. Synthesis of USB-SPCLs 34 II-3-2. Crystallization behaviors of USB-SPCLs 61 II-4. Conclusion 67 References and Notes 68 CHAPTER III TOTAL-MOLECULAR-WEIGHT-DEPENDENT ROUSE DYNAMICS OF ULTRA-SMALL-BRANCHED STAR POLY(ε-CAPROLACTONE)S AS A SINGLE COARSE-GRAIN UNIT 70 III-1. Introduction 70 III-2. Experimental Section 73 III-2-1. Materials 73 III-2-2. Characterization 74 II-3. Results and Discussion 75 III-3-1. Glass transition behaviors of USB-SPCLs 75 III-3-2. Viscoelastic behaviors and molecular motions of USB-SPCLs 81 III-4. Conclusion 99 References and Notes 100 CHAPTER IV ULTRA-SMALL-BRANCHED STAR POLY(ε-CAPROLACTONE)S AS PHTHALATE-FREE PVC PLASTICIZERS DESIGNED FOR NON-TOXICITY AND IMPROVED MIGRATION RESISTANCE 104 IV-1. Introduction 104 IV-2. Experimental Section 107 IV-2-1. Materials 107 IV-2-2. Synthesis and characterization of USB-SPCLs 107 IV-2-3. Acute toxicity test of USB-SPCLs 110 IV-2-4. Processing properties of USB-SPCLs 110 IV-2-5. Characterization of the flexible PVCs 111 IV-2-6. Migration resistance test of the flexible PVCs 112 IV-3. Results and Discussion 114 IV-3-1. Synthesis and characterization of USB-SPCLs 114 IV-3-2. Biological safety of USB-SPCLs 120 IV-3-3. Processing properties of PVC/USB-SPCLs 121 IV-3-4. Physical properties of the flexible PVCs 131 IV-3-5. Migration resistance of USB-SPCLs 141 IV-4. Conclusion 145 References and Notes 146 Chapter V PHOTON CORRELATION DYNAMICS OF ULTRA-SMALL-BRANCHED POLY(ε-CAPROLACTONE)S AND ITS INTERACTION WITH PLASTICIZATION IN MISCIBLE BLEND SYSTEM 148 V-1. Introduction 148 V-2. Experimental Section 154 V-2-1. Materials 154 V-2-2. Synthesis of USB-SPCLs 154 V-2-3. PCS analysis 158 V-2-4. Differential scanning calorimetry (DSC) analysis 159 V-3. Results and Discussion 160 V-4. Conclusion 180 References and Notes 181 Chapter VI HETEROGENEOUS GLASS TRANSITION DYNAMICS OF INDIVIDUAL PVC COMPONENT PLASTICIZED BY ULTRA-SMALL-BRANCHED STAR POLY(-CAPROLACTONE) 185 VI-1. Introduction 185 VI-2. Experimental Section 191 VI-2-1. Materials 191 VI-2-2. Preparation of L-PVC 191 VI-2-3. Preparation of USB-SPCL 196 VI-2-4. Preparation of pyrene-labeled and -doped PVC/USB-SPCL films 196 VI-2-5. DSC analysis 200 VI-2-6. FS analysis 200 VI-3. Results and Discussion 202 VI-4. Conclusion 223 References and Notes 224 KOREAN ABSTRACT 228 LIST OF PAPERS, PATENTS, AND SYMPOSIUMS 232 | - |
dc.format | application/pdf | - |
dc.format.extent | 10725828 bytes | - |
dc.format.medium | application/pdf | - |
dc.language.iso | en | - |
dc.publisher | 서울대학교 대학원 | - |
dc.subject | Ultra-small branches | - |
dc.subject | Poly(ɛ-caprolactone) | - |
dc.subject | Star-shaped polymer | - |
dc.subject | Plasticizer | - |
dc.subject | Poly(vinyl chloride) | - |
dc.subject | Molecular dynamics | - |
dc.subject | Dynamic mechanical spectrometry | - |
dc.subject | Photon correlation spectroscopy | - |
dc.subject | Fluorescence spectroscopy | - |
dc.subject.ddc | 620.1 | - |
dc.title | Synthesis and Dynamic Properties of Ultra-Small-Branched Star Poly(ε-caprolactone)s and Their Application to Alternative Plasticizers | - |
dc.title.alternative | 초단가지 성형구조 폴리(입실론-카프로락톤)의 합성과 동역학적 특성 분석 및 이들의 대체가소제 응용 | - |
dc.type | Thesis | - |
dc.contributor.AlternativeAuthor | Woohyuk Choi | - |
dc.description.degree | Doctor | - |
dc.contributor.affiliation | 공과대학 재료공학부 | - |
dc.date.awarded | 2017-08 | - |
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