Table of content
INTRODUCTION AND AIMS OF THE THESIS 1
General introduction 1
1. Polymer nanocomposites 1
2. Polymer/clay nanocomposites 2
3. Potential impact of polymer/clay nanocomposites 4
4. Supercritical carbon dioxide 5
5. Solubility in supercritical carbon dioxide 6
Scope and aim of the thesis 7
Thesis outline 9
References 10
LITERATURE REVIEW 13
Part A: Patenting activity in manufacturing organoclays for nanocomposite
applications 13
1. Introduction 13
2. Organoclays for in situ intercalative polymerization method 15
3. Organoclays for intercalation in solution 19
4. Organoclays for melt intercalation method 20
5. Polymer/organoclay masterbatches 23
6. Current and future developments 24
Part B: Organoclays with thermally stable oniums 25
1. Introduction 25
2. Organoclays with imidazolium salts 27
3. Organoclays with phosphonium salts 30
4. Current and future developments 32
References 34
CHAPTER 1:CLAY ORGANOMODIFICATION IN scCO2 39
Introduction 39
Experimental section 41
1. Materials 41
2. Modification of pristine clays 41
3. Characterization 41
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Results and discussion 42
1. Ionic exchange with various ammonium, imidazolium and phosphonium salts 42
2. Ionic exchange at higher temperature 45
3. Ionic exchange with addition of a co-solvent 45
4. Determination of yield of exchange 46
5. Correlation of interlayer distance with organic content 49
6. Optimization of conditions 50
6.1. Influence of quantity of surfactant 50
6.2. Reproducibility of ionic exchange 51
6.3. Influence of clay content 51
6.4. Influence of the presence of water 53
7. Clay organomodification in pilot reactor 54
Conclusions 55
References 56
CHAPTER 2:ORGANOCLAY DISPERSION IN POLYAMIDE-6 AND IMPLICATION
OF ONIUM STABILITY ON FIRE PROPERTIES 59
Introduction 59
Experimental section 60
1. Materials 60
2. Modification of pristine clays 61
3. Preparation of PA-6/clay nanocomposites 61
4. Characterization 61
Results and discussion 64
1. Preparation of organoclays in supercritical carbon dioxide 64
2. Thermogravimetric analysis of the organoclays 66
3. Preparation of nanocomposites with PA-6 69
3.1. TEM analysis 69
3.2. X-ray diffraction 70
3.3. Rheology 70
3.4. Solid-state NMR 71
3.5. Thermogravimetric analysis 72
3.6. Cone calorimetry 73
Table of content
Conclusions 75
References 76
CHAPTER 3:EFFECT OF CLAY MODIFICATION ON STRUCTURE AND TENSILE PROPERTIES OF POLYAMIDE-6 NANOCOMPOSITES 79
Introduction 79
Experimental section 80
1. Materials 80
2. Preparation of the nanocomposites 81
3. Characterization 81
Results and discussion 83
1. Clay characteristics 83
1.1. X-ray diffraction and gallery structure 84
1.2. Surface energy and particle size 85
2. Composite structure 86
2.1. X-ray diffraction 86
2.2. TEM analysis 88
2.3. SEM analysis 89
2.4. Rheology 90
2.5. Crystallization 91
3. Tensile properties 91
3.1. Tensile modulus 92
3.2. Yield stress 92
3.3. Estimation of extent of reinforcement and exfoliation 93
Conclusions 96
References 98
CHAPTER 4:ORGANOCLAY DISPERSION IN POLY(m-XYLYLENE ADIPAMIDE)
AND BARRIER PROPERTIES 101
Introduction 101
Experimental section 102
1. Materials 102
2. Preparation of PA mXD-6/clay nanocomposites 103
Table of content
3. Characterization 103
Results and discussion 104
1. Structure and morphology of nanocomposites 105
2. Barrier properties 107
3. Non-isothermal crystallization analysis 108
4. Thermal characterization of PA mXD-6 nanocomposites 110
Conclusions 111
References 112
CHAPTER 5:FUNCTIONAL ORGANOCLAYS AND ROUTES FOR THE IN SITU
PREPARATION OF POLYMER NANOCOMPOSITES IN SCCO2 113
Introduction 113
Experimental section 115
1. Materials 115
2. Organomodifiers synthesis 115
3. Modification of clay 115
4. Polymerization 116
5. Characterization 116
Results and discussion 117
1. Preparation of functional organoclays in scCO2 117
2. Polymerization in scCO2 121
2.1. Free radical polymerization with methacrylate-bearing clays 121 2.2. Free radical polymerization with PDMS-clay 123 2.3. Atom transfer radical polymerization with initiator-modified clay 126
Conclusions 131
References 132
CONCLUSIONS AND OUTLOOK 135
Conclusions 135
Outlook 137
References 140
LIST OF ABBREVIATIONS 141
