TABLE OF CONTENTS
1. INTRODUCTION 5
1.1. BIODEGRADABLE POLYMERS 8
1.2. POLYHYDROXYALKANOATES (PHAS) 10
1.2.1. GENERAL PROPERTIES OF PHAS 14
1.2.2. PROCESSING OF PHAS 15
1.2.3. BIODEGRADABILITY OF PHAS 17
1.2.4. APPLICATIONS AND COSTS OF PHAS 19
1.3. PHAS BASED BLENDS AND COMPOSITES 20
1.3.1. PHAS BASED BLENDS 20
1.3.2. PHAS – BIOCERAMICS COMPOSITES 23
1.3.3. PHAS – LAYERED SILICATES COMPOSITES 24 1.3.3.1. Structure and Properties of Layered Silicates 25 1.3.3.2. Preparation Techniques of Polymer – Layered Silicate Nanocomposites 27 1.3.3.3. Characterization of Polymer – Layered Silicate Nanocomposites 28 1.3.3.4. Properties of PHAs – Layered Silicates Composites 28
1.3.4. PHAS – NATURAL FIBRES COMPOSITES 30
1.3.4.1. Properties of Natural Fibres 30
1.3.4.2. Composition and Structure of Natural Fibres 33 1.3.4.3. Surface Modification of Natural Fibres 36 1.3.4.4. Properties of PHAs – Natural Fibres Composites 38
1.4. LIFE CYCLE ASSESSMENT (LCA) 42
1.4.1. LCA GENERALITIES 42
1.4.2. GOAL AND SCOPE DEFINITION 44
1.4.3. LIFE CYCLE INVENTORY (LCI) 45
1.4.4. LIFE CYCLE IMPACT ASSESSMENT (LCIA) 47
1.4.5. LIFE CYCLE INTERPRETATION 50
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2. OBJECTIVES OF THE WORK 53
3. EXPERIMENTAL 55
3.1. MATERIALS 55
3.1.1. SOLVENTS AND REAGENTS 55
3.1.2. PROCESS ADDITIVES 55
3.1.3. FILLERS 55
3.1.4. POLYMERS 55
3.2. PHB STABILIZATION 56
3.2.1. PHB STABILIZATION WITH ANOX 20TM AND ALKANOX 240TM 56
3.2.2. PHB STABILIZATION WITH STABAXOL®P200 57
3.3. PHB – NATURAL FIBRES COMPOSITES 58
3.3.1. MODIFICATION OF NATURAL FIBRES 58
3.3.1.1. Alkalization of Sugar Cane Bagasse 58
3.3.1.2. Esterification of Natural Fibres 58
3.3.2. PREPARATION OF PHB – NATURAL FIBRES COMPOSITES 59 3.4. PHB – ORGANOPHILIC MONTMORILLONITE COMPOSITES 60 3.4.1. PREPARATION OF PHB – ORGANOPHILIC MONTMORILLONITE COMPOSITES BY
SOLUTION-CASTING 60
3.4.2. PREPARATION OF SILANE MODIFIED ORGANOPHILIC MONTMORILLONITE 61 3.4.3. PREPARATION OF PHB – ORGANOPHILIC MONTMORILLONITE COMPOSITES BY MELT
PROCESSING 61
3.5. CHARACTERIZATION 62
3.5.1. TRANSMISSION FOURIER TRANSFORM INFRARED SPECTROSCOPY (FT-IR) 62 3.5.2. PHOTOACOUSTIC FOURIER TRANSFORM INFRARED SPECTROSCOPY (PAS-FT-IR) 62 3.5.3. NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY (NMR) 62 3.5.4. POLARIZED OPTICAL MICROSCOPY (POM) 62 3.5.5. SCANNING ELECTRON MICROSCOPY (SEM) 63 3.5.6. WIDE ANGLE X-RAY SCATTERING (WAXS) 63 3.5.7. GEL PERMEATION CROMATOGRAPHY (GPC) 63
3.5.8. THERMOGRAVIMETRIC ANALYSIS (TGA) 63
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3.5.10. DYNAMIC MECHANICAL THERMAL ANALYSIS (DMTA) 65
3.5.11. MECHANICAL TESTS 65
3.5.12. OXYGEN PERMEABILITY 66
3.5.13. DETERMINATION OF THE DEGREE OF SUBSTITUTION OF ESTERFIED NATURAL FIBRES 66
4. RESULTS AND DISCUSSION 69
4.1. PHB STABILIZATION 69
4.1.1. PHB STABILIZATION WITH ANOX 20TM AND ALKANOX 240TM 72
4.1.1.1 Structural Characterization 74
4.1.1.2. Molecular Weight Characterization 77
4.1.1.3. Thermal Characterization 85
4.1.1.4. Mechanical Characterization 93
4.1.2. PHB STABILIZATION WITH STABAXOL® P200 102
4.1.2.1. Morphological Characterization 103
4.1.2.2. Structural Characterization 105
4.1.2.3. Molecular Weight Characterization 108
4.1.2.4. Thermal Characterization 110
4.1.2.5. Mechanical Characterization 116
4.2. PHB – NATURAL FIBRES COMPOSITES 119
4.2.1. MODIFICATION OF NATURAL FIBRES 119
4.2.1.1. Morphological Characterization 123
4.2.1.2. Structural Characterization 123
4.2.1.3. Chemical Characterization 127
4.2.1.4. Thermal Characterization 131
4.2.2. PHB – NATURAL FIBRES COMPOSITES 137
4.2.2.1. Morphological Characterization 138
4.2.2.2. Structural Characterization 142
4.2.2.3. Molecular Weight Characterization 150
4.2.2.4. Thermal Characterization 153
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4.3. PHB – ORGANOPHILIC MONTMORILLONITE COMPOSITES 172 4.3.1. PHB – ORGANOPHILIC MONTMORILLONITE COMPOSITES PREPARED BY SOLUTION
-CASTING 172
4.3.1.1. Morphological Characterization 173
4.3.1.2. Thermal Characterization 176
4.3.2. PHB – ORGANOPHILIC MONTMORILLONITE COMPOSITES PREPARED BY MELT
PROCESSING 180
4.3.2.1. Morphological Characterization 182
4.3.2.2. Structural Characterization 185
4.3.2.3. Molecular Weight Characterization 191
4.3.2.4. Thermal Characterization 192
4.3.2.5 Mechanical Characterization 201
4.3.2.6. Oxygen Permeability 204
4.4. LIFE CYCLE ASSESSMENT OF PHB BASED COMPOSITES 206
4.4.1. GOAL AND SCOPE DEFINITION 206
4.4.1.1. Definition of Functional Units 207
4.4.1.2. Properties of PHB Based Composites 207
4.4.1.3. System Boundaries 209
4.4.2. INVENTORY ANALYSIS 212
4.4.3. IMPACT ASSESSMENT 214
4.4.4. INTERPRETATION 216
4.4.4.1. Life cycle Interpretation 218
4.4.4.2. Sensitivity Analysis on Internal Car Panels 222
5. CONCLUDING REMARKS 225
REFERENCES 229
