Silicon-containing block copolymers with well-defined, branched architectures [Elektronische Ressource] : synthesis, characterization and morphological studies / vorgelegt von Alejandra Teresa García Marcos

Informations

• Publié par: johannes_gutenberg-universitat_mainz
• Publié le: 01 janvier 2006
• Nombre de lectures: 58
• Poids de l'ouvrage: 73 Mo

Extrait

SILICON-CONTAINING BLOCK COPOLYMERS WITH
WELL-DEFINED, BRANCHED ARCHITECTURES
- Synthesis, Characterization and Morphological Studies -



Dissertation zur Erlangung des Grades
“Doktor der Naturwissenschaften”


am Fachbereich Chemie, Pharmazie und Geowissenschaften der
Johannes Gutenberg-Universität Mainz



vorgelegt von
Alejandra Teresa García Marcos
geboren am 15 Oktober 1975 in Avilés/Asturias (Spanien)


Mainz, im April 2006



Die vorliegende Arbeit wurde in der Zeit von
Oktober 2001
bis
Oktober 2005
am Institut für Organische und Makromolekulare Chemie
der Johannes Gutenberg-Universität Mainz
unter der Betreuung von
Herrn Prof. Dr. Holger Frey
angefertigt











Tag der mündlichen Prüfung: 21 Juni 2006

Contents

Preface v


1. GENERAL INTRODUCTION AND MOTIVATION 1
1.1. Block copolymers 1
1.1.1. What are block copolymers? 1
1.1.2. Why are block copolymers interesting? Applications 2
1.1.3. Synthesis of block copolymers. Developments 3
1.1.4. Solid-state phase behavior 5
1.2. Block copolymer architecture 10
1.2.1. Star-block, miktoarm star and graft copolymers morphology 10
1.2.2. Other polymeric complex systems 17
1.3. Linear-dendritic block copolymers 17
1.3.1. Linear-dendrimer block copolymer structures 18
1.3.1.1. Solid-state properties. Bulk morphologies 26
1.4. Motivation and objectives of research described in this thesis 28
1.4.1. Why linear-hyperbranched diblock copolymers? 28
1.4.2. The two strategies for the preparation of
linear-hyperbranched diblock copolymers 29
1.4.3. Actual synthesis employed and objectives of research 31
1.5. References 32

2. SYNTHESIS AND CHARACTERIZATION OF
POLYSTYRENE-POLYBUTADIENE DIBLOCK COPOLYMERS 39
2.1. Introduction 39
2.2. Nomenclature 40
2.3. Results and discussion 40
2.4. Experimental 50
2.5. References 54



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3. SYNTHESIS AND CHARACTERIZATION OF
AB ORGANOSILICON BRANCHED MONOMERS 56 n
3.1. Introduction 56
3.2. Results and discussion 58
3.2.1. AB -carbosilane type monomers: synthesis and characterization 58 n
3.2.2. AB -alkoxysilane type monomers: synthesis and characterization 61 n
3.3. Experimental 63
3.3.1. Materials 63
3.3.2. Synthesis of 3-bromoprop-1-ene and 11-bromoundec-1-ene 63
3.3.3. Synthesis of AB -alkenylsilane type monomers; n = 1, 2, 3 64 n
3.3.4. Synthesis of AB -alkenoxysilane type monomers; n = 1, 2 70 n
3.4. References 74

4. MECHANISTIC APPROACH: THE HYDROSILYLATION REACTION 77
4.1. Introduction 77
4.2. Metal-assisted hydrosilylation mechanisms 78
4.2.1. Chalk-Harrod mechanism 79
4.2.2. Lewis mechanism based on colloidal platinum species 81
4.2.3. Lewis mechanism based on monomeric platinum 84
4.3. Competing side reactions during hydrosilylation ad their mechanisms 88
4.3.1. Alkene rearrangements 88
4.3.1.1. Alkene isomerization 88
4.3.1.2. Alkene hydrogenation 92
4.3.1.3. Alkene dimerization 93
4.3.2. Rearrangements reactions involving silicon 95
4.3.2.1. Dyotropic rearrangements 95
4.4. References 96

5. SYNTHESIS AND CHARACTERIZATION OF
HYPERBRANCHED AND BRUSH-LIKE POLYALKENYLSILANES 99
5.1. Introduction 99
5.2. Results and discussion 103
5.2.1. Polymerization 103
5.2.2. Kinetic studies 105
5.2.3. Effect of monomer concentration 108
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5.2.4. Chemical structure and composition 109
5.2.5. Degree of branching 126
5.2.6. Thermal properties 129
5.3. Conclusions 130
5.4. Experimental 132
5.5. References 134

6. LINEAR-HYPERBRANCHED DIBLOCK COPOLYMERS CONSISTING
OF POLYSTYRENE AND DENDRITIC POLYCARBOSILANE BLOCK 137
6.1. Introduction 137
6.2. Nomenclature 138
6.3. Results and discussion 139
6.3.1. Synthetic strategy and compositional characterization 139
6.3.2. Chemical structural characterization 145
6.3.3. Solid-state behavior 157
6.3.4. Analytical microscopy 170
6.4. Conclusions 171
6.5. Experimental 172
6.6. References 174

7. LINEAR BRUSH-LIKE DIBLOCK COPOLYMERS CONSISTING
OF POLYSTYRENE AND POLYCARBOSILANE BLOCK 177
7.1. Introduction 177
7.2. Nomenclature 179
7.3. Results and discussion 179
7.3.1. Synthetic strategy and compositional characterization 179
7.3.2. Chemical structural characterization 185
7.3.3. Solid state behavior 190
7.4. Conclusions 215
7.5. Experimental 216
7.6. References 217




iii


8. LINEAR-HYPERBRANCHED AND BRUSH-LIKE DIBLOCK COPOLYMERS
CONSISTING OF POLYSTYRENE AND POLYALKOXYSILANE BLOCK 222
8.1. Introduction 222
8.2. Nomenclature 223
8.3. Results and discussion 224
8.3.1. Synthetic strategy and compositional characterization 224
8.3.2. Chemical structural characterization 232
8.3.3. Characterization data and thermal properties 240
8.3.4. Solid state properties 248
8.4. Conclusions 266
8.5. Experimental 268
8.6. References 271

9. EXPERIMENTAL – CHARACTERIZATION METHODS 276
9.1. Spectroscopic analysis 276
9.2. Mass spectroscopy – Elemental analysis 276
9.3. Molecular weight 276
9.4. Thermal properties 276
9.5. Morphology 276

Appendix Chapter 3:
Characterization of AB organosilicon branched monomers 279 n

Appendix Chapter 7:
Characterization of linear brush-like diblock copolymers 299

Summary I
List of symbols and abbreviations II
Scientific contributions VI





iv


Preface

This thesis essentially consists of three parts. In the first part a general introduction to
block copolymers, miktoarm-star and linear-dendritic copolymers, giving special emphasis on
the studies of their solid-state properties, is presented. This is followed by a short description
of the motivation of this work.

The second part comprises Chapters 2, 3, 4 and 5. These chapters are essential building
blocks for the ensuing structure discussions. Chapter 2 explains how the linear polystyrene-b-
polybutadiene (PS-b-PBD) diblock copolymers, used as templates for the subsequent grafting
reactions, are prepared by living anionic polymerization. The characterization data of the
different diblock copolymers prepared and their acronyms are provided in Table 2.1. In
Chapter 3 synthesis and characterization of different AB alkenylsilane and alkenoxysilane n
monomers, as precursors for the hyperbranched and brush-like polymers, is described. The
Appendix of Chapter 3 complements the characterization of the organosilicon monomers. A
mechanistic approach to the afterwards employed metal-catalyzed hydrosilylation reaction is
presented in Chapter 4. To understand the formation of the side-products, some indispensable
knowledge about the different hydrosilylation mechanisms discussed at present is given.
Chapter 5 explains in-depth the structural and compositional characterization of
hyperbranched and brush-like polycarbosilanes, synthesized by the “one-pot” polymerization
approach of the AB alkenylsilane monomers. This episode is of significance, as the n
polycarbosilanes are part of more complex architectures in the next chapters.

The third part is the central theme of this dissertation and encompasses Chapters 6, 7 and 8.
The main topic of these chapters is the morphological behavior of unusual AB block
copolymer architectures when comparing with that of linear diblock copolymers. A general
strategy for the preparation of well-defined linear-hyperbranched systems is developed in
Chapter 6. This is based on slow monomer addition of branched AB carbosilane monomers 2
to the linear PS-b-PBD block copolymer precursor. In this manner, linear-hyperbranched
polycarbosilane diblock copolymers are obtained and the bulk morphology is studied by
transmission electron microscopy (TEM), atomic force microscopy (AFM) and temperature-
dependent Small-Angle X-ray Scattering (SAXS) measurements. An evaluation of the
morphological features of these peculiar systems is given in Chapter 6 and analogous linear
brush-like polycarbosilanes are analyzed in Chapter 7. Unusual morphologies are observed
for these structures and a qualitative explanation is given to explain the observed results.
v


Chapter 8 deals with the morphological studies of related linear-hyperbranched and brush-like
polyalkoxysilanes. The morphology of the linear-hyperbranched polyalkoxysilanes show
interestingly how complications arise when one of the segregating blocks can crystallize.
Additionally, the grafting efficiency of the alkenoxysilane and alkylsilane monomers is
studied and compared.






























vi

Chapter 1
CHAPTER 1



GENERAL INTRODUCTION AND MOTIVATION