Corté, Laurent (2006) Renforcement des polymères semi-cristallins. PhD thesis Chimie et Physico-chimie des polymères, Matière Molle et Chimie, ESPCI.
Full text available as:
|
|
Abstract
The impact resistance of semi-crystalline polymers is greatly improved by dispersing (sub)micronic particles that cavitate and induce the extensive plastic deformation of the matrix rather than its brittle failure. We were concerned with several aspects of this phenomenon through the study of toughened polyamide systems. We show that nanostructured particles of block copolymers yield remarkable toughening without the loss in rigidity that is obtained with rubber particles. Furthermore, the structure of these block copolymers seems to govern the breakup and coalescence of particles during blending. More generally, microscopic observations and various thermomechanical treatments show that the crystalline organization of the matrix is determinant for toughening. Based on these results, we propose a model for toughening which considers the physical approaches to fracture in heterogeneous media and explains the physical origin of a critical matrix confinement necessary to obtain a ductile behavior. The proposed theory predicts how this characteristic length depends on crystalline organization, particle size and temperature for the studied polyamide-12 systems as well as for other systems studied in the literature.
| Item Type: | PhD Thesis (PhD) |
|---|---|
| Thesis Supervisor: | Leibler, Ludwik |
| Date: | January 2006 |
| Board of examiners: | Billon, Noelle and Meijer, Han E.H. and de Gennes, Pierre-Gilles and Bouchaud, Elizabeth and Brochard-Wyart, Françoise and Glotin, Michel |
| Ecole Doctorale: | ED 397 PHYSIQUE ET CHIMIE DES MATERIAUX |
| Discipline: | Chimie et Physico-chimie des polymères |
| Collection (Fonds): | ESPCI |
| Institution: | ESPCI |
| Department: | Matière Molle et Chimie |
| Subjects: | 4. Materials Science, Mechanics and Mechanical Engineering |
| Uncontrolled Keywords: | Semi-crystalline polymers, Block copolymers, Polyamide, Toughening, Fracture, Brittle-to-ductile transition, Polymères semi-cristallins, Copolymères à blocs, Polyamide, Renforcement, Fracture, Transition ductile-fragile |
Table of content
Introduction - 3
Références 8
Notations - 9
Chapitre 1: Etude bibliographique - 11
Notions de mécanique de la rupture 12
Préparation des systèmes renforcés 20
Principe général du renforcement 22
Les paramètres du renforcement 25
Origine physique de la distance interparticulaire critique, Lc 40
Conclusion 46
Références 48
Chapitre 2: Caractérisation des dispersions par analyse d'image - 51
Introduction 54
Experimental 57
Results and Discussion 58
Conclusion 70
Appendix A: Average ligament thickness 72
References 73
Chapitre 3: Dispersions de polymères nanostructurés - 75
References 85
Chapitre 4: Renforcer sans perdre en module - 87
Introduction 90
Experimental 91
Results 95
1Discussion 103
Conclusion 109
References 110
Chapitre 5: Organisation cristalline et renforcement - 113
Introduction 116
Experimental 118
Results 120
Discussion 127
Conclusions 130
References 131
Chapitre 6: Les effets de mise forme et d'orientation cristalline - 135
Structure cristalline des barreaux injectés - 137
Sensibilité à l'effet de peau 142
Sensibilité à l'orientation cristalline 150
Références 167
Chapitre 7: Modélisation du renforcement - 169
Introduction 171
Model 173
Comparison with experimental data 185
Conclusion 191
References 192
Conclusion - 195
Annexes - 199
A1 - Techniques expérimentales - 201
A2 - Effets des conditions d'extrusion sur les dispersions PA/SBM - 207
A3 - Dispersions de SBM dans d'autres matrices PA - 211
A4 - Choc à basse température - 215
A5 - Observations de l'endommagement - 219
A6 - Effets du traitement thermique - 223
A7 - Observations MET de l'organisation cristalline 225
A8 - Sensibilité aux conditions d'injection - 239
| ID Code: | 1649 |
|---|---|
| Deposited By: | Laurent Corté |
| Deposited On: | 07 April 2006 |
Repository Staff Only: edit this item