Natural composites, in particular nacre, often combine high strength and toughness thanks to highly ordered architectures and controlled geometries of the reinforcement components. However, combining strength, toughness and resorbability in synthetic materials remains a challenge in particular in the field of bone graft substitutes. In the present study, calcium phosphate-(CaP-)based materials with designed architectures inspired from natural composite materials were achieved. CaP platelets obtained by precipitation in organic medium were first aligned in chitosan matrices by solvent casting in ambient conditions. Efficient strengthening was obtained with 15 vol-% ceramic, reaching cortical bone strength (150 MPa) and preserving good ductility (5 % deformation). In a weak magnetic field, high spatial arrangement without percolation was maintained up to 20 vol-%. With directional freezing, good alignment of the platelets could be pushed up to 50 vol-%. In parallel, in situ recrystallization of CaP blocks in hydrothermal conditions led to hierarchical structures. The strength and the work-of-fracture were enhanced (300%) thanks to a change of failure mode.
| Identifer | oai:union.ndltd.org:DRESDEN/oai:qucosa.de:bsz:105-qucosa-162693 |
| Date | 21 May 2015 |
| Creators | Galea, Laetitia |
| Contributors | TU Bergakademie Freiberg, Maschinenbau, Verfahrens- und Energietechnik, Prof. Dr.-Ing. habil. Christos G. Aneziris, Prof. Dr. Thomas Graule, Prof. Dr. Marc Bohner, Prof. Dr.-Ing. habil. Christos G. Aneziris |
| Publisher | Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola" |
| Source Sets | Hochschulschriftenserver (HSSS) der SLUB Dresden |
| Language | English |
| Detected Language | English |
| Type | doc-type:doctoralThesis |
| Format | application/pdf |
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