5182.1:
Biomimetics: Transformation of the biological nanostructures of natural materials into high-performance ceramics
Abstract
Wood is built in the nanometer scale from fibrils and a (bio)polymeric matrix which forms the cell walls. Cell walls are characterised by nanoporosity. The composite-like structures of wood are mainly responsible for outstanding mechanical performance, especially high specific strength. During pyrolysis these structures disappear due to decomposition of the cellulose, lignin and hemicellulose and a less diverse carbonstructure remains.
The subject of this project is to preserve the nano-wood structures to the pyrolysed and ceramic state to achieve nanofilters and structural ceramics with outstandig mechanical performance due to the fiber reinforced composite structures mainly for filter (hot gas, soot) and catalyst carrier applications. Two approaches are made: 1. Preservation of nanostructures during pyrolysis by infiltration of a sol and 2. production of a negative of nanoporous cell wall structures via preceramic precursor infiltration. In a conversion step the silicon precursors are converted with carbon (derived from wood) to SiC in different degrees and nanoporous ceramics, reinforced in a nanoscale, are achieved.