Structure and Mechanical Properties of Wood

Research project P 14331 Structure and Mechanical Properties of Wood Peter FRATZL 06.03.2000 In a simple physical picture, wood can be considered as a cellular material composed of parallel hollow cylinders (wood cells) which are made of cellulose fibrils embedded in a lignin-rich matrix. From numerous studies, including work by the applicants,. it is known that the mechanical properties (such as stiffness or extensibility of the cell wall) depend considerably on general parameters describing the composite architecture of the material. Such parameters include the typical orientation of the cellulose fibrils with respect to the axis of the wood cells or the lignin content (i.e. the volume fraction of matrix) of the cell wall. In the context of this research proposal, it is planned to carry out systematic studies on the dependence of the mechanical properties on composite architecture, the main goal being to uncover the optimization principles which lead to the outstanding mechanical properties of wood. The experimental approach will include in-situ mechanical experiments using x-ray diffraction, microdiffraction using synchrotron radiation, environmental scanning electron microscopy, atomic force microscopy and nanoindentation.