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BP: Fachverband Biologische Physik

BP 26: Posters II

BP 26.10: Poster

Thursday, February 28, 2008, 17:00–19:30, Poster A

Mechanical properties of Wood investigated using X-Ray Scattering under defined humidity conditions — •Tomasz Pazera¹, Igor Krasnov¹, Imke Diddens¹, Florian Kunze¹, Henning Vogt¹, Richard Davies³, Manfred Burghammer³, Sergio S. Funari², and Martin Müller¹ — ¹Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel — ²HASYLAB at DESY, Hamburg — ³ESRF, Grenoble, France

Wood is a composite material that mainly consists of stiff cellulose crystals surrounded by a softer, water adsorbing matrix. The mechanical properties of pine earlywood have been studied in combined X-ray diffraction and stretching experiments at defined humidity conditions. We observed explicit variations in both the crystal strain and the stress-strain curves of wood. The most radical discrepancy in the behaviour of the whole wood-fibre was estimated to happen between 85%-100% relative humidity. In this range, the matrix shows strong macerating effects. By stretching in direction of the fibre axis we received information about changes in the correlation of crystal strain and force transfer inside the fibre at different humidities. Furthermore, an investigation of single fibres shows explicit changes in the orientation of the microfibrils in the cell wall.