Dresden 2009 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 37: Biopolymers (joint session CPP/BP)

CPP 37.6: Vortrag

Donnerstag, 26. März 2009, 15:45–16:00, ZEU 114

Anisotropic elastic properties of cellulose measured using inelastic X--ray scattering — Imke Diddens¹, Bridget Murphy¹, Michael Krisch², and •Martin Müller³ — ¹IEAP, Universität Kiel, 24098 Kiel — ²ESRF, BP 220, 38043 Grenoble, France — ³GKSS Forschungszentrum Geesthacht, Max-Planck-Str. 1, 21502 Geesthacht

Plant fibers such as linen are remarkably stiff materials in the longitudinal direction of the fiber. As plant cell walls are composites made of cellulose nanocrystals, the so-called microfibrils, embedded in a disordered matrix, those nanocrystals should exhibit an even higher elastic modulus G. We have determined the elastic properties of cellulose microfibrils via the sound velocities measured by inelastic X--ray scattering (IXS). The IXS technique is particularly sensitive to crystal properties by discriminating the contribution of disordered material. A strong anisotropy is observed [1], with a much lower elastic modulus perpendicular to the fiber direction (G1 = 15 GPa) than parallel to it (G2 = 220 GPa). The latter modulus is considerably higher than all values previously determined and will have a significant impact on models for the elastic properties of cellulose microfibrils and of composites based on them.

[1] I. Diddens, B. Murphy, M. Krisch, M. Müller, Macromolecules, ASAP online, in press.