Dresden 2009 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 14: POSTERS Nanoparticles
CPP 14.14: Poster
Dienstag, 24. März 2009, 14:00–16:30, P3
A universal relationship concerning the mechanical properties of amorphous materials: the generalized Cauchy relation — •Martine Philipp1, Ulrich Müller1, Roland Sanctuary1, Patrick Alnot2, and Jan Krüger1 — 1LPM, University of Luxembourg, Luxembourg, Luxembourg — 2LPMIA, University of Nancy, Nancy, France
Classical Cauchy relations (CR) are known for crystals from solid state physics. They reduce the number of independent elastic moduli compared to that given by point symmetry. From the theoretical viewpoint such CR are not expected for amorphous materials. However, a linear relationship between the longitudinal and shear elastic moduli c11(x) and c44(x), called generalized CR (gCR) c11(x) = 3c44(x) + A (x: driving parameter), was observed for many amorphous materials at high probe frequencies. The Cauchy parameter A is a constant for a given material. Recently it has been shown that the gCR with the same parameter A holds even true when varying consecutively different parameters x (like temperature, chemical conversion). This implies that the independency of the elastic moduli is strongly reduced for a given material.
In this presentation the combination of the two parameters chemical conversion and different amount of nanoparticles will be discussed for a reactive epoxy/silica nanocomposite. A new interpretation of the gCR and its parameter A will be given in terms of the local morphology of the considered material. All investigations were performed by Brillouin spectroscopy.