Regensburg 2010 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 49: Elastomers and Gels
CPP 49.7: Talk
Friday, March 26, 2010, 11:45–12:00, H48
Coupling strength between optical polarizability and structural formation during the chemically induced gelation and glass transition in epoxies — •Martine Philipp1, Carsten Wehlack2, Wulff Possart2, Ulrich Müller1, Roland Sanctuary1, and Jan Krüger1 — 1Laboratory for condensed matter physics, University of Luxembourg, Luxembourg — 2Lehrstuhl für Adhesion und Interphasen in Polymeren, Universität des Saarlandes, Germany
The chemically induced gelation and glass transition are investigated during the network formation in epoxies. The refractive index turns out to be astonishingly sensitive to structural formation close to the macroscopically isostructural phase transitions. Indeed, the evolution of the refractive index is not only determined by the mass density's behaviour, in the sense of the Lorentz-Lorenz relationship, but additional relevant contributions of the electronic polarizability at optical frequencies are evidenced. The gelation and the glass transition seem to influence the optical polarizability in strongly different manners. Topological disturbances, like nanoparticles will be shown to diminish the optical polarizability during gelation close to the sol-gel transition. High performance refractometry and infrared spectroscopy are combined as experimental techniques.