Dresden 2006 – wissenschaftliches Programm
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CPP: Chemische Physik und Polymerphysik
CPP 11: POSTER Disperse Polymer Systems
CPP 11.22: Poster
Dienstag, 28. März 2006, 17:00–19:00, P3
Influence of pre-history and shear flow on the frequency dependent conductivity of carbon nanotube-filled polymers — •Ingo Alig1, Sergej M. Dudkin1, Dirk Lellinger1, Sven Pegel2, and Petra Pötschke2 — 1Deutsches Kunststoff-Institut, Schlossgartenstr. 6, D-64289 Darmstadt — 2Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Str. 6, D-01069 Dresden
The influence of pre-history and shear response on AC conductivity of polymer-dispersed multi-walled carbon nanotubes (MWNT) are presented. Different composites of amorphous and crystalline polymers filled with different amounts of MWNT are investigated. The measurements are performed in a plate-plate geometry which allows simultaneous measurements of electrical and rheological properties. The conductivity spectra are recorded under non-isothermal conditions (melting, annealing, crystallization) and during isothermal relaxation after application of a steady state shear field. The measurements exhibit extraordinary changes in dielectric properties depending on mixing conditions, thermal history and/or external flow. Particularly, the changes in conductivity after transient shear indicate long-term relaxations in the conductive network formed by the nanotubes. The changes in AC conductivity are related to changes in (i) tube-polymer-tube interaction and (ii) tube orientation. The conductivity/permittivity spectra are discussed in the frame of percolation theory. In addition to the laboratory experiments, we will present results from in-line conductivity measurements during extrusion.
/1/ P.Pötschke, S.M. Dudkin, I. Alig, Polymer 44 (2003) 5023-5030