Dresden 2006 – wissenschaftliches Programm
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CPP: Chemische Physik und Polymerphysik
CPP 7: SYMPOSIUM Disperse Polymer Systems I
CPP 7.8: Vortrag
Dienstag, 28. März 2006, 12:00–12:15, ZEU 160
Shear and melt elongation of polycarbonate/multiwalled carbon nanotubes composites — •U.A. Handge1 and P. Pötschke2 — 1Institute of Polymers, Dept. of Materials, ETH Zürich, 8093 Zürich, Switzerland — 2Leibniz Institute of Polymer Research Dresden, Dept. of Polymer Reactions and Blends, Hohe Strasse 6, 01069 Dresden, Germany
The discovery of carbon nanotubes initiated intensive research activities which also led to applications of these remarkable molecules. For example, composites that consist of commercial polymers and carbon nanotubes can serve as possible antistatic or conductive materials. Processing of polymers is intimately associated with their rheological properties. In this work, we studied the rheological properties of pure polycarbonate and a polycarbonate/multiwalled carbon nanotubes (PC/MWCNT) composite in the melt. The weight fraction of the multiwalled carbon nanotubes for the composite was 2 wt.% and the test temperature was T = 190 oC. We performed linear viscoelastic shear oscillations and elongational tests that were followed by recovery experiments using the uniaxial elongational rheometer RME. The analysis of the linear viscoelastic shear oscillations of the composite revealed that at low and large frequencies elastic forces dominated. In melt elongation, the transient viscosity of the PC/MWCNT composite did not differ much from the elongational viscosity of pure polycarbonate. However, the recovered stretch of the composite was significantly smaller than the corresponding values for pure polycarbonate. We discuss these results by taking into account the extension of the macromolecules in elongational flows and the yield stress of the composite.