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CPP: Chemische Physik und Polymerphysik

CPP 18: Polymer Materials II

CPP 18.4: Vortrag

Mittwoch, 29. März 2006, 16:30–16:45, ZEU 114

Thermoplastic Elastomers with Piezoelectric Properties — •Torsten Finnberg, Reza Ghahary, and Bernd-Joachim Jungnickel — Deutsches Kunststoff-Institut, Schlossgartenstrasse 6, 64289 Darmstadt, Germany

The strong piezoelectricity of some polymers results from a favorable combination of permanent polarisation and deformability. The latter may be enhanced by inserting the polarized entities in an elastomeric matrix. We have synthesized thermoplastic elastomers based on poly (ethyl acrylate), PEA, and polyamide-11, PA-11, with a PA-11 content of 30 wt-%. The PA-11 should contribute the ferroelectric polarization, and the PEA ensures the rubber-like elasticity. Due to the low dielectric strength of that material, poling was possible only up to 30 MV/m, and the resulting polarization was caused by dipole orientations in the amorphous phase and the surface of the crystalline phase of the PA-11 rather than being a real ferroelectric remanent polarization. The polarization was nevertheless stable and lead to a quasistatic piezoelectric coefficient of about 1 pC/N. That value exceeded that of about 0.4pC/N of the pure PA-11 as prepared at the same conditions. The results prove that the balance between polarization and deformability in piezoelectric polymers may be shifted to the latter with gain - or at least without loss - in performance but leading to a piezoelectric material with interesting mechanical properties.