Berlin 2005 – wissenschaftliches Programm
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CPP: Chemische Physik und Polymerphysik
CPP 29: POSTER: Polymer physics
CPP 29.49: Poster
Dienstag, 8. März 2005, 16:30–18:30, Poster TU D
Determination of Pyroelectric Coefficient in Polyethylene Terephthalate — •Francisco Camacho González, Axel Mellinger, and Reimund Gerhard-Multhaupt — Department of Physics, University of Potsdam, Am Neuen Palais 10, 14469 Potsdam, Germany
The current measured in a thermally stimulated discharge (TSD) experiment shows the contribution of dipoles and free carriers. To discern between dipoles and free carriers in Polyethylene Terephthalate (PETP), cycles of thermally stimulated polarization current (TSPC) and thermally stimulated current (TSC) were performed. Experimental results show the presence of a bimodal peak with two maxima around 202 and 212 K, which are related to the dipoles. Charge contribution shows also a bimodal peak with maxima at 202 and 218 K. In order to learn more about the dipole contribution, the pyroelectric coefficient was determined. To measure small pyroelectric coefficients, experimental results from PETP samples under two different conditions were analyzed using the fast fourier transform (FFT). In the first case, where the sample was charged at 383 K under 26 V/µm and a partial TSD was performed, a pyroelectric coefficient of around 60 nC/m2K was determined. In the second case, coefficients of about 6 nC/m2K were obtained exposing a sample to a low electric field (1 V/µm).