Dielectric investigation of polytetrafluoroethylene manufactured by a newly spark plasma sintering (SPS) technique

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H. LAHLALI, A. MDARHRI, I. EL ABOUDI, M. EL AZHARI, M. ZAGHRIOUI, C. HONSTETTRE

Abstract. A new processing method named Spark Plasma Sintering (SPS) is particularly adapted to process a dense polymer polytetrafluoroethylene (PTFE) which is difficult to sinter by conventional techniques. It consists in applying simultaneous electric current and pressure directly on the micrometric particles powder. The aim of the present work is to highlight the dielectric properties response of PTFE synthesized by the SPS technique in a low frequency domain typically between 100Hz and 10 MHz and over a temperature range from 313 to 553 K. In a first step, the dielectric constant measured at room temperature indicates a slight decrease when the frequency increases reflecting the general trend for this kind of materials. By growing the temperature up to 553 K, the dielectric constant spectra show a notable increase and the obtained values can reach four times more than of those measured at room temperature. This unexpected behavior is then compared to the dielectric spectra response highlighted by commercially PTFE samples manufactured by using two conventional methods i.e. extrusion and molding. It is found that the processing parameters affect greatly the dielectric properties measured either at room temperature or in 313-553 Ktemperature range. Thermogravimetry Analysis (TGA) is used to probe the thermal stability of different PTFE samples used in this study. From this experimental investigation, it is concluded that the SPS technique can be seen as an efficient and rapid route to manufacturing polymer materials with tailored dielectric properties for many useful applications.

Keywords
PTFE, SPS Process, Dielectric Properties, Extrusion, Molding, Temperature Effect, Microstructure

Published online 12/10/2016, 4 pages
Copyright © 2016 by the author(s)
Published under license by Materials Research Forum LLC., Millersville PA, USA
Citation: H. LAHLALI, A. MDARHRI, I. EL ABOUDI, M. EL AZHARI, M. ZAGHRIOUI, C. HONSTETTRE, ‘Dielectric investigation of polytetrafluoroethylene manufactured by a newly spark plasma sintering (SPS) technique’, Materials Research Proceedings, Vol. 1, pp 38-41, 2016
DOI: http://dx.doi.org/10.21741/9781945291197-10

The article was published as article 10 of the book Dielectric Materials and Applications

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