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Thermal ageing of PTFE in the melted state: Influence of interdiffusion on the physicochemical structure

Henri, Victor and Dantras, Eric and Lacabanne, Colette and Dieudonne, Anca Goleanu and Koliatene, Flavien Thermal ageing of PTFE in the melted state: Influence of interdiffusion on the physicochemical structure. (2020) Polymer Degradation and Stability, 171. 1-8. ISSN 0141-3910

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Official URL: https://doi.org/10.1016/j.polymdegradstab.2019.109053

Abstract

PTFE is one of the most used polymer for electrical insulation. For future aircraft, PTFE will be exposed to thermal constraints above its melting temperature. Its high melt viscosity allows PTFE to be operable but it will be subjected to thermal-oxidative ageing. PTFE presents two initial states, associated with its thermal history corresponding to the interdiffusion phenomenon. In the case of thermo-oxidative ageing in the melt, interdiffusion impairs the thermal stability by shifting the thermal degradation towards lower temperature. While interdiffusion reduces the thermal stability for long time ageing, strong physical interactions reduce the impact of degradation on the mechanical behaviour for short time ageing. Chemical ageing induced by degradation promotes recrystallisation of PTFE shorter chains; this crystalline phase modifies the β anelastic relaxation mode. The tan δ thermograms allows us to identify the β1 and β2 components of the anelastic effects of respectively the triclinic/hexagonal and hexagonal/pseudo hexagonal transitions observed by X-Rays Diffraction. Upon chemical ageing, the evolution of the β mode is mainly governed by the decrease in the β2 component corresponding to the pseudo-hexagonal phase.

Item Type:Article
HAL Id:hal-02436683
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UT3 (FRANCE)
Other partners > SAFRAN (FRANCE)
Laboratory name:
Funders:
National Agency for Research and Technology - ANRT
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Deposited By: cirimat webmestre
Deposited On:13 Jan 2020 11:00

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