Title:	Dielectric, structural and mechanical properties of thermally aged biaxially oriented polymeric substrates for flexible electronics
Authors:	Hornak, Jaroslav Kadlec, Petr Kopřiva, Jiří Polanský, Radek
Citation:	HORNAK, J. KADLEC, P. KOPŘIVA, J. POLANSKÝ, R. Dielectric, structural and mechanical properties of thermally aged biaxially oriented polymeric substrates for flexible electronics. POLYMER DEGRADATION AND STABILITY, 2022, roč. 199, č. May 2022, s. 1-10. ISSN: 0141-3910
Issue Date:	2022
Publisher:	Elsevier
Document type:	článek article
URI:	2-s2.0-85127113721 http://hdl.handle.net/11025/47717
ISSN:	0141-3910
Keywords in different language:	dielectric properties;flexible substrates;polyethylene naphthalate;polyethylene terephthalate;structural properties;thermal aging
Abstract in different language:	Two materials, polyethylene naphthalate (PEN) and polyethylene terephthalate (PET), which are often used as flexible substrates for electronics, were exposed to accelerated thermal aging at temperatures of 190 °C and 210 °C for 50 0 0 and 20 0 0 h, respectively. Changes in their thermal, dielectric, and me- chanical properties were investigated. The results revealed that dielectric losses increase slower for PET than for PEN at lower aging temperatures. In contrast, at higher aging temperatures, similar behavior was observed for both materials. During aging, the dissipation factors of PET and PEN increased by one order of magnitude over those of the original states. The dielectric frequency-temperature characteristics obtained by broadband dielectric spectroscopy (BDS) shifted and indicated changes in the individual di- electric relaxation mechanisms (i.e., α, β, β∗). Discoloration induced by thermal aging and quantified by ultraviolet–visible spectroscopy by the peak at 453 nm was detected primarily in the spectrum of PEN. The mechanical tensile strength of PET deteriorated considerably (10 times) after only a few hundred hours, whereas PEN was stable after even longer exposure times. It was found that all of the changes mentioned above are primarily related to the change in the crystalline-to-amorphous phase ratio, as demonstrated by differential scanning calorimetry (DSC) and supported by density measurements.
Rights:	Plný text je přístupný v rámci univerzity přihlášeným uživatelům. © Elsevier
Appears in Collections:	Články / Articles (RICE) Články / Articles (KET) OBD

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