Experimental and numerical analyses on terahertz spectra of oxidized cross-linked polyethylene

Komatsu, Marina; Hosobuchi, Masashi; Ohki, Yoshimichi; Mizuno, Maya; Fukunaga, Kaori; Xie, Xiaojun; Cheng, Yonghong

doi:10.1109/icsd.2013.6619803

Cited by 4 publications

(2 citation statements)

References 17 publications

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“…2-4, regardless of whether the spectra were taken before or after the irradiation. We have also confirmed that cross-linking does not affect THz spectra in the wavenumber range from 20 to 100 cm ¹1 , 28) although a description of this is omitted. Furthermore, we have already reported that a very broad increase in absorption similar to that shown in Fig.…”

Section: Broad Peak In a Wide Thz Rangesupporting

confidence: 61%

Terahertz absorption spectra of oxidized polyethylene and their analysis by quantum chemical calculations

Komatsu

Hosobuchi

Xie

et al. 2014

Jpn. J. Appl. Phys.

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Low-density polyethylene, either cross-linked or not, was oxidized and its absorption spectra were measured in the terahertz (THz) range and infrared range. The absorption was increased by the oxidation in the whole THz range. In accord with this, infrared absorption due to carbonyl groups appears. Although these results indicate that the increase in absorption is induced by oxidation, its attribution to resonance or relaxation is unclear. To clarify this point, the vibrational frequencies of three-dimensional polyethylene models with and without carbonyl groups were quantum chemically calculated. As a result, it was clarified that optically inactive skeletal vibrations in polyethylene become active upon oxidation. Furthermore, several absorption peaks due to vibrational resonances are induced by oxidation at wavenumbers from 20 to 100 cm %1 . If these absorption peaks are broadened and are superimposed on each other, the absorption spectrum observed experimentally can be reproduced.Therefore, the absorption is ascribable to resonance.

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Section: Broad Peak In a Wide Thz Rangesupporting

confidence: 61%

Terahertz absorption spectra of oxidized polyethylene and their analysis by quantum chemical calculations

Komatsu

Hosobuchi

Xie

et al. 2014

Jpn. J. Appl. Phys.

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“…This result is in good accordance with the MIR spectra, which shows a decrease in the number of CH 2 groups and an increase in the number of OH groups. This oxidative degradation brought about by a cooperative reaction of heat and gamma rays seems to be responsible for the significant increase in THz absorption, as we already reported as to the degradation of XLPE and EPDM .…”

Section: Resultssupporting

confidence: 65%

Aging behavior of flame‐retardant cross‐linked polyethylene in nuclear power plant environments

Yang

Kaneko

Hirai

et al. 2019

IEEJ Transactions Elec Engng

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Sheets of flame‐retardant cross‐linked polyethylene (FR‐XLPE) were aged thermally at 80, 100, 135, and 155 °C for various periods from 100 to 800 h. They were also aged concurrently by heat and gamma rays at the same temperatures for the same periods at a dose rate of 100 Gy/h. For these sheets, we measured indenter modulus, elongation at break, complex permittivity, and absorption spectra at midinfrared and THz frequencies. As a result, it has become clear that the aging at 135 °C makes FR‐XLPE hard regardless of the presence of concurrent irradiation of gamma rays. This makes the transport of charge carriers difficult. Therefore, both the real and the imaginary parts of complex permittivity decrease, which is significant if the measurement frequency is low. However, this tendency becomes opposite as the samples were aged at 155 °C by heat or concurrently by heat and radiation. Using indenter modulus as an indicator, it has become clear that the aging progress is composed of two different stages, which could be a good clue to the explanation of these opposite changes in complex permittivity. On the other hand, the samples aged at 155 °C concurrently by heat and radiation show larger values in the indenter modulus and in two parts of complex permittivity than the samples aged at the same temperature only by heat. This is probably due to the oxidative degradation induced by the cooperative reaction of heat and radiation. © 2019 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

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Measurements of THz absorption peaks in photo-degraded polyethylene and their assignment by quantum chemical calculations

Hosobuchi

Komatsu

Xie

et al. 2013

2013 Annual Report Conference on Electrical Insulation and Dielectric Phenomena

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Experimental and numerical analyses on terahertz spectra of oxidized cross-linked polyethylene

Cited by 4 publications

References 17 publications

Terahertz absorption spectra of oxidized polyethylene and their analysis by quantum chemical calculations

Terahertz absorption spectra of oxidized polyethylene and their analysis by quantum chemical calculations

Aging behavior of flame‐retardant cross‐linked polyethylene in nuclear power plant environments

Measurements of THz absorption peaks in photo-degraded polyethylene and their assignment by quantum chemical calculations

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