Relationship between global and segmental dynamics of poly(butylene oxide) studied by broadband dielectric spectroscopy

Relationship between segmental relaxation and normal-mode relaxation has been studied for molten poly(butylene oxide)s having various molecular weights by broadband dielectric spectroscopy over a wide temperature (T) range. We found that T dependence of the segmental relaxation time, τs, was weaker...

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Veröffentlicht in:The Journal of chemical physics 2018-01, Vol.148 (3), p.034904-034904
Hauptverfasser: Urakawa, Osamu, Yamane, Minoru, Tomie, Shota, Inoue, Tadashi, Shikata, Toshiyuki, Adachi, Keiichiro
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Sprache:eng
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Zusammenfassung:Relationship between segmental relaxation and normal-mode relaxation has been studied for molten poly(butylene oxide)s having various molecular weights by broadband dielectric spectroscopy over a wide temperature (T) range. We found that T dependence of the segmental relaxation time, τs, was weaker than the normal mode time, τn, at high T(>250 K ∼ Tg + 50 K), and the τn/τs ratio systematically decreased with increasing temperature. This high temperature complexity, whose mechanism has not been discussed in detail so far, was quantitatively explained by assuming the two step processes: local conformation change of polymers (elementary process) occurs first, and then the motion of a segment unit (second process) occurs. It was also found that the elementary process was strongly correlated with the experimentally observed β-relaxation.
ISSN:0021-9606
1089-7690
DOI:10.1063/1.5006364