論文

査読有り
2017年6月

Re-examination of terminal relaxation behavior of high-molecular-weight ring polystyrene melts

RHEOLOGICA ACTA
  • Yuya Doi
  • ,
  • Atsushi Matsumoto
  • ,
  • Tadashi Inoue
  • ,
  • Takuro Iwamoto
  • ,
  • Atsushi Takano
  • ,
  • Yushu Matsushita
  • ,
  • Yoshiaki Takahashi
  • ,
  • Hiroshi Watanabe

56
6
開始ページ
567
終了ページ
581
記述言語
英語
掲載種別
研究論文(学術雑誌)
DOI
10.1007/s00397-017-1014-3
出版者・発行元
SPRINGER

For high-molecular-weight (M) ring polymers with low contamination of linear chains, recent viscoelastic tests revealed broad terminal relaxation associated with no clear entanglement plateau. This relaxation behavior is qualitatively similar to that deduced from molecular models (double-folded lattice-animal model and the fractal loopy globule model) for entangled ring polymers, but quantitatively important differences are also noted: For example, the full terminal relaxation of those polymers is slower than the model prediction. This study re-examined the viscoelastic data of entangled high-M ring polystyrene (PS) samples (coded as R-240; M = 244x10(3)) specifically for two points: the purity of the ring samples after the viscoelastic tests and the molecular origin of the stress. For the first point, the R-240 samples contaminated with linear chains at low but different levels were prepared by tuning either the purification efficiency or the retention time of the sample at high temperature (T) before/during the viscoelastic test. The fraction w (L) of the linear contaminant, determined after the viscoelastic measurement, was ranging from 0.7 to 4.9%, and the extrapolation of the modulus data to w (L) = 0 gave the data for the ideally pure ring melt. This pure ring melt exhibited broad terminal relaxation that started faster but completed slower compared to the model prediction, indicating that the ring relaxation is not well described by the current model(s) even in the absence of linear contaminant. For the second point, dynamic birefringence measurements were conducted for the R-240 samples with w (L) = 4.6 and 1.0%. These samples obeyed the stress-optical rule, and their stress-optical coefficient was indistinguishable from that for linear PS samples, revealing that the stress of the ring PS chains reflects the orientational anisotropy of the chains (as is the case also for linear chains). The relaxation behavior of pure ring PS melt is discussed on the basis of these findings, with the focus being placed on the ring-ring threading not considered in the models.

Web of Science ® 被引用回数 : 10

リンク情報
DOI
https://doi.org/10.1007/s00397-017-1014-3
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000402045100004&DestApp=WOS_CPL

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