Glass transition behavior of hyper-branched polystyrenes

Kei ichi Akabori, Hironori Atarashi, Masaaki Ozawa, Tetsuo Kondo, Toshihiko Nagamura, Keiji Tanaka

研究成果: ジャーナルへの寄稿学術誌査読

18 被引用数 (Scopus)

抄録

Hyper-branched polystyrenes (HBPS) were synthesized. The bulk glass transition temperature (Tg) measured by differential scanning calorimetry (DSC) for two kinds of HBPS with an equivalent Mw, which were fractionated from different lots, were different, being respectively higher and lower than that of the corresponding linear polystyrene (PS). Infrared spectroscopy revealed that the Tg of HBPS increased with an increasing extent of intramolecular cross-linking, or cyclization, in the molecule. The segmental dynamics of HBPS was examined by dynamic mechanical analysis. The relaxation temperature for the segmental motion in HBPS was consistent with the DSC results. The fragility index was always lower for HBPS than for the linear PS, regardless of its primary structure and chain end chemistry. This would indicate that the segmental motion for HBPS is less cooperative than that of the linear PS, probably due to a lack of intermolecular chain entanglements in HBPS.

本文言語英語
ページ(範囲)4868-4875
ページ数8
ジャーナルpolymer
50
20
DOI
出版ステータス出版済み - 9月 23 2009

!!!All Science Journal Classification (ASJC) codes

  • 有機化学
  • ポリマーおよびプラスチック
  • 材料化学

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