熱可塑性弾性体における新しい概念:高結晶度と大きなモジュールを持つ非伝統的な弾性体であるシンディオタキシ性ポリプロピレン (Syndiotactic polypropylene) のケース
Finizia Auriemma1, Claudio De Rosa
1Dipartimento di Chimica, Università di Napoli Federico II, Complesso Monte Sant'Angelo, via Cintia, 80126 Napoli, Italy. auriemma@chemistry.unina.it
Journal of the American Chemical Society
|October 23, 2003
まとめ
シンジオタキシカルポリプロピレン (sPP) は,可逆的な結晶-結晶相移行により,ユニークな弾性を示します. ストレッチとリラクゼーションの間に観察されるこのマルテンシット型変容は,素材の非常識な弾性行動を説明します.
科学分野:
- マテリアルサイエンス 材料科学
- ポリマー物理学 ポリマー物理学
- クリスタログラフィーです.
背景:
- シンジオタクティックポリプロピレン (sPP) は,高結晶性にもかかわらず,顕著な弾性特性を示しています.
- この異常な弾力性は,可逆的な結晶-結晶相移行に関連しています.
- この移行を理解することは,従来とは異なる弾性体としてのsPPの振る舞いを説明する鍵です.
研究 の 目的:
- サイクル変形中のsPPにおける結晶-結晶相移行のメカニズムと時間スケールを調査する.
- シンディオタクティックポリプロピレンにおける弾性性の起源を解明する.
- フェーズトランジションがsPPの弾性物質特性に起因するかどうかを判断する.
主な方法:
- 時間分解の広角X線 difraktion (WAXD) 測定.時間分解の広角X線 difraktion (WAXD) 測定.
- ヨーロッパのシンクロトロン放射線施設 (ESRF) のビームラインID11で利用された高流量シンクロトロン放射線.
- sPP繊維のサイクルストレッチとリラクゼーション実験.
主要な成果:
- 変形中の構造的変容は,in situで分析されました.
- ストレス誘発の相変遷は,マルテンシート変形として識別された.
- 移行は容易かつ直接的に起こることが観察されました.
結論:
- シンディオタキシカルポリプロピレンの弾性性は,部分的にエンタルピック由来である.
- 観測されたマルテンシート変換は,sPPの可逆弾性のためのメカニズムを提供します.
- この研究は,高度な弾性材料としてのsPPの基本的な振る舞いを明らかにします.
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