メタテシス化学を用いたエチレン/プロピレンコポリマーにおけるランダムメチル分岐のモデリング:合成と熱的行動
John C Sworen1, Jason A Smith, Kenneth B Wagener
1The George and Josephine Butler Polymer Research Laboratory, Department of Chemistry, University of Florida, Gainesville, Florida 32611-7200, USA.
Journal of the American Chemical Society
|February 20, 2003
まとめ
研究者らは,エチレン/プロピレン (EP) コポリマーをランダムにモデル化し,アサイクリックディエネメタテシス (ADMET) ポリメリゼーションを用いた. 彼らは,高エチレンEPコポリマーの六角形相を観察し,枝分かれが増加すると融点が低下することを発見しました.
科学分野:
- ポリマー化学のポリマー化学について
- マテリアルサイエンス 材料科学
背景:
- エチレン/プロピレン (EP) コポリマーは広く使用されていますが,その正確な構造-特性関係は複雑です.
- コポリマー構造と熱特性に対する分岐の影響を理解することは,材料設計において極めて重要です.
研究 の 目的:
- エチレン/プロピレン (EP) コポリマーをランダムにモデル化・合成し,アサイクリックディエネメタテシス (ADMET) ポリメリゼーションを用いて制御された分岐を図る.
- これらの共ポリマーの主要な構造とより高いレベルの構造を特徴付ける.
- 枝の内容と関連して,熱的行動と相変化を調査する.
主な方法:
- ADMETポリメリゼーションによる6つのモデルEPコポリマーの合成.
- 核磁共振 (NMR),赤外線 (IR) スペクトロスコピー,差分スキャニングカロメトリー (DSC),広角X線 difrraction (WAXD),およびゲル浸透染色体 (GPC) を使用して特徴づけました.
- 構造的特徴,相行動,および熱的性質の分析.
主要な成果:
- 異なるメチル分岐含有量 (1.5〜55.6/1000炭素分) のEP共ポリマーが成功して合成されました.
- 外部操作なしに,高エチレン含有量 (90%) のEPコポリマーにおける六角形相の最初の観測.
- 溶解点と融合熱の減少は,枝分子の含有量の増加とともに観察されました.
結論:
- ADMETポリメリゼーションは,制御された分岐を持つランダムなEP共ポリマーをモデル化するための経路を提供します.
- 高いエチレン含有量のEP共ポリマーは,固有の六角形相形成を示すことができます.
- 枝分かれは,EP共ポリマーの熱特性と結晶性に影響を及ぼします.
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