Hindered lithium dialkylamide initiators for the living anionic polymerization of methacrylic esters

Timothy Edward Long*, R. A. Guistina, B. A. Schell, J. E. Mcgrath

*この研究の対応する著者

研究成果: Article査読

21 被引用数 (Scopus)

抄録

Lithium diisopropylamide is an efficient initiator for the anionic polymerization of methyl methacrylate in polar solvents at –78°C. Predictable molecular weights based on the initiator concentration were obtained, yields were quantitative, and molecular weight distributions were relatively narrow (<1.30). The presence of an amino end group and confirmation of the initiation mechanism were confirmed by potentiometric titration using HClO4. Number‐average molecular weights determined by titration agreed well with values determined by SEC. Other lithium dialkylamides that contain larger alkyl groups such as lithium diisobutylamide were less efficient initiators. This was attributed to the more nucleophilic anion due to less steric hindrance near the nitrogen atom. Molecular weight distributions were significantly broadened (>2.0), and molecular weight control was not achieved. However, polymer yields were quantitative. In all cases, PMMA stereochemistry was indicative of a solvent‐separated lithium counterion, and triad compositions were identical to organolithium initiated homopolymers, i.e., 78% syndiotactic, 20% heterotactic, and 2% isotactic. © 1994 John Wiley & Sons, Inc.

本文言語English
ページ(範囲)2425-2430
ページ数6
ジャーナルJournal of Polymer Science Part A: Polymer Chemistry
32
13
DOI
出版ステータスPublished - 1994 1 1
外部発表はい

ASJC Scopus subject areas

  • ポリマーおよびプラスチック
  • 有機化学
  • 材料化学

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