Controlled Anionic Homo- and Copolymerization of Ethylene Oxide and Propylene Oxide by Monomer Activation

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• 作者：Virginie Rejsek ; David Sauvanier ; Cyrille Billouard ; Philippe Desbois ; Alain Deffieux ; Sté ; phane Carlotti
• 刊名：Macromolecules
• 出版年：2007
• 出版时间：September 4, 2007
• 年：2007
• 卷：40
• 期：18
• 页码：6510 - 6514
• 全文大小：96K
• 年卷期：v.40,no.18(September 4, 2007)
• ISSN：1520-5835

文摘

The anionic polymerization of ethylene oxide initiated by alkali metal-based initiators suffers fromlow polymerization rates even in polar media. We found that the addition of triisobutylaluminum to initiatorslike alkali metal alkoxides or tetraalkylammonium salts strongly enhances the ethylene oxide polymerizationrate, while keeping its living character. At ratio [i-Bu₃Al]/[initiator] = 1.5, the controlled synthesis of poly(ethylene oxide) of relatively high molar masses is achieved in short time at room temperature in dichloromethaneor toluene. Beside the formation of an aluminate 1:1 complex involving i-Bu₃Al and the initiator, a second complexbetween the trialkylaluminum and the oxirane is formed, which strongly increases the reactivity of the epoxidemonomer. Gradient di- and triblock ethylene oxide/propylene oxide copolymers of high molar mass are readilyprepared with this system.