Anionic ring-opening polymerization of ?-caprolactone in supercritical carbon dioxide: parameters influencing the reactivity

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• 作者：Bergeot ; Vincent ; Tassaing ; Thierry ; Besnard ; Marcel ; Cansell ; Franç ; ois ; Mingotaud ; Anne-Franç ; oise
• 关键词：Polymerization ; Phase diagrams ; IR spectroscopy ; Supercritical carbon dioxide
• 刊名：The Journal of Supercritical Fluids
• 出版年：2004
• 出版时间：March, 2004
• 年：2004
• 卷：28
• 期：2-3
• 页码：249-261
• 全文大小：302 K

文摘

The anionic ring-opening polymerization of ?-caprolactone in supercritical CO₂ is described using different metal alkoxides as initiators. The solubility of the monomer in supercritical CO₂ has been studied at various pressures and temperatures, leading to the determination of the corresponding phase diagrams. The study of the polymerization initiated by Y(OiPr)₃, La(OiPr)₃, and Al(OiPr)₃ has shown a difference in reactivity according to the metal and the temperature. The polymerization rate was also strongly decreased compared with that of polymerization carried out in regular solvents. In order to understand more fully this phenomenon, the interactions between initiators and CO₂ have been characterized by IR spectroscopy. This has confirmed reactions between ionic alkoxides and CO₂ to yield carbonates, whereas less ionic species have a lesser reactivity toward CO₂.