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| Untersuchte Arbeit: Seite: 50, Zeilen: 1-11 |
Quelle: Yin 2004 Seite(n): 11, Zeilen: 12-21 |
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| Bimolecular system
At the beginning of the 90 s, George and his group tried the polymerizations of styrene derivatives at 130 °C in bulk, containing a n [sic] initiating system composed of benzoyl peroxide and a stable nitroxide (TEMPO) in a molar ratio of 1.3:1 [Geo93]. At these elevated temperatures the C-O bond in the formed alkoxyamine becomes unstable, releasing the nitroxide, which now can act as a polymerization mediator, not as an inhibitor as it is at low temperatures. They obtained high molecular weight and low polydispersity materials. A linear increase of molecular weight with conversion typical for a living polymerization procedure was observed. The PD (PD = 1.2 - 1.3), which was significantly lower than the theoretical limits for a free radical process of 1.5 and the typical values of ca. 2.0 for free radical systems. [Geo93] Georges, M. K.; Veregin, R. P. N.; Kazmaier, P. M.; Hamer, G. K. Macromolecules 1993, 26, 2987. |
• Bimolecular system
In 1993, George et al10 tried the polymerizations of styrene derivatives at 130°C in bulk, containing an initiating system composed of benzoyl peroxide and a stable nitroxide (TEMPO) in a molar ratio of 1.3:1. At these elevated temperatures the C-O bond in the formed alkoxyamine becomes unstable, releasing the nitroxide, which can now act as a polymerization mediator, not as an inhibitor as it is at low temperatures. They obtained high molecular weight and low polydispersity materials. A linear increase of molecular weight with conversion typical for a living polymerization procedure was observed. The PD (PD = 1.2-1.3), which was significantly lower than the theoretical lower, limits for a free radical process of 1.5 and the typical values of ca. 2.0 for free radical systems. 10. Georges, M.K.; Veregin, R.P.N.; Kazmaier, P.M.; Hamer, G.K. Macromolecules, 1993, 26, 2987. |
No source given. Nothing has been marked as a citation. Continues from page 49 (see Bsi/Fragment_049_01). |
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