کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5186288 | 1381100 | 2007 | 7 صفحه PDF | دانلود رایگان |
A new cyclic nitroxide 1 and the corresponding alkoxyamines 9 and 10 were synthesized and the polymerization of styrene (St) initiated with 10 was investigated. The NO-C bond of 9 is very weak, cleaving at room temperature. On the other hand, alkoxyamine 10 is stable at room temperature and the Aact and Eact for the NO-C bond homolysis were determined to be 1.4 Ã 1015 sâ1 and 124.5 kJ molâ1, respectively. When the polymerization of St was carried out at 70 °C, the resultant poly(St) showed narrow polydispersities below 1.25. In the polymerization at 90 °C, the resulting poly(St) showed narrow polydispersity until 60% conversion, but Mw/Mn was rapidly increased above 60% conversion. On the other hand, the polymerization at 120 °C gave poly(St) with broad polydispersities. The unusual polymerization behavior was discussed on the basis of the SEC and ESR results.
Journal: Polymer - Volume 48, Issue 3, 26 January 2007, Pages 743-749