EPR Study of Backbiting in the Aqueous-Solution Polymerization of Acrylamide.
EPR Study of Backbiting in the Aqueous-Solution Polymerization of Acrylamide.
复制标题
丙烯酰胺水溶液聚合中反向反应的 EPR 研究。
DOI：
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发表时间：
2015
影响因子：
4.6
通讯作者：
M. Buback
中科院分区：
文献类型：
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作者：
H. Kattner;M. Buback
通过电子顺磁共振(EPR)光谱，研究了丙烯酰胺(AAM)在水溶液中均聚合过程中产生的自由基类型，这些自由基是在固定条件下以光化学方式产生的。中链AAM自由基(MCRs)被EPR清晰地识别出来，说明二次传播的AAM自由基(SPR)发生了背靠背反应。在50℃以上，MCR的比例甚至超过SPR的比例。然而，在相同温度下，背后攻击的程度远远低于丙烯酸丁酯聚合的程度。
Via electron paramagnetic resonance (EPR) spectroscopy, the type of radicals occurring during acrylamide (AAm) homopolymerization in aqueous solution is investigated between -5 and +100 °C. The radicals are produced photochemically under stationary conditions. Midchain AAm radicals (MCRs) are clearly identified by EPR which demonstrates that secondary propagating AAm radicals (SPRs) undergo backbiting reactions. Above 50 °C, the fraction of MCRs even exceeds the one of SPRs. The extent of backbiting is however well below the one in butyl acrylate polymerization at identical temperature.