Thiocarbonylthio Compounds (SC(Z)S−R) in Free Radical Polymerization with Reversible Addition-Fragmentation Chain Transfer (RAFT Polymerization). Effect of the Activating Group Z
作者:John Chiefari、Roshan T. A. Mayadunne、Catherine L. Moad、Graeme Moad、Ezio Rizzardo、Almar Postma、Melissa A. Skidmore, and、San H. Thang
DOI:10.1021/ma020883+
日期:2003.4.1
Free-radical polymerization in the presence of suitable addition−fragmentation chain transfer agents [SC(Z)S−R] (RAFT agents) possess the characteristics of a living polymerization (i.e., polymer products can be reactivated for chain extension and/or block synthesis, molecular weights are predetermined by RAFT agent concentration and conversion, narrow polydispersities are possible). Styrene polymerizations
在合适的加成-断裂链转移剂[SC (Z)S-R](RAFT剂)存在下的自由基聚合具有活性聚合的特征(即,可以将聚合物产物重新活化以进行链增长和/或嵌段合成,分子量由RAFT剂的浓度和转化率预先确定,可能会有较窄的多分散性。对两个系列的RAFT试剂[S C(Z)S-CH 2 Ph和S C(Z)S-C(Me)2 CN]进行苯乙烯聚合(110℃,热引发)。链转移系数降低在串联其中Z为Ph> SCH 2 pH约SMe的〜我〜ñ -吡咯»OC 6 ˚F 5 > Ñ-内酰胺> OC 6 H 5 > O(烷基)≫ N(烷基)2(仅该系列的前五个在间歇聚合中提供窄的多分散性聚苯乙烯(<1.2))。更一般地,在二硫代苯甲酸酯>三硫代碳酸酯-二硫代链烷酸酯>二硫代碳酸酯(黄原酸酯)>二硫代氨基甲酸酯系列中,链转移系数降低。然而,Z上的吸电子取代基可以增强RAFT剂改变上述顺序的活性。因此,使氧或氮孤对更不可用