【摘要】 以商用蓝光发光二极管(LED)为可见光光源,十二烷基-S’-(α,α’-二甲基-α″-乙酸)三硫代碳酸酯(DDMAT)为可逆加成-断裂链转移聚合(RAFT)试剂,不加光引发剂或光催化剂,实现了可见光诱导苯乙烯(St)的常温快速RAFT聚合.研究结果表明,该聚合具有活性聚合的特征;当光源关闭时,聚合停止,当光源开启时,聚合进行,且光的开关循环对聚合的活性没有影响.通过原位核磁的方法对DDMAT的光致断裂和光致降解行为进行了研究,该结果有助于进一步了解可见光诱导St的常温快速聚合的化学过程.更多还原

【Abstract】 The implementation of photoinitiators and photocatalysts-free visible light induced reversible addition-fragmentation chain transfer( RAFT) polymerization processes at room temperature has the potential to afford greener methodology to the preparation of polymeric materials. However,these previous works pointed out that photoinduced RAFT polymerization of styrene( St) at room temperature was very slowly even with exogenous photoinitiators or photocatalysts. In this work, we aim to overcome these drawbacks via the implementation of commercial blue light-emitting diodes( LEDs) as visible light source in the RAFT polymerization of St at room temperature with S-1-dodecyl-S’-( α,α’-dimethyl-α″-aceticacid) trithiocarbonate( DDMAT) as RAFT agent,without exogenous photoinitiators or photocatalysts. The polymerization rate was comparatively rapid and the results of polymerization kinetics of St show that the polymerization exhibits good living characteristics. Importantly,the polymerization could be instantly switch "On"or "Off "in response to visible light,and the switching cycles of light had no effect on the living character of polymerization. Finally,the photo-fragmentation and photo-degradation of DDMAT were investigated by in situ ~1 H NMR( nuclear magnetic resonance) spectroscopy. The detailed study provides a deeper understanding of the chemical processes of the polymerization method.更多还原