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Self-accelerating click reaction for preparing cyclic polymers from unconjugated vinyl monomers
Polymer ( IF 4.6 ) Pub Date : 2018-01-04 , DOI: 10.1016/j.polymer.2017.12.071
Zi Li , Lin Qu , Wen Zhu , Jian'an Liu , Ji-Qiang Chen , Peng Sun , Ying Wu , Zhengping Liu , Ke Zhang

An efficient metal-free bimolecular homodifunctional ring-closure method was developed specifically for preparing well-defined cyclic polymers from unconjugated vinyl monomers. In this approach, well-defined homodifunctional linear polymers with azide terminals were prepared by using the reversible addition chain transfer polymerization/macromolecular design by interchange of xanthates (RAFT/MADIX) to polymerize unconjugated vinyl monomers in the presence of a diazide xanthate chain transfer agent. The self-accelerating double strain-promoted azide-alkyne cycloaddition (DSPAAC) reaction was then applied to ring-close the linear polymer precursors with sym-dibenzo-1,5-cyclooctadiene-3,7-diyne (DBA) as small linkers, leading to the formation of corresponding cyclic polymers. By virtue of the self-accelerating property of DSPAAC ring-closing reaction, this novel method smartly eliminated the requirement of equimolar amounts of the telechelic polymers and small linkers in the traditional bimolecular ring-closure methods for pure cyclic polymers. More importantly, the usage of excess DBA small linkers could significantly enhance the preparation efficiency of cyclic polymers. Moreover, the cyclic polymers resulted from this novel method could be conveniently cleaved back to linear polymers by a mild aminolysis of the S-C(S) bond within the cyclic polymer backbone.



中文翻译:

自加速点击反应由非共轭乙烯基单体制备环状聚合物

专门开发了一种有效的无金属双分子同双官能团闭环方法,该方法用于从未结合的乙烯基单体制备定义明确的环状聚合物。在这种方法中,通过使用可逆加成链转移聚合/大分子设计,通过交换黄原酸酯(RAFT / MADIX)以在重氮叠氮黄原酸酯链转移剂的存在下聚合未共轭的乙烯基单体,来制备具有叠氮化物末端的定义明确的均二官能线性聚合物。 。然后自加速双张力促进叠氮化物-炔环加成(DSPAAC)反应物施加到环闭所述线型聚合物前体与符号-二苯并-1,5-环辛二烯-3,7-二炔(DBA)作为小接头,导致形成相应的环状聚合物。凭借DSPAAC闭环反应的自加速特性,该新方法巧妙地消除了传统纯双环聚合物双分子闭环方法中等摩尔量的远螯聚合物和小接头的需求。更重要的是,使用过量的DBA小连接子可以显着提高环状聚合物的制备效率。而且,由该新方法得到的环状聚合物可以通过在环状聚合物主链内对SC(S)键进行温和的氨解而方便地裂解成线性聚合物。

更新日期:2018-01-04
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