Synthesis of star-branched polymers by means of anionic living polymerization coupled with functional group transformation
Synthesis of star-branched polymers by means of anionic living polymerization coupled with functional group transformation
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DOI：
10.1021/ma981673t
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发表时间：
1999-04-20
期刊：
影响因子：
5.5
通讯作者：
Hirao, A
中科院分区：
文献类型：
--
作者：
Hayashi, M;Kojima, K;Hirao, A
为了合成定义明确的规则和异臂星形支化聚合物，我们开发了一种基于阴离子活性聚合和官能团转化的新方法。在我们的方法中采用的合成过程包括以下三个反应阶段：第一阶段是通过聚苯乙烯锂与特殊设计的试剂反应，制备具有一定数量的甲氧基甲基苯基的前体聚合物。由此引入的甲氧基甲基苯基在第二阶段反应中被定量地转化为氯甲基苯基。在第三阶段，阴离子活性聚合物与氯化前体聚合物偶联反应，得到所需的星形支化聚合物。事实上，利用上述方法已成功合成了控制良好的三臂、四臂和六臂星形聚苯乙烯。更有趣的是，定义明确的杂化四臂ABC(2)和五臂AB(4)星形聚合物可以很容易地通过改变活性聚合物进行反应而获得。用SEC分馏分离得到星形支化聚合物。通过SEC， H-1核磁共振，光散射和粘度测量证明了它们明确的和可控的结构。
To synthesize well-defined regular and heteroarmed star-branched polymers, we have developed a new and versatile methodology based on anionic living polymerization coupled with functional group transformation. The synthetic procedure employed in our methodology involves the following three reaction stages: The first stage is to prepare the precursory polymers with a defined number of methoxymethylphenyl groups by reacting polystyryllithium with specially designed reagents. The methoxymethylphenyl groups thus introduced are quantitatively transformed into chloromethylphenyl groups in the second stage reaction. At the third stage, anionic living polymers are reacted to couple with the chlorinated precursory polymers to afford the desired star-branched polymers. in fact, well-controlled three-, four-, and six- armed star polystyrenes were successfully synthesized by using the above-mentioned procedure. More interestingly, well-defined hetero four-armed ABC(2) and five-armed AB(4) star polymers have been readily obtained simply by changing living polymers to be reacted. The resulting star-branched polymers were isolated by SEC fractionation. Their well-defined and controlled structures were demonstrated by SEC, H-1 NMR, light scattering, and viscosity measurements.