Development of branching in living radical copolymerization of vinyl and divinyl monomers
Development of branching in living radical copolymerization of vinyl and divinyl monomers
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DOI：
10.1021/ma061811b
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发表时间：
2006-10-31
期刊：
影响因子：
5.5
通讯作者：
Findlay, Paul
中科院分区：
文献类型：
--
作者：
Bannister, Iveta;Billingham, Norman C.;Findlay, Paul
以甲基丙烯酸2-羟丙酯（HPMA）为支化剂，乙二醇二甲基丙烯酸酯（EGDMA）或双酚A二甲基丙烯酸酯（BPDMA）为支化剂，在甲醇中于20 ℃进行了原子转移自由基聚合（ATRP）。使用EGDMA，获得可溶性支化共聚物，条件是每个主链引入少于一种支化剂：如预期的，更高水平的EGDMA导致凝胶化。对聚合物的分子量和多分散性变化的分析表明，高度支化链的形成仅在高转化率（> 90%）下发生。链偶联接近Flory-Stockmayer理论预测的理想行为，表明所有双键都具有相同的反应性，并且与常规自由基聚合相比，没有显著的环化。通过比较EGDMA支化剂的消耗与来自理论和模拟的预测，证实了这种分析。用BPDMA作为支化剂，获得了类似的结果，尽管支化的效率略低。
The branching copolymerization of 2-hydroxypropyl methacrylate ( HPMA) with either ethylene glycol dimethacrylate (EGDMA) or bisphenol A dimethacrylate (BPDMA) as the branching agent has been carried out using atom transfer radical polymerization (ATRP) in methanol at 20 C. With EGDMA, soluble branched copolymers were obtained provided that less than one branching agent was incorporated per primary chain: higher levels of EGDMA led to gelation, as expected. Analysis of the changes in the molecular weight and polydispersity of the polymers shows that the formation of highly branched chains occurs only at high (> 90%) conversions. Chain coupling is close to the ideal behavior predicted by the Flory-Stockmayer theory, suggesting that all double bonds are equally reactive and that there is no significant cyclization, in contrast to conventional free radical polymerization. This analysis is confirmed by comparison of the consumption of the EGDMA branching agent with predictions from both theory and simulation. With BPDMA as the branching agent, similar results are obtained although branching is slightly less efficient.