Chain‐growth polycondensation of monomer consisting of two aromatic rings: Synthesis of well‐defined poly(ether sulfone) from 4‐fluoro‐4′‐hydroxydiphenyl sulfone
Chain‐growth polycondensation of monomer consisting of two aromatic rings: Synthesis of well‐defined poly(ether sulfone) from 4‐fluoro‐4′‐hydroxydiphenyl sulfone
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由两个芳环组成的单体的链增长缩聚：从4-氟-4-羟基二苯砜合成结构明确的聚醚砜
DOI：
10.1002/pola.10429
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
A. Yokoyama
中科院分区：
文献类型：
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作者：
T. Yokozawa;Takahisa Taniguchi;Yukimitsu Suzuki;A. Yokoyama
含有缩合聚合物或低聚物的明确定义的聚合物的自组装由于其令人惊讶的性质或功能性而最近受到广泛关注。1这些聚合物中的缩合聚合物单元通过常规缩聚制备，并且具有宽的分子量分布2 -10，除了几个实施例11-17之外，而具有单一分子量的缩合低聚物单元通过逐步合成制备。18-34具有低多分散性的缩聚物的一般合成方法将促进基于自组织的新材料的开发。我们已经成功地通过链增长缩聚反应合成了具有限定分子量和低多分散性的缩聚物，其中单体选择性地与聚合物端基反应，而不与其它单体反应。35-38在3-氰基-4-氟苯酚钾通过芳族亲核取代产生芳族聚醚的链增长缩聚中，37我们利用了单体和聚合物之间不同的取代基效应;单体中酚盐的供电子性质强烈地降低了与氟键合的碳原子的亲电性，而聚合物中的醚键不会使聚合物末端的芳族氟化物强烈失活。因此，单体仅与聚合物端基选择性地反应，如活性聚合，以得到明确定义的芳族聚醚。氟的芳族亲核取代需要单体氟邻位的吸电子氰基，考虑到单体和聚合物之间的取代基效应相同，以及氟帕拉的吸电子基团对芳族取代的有效性，我们预期由两个芳环在帕拉连接到吸电子键的单体1也将经历链增长缩聚（方案1）。1的这种缩聚在以下两个方面是令人感兴趣的。第一，单体中的酚盐和聚合物中的醚键之间的不同取代基效应是否通过与吸电子键连接的两个芳环有效地改变了氟的反应性？据报道，苯环上的取代基影响化合物如1，39-42中另一个苯环上的氟，但链增长缩聚尚未被研究。第二，1的一些单体已经用于生产工程塑料。这意味着这些聚合物本身不仅具有良好的机械性能，
The self-assembly of well-defined polymers containing condensation polymers or oligomers has recently received much attention because of their surprising properties or functionality. 1 The condensation polymer units in these polymers are prepared by conventional polycondensation and possess a broad molecular weight distribution2–10 except for several examples, 11–17 whereas the condensation oligomer units with a single molecular weight are prepared by stepwise synthesis. 18–34 A general synthetic method for condensation polymers with low polydispersites would promote the development of new materials on the basis of self-organization. We have succeeded in synthesizing condensation polymers having defined molecular weights and low polydispersities by chain-growth polycondensation where monomers react with the polymer end group selectively, not with other monomers. 35–38 In the chain-growth polycondensation of potassium 3-cyano-4-fluorophenolate yielding aromatic polyethers via aromatic nucleophilic substitution, 37 we took advantage of different substituent effects between monomer and polymer; the electron-donating nature of the phenoxide in the monomer strongly reduces the electrophilicity of the carbon atom bonding to fluorine, whereas the ether linkage in the polymer does not strongly deactivate the polymer end aromatic fluoride. The monomers therefore react with only the polymer end group selectively like living polymerization to give well-defined aromatic polyethers. The electron-withdrawing cyano group at the ortho position of fluorine of the monomer is required for aromatic nucleophilic substitution of fluorine.Considering the same substituent effects between monomer and polymer and the effectiveness of the electron-withdrawing group at the para position of fluorine for aromatic substitution, we expected that monomers 1 consisting of two aromatic rings connecting to an electron-withdrawing linkage at the para position would also undergo chain-growth polycondensation (Scheme 1). This polycondensation of 1 is of interest in the following two aspects. First, does the different substituent effects between the phenoxide in monomer and the ether linkage in polymer effectively change the reactivity of fluorine through the two aromatic rings connected with the electron-withdrawing linkage? It has been reported that the substituent on the benzene ring affects fluorine on the other benzene ring in compounds like 1, 39–42 but chain-growth polycondensation has not been examined. Second, some monomers of 1 have already been used for the production of engineering plastics. This means that those polymers themselves not only have good mechanical properties but