Synthesis of Well‐Defined Figure‐of‐Eight‐Shaped Polymers by a Combination of ATRP and Click Chemistry
Synthesis of Well‐Defined Figure‐of‐Eight‐Shaped Polymers by a Combination of ATRP and Click Chemistry
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DOI：
10.1002/marc.200800337
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发表时间：
2008-10
影响因子：
4.6
通讯作者：
Gang‐Yin Shi;C. Pan
中科院分区：
文献类型：
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作者：
Gang‐Yin Shi;C. Pan
通过原子转移自由基聚合（ATRP）和点击化学的结合，制备了具有受控分子量和窄多分散性的明确的八字形（8 形）聚苯乙烯（PS）。该合成涉及两个步骤：1) 制备具有两个叠氮基的线性四官能PS，每个叠氮基位于聚合物链的两端，两个乙炔基位于链的中间。 2）通过点击反应将线性四官能PS在极低浓度下进行分子内环化，生成8形聚苯乙烯。所得中间体和目标聚合物通过 1 H NMR、FT-IR 光谱以及凝胶渗透色谱进行表征。通过差示扫描量热法测定了玻璃化转变温度 (T g s )，发现环化引起的链迁移率降低导致 8 形聚苯乙烯与其相应的前体相比具有更高的 T g s 。
Well-defined figure-of-eight-shaped (8-shaped) polystyrene (PS) with controlled molecular weight and narrow polydispersities has been prepared by the combination of atom transfer radical polymerization (ATRP) and click chemistry. The synthesis involves two steps: 1) Preparation of a linear tetrafunctional PS with two azido groups, one at each end of the polymer chain, and two acetylene groups at the middle of the chain. 2) Intramolecular cyclization of the linear tetrafunctional PS at a very low concentration by a click reaction to produce the 8-shaped polystyrenes. The resulting intermediates and the target polymers were characterized by 1 H NMR and FT-IR spectroscopy, and gel permeation chromatography. The glass transition temperatures (T g s) were determined by differential scanning calorimetry and it was found that the decrease in chain mobility by cyclization resulted in higher T g s for 8-shaped polystyrenes as compared to their corresponding precursors.