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Polymer Classification: Stereospecificity01:26

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Polymerization generates chiral centers along the entire backbone of a polymer chain. Accordingly, the stereochemistry of the substituent group has a significant effect on polymer properties. Polymers formed from monosubstituted alkene monomers feature chiral carbons at every alternate position in the polymer backbone. Relative to the predominant orientation of substituents at the adjacent chiral carbons, the polymer can exist in three different configurations: isotactic, syndiotactic, and...
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Step-growth or condensation polymerization is a stepwise reaction of bi or multifunctional monomers to form long-chain polymers. As all the monomers are reactive, most of the monomers are consumed at the early stages of the reaction to form small chains of reactive oligomers, which then combine to form long polymer chains in the late stages. Hence, the reaction has to proceed for a long time to achieve high molecular weight polymers.
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The introduction of polyesters has brought major development to the textile industry. The wrinkle-free behavior of polyester blends has eliminated the need for starching and ironing clothes.
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Ziegler–Natta polymerization is another form of addition or chain‐growth polymerization used for synthesizing linear polymers over branched polymers. The catalyst used for polymerization is the Ziegler–Natta catalyst, named after Karl Ziegler and Giulio Natta, who developed it in 1953. This catalyst is an organometallic complex of titanium tetrachloride and triethyl aluminum, with the active form of the catalyst being an alkyl titanium compound. Using the Ziegler–Natta...
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Polymers are classified as linear or branched on the basis of their chain architecture. The polymer chains in linear polymers have a long chain-like structure with minimal to no branching at all. Even if a polymer features large substituent groups on the monomer, which appear as branches to the skeleton, it is not considered a branched polymer. A branched polymer contains secondary polymer chains that arise from the main polymer chain. The branching occurs when the polymer growth shifts from...
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Step growth polymerization involves bi or multifunctional monomers. Bifunctional monomers react to form linear step growth polymers, whereas multifunctional monomers react to form non-linear or branched polymers.
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高同位性聚合物的特异分离聚合物

Xuanhua Guo1,2,3,4, Guangqiang Xu1,2,3,4, Rulin Yang1,2,3

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概括
此摘要是机器生成的。

研究人员开发了一种新的双联体策略,用于奇拉催化剂,首次实现了赛米乙醇 (Pegl) 的完美非对称动态分辨率聚合 (AKRP). 这一突破增强了聚合物的特性, 并提供了通用的催化剂设计策略.

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科学领域:

  • 聚合物化学
  • 材料科学
  • 催化剂

背景情况:

  • 隔离性聚合物具有独特的材料特性,但它们通过特定的分离聚合物从血单体合成仍然具有挑战性.
  • 非对称动态分辨率聚合 (AKRP) 为高同位性聚合物提供了一条途径,但一般催化剂设计策略很少.

研究的目的:

  • 为AKRP设计高度反选择性催化剂制定一个总体和明确的策略.
  • 通过使用新型催化剂系统,首次实现了完美的赛血甲基化物 (Pegl) AKRP.

主要方法:

  • 用一种新的双联体策略来设计合物 (BisSalen) 和 (Al) 复合物.
  • 研究了催化剂的反抗选择性,以测量Pegl的AKRP.
  • 一系列具有不同双联体的 (BisSalen) Al 复合物被合成并测试.

主要成果:

  • 一种新的奇拉 (BisSalen) Al复合体表现出高的反选择性,使赛米Pegl的完美AKRP成为可能.
  • 增强的酶选择性归因于由双联体产生的更狭窄的不对称微环境.
  • 开发的双联体策略被证明是一般性的,各种 (BisSalen) Al复合物显示出有效性.

结论:

  • 新的双联体策略为AKRP设计反选择性催化剂提供了通用和有效的方法.
  • 这项工作代表了第一次成功地展示了完美的AKRP,为高级聚合物合成铺平了道路.
  • 这些发现对具有量身定制性质的明确异质聚合物的合成具有重要意义.