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相关概念视频

Olefin Metathesis Polymerization: Ring-Opening Metathesis Polymerization (ROMP)01:16

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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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Recently, the development of olefin metathesis polymerization advanced the field of polymer synthesis. Simply put, the reorganization of substituents on their double bonds between two olefins in the presence of a catalyst is known as the olefin metathesis reaction. The use of metathesis reaction for polymer synthesis is called olefin metathesis polymerization.
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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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精确的非平衡性聚烯糖醇聚素

James S W Seale1, Bo Song1, Yunyan Qiu1

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概括

分子可以通过在不具有内在亲和力的聚合物链上捕获环来产生不平衡的聚. 这一突破使得新材料的特性和应用成为可能.

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科学领域:

  • 超分子化学
  • 聚合物科学
  • 材料科学

背景情况:

  • 传统的聚氨酸合成需要特定的环聚合物亲和力,限制了材料设计.
  • 非平衡的多素,具有缺乏亲和力的捕获环,具有独特的特性.
  • 分子为克服合成限制提供了一种新的策略.

研究的目的:

  • 通过分子和电合成合成非平衡多.
  • 为了研究环环的接在聚乙烯糖 (PPG) 链上.
  • 描述合成的多素的特性,包括溶解性和热稳定性.

主要方法:

  • 通过铜催化酸循环添加剂将带连接到聚乙烯糖 (PPG) 链上.
  • 用于合成基于PPG的多素的单电合成协议.
  • 聚素溶解度,水力动态直径和扩散常数的表征.
  • 研究热降解和环脱线.

主要成果:

  • 以PPG为基础的多素的成功合成,其中最多有10个环环.
  • 仅用两个环进行线接后,疏水性PPG聚合物就变得水溶性.
  • 根据螺纹环的数量,水力动力学特性有所不同.
  • 在高温下,非平衡聚素呈现逐渐降解和环脱线.

结论:

  • 分子有效地使低亲和系的非平衡多合成.
  • 螺纹环的数量显著影响了聚素的溶解性和物理性质.
  • 合成的聚氨酸具有可调节的特性和动态应用的潜力.