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相关概念视频

Anionic Chain-Growth Polymerization: Overview01:20

Anionic Chain-Growth Polymerization: Overview

2.0K
The polymerization process that involves carbanion as an intermediate is called anionic polymerization. It is also a type of addition or chain-growth polymerization. Anionic polymerization gets initiated by a strong nucleophile such as an organolithium or a Grignard reagent. The most commonly used initiator for anionic polymerization is butyl lithium. Monomers involved in anionic polymerization must possess a vinyl group bonded to one or two electron-withdrawing groups. For instance,...
2.0K
Olefin Metathesis Polymerization: Ring-Opening Metathesis Polymerization (ROMP)01:16

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

2.5K
Ring-opening metathesis polymerization or ROMP involves strained cycloalkenes as starting materials. The mechanism of ROMP proceeds by reacting cycloalkene with Grubbs catalyst to give metallacyclobutane intermediate which undergoes a ring-opening reaction to form new carbene. The new carbene reacts with another molecule of cycloalkene. Repetition of these steps leads to the formation of an unsaturated open-chain polymer product. All these steps are reversible, however, relieving the ring...
2.5K
Cationic Chain-Growth Polymerization: Mechanism00:57

Cationic Chain-Growth Polymerization: Mechanism

2.2K
The cationic polymerization mechanism consists of three steps: initiation, propagation, and termination. In the initiation step of the polymerization process, the π bond of a monomer gets protonated by the Lewis acid catalyst, which is formed from boron trifluoride and water. The protonation of the π bond generates a carbocation stabilized by the electron‐donating group. In the propagation step, the π bond of the second monomer acts as a nucleophile and attacks the...
2.2K
Anionic Chain-Growth Polymerization: Mechanism01:04

Anionic Chain-Growth Polymerization: Mechanism

2.0K
The mechanism for anionic chain-growth polymerization involves initiation, propagation, and termination steps. In the initiation step, a nucleophilic anion, such as butyl lithium, initiates the polymerization process by attacking the π bond of the vinylic monomer. As a result, a carbanion, stabilized by the electron‐withdrawing group, is generated. The resulting carbanion acts as a Michael donor in the propagation step and attacks the second vinylic monomer, which acts as a Michael...
2.0K
Base-Catalyzed Ring-Opening of Epoxides02:26

Base-Catalyzed Ring-Opening of Epoxides

8.2K
Due to their highly strained structures, epoxides can readily undergo ring-opening reactions through nucleophilic substitution, either in the presence of an acid or a base. The nucleophilic substitution reactions in the presence of acid are called acid-catalyzed ring-opening reactions, and nucleophilic substitution reactions in the presence of a base are called base-catalyzed ring-opening reactions. Epoxides undergo base-catalyzed ring-opening reactions in the presence of a strong nucleophile...
8.2K
Acid-Catalyzed Ring-Opening of Epoxides02:24

Acid-Catalyzed Ring-Opening of Epoxides

7.0K
Epoxides that are three-membered ring systems are more reactive than other cyclic and acyclic ethers. The high reactivity of epoxides originates from the strain present in the ring. This ring strain acts as a driving force for epoxides to undergo ring-opening reactions either with halogen acids or weak nucleophiles in the presence of mild acid. The acid catalyst converts the epoxide oxygen, a poor leaving group, into an oxonium ion, a better leaving group, making the reaction feasible. The...
7.0K

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相关实验视频

Updated: May 26, 2025

Controlled Photoredox Ring-Opening Polymerization of O-Carboxyanhydrides Mediated by Ni/Zn Complexes
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Controlled Photoredox Ring-Opening Polymerization of O-Carboxyanhydrides Mediated by Ni/Zn Complexes

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阴离子-阳离子同步环开放聚合.

Wenli Wang1,2, Xue Liang2, Hengxu Liu2

  • 1Department of Gynecology and Obstetrics, Shanghai Key Laboratory of Anesthesiology and Brain Functional Modulation, Clinical Research Center for Anesthesiology and Perioperative Medicine, Translational Research Institute of Brain and Brain-Like Intelligence, Shanghai Fourth People's Hospital, School of Medicine, Tongji University, Shanghai, 200434, China.

Nature communications
|February 22, 2025
PubMed
概括
此摘要是机器生成的。

我们开发了一种新的单聚合法,可以同时进行阴离子和阳离子环开放聚合. 这种技术克服了以前的局限性,为生物材料应用产生具有固有的抗菌特性的先进块共聚物.

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Depolymerizable Olefinic Polymers Based on Fused-Ring Cyclooctene Monomers
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Synthesis of Monodisperse Cylindrical Nanoparticles via Crystallization-driven Self-assembly of Biodegradable Block Copolymers
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Controlled Photoredox Ring-Opening Polymerization of O-Carboxyanhydrides Mediated by Ni/Zn Complexes
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Depolymerizable Olefinic Polymers Based on Fused-Ring Cyclooctene Monomers
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Depolymerizable Olefinic Polymers Based on Fused-Ring Cyclooctene Monomers

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Synthesis of Monodisperse Cylindrical Nanoparticles via Crystallization-driven Self-assembly of Biodegradable Block Copolymers
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科学领域:

  • 聚合物化学 聚合物化学
  • 材料科学 材料科学 材料科学
  • 有机合成 有机合成

背景情况:

  • 由于终结问题,不兼容的机制 (阴离子和阳离子) 的同时聚合具有挑战性.
  • 同步的阴离子-阴离子聚合是特别困难的,因为潜在的链末合.
  • 木盐可以抑制终端合,提供一种潜在的解决方案.

研究的目的:

  • 开发一种用于同时进行阴离子和阴离子环开放聚合 (CAP) 的新方法.
  • 为了合成多功能多氧化-块-聚 (POx-b-PCE) 共聚合物.
  • 研究合成的块共聚合物的自我组装和抗菌特性.

主要方法:

  • 利用木盐作为序列启动和同时传播的启动剂.
  • 使用二氧化 (Ox) 的阳离子环开放聚合 (CROP) 和循环 (CE) 的阳离子环开放聚合 (AROP).
  • 使用CAP方法合成了一种特定的块共聚合物 (PAPOZ20-b-PCL5).

主要成果:

  • 成功演示了一种用于合成POx-b-PCE共聚合物的单CAP方法.
  • 合成的PAPOZ20-b-PCL5块共聚物自组装成状聚合物.
  • 这些菌根在没有添加抗生素的情况下表现出显著的本质抗菌活性.

结论:

  • 开发的CAP方法有效地克服了同时不兼容的聚合物的挑战.
  • 这种方法为创建多元组件共聚合物提供了一种多功能途径.
  • 由此产生的区块共聚合物显示出作为具有固有的抗菌功能的新生物材料的前景.