まとめ
ガス相ポリメリゼーションの研究は,単一ポリマー分子を検出する雲室を使用して可能になりました. この技術は,凝縮と集積を防止し,ポリメリゼーション機構の詳細な研究を可能にします.
科学分野:
- ポリマー化学のポリマー化学について
- 物理化学 物理化学
- 化学工学は化学工学というものです.
背景:
- ガス相ポリメリゼーションの研究は,ポリマー凝縮による課題です.
- 伝統的な方法は高濃度で苦労し,集積と不正確なデータにつながります.
研究 の 目的:
- ガス相ポリメリゼーションの研究の限界を克服するために.
- 単一分子レベルでのポリメリゼーション機構の調査を可能にする.
- ラジカル,イオン,リング開きを含む様々なポリメリゼーションタイプを探求する.
主な方法:
- 単一ポリマー分子を検出するための雲室技術を活用しました.
- 液滴の核化を誘発するために超飽和モノマー蒸気を使用します.
- 聚合と凝縮を避けるために,成長ポリマーの低濃度を維持しています.
主要な成果:
- ガス相における個々のポリマー分子の検出と研究に成功しました.
- ラジカルとイオンを含むチェーンポリメリゼーションの調査を可能にしました.
- 成長するポリマーラジカルの再結合を防止し",死んだ"ポリマーの形成を回避します.
結論:
- 雲室技術は,ガス相ポリメリゼーションの研究に新しいアプローチを提供します.
- この方法は,ポリメリゼーションの運動学とメカニズムの詳細な検討を可能にします.
- 超低速化学と放射線誘発ポリメリゼーションの研究の道を開く.
関連する概念動画
01:03Step-Growth Polymerization: Overview
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.
Many natural and synthetic polymers are produced by...
Many natural and synthetic polymers are produced by...
01:17Ziegler–Natta Chain-Growth Polymerization: Overview
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 catalyst, high molecular...
01:08Molecular Weight of Step-Growth Polymers
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.
As the step-growth polymerization involves step-wise condensation of monomers, the molecular weight also builds up eventually. Consequently, high molecular weight polymers are obtained at the late stages of the polymerization, where 99% of monomers have been consumed.
The extent of the...
As the step-growth polymerization involves step-wise condensation of monomers, the molecular weight also builds up eventually. Consequently, high molecular weight polymers are obtained at the late stages of the polymerization, where 99% of monomers have been consumed.
The extent of the...
00:57Cationic Chain-Growth Polymerization: Mechanism
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 generated carbocation,...
01:10Radical Chain-Growth Polymerization: Overview
Chain-growth or addition polymerization is successive addition reactions of monomers with a polymer chain. In radical chain-growth polymerization, the reaction proceeds via a free-radical intermediate. The free radical is formed from radical initiators, which spontaneously generate free radicals by homolytic fission. Organic peroxides (such as dibenzoyl peroxide, as shown in Figure 1) or azo compounds are popular radical initiators. A low concentration ratio of radical initiator to monomer is...
01:09Radical Chain-Growth Polymerization: Mechanism
The radical chain-growth polymerization mechanism consists of three steps: initiation, propagation, and termination of polymerization. The polymerization initiates when a free radical generated from the radical initiator adds to the unsaturated bond in the monomer. The unpaired electron of the free radical and one π electron in the unsaturated bond creates a σ bond between the free radical and the monomer. As a result, the other π electron in the unsaturated bond converts this species into the...