関連する実験動画
Updated: Feb 17, 2026

06:07
Studying Large Amplitude Oscillatory Shear Response of Soft Materials
Published on: April 25, 2019
13.7K
トポロジー依存ポリマーの伸縮と溶液中の切断は,極端な切断速度で起こる.
Bas G P van Ravensteijn1, Patrick T Corona1, Anukta Datta1
1Department of Chemical Engineering, University of California Santa Barbara, Santa Barbara, California 93106, United States.
ACS polymers Au
|February 16, 2026
まとめ
エンジニアリングポリマートポロジーは,極端なフロー下で流体の性質を制御するための鍵です. この研究は,分子リラクゼーション時間がポリマー鎖の伸縮と安定性を決定し,より弾力的なポリマーを作成するための洞察を提供することを明らかにしています.
科学分野:
- ポリマーサイエンスの科学
- 整形外科医 整形外科医 整形外科医
- マテリアルサイエンス 材料科学
背景:
- ポリマートポロジーの制御は,高切断率の流れにおけるレオロジーと機械的安定性にとって極めて重要です.
- 高切断速度のポリマー行動を研究するための既存の方法は,しばしば間接的 (ex situ) である.
研究 の 目的:
- ポリマーのトポロジー,レオロジー,および極端な切断速度下での機械的安定性との関係を調査する.
- 分子リラクゼーション時間がポリマーの変形と分解にどのように影響するかを理解する.
主な方法:
- 毛細血管リオメトリー (毛細血管リオメトリー-SANS) と統合された新しい局所小角中性子散射 (SANS) 測定を用いた.
- 線形,分岐形,星形ポリマーの溶液粘度およびポリマー変形を同時に測定した.
- in situの発見とex situの鎖分裂測定を相関させた.
主要な成果:
- 分子リラクゼーション時間が主に,薄くしたポリマー溶液における鎖の伸縮と切断の薄化の発生を制御することを示した.
- ポリマーの変形と鎖分裂の間の直接的な相関が観察されました.
- ポリマーの分岐は,リラックスダイナミクスを変化させることで,機械的な劣化に対する回復力を高めることを推測した.
結論:
- ポリマー鎖の変形と高圧切断下での分裂との直接的なリンクを確立しました.
- ポリマーの行動と安定性を決定する分子リラクゼーション時間の重要な役割を強調した.
- エンジニアリングトポロジー制御されたポリマーに洞察を提供し,レオロギー特性と機械的回復力を強化しました.
関連する概念動画
Polymer Classification: Architecture
3.9K
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...
3.9K
Molecular Weight of Step-Growth Polymers
2.9K
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...
2.9K
Plastic Behavior
614
A material's elastic behavior is characterized by the disappearance of stress once the load is removed, allowing the material to return to its original state. However, when stress surpasses the yield point, yielding commences, marking the onset of plastic deformation or permanent set. This change from elastic to plastic behavior is influenced by the peak stress value and the duration before the load is removed. An intriguing observation occurs when a specimen is loaded, unloaded, and...
614
Polymer Classification: Stereospecificity
3.3K
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...
3.3K
Step-Growth Polymerization: Overview
4.5K
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...
4.5K
Radical Chain-Growth Polymerization: Chain Branching
2.5K
The skeletal structure of polymers synthesized via radical polymerization is always branched. For example, the polymerization of ethylene by radical polymerization results in a low-density grade of polyethylene with a heavily branched skeletal structure. Here, the radical site abstracts hydrogen from the growing chain, and the radical site shifts from the end (a primary carbon center) to anywhere within the growing chain (a secondary carbon center). Consequently, the part of the chain from the...
2.5K

