Jove
Visualize
联系我们
JoVE
x logofacebook logolinkedin logoyoutube logo
关于 JoVE
概览领导团队博客JoVE 帮助中心
作者
出版流程编辑委员会范围与政策同行评审常见问题投稿
图书馆员
用户评价订阅访问资源图书馆顾问委员会常见问题
研究
JoVE JournalMethods CollectionsJoVE Encyclopedia of Experiments存档
教育
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab Manual教师资源中心教师网站
使用条款与条件
隐私政策
政策

相关概念视频

Polymer Classification: Architecture01:14

Polymer Classification: Architecture

2.7K
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...
2.7K
Polymers: Molecular Weight Distribution01:10

Polymers: Molecular Weight Distribution

3.3K
For any given polymer, the weight average molecular weight (Mw) is higher than, if not equal to, the number average molecular weight (Mn). The only situation in which the weight average molecular weight and the number average molecular weight are equal is when a polymer consists only of chains with equal molecular weight. However, this never happens in a synthetic polymer, since it is difficult to control the polymerization process up to a molecular level with accuracy to a hundred percent.
3.3K
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
Radical Chain-Growth Polymerization: Chain Branching01:17

Radical Chain-Growth Polymerization: Chain Branching

1.9K
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...
1.9K
Polymers: Defining Molecular Weight01:01

Polymers: Defining Molecular Weight

2.8K
Unlike small molecules with definite molecular weights, polymers are a mixture of individual polymer chains of varying lengths, each with a unique molecular weight.  So, the molecular weight of a polymer is expressed as an average value based on the average size of the polymer chains. The two most common forms of averages used for polymers are the number average molecular weight and weight average molecular weight.
The number average molecular weight (Mn) is the summation of the number...
2.8K
Molecular Weight of Step-Growth Polymers01:08

Molecular Weight of Step-Growth Polymers

2.2K
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...
2.2K

您也可能阅读

相关文章

通过共同作者、期刊和引用图与本文相关的文章。

排序
Same author

Cingulate Gradient Dysfunction in End-Stage Renal Disease: Associations With Clinical Phenotypes and Exploratory Transcriptomic Signatures.

CNS neuroscience & therapeutics·2026
Same author

Diagnostic performance of <sup>18</sup>F-FDG PET-CT and SPECT for bone metastases from colorectal cancer: a retrospective study.

Frontiers in oncology·2026
Same author

Investigating the human anellome across the lifespan reveals sex-specific biphasic trajectories.

npj aging·2026
Same author

Autoinflammation with infantile enterocolitis induced by a heterozygous variant (c.1357C > T) in the NLRC4 gene: a case report.

Frontiers in pediatrics·2026
Same author

Effects of Topological Constraints on Equilibrium Swelling of Polymer Gels.

ACS polymers Au·2026
Same author

Corrigendum to "Traditional Chinese medicine pattern differentiation combined with Western risk stratification for febrile infants with enterovirus infection" [J Formos Med Assoc (2026) 7 S0929-6646(26)00490-0].

Journal of the Formosan Medical Association = Taiwan yi zhi·2026

相关实验视频

Updated: Jun 11, 2025

Depolymerizable Olefinic Polymers Based on Fused-Ring Cyclooctene Monomers
08:12

Depolymerizable Olefinic Polymers Based on Fused-Ring Cyclooctene Monomers

Published on: December 16, 2022

3.2K

在环线性聚合物混合物中测量拓约束放松.

Daniel L Vigil1, Ting Ge2, Michael Rubinstein3,4

  • 1<a href="https://ror.org/01apwpt12">Sandia National Laboratories</a>, Albuquerque, New Mexico 87185, USA.

Physical review letters
|September 27, 2024
PubMed
概括

在聚合物混合物中的拓约束被高效地使用高斯连接积分来评估. 这种方法表明,在与环聚合物相比更为线性的混合物中,约束放松取决于线性聚合物重复.

更多相关视频

Synthesis of Cyclic Polymers and Characterization of Their Diffusive Motion in the Melt State at the Single Molecule Level
06:55

Synthesis of Cyclic Polymers and Characterization of Their Diffusive Motion in the Melt State at the Single Molecule Level

Published on: September 26, 2016

7.8K
Flexural Rigidity Measurements of Biopolymers Using Gliding Assays
07:55

Flexural Rigidity Measurements of Biopolymers Using Gliding Assays

Published on: November 9, 2012

10.8K

相关实验视频

Last Updated: Jun 11, 2025

Depolymerizable Olefinic Polymers Based on Fused-Ring Cyclooctene Monomers
08:12

Depolymerizable Olefinic Polymers Based on Fused-Ring Cyclooctene Monomers

Published on: December 16, 2022

3.2K
Synthesis of Cyclic Polymers and Characterization of Their Diffusive Motion in the Melt State at the Single Molecule Level
06:55

Synthesis of Cyclic Polymers and Characterization of Their Diffusive Motion in the Melt State at the Single Molecule Level

Published on: September 26, 2016

7.8K
Flexural Rigidity Measurements of Biopolymers Using Gliding Assays
07:55

Flexural Rigidity Measurements of Biopolymers Using Gliding Assays

Published on: November 9, 2012

10.8K

科学领域:

  • 凝聚物质物理学 凝聚物质物理学
  • 聚合物科学 聚合物科学
  • 类风病学 类风病学 类风病学

背景情况:

  • 聚合物为研究拓约束提供了多样化的链形拓.
  • 线性和环形聚合物的混合物表现出新兴的质性质,往往超过单个组件的粘度.
  • 这些新兴的行为源于长期存在的拓约束,当线性聚合物线环聚合物时形成.

研究的目的:

  • 为了证明高斯连接积分在环线性聚合物混合物中量化拓约束放松的实用性.
  • 阐明聚合物拓学和混合物风学之间的关系.

主要方法:

  • 利用高斯连接积分有效计算拓约束的放松动态.
  • 研究环线性聚合物混合物,专注于大多数线性组成.

主要成果:

  • 高斯连接积分为评估拓约束放松提供了一种有效的方法.
  • 在大多数线性混合物中,放松率主要由线性聚合物的重复动力学决定.
  • 在这样的混合物中,环的扩散时间 (τ_{d,R}) 与环长度 (N_{R}) 和线性链长度 (N_{l}) 的尺度为 τ_{d,R}∼N_{R}^{2}N_{L}^{3.4}.

结论:

  • 高斯连接积分是理解聚合物混合物的拓动态的一个强大的工具.
  • 线性聚合物的重复是控制多数线性混合物的拓约束放松的主要机制.
  • 缩放关系为这些复杂的聚合物系统的质行为提供了定量见解.