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相关概念视频

Polymers: Molecular Weight Distribution01:10

Polymers: Molecular Weight Distribution

3.2K
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.
3.2K
Polymers: Defining Molecular Weight01:01

Polymers: Defining Molecular Weight

2.7K
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...
2.7K
Molecular Weight of Step-Growth Polymers01:08

Molecular Weight of Step-Growth Polymers

2.1K
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...
2.1K
Polymer Classification: Architecture01:14

Polymer Classification: Architecture

2.6K
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...
2.6K
Step-Growth Polymerization: Overview01:03

Step-Growth Polymerization: Overview

3.4K
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...
3.4K
Polymer Classification: Stereospecificity01:26

Polymer Classification: Stereospecificity

2.4K
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...
2.4K

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相关实验视频

Updated: May 22, 2025

Characterization of Synthetic Polymers via Matrix Assisted Laser Desorption Ionization Time of Flight MALDI-TOF Mass Spectrometry
06:56

Characterization of Synthetic Polymers via Matrix Assisted Laser Desorption Ionization Time of Flight MALDI-TOF Mass Spectrometry

Published on: June 10, 2018

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基于分子重量分布的机器学习设计聚合物

Jenny Hu1, Zachary M Sparrow1, Brian G Ernst1

  • 1Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States.

Journal of the American Chemical Society
|March 14, 2025
PubMed
概括
此摘要是机器生成的。

研究人员开发了一种机器学习模型,将聚合物分子量分布与高密度聚乙烯 (HDPE) 的特性联系起来. 这样可以设计定制的HDPE材料和回收塑料废物,减少对环境的影响.

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Polymer Microarrays for High Throughput Discovery of Biomaterials
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Polymer Microarrays for High Throughput Discovery of Biomaterials

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Characteristics of Precipitation-formed Polyethylene Glycol Microgels Are Controlled by Molecular Weight of Reactants
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Characteristics of Precipitation-formed Polyethylene Glycol Microgels Are Controlled by Molecular Weight of Reactants

Published on: December 23, 2013

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相关实验视频

Last Updated: May 22, 2025

Characterization of Synthetic Polymers via Matrix Assisted Laser Desorption Ionization Time of Flight MALDI-TOF Mass Spectrometry
06:56

Characterization of Synthetic Polymers via Matrix Assisted Laser Desorption Ionization Time of Flight MALDI-TOF Mass Spectrometry

Published on: June 10, 2018

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Polymer Microarrays for High Throughput Discovery of Biomaterials
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Polymer Microarrays for High Throughput Discovery of Biomaterials

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Characteristics of Precipitation-formed Polyethylene Glycol Microgels Are Controlled by Molecular Weight of Reactants
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Characteristics of Precipitation-formed Polyethylene Glycol Microgels Are Controlled by Molecular Weight of Reactants

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科学领域:

  • 聚合物科学
  • 材料科学
  • 机器学习

背景情况:

  • 高密度聚乙烯 (HDPE) 是一种广泛使用的商品塑料,对环境有很大影响.
  • 开发塑料废弃物和材料使用的可持续解决方案至关重要.

研究的目的:

  • 建立基于分子重量分布的机器学习方法来预测HDPE的物理特性.
  • 设计具有可调节性质的HDPE,并使消费后聚乙烯废物的利用成为可能.

主要方法:

  • 利用机器学习绘制聚合物分子重量分布 (MWD) 与HDPE的拉伸性和质性之间的关系.
  • 通过开发的机器学习模型生成具有用户指定的特性的HDPE材料.

主要成果:

  • 成功建立了一个将MWD与HDPE物理特征联系起来的预测模型.
  • 证明了设计和产生具有用户定义的理想性质的HDPE的能力.
  • 展示了降解后消费聚乙烯废物的利用潜力.

结论:

  • 机器学习方法有助于设计具有更好的性能的下一代商品材料.
  • 这种方法使得聚合物回收效率更高,大大降低了HDPE对环境的影响.