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相关概念视频

Characteristics and Nomenclature of Homopolymers01:00

Characteristics and Nomenclature of Homopolymers

Polymers that are made up of identical monomer units are called homopolymers. Only one repeating unit is involved in the construction of the homopolymer structure. For example, as depicted in Figure 1, polypropylene is a homopolymer constituted of propylene monomers. Here, the only repeating unit in the polymer chain is propylene.
Polymers02:34

Polymers

The word polymer is derived from the Greek words “poly” which means “many” and “mer” which means “parts”. Polymers are long chains of molecules composed of repeating units of smaller molecules, known as monomers. They either occur naturally, such as DNA and proteins, or can be constructed synthetically, like plastics. They have varied structural characteristics, such as linear chains, branched chains, or complex networks, that contribute to the properties that they exhibit. Additionally,...
Polymers02:34

Polymers

The word polymer is derived from the Greek words “poly” which means “many” and “mer” which means “parts”. Polymers are long chains of molecules composed of repeating units of smaller molecules, known as monomers. They either occur naturally, such as DNA and proteins, or can be constructed synthetically, like plastics. They have varied structural characteristics, such as linear chains, branched chains, or complex networks, that contribute to the properties that they exhibit. Additionally,...
Polymers02:34

Polymers

The word polymer is derived from the Greek words “poly” which means “many” and “mer” which means “parts”. Polymers are long chains of molecules composed of repeating units of smaller molecules, known as monomers. They either occur naturally, such as DNA and proteins, or can be constructed synthetically, like plastics. They have varied structural characteristics, such as linear chains, branched chains, or complex networks, that contribute to the properties that they exhibit. Additionally,...
Polymer Classification: Crystallinity01:21

Polymer Classification: Crystallinity

Unlike ionic or small covalent molecules, polymers do not form crystalline solids due to the diffusion limitations of their long-chain structures. However, polymers contain microscopic crystalline domains separated by amorphous domains.
Crystalline domains are the regions where polymer chains are aligned in an orderly manner and held together in proximity by intermolecular forces. For example, chains in the crystalline domains of polyethylene and nylon are bound together by van der Waals...
Olefin Metathesis Polymerization: Overview01:13

Olefin Metathesis Polymerization: Overview

Recently, the development of olefin metathesis polymerization advanced the field of polymer synthesis. Simply put, the reorganization of substituents on their double bonds between two olefins in the presence of a catalyst is known as the olefin metathesis reaction. The use of metathesis reaction for polymer synthesis is called olefin metathesis polymerization.
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists of a...

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Proceedings of the National Academy of Sciences of the United States of America·1983
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相关实验视频

Updated: Jul 12, 2026

Scattering And Absorption of Light in Planetary Regoliths
11:34

Scattering And Absorption of Light in Planetary Regoliths

Published on: July 1, 2019

在哈雷彗星中发现了太空中的第一个聚合物.

W F Huebner

    Science (New York, N.Y.)
    |August 7, 1987
    PubMed
    概括

    聚氧甲的短聚合物链被确定为哈雷彗星内部昏迷中的重离子质谱的来源. 这些发现与意想不到的昏迷观察结果一致,为彗星组成提供了新的见解.

    科学领域:

    • 彗星科学 彗星科学
    • 天体化学是天体化学.
    • 空间物理 空间物理

    背景情况:

    • 彗星的内部昏迷是一个复杂的区域,包含各种化学物种.
    • 以前对哈雷彗星昏迷的观测揭示了意想不到的化学特征.
    • 了解彗星的组成对于破译早期太阳系至关重要.

    研究的目的:

    • 为了分析来自哈雷彗星内部昏迷的重离子质谱.
    • 为了确定观察到的光谱数据的分子来源.
    • 为了使光谱发现与彗星环境的现有知识相协调.

    主要方法:

    • 对重离子质谱数据的分析.
    • 利用Giotto航天器上的PICCA仪器的数据.
    • 与已知分子性质的光谱峰值的比较.

    主要成果:

    • 确定了聚氧甲的短聚合物链作为光谱的来源.
    • 观测到六个不同的质量峰值,范围大约从45到120个原子质量单位.
    • 聚氧甲基的特性与以前意想不到的昏迷观察结果一致.

    结论:

    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

    Particles without a Box: Brush-first Synthesis of Photodegradable PEG Star Polymers under Ambient Conditions
    06:56

    Particles without a Box: Brush-first Synthesis of Photodegradable PEG Star Polymers under Ambient Conditions

    Published on: October 10, 2013

    相关实验视频

    Last Updated: Jul 12, 2026

    Scattering And Absorption of Light in Planetary Regoliths
    11:34

    Scattering And Absorption of Light in Planetary Regoliths

    Published on: July 1, 2019

    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

    Particles without a Box: Brush-first Synthesis of Photodegradable PEG Star Polymers under Ambient Conditions
    06:56

    Particles without a Box: Brush-first Synthesis of Photodegradable PEG Star Polymers under Ambient Conditions

    Published on: October 10, 2013

    • 聚氧甲是哈雷彗星内部昏迷中的重要组成部分.
    • 聚氧甲的存在有助于解释彗星昏迷中的异常观测.
    • 这一发现为彗星的化学复杂性提供了新的视角.