相关实验视频
Updated: Jun 11, 2025

08:00
DNA Nanotubes as a Versatile Tool to Study Semiflexible Polymers
Published on: October 25, 2017
6.9K
在半晶聚合物中测量领带链和被困的纠
Amanda G McDermott1, Paul J DesLauriers2, Jeff S Fodor2
1Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA.
Macromolecules
|October 9, 2024
概括
一种新的无标签方法使用蒸汽膨胀和中子散射量化聚合物中的弹性有效分子. 这揭示了初始分子网络与产量后拉伸性质之间的直接相关性.
科学领域:
- 聚合物科学 聚合物科学
- 材料科学 材料科学 材料科学
- 物理化学 物理化学
背景情况:
- 在半晶聚合物中量化弹性有效分子 (应力传递器) 对于理解机械性质至关重要.
- 现有的方法可能缺乏精度或需要标签,限制其适用性.
研究的目的:
- 开发和演示一种新的无标签方法,用于量化半晶聚合物中的弹性有效分子含量 (p).
- 将这些内容与机械性能相关联,并与理论模型进行比较.
主要方法:
- 使用化蒸汽和小角度中子散射 (SANS) 进行无标签量化.
- 将实验结果与半经验预测和结构参数 (例如,应变硬化模量,β参数) 进行比较.
主要成果:
- 建立了初始弹性活性分子网络和产后拉力值之间的强烈对应.
- 模拟表明同聚合物比共聚合物具有更多的桥梁纠.
- 发现修改后的弗洛里-雷纳理论与实验数据相匹配,与迈克尔斯-豪斯莱恩理论不同.
结论:
- 最初的分子网络决定了产量后的拉伸性能,无论后来的形态变化如何.
- 结合分子对机械性能的影响比桥梁纠更大.
- 开发的方法提供了一种可靠的方式来量化聚合物中的关键分子参数.
相关概念视频
Polymer Classification: Crystallinity
2.8K
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...
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...
2.8K
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

