分析超分子聚合物的分子重量分布
Stephan A Schmid1, Robert Abbel, Albertus P H Schenning
1Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU, United Kingdom.
Journal of the American Chemical Society
|November 13, 2009
概括
超分子聚合形成线性聚合物链. 弗洛里分布准确地模拟了链条长度,揭示了类似于共价聚凝聚反应的阶段式生长过程.
科学领域:
- 超分子化学 超分子化学
- 聚合物科学 聚合物科学
- 频谱学是一种光谱学.
背景情况:
- 研究超分子线性聚合物链的形成.
- 了解形成对链条长度分布的影响.
研究的目的:
- 探索超分子聚合物链中的激发能量迁移.
- 为了将实验数据与蒙特卡洛模拟进行链条长度分布的比较.
主要方法:
- 时间分辨率光发光 (PL) 谱学用于监测能量转移.
- 蒙特卡洛模拟包括链结构和传输速率.
- 测试各种重量分布函数 (弗洛里,波桑,单分散).
主要成果:
- 弗洛里分布假设与实验和模拟数据有很好的一致性.
- 波桑和单分散分布低估了长链的存在.
- 超分子聚合采用相似的步骤过程,类似于多重凝结.
结论:
- 超分子聚合具有类似于线性共价聚合物聚凝的特性.
- 构建块的同等反应性驱动了一个动态的链增长过程.
相关概念视频
Determination of Molar Masses of Polymers I
Polymerization produces macromolecules with a range of chain lengths due to the random nature of molecular growth processes. As chains form and terminate at different stages, a single polymer sample contains molecules of varying sizes rather than a uniform structure. This variability is described using average molar masses and distribution-related parameters, which together provide a comprehensive understanding of polymer characteristics.The distribution of molar masses plays a critical role in...
Determination of Molar Masses of Polymers II
Polymer samples typically consist of macromolecular chains with a distribution of lengths, resulting in a range of molar masses rather than a single discrete value. Conventional descriptors such as the number-average molar mass and weight-average molar mass quantify this distribution but do not fully capture polymer behavior in solution..The viscosity-average molar mass provides a more realistic description of polymer behavior in solution because it accounts for the enhanced contribution of...
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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.
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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...
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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...
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...
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...


