polydispersity

简明释义

英[/ˌpɒl.i.dɪsˈpɜr.sɪ.ti/]美[/ˌpɒl.i.dɪsˈpɜr.sɪ.ti/]

n. [化学] 多分散性

英英释义

单词用法

同义词

反义词

例句

1.The disclosure provides for a process and polymerization system to produce isoolefin polymers (72) utilizing polymorphogenates (16, 26) in the catalyst system to control polydispersity (MWD).

本公开内容提供了制备异烯烃聚合物（72）的方法和聚合系统，其在催化剂体系中使用多成形剂（16，26），以控制多分散性（MWD）。

2.The particle diameter and its polydispersity were determined with laser dynamic light-scattering method.

采用激光动态光散射法检测粒度与粒度分布。

3.A nonwoven web formed of substantially continuous spunmelt fibers is formed from a homopolymer of polypropylene having a skewed molecular weight distribution and a polydispersity of less than 3.5.

由基本上连续的熔纺纤维形成的无纺网幅是从具有偏斜分子量分 布和低于3.5的多分散性的聚丙烯均聚物形成的。

4.Atom transfer radical polymerization (ATRP), which can yield polymers with controlled molecular weight and low polydispersity, is an effective approach to realize living radical polymerization.

原子转移自由基聚合(ATRP)反应是实现活性聚合的一种颇为有效的途径，可以合成分子量可控、分子量分布窄的各种聚合物。

5.The additives could increase the polydispersity of asphaltene colloidal particles as well.

可溶性添加物能够增加沥青质胶团的分散度，使之更趋向多分散。

6.The data of GPC indicate that the number-average molecular is 4934 and the polydispersity is 1.978 with a narrow molecular distribution.

GPC测得共聚物的数均分子量为4934，多分散指数是1.978，具有较窄的分子量分布。

7.These parameters can accurately predict the polydispersity index.

这些参数可准确预测多分散指数。

8.The model contains a single set of kinetic and thermodynamic parameters that accurately predicts the polymer production rate, molecular weight, and polydispersity index.

模型模拟结果显示模型计算的分子量及其分布、聚丙烯产量与工业数据较好的吻合。

9.The influence of APG0810 concentration, initiator concentration and salt concentration on particle size and polydispersity of polystyrene has been discussed.

着重研究了表面活性剂浓度、引发剂浓度以及无机盐浓度对产物粒径和多分散度的影响。

10.A nonwoven web formed of substantially continuous spunmelt fibers is formed from a homopolymer of polypropylene having a skewed molecular weight distribution and a polydispersity of less than 3.5.

由基本上连续的熔纺纤维形成的无纺网幅是从具有偏斜分子量分 布和低于3.5的多分散性的聚丙烯均聚物形成的。

11.Researchers often measure the polydispersity index to assess the uniformity of nanoparticles.

研究人员通常测量多分散性指数来评估纳米颗粒的均匀性。

12.A high polydispersity can affect the mechanical properties of materials.

高多分散性可能会影响材料的机械性能。

13.In drug delivery systems, low polydispersity is desired for consistent therapeutic effects.

在药物递送系统中，低多分散性是为了获得一致的治疗效果。

14.A narrow polydispersity distribution is crucial for producing high-quality emulsions.

狭窄的多分散性分布对于生产高质量乳液至关重要。

15.The polydispersity of the polymer sample indicates a wide range of molecular weights.

该聚合物样品的多分散性表示分子量范围广泛。

作文

In the field of materials science and chemistry, the term polydispersity refers to the distribution of molecular weights in a given sample. This concept is critical when analyzing polymers, colloids, and other complex mixtures. To understand polydispersity, one must first grasp the idea of molecular weight and how it affects the properties of materials. Polymers, for instance, are made up of long chains of repeating units, and the length of these chains can vary significantly. When a polymer sample has a wide range of chain lengths, it exhibits high polydispersity, which means that the molecular weight distribution is broad. Conversely, a sample with uniform chain lengths has low polydispersity.The significance of polydispersity lies in its influence on the physical and chemical properties of materials. For example, in the production of plastics, a polymer with low polydispersity will generally have more consistent mechanical properties, making it easier to predict how the material will behave under stress. In contrast, materials with high polydispersity may exhibit varying strength, flexibility, and thermal properties, which can complicate their use in applications where reliability is paramount.Moreover, polydispersity can affect the processing of materials. In processes such as extrusion or injection molding, a polymer with a narrow molecular weight distribution will flow more uniformly, leading to better quality products. On the other hand, a broad distribution can cause issues like clogging or uneven flow, resulting in defects in the final product. Therefore, controlling polydispersity during the synthesis of polymers is crucial for manufacturers aiming to produce high-quality materials.In addition to its implications in manufacturing, polydispersity also plays a role in biological systems. For instance, the distribution of lipids in cell membranes can exhibit polydispersity, influencing membrane fluidity and functionality. Similarly, proteins can have varying molecular weights due to post-translational modifications, impacting their interactions within biological pathways.To measure polydispersity, scientists often use a parameter known as the polydispersity index (PDI), which is calculated by dividing the weight-average molecular weight by the number-average molecular weight. A PDI value close to 1 indicates a narrow distribution, while higher values signify greater heterogeneity. This quantitative approach helps researchers and engineers assess the polydispersity of their samples and make informed decisions about material selection and processing techniques.In conclusion, polydispersity is a fundamental concept in materials science that describes the distribution of molecular weights within a sample. Understanding polydispersity is essential for predicting the behavior of materials in various applications, from industrial manufacturing to biological systems. By controlling and measuring polydispersity, scientists and engineers can enhance the performance and reliability of materials, leading to advancements in technology and improved outcomes in diverse fields.

在材料科学和化学领域，术语polydispersity指的是给定样品中分子量的分布。这个概念在分析聚合物、胶体和其他复杂混合物时至关重要。要理解polydispersity，首先必须掌握分子量的概念以及它如何影响材料的性质。例如，聚合物是由长链重复单元组成的，这些链的长度可能会有显著的变化。当聚合物样品具有广泛的链长范围时，它表现出高polydispersity，这意味着分子量分布是广泛的。相反，具有均匀链长的样品则具有低polydispersity。polydispersity的重要性在于它对材料的物理和化学性质的影响。例如，在塑料生产中，具有低polydispersity的聚合物通常会具有更一致的机械性能，使得更容易预测材料在受力下的表现。相比之下，具有高polydispersity的材料可能会表现出不同的强度、柔韧性和热性能，这可能会使其在需要可靠性的应用中复杂化。此外，polydispersity还会影响材料的加工。在挤出或注塑等工艺中，具有狭窄分子量分布的聚合物将更均匀地流动，从而导致更高质量的产品。另一方面，广泛的分布可能会导致堵塞或不均匀流动，导致最终产品出现缺陷。因此，在聚合物合成过程中控制polydispersity对于旨在生产高质量材料的制造商至关重要。除了在制造中的影响外，polydispersity在生物系统中也起着作用。例如，细胞膜中脂质的分布可能会表现出polydispersity，影响膜的流动性和功能。同样，蛋白质由于翻译后修饰而具有不同的分子量，这影响了它们在生物途径中的相互作用。为了测量polydispersity，科学家们通常使用一个称为多分散指数（PDI）的参数，该参数通过将重平均分子量除以数平均分子量来计算。接近1的PDI值表示狭窄的分布，而较高的值则表示更大的异质性。这种定量方法帮助研究人员和工程师评估他们样品的polydispersity并做出有关材料选择和加工技术的明智决策。总之，polydispersity是材料科学中的一个基本概念，描述了样品中分子量的分布。理解polydispersity对于预测材料在各种应用中的行为至关重要，从工业制造到生物系统。通过控制和测量polydispersity，科学家和工程师可以增强材料的性能和可靠性，从而促进技术进步和改善各个领域的成果。