ポリマー:超高分子量ポリチレンの合成と特徴付け

D McIntyre, L J Fetters, E Slagowski

Science (New York, N.Y.)

|June 2, 1972

まとめ

高分子量ポリスティレンは,光散射と超遠心分離を用いて特徴づけられました. マーク・ホウインク方程式は,特定の溶媒と温度条件 (セータ溶媒/温度) の下でのみ,柔軟なポリマーに適用できます.

科学分野:

ポリマーサイエンスの科学
物理化学物理化学

背景:

高分子量ポリマーの特徴づけは,その性質を理解するために重要である.
分子重量と粘度との関係は,ポリマー科学において根本的なものである.

研究の目的:

非常に高い分子量を持つポリステルレンを特徴づけるために.
これらのポリマーに対するマーク・ホウインク方程式の適用性を調査する.

主な方法:

光散乱の測定. 光散乱を測定する.
均衡型超遠心分離法である.
テータ溶媒における粘度測定.

主要な成果:

分子重量44 x 10^6 g/molまでのポリステルレンは成功裏に特徴づけられました.
マーク・ホウインク方程式は,柔軟なポリマーで正確な結果を出すために,テータ温度でテータ溶剤で測定を行う必要があります.

結論:

高分子量ポリステルレンは,確立された物理的方法を使用して信頼性のある特徴づけが可能です.
ポリマーの分子量決定におけるマーク・ホウインク方程式の有効な適用には,セータ溶媒とセータ温度条件の厳格な遵守が必要である.

さらに関連する動画

10:22

Designed for Molecular Recycling: A Lignin-Derived Semi-aromatic Biobased Polymer

Published on: November 30, 2020

09:22

Fabricating Superhydrophobic Polymeric Materials for Biomedical Applications

Published on: August 28, 2015

関連する概念動画

01:08

Molecular Weight of Step-Growth Polymers

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...

01:14

Polymer Classification: Architecture

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...

01:10

Polymers: Molecular Weight Distribution

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.

01:26

Polymer Classification: Stereospecificity

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...

01:24

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...

01:01

Polymers: Defining Molecular Weight

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...

関連する実験動画