Basis for the Preparative Fractionation of a Statistical Copolymer (SAN) with Respect to Either Chain Length or Chemical Composition

Loske, Stefan; Schneider, Alyssa F.; Wolf, Bernhard

doi:10.1021/ma0343838

Cited by 8 publications

(3 citation statements)

References 19 publications

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“…Moreover, its separation force is not confined to linear polymers differing in molar mass only; the sorting criteria can be tailored according to the particular task. In this manner it is for instance possible to fractionate copolymers primarily with respect to their chemical composition, [14] instead of chain length, or star shaped macromolecules according to the number of arms they are composed of.…”

Section: Discussionmentioning

confidence: 99%

“…This means that the sorting of molecules according to the procedures outlined above takes place almost exclusively with respect to the molar mass of the molecules, irrespective of their chemical composition. This problem can be solved, for instance for random copolymers [14] (stochastic sequence of monomeric units A and B), by inducing the formation of two liquid phases via a properly chosen second polymer instead of a low molecular liquid of low solvent power (cf. r.h.s.…”

Section: Basic Principlesmentioning

confidence: 99%

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Large Scale Fractionation of Macromolecules

Eckelt

Haase

Loske

et al. 2004

Macro Materials & Eng

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Summary: Access to sufficiently large amounts of material with adequate molecular and chemical uniformity from polydisperse natural products or synthetic materials has been a long‐standing challenge to polymer scientists. We have developed a broadly applicable preparative fractionation method consisting of a special kind of continuous extraction removing the easier soluble components from the initial product. It is rendered possible by the use of spinning nozzles through which a concentrated polymer solution is pressed into a liquid of tailored thermodynamic quality. The initially produced jets of the source phase disintegrate rapidly into minute droplets of typically 50 μm diameter. This efficient subdivision provides the large surfaces and short routs of transport required for successful fractionation. Thus the pronounced kinetic hindrances resulting from the high viscosities of reasonable concentrated polymer solutions can be overcome. We portray the principal features of continuous spin fractionation and present two examples of practical importance.

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Section: Discussionmentioning

confidence: 99%

Section: Basic Principlesmentioning

confidence: 99%

Large Scale Fractionation of Macromolecules

Eckelt

Haase

Loske

et al. 2004

Macro Materials & Eng

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“…General consideration of the effect of chemical heterogeneity on copolymer properties has so far been limited 15. The chemical heterogeneity of copolymers affects the separation processes, eg in the determination of molecular weights by chromatographic methods16–19 or liquid–liquid phase equilibria used for copolymer fractionation 20, 21. Its impact on the integral properties has not been systematically studied.…”

Section: Introductionmentioning

confidence: 99%

The effect of chemical heterogeneity on the properties of statistical copolymers: the conductivity of poly(aniline‐co‐2‐bromoaniline)

Stejskal

2004

Polymer International

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Chemical heterogeneity can influence the properties of statistical copolymers. It is shown that any integral property of a copolymer will depend on the chemical heterogeneity if such a property is a non‐linear function of copolymer composition. This is illustrated by means of the conductivity of copolymers of aniline and 2‐bromoaniline. The monomer reactivity ratios of this monomer pair are rA (aniline) = 0.94 and rB (2‐bromoaniline) = 0.31. The dependence of conductivity on the copolymer composition is non‐linear. Consequently, the conductivity depends on the compositional distribution, ie on the extent of chemical heterogeneity. Heterogeneous high‐conversion copolymers have lower conductivity than corresponding relatively homogeneous low‐conversion copolymers. The change in the average copolymer composition with increasing conversion is demonstrated for a copolymerization mixture containing 30 mol% aniline. The conductivity decreases at the same time as the chemical heterogeneity of the copolymer develops. The change in the average copolymer composition alone cannot explain the observed conductivity decrease. The conductivity is dependent not only on average composition but also on the chemical composition distribution. Copyright © 2004 Society of Chemical Industry

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Characterization of Polymers

Pethrick

2004

Encyclopedia of Polymer Science and Technology

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In order to effectively use polymeric materials, it is important to understand what factors influence their physical and chemical properties. This article attempts to develop a framework for the systematic discussion of the characteristics of polymeric materials in terms of the methods used in their synthesis, the dominant nature of the organization or lack of it in the solids state, and their process ability. Many properties of a polymer are influenced by the length or the polymer chain or its size, and techniques which allow quantification of these properties are very important in defining the nature of a polymer. The final physical properties of a polymer can be influenced by the nature of the structure developed on formation of a solid, and relating physical properties to morphology is often required in order to understand the subtle effects which can be observed and to make polymeric materials commercially interesting for a wide range of applications.

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Basis for the Preparative Fractionation of a Statistical Copolymer (SAN) with Respect to Either Chain Length or Chemical Composition

Cited by 8 publications

References 19 publications

Large Scale Fractionation of Macromolecules

Large Scale Fractionation of Macromolecules

The effect of chemical heterogeneity on the properties of statistical copolymers: the conductivity of poly(aniline‐co‐2‐bromoaniline)

Characterization of Polymers

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