Phase separation in random copolymers from high conversion free radical polymerization, 2. Chemical heterogeneity analysis of poly(styrene-co-ethyl acrylate) by gradient HPLC

Braun, Dietrich; Krämer, Inge; Pasch, Harald; Mori, Sadao

doi:10.1002/(sici)1521-3935(19990501)200:5<949::aid-macp949>3.0.co;2-1

Cited by 21 publications

(5 citation statements)

References 14 publications

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“…As has been shown previously, suitable chromatographic conditions are a C 18 reversed stationary phase and a linear gradient of THF/ACN as the mobile phase. [14] The chromatographic separation of a set of styreneethyl acrylate copolymers (SEA) according to chemical composition is shown in Fig. 1.…”

Section: Resultsmentioning

confidence: 99%

On-line coupling of gradient-HPLC and1H NMR for the analysis of random poly[(styrene)-co-(ethyl acrylate)]s

Krämer

Hiller²,

Pasch³

2000

Macromol. Chem. Phys.

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Section: Resultsmentioning

confidence: 99%

On-line coupling of gradient-HPLC and1H NMR for the analysis of random poly[(styrene)-co-(ethyl acrylate)]s

Krämer

Hiller²,

Pasch³

2000

Macromol. Chem. Phys.

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“…Both isocratic [1] and gradient-based liquid chromatography [2,3] have been utilized to characterize oligomer, [4] polymer [5,6] or copolymer blend, [7] statistical, [2] block, [8,9] and graft copolymers [10] as well as to separate homopolymers according to their tacticity. [11,12] Based on the different elution behavior of homopolymers with respect to the eluent composition (exclusion, transition, adsorption), [1] several attempts have been made to develop isocratic elution methods for the determination of statistical or block copolymer composition.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Random Copolymers by Liquid Chromatography under Limiting Conditions of Adsorption

Sauzedde

Bartkowiak

Hunkeler

2006

International Journal of Polymer Analysis and Characterization

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Liquid chromatography under limiting conditions of adsorption (LC LCA) can be considered as a new tool to perform, simultaneously, molar mass and composition determination of statistical copolymers and to separate copolymer blends as a function of copolymer composition or microstructure. The suitability of LC LCA has been demonstrated for two series of statistical copolymers, poly(styrene-co-methyl methacrylate), poly(S=MMA), varying either in molar mass or composition. The binary eluent consisted of a mixture of n-hexane and THF, containing either 26 or 30 vol.% of n-hexane, respectively, for low and high LC LCA. Two parameters, the ratio of peak area over height and the ratio of peak area of chromatograms obtained by LC LCA and size exclusion chromatography (SEC), were employed to evaluate statistical copolymer elution through LC LCA. From the peak analyses, macromolecule recovery was complete over the entire composition and the molar mass ranges. LC LCA and SEC were further compared, and off-line fractionation was subsequently performed using a combination of both methods, with different statistical copolymer solutions having narrow, broad, and bimodal composition distributions.

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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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Phase separation in random copolymers from high conversion free radical polymerization, 2. Chemical heterogeneity analysis of poly(styrene-co-ethyl acrylate) by gradient HPLC

Cited by 21 publications

References 14 publications

On-line coupling of gradient-HPLC and1H NMR for the analysis of random poly[(styrene)-co-(ethyl acrylate)]s

On-line coupling of gradient-HPLC and1H NMR for the analysis of random poly[(styrene)-co-(ethyl acrylate)]s

Characterization of Random Copolymers by Liquid Chromatography under Limiting Conditions of Adsorption

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

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