HPLC‐1H‐NMR Characterization of Polystyrene‐block‐Polyisoprene Copolymers: LCCC‐1H‐NMR Using a Single Mobile Phase

Sinha, Pritish; Hiller, Wolf; Pasch, Harald

doi:10.1002/masy.201450305

Cited by 7 publications

(5 citation statements)

References 28 publications

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“…The method enables—especially in the 2D combination with another polymer HPLC method—independent estimation of molecular characteristics of constituents of numerous complex polymers and complex polymer systems . If assisted by other appropriate characterization methods such as NMR or MALDI‐TOF LC CC can invaluably contribute to progress in science and technology of synthetic polymers. So far, LC CC is the only method, which permits at least approximate assessment of molar mass average and dispersity of particular blocks in block copolymers.…”

Section: Discussionmentioning

confidence: 99%

“…This ingenious idea was for the first time in practice employed by Zimina et al. and afterward by numerous other authors . Later, some uncertainty was expressed concerning straightforward universal applicability of LC CC for molecular characterization of complex polymers including determination of molar mass average and dispersity of the noninteractive blocks in diblock copolymers , however they mostly remained overlooked.…”

Section: Coupled Lc Methodsmentioning

confidence: 99%

“…Considering the random walk model, Guttman et al [21] theoretically confirmed the concept of invisibility proposed by Gorbunov and Skvortsov. This ingenious idea was for the first time in practice employed by Zimina et al [22][23][24] and afterward by numerous other authors [25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40]. Later, some uncertainty was expressed concerning straightforward universal applicability of LC CC for molecular characterization of complex polymers including determination of molar mass average and dispersity of the noninteractive blocks in diblock copolymers [41][42][43], however they mostly remained overlooked.…”

Section: Coupled Lc Methodsmentioning

confidence: 99%

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Critical assessment of “critical” liquid chromatography of block copolymers

Berek

2016

J of Separation Science

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Brief elucidation is presented of potential difficulties the researcher can face in the course of the molecular characterization of block copolymers with help of liquid chromatography under critical conditions. The impediments include the demanding identification of critical conditions, the limited area of applicable polymer molar mass, the high sensitivity of critical conditions toward minute changes in experimental conditions including changes in the interactivity of the column packing, extensive band broadening, limited sample recovery, pressure effects, detection problems, coelution of block copolymers with their noninteractive parent homopolymers, possible effect of the noninteracting chains of block copolymers on the behavior of the interacting blocks, and role of preferential solvation of macromolecules in mixed solvents. These matters may complicate proper data evaluation and challenge the exactness of results obtained. Special attention is paid to the so far neglected phenomena of preferential solvation, which may affect not only detection of block copolymers but also their retention. The latter occurrence is demonstrated by the behavior of both poly(methyl methacrylate)s eluted from bare silica gel in a mixed eluent tetrahydrofuran plus toluene and polystyrenes eluted from silica gel C18 bonded phase with the mobile phase of tetrahydrofuran/n-hexane.

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Section: Discussionmentioning

confidence: 99%

Section: Coupled Lc Methodsmentioning

confidence: 99%

Section: Coupled Lc Methodsmentioning

confidence: 99%

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Critical assessment of “critical” liquid chromatography of block copolymers

Berek

2016

J of Separation Science

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“…[53] LC-NMR has also been shown to be a very effective way to analyze PS-PI block copolymers. [54,55] As was pointed out in the introduction, there are a number of microstructural features that are characteristic for polymers. Probably, the feature that is least addressed by advanced fractionation methods is isotope distribution.…”

Section: Microstructure Analysis By Column-based Fractionationsmentioning

confidence: 96%

“…In a similar approach, the molar mass and microstructure analysis of PI‐ b ‐PMMA copolymers was conducted by SEC‐NMR . LC‐NMR has also been shown to be a very effective way to analyze PS‐PI block copolymers …”

Section: Microstructure Analysis By Column‐based Fractionationsmentioning

confidence: 99%

Advanced fractionation methods for the microstructure analysis of complex polymers

Pasch

2015

Polymers for Advanced Techs

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This review discusses some recent work on the microstructure analysis of complex polymers using advanced fractionation methods. Complex polymers are distributed in a number of molecular parameters including molar mass, chemical composition, molecular architecture, and microstructure. Molar mass and chemical composition analysis is typically conducted by a range of spectroscopic and chromatographic methods, size exclusion chromatography and high-performance liquid chromatography (HPLC) being the most important fractionation methods. It is shown that HPLC is also very sensitive regarding polymer microstructure and can be used for the fractionation of e.g. polymethacrylates, polyisoprene, and polybutadiene. The best approach to the quantitative analysis of microstructure distributions is the on-line coupling of the fractionation with 1 H nuclear magnetic resonance spectroscopy. The spectroscopic analysis of chromatographic fractions provides concentration profiles of the tactic units as a function of the chromatographic separation and can be used for both HPLC and size exclusion chromatography. Apart from column-based fractionations, channel-based fractionations such as thermal field flow fractionation are powerful tools for microstructure analysis of complex polymers. It has been shown very recently that thermal field flow fractionation is capable of fractionating polyisoprene and polybutadiene according to microstructure.

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Fractionation of Polymers

Lederer¹,

Ndiripo²

2023

Encyclopedia of Polymer Science and Technology

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Synthetic and natural polymers exist in microstructural distributions, such as chain length, size, chemical composition, branching, tacticity, or comonomer sequence distributions. Polymer fractionation techniques are essential for the analysis of these distributions and help in understanding polymerization mechanisms and material properties. In this article, the theoretical basics of general fractionation approaches and specific fractionation techniques are discussed. Details are given on fractionation techniques for molar mass and chemical composition distribution analysis, such as temperature rising elution fractionation (TREF), crystallization analysis fractionation (CRYSTAF), or crystallization elution fractionation (CEF). In addition, column‐based and channel‐based fractionation methods are extensively discussed. Theoretical and practical aspects of the analysis of molar mass distributions using size exclusion chromatography (SEC) as well as chemical composition distributions by interaction chromatography (SGIC, TGIC, LCCC) and multidimensional separations (2D‐LC) are reviewed and compared. General aspects and details on asymmetrical flow and thermal field flow fractionation techniques (AF4 and ThFFF) are discussed and examples of suitable physical and chemical detectors coupled to fractionation devices for the analysis of size, conformation, or chemical composition and topology are demonstrated.

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HPLC‐¹H‐NMR Characterization of Polystyrene‐block‐Polyisoprene Copolymers: LCCC‐¹H‐NMR Using a Single Mobile Phase

Cited by 7 publications

References 28 publications

Critical assessment of “critical” liquid chromatography of block copolymers

Critical assessment of “critical” liquid chromatography of block copolymers

Advanced fractionation methods for the microstructure analysis of complex polymers

Fractionation of Polymers

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