Molar Mass and Microstructure Analysis of PI‐<i>b‐</i>PMMA Copolymers by SEC‐NMR

Hehn, Mathias; Hiller, Wolf; Wagner, Thomas; Thiel, Jürgen; Pasch, Harald

doi:10.1002/macp.201100645

Cited by 24 publications

(40 citation statements)

References 28 publications

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Section: Resultsmentioning

confidence: 99%

Quantitative Studies of Block Copolymers and Their Containing Homopolymer Components by Diffusion Ordered Spectroscopy

Hiller

2019

Macro Chemistry & Physics

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Several polystyrene‐b‐poly(methyl methacrylate) (PS‐b‐PMMA) and polyisoprene‐b‐PMMA (PI‐b‐PMMA) block copolymers are studied with high‐resolution diffusion ordered spectroscopy (DOSY) in order to quantify the amounts and molar masses of the copolymers and the containing homopolymers. These studies are particularly challenging because these homopolymers and one block of the copolymers consist of the same monomer type with different molar masses and compositions and cause a total overlap of these polymer components in the NMR spectra. However, DOSY can be proven as a powerful tool for separation and quantification of these moieties. Whereas exponential fittings only deliver averaged diffusion data, biexponential fittings of the individual magnetization curves can separate the overlapping polymer parts. This DOSY approach can be successfully tested for different blends of PS as well as PS and PS‐b‐PMMA of different molar masses and weighed compositions. The DOSY separation is also compared to size exclusion chromatography (SEC). In the case of the PS‐b‐PMMA and PI‐b‐PMMA block copolymers, DOSY identifies the contaminations with homopolymers, quantifies their individual amounts as well as determines the molar masses of both the copolymers and homopolymers. Two mathematical evaluations are used for quantifying these homopolymers with DOSY. These results are compared with the online coupling of SEC and NMR.

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Section: Resultsmentioning

confidence: 99%

Quantitative Studies of Block Copolymers and Their Containing Homopolymer Components by Diffusion Ordered Spectroscopy

Hiller

2019

Macro Chemistry & Physics

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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.…”

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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“…Similar works on SEC–HF‐NMR combinations followed. Among the systems investigated were PI‐PMMA block copolymers, PI with different microstructures, and PS‐PMMA block copolymers . Despite these and other successful studies, the usage of SEC–HF‐NMR lags behind the other mentioned information‐rich detectors, which is most likely due to operational requirements and the high costs and complexity of HF‐NMR instruments especially when compared with those of a typical SEC setup.…”

Section: Introductionmentioning

confidence: 99%

Medium Resolution ¹H‐NMR at 62 MHz as a New Chemically Sensitive Online Detector for Size‐Exclusion Chromatography (SEC–NMR)

Höpfner

Ratzsch

Botha

et al. 2018

Macromol. Rapid Commun.

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A state-of-the-art, medium-resolution H-NMR spectrometer (62 MHz) is used as a chemically sensitive online detector for size-exclusion chromatography of polymers such as polymethylmethacrylate (PMMA) and polystyrene (PS). The method uses protonated eluents and works at typical chromatographic conditions with trace amounts of analytes (<0.5 g L after separation). Strong solvent suppression, e.g., by a factor of 500, is achieved by means of T -filtering and mathematical subtraction methods. Substantial improvements are made with respect to previous work in terms of the sensitivity (signal-to-noise ratio up to 130:1, PMMA OCH ) and selectivity (peak width, full width half maximum (FWHM) 4 Hz on-flow). Typical homopolymers and a blend are investigated to deformulate their composition along the dimensions of molecular weight and NMR chemical shift. These results validate this new hyphenated chromatography method, which can greatly facilitate analysis and is much more effective than previously published results.

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Molar Mass and Microstructure Analysis of PI‐b‐PMMA Copolymers by SEC‐NMR

Cited by 24 publications

References 28 publications

Quantitative Studies of Block Copolymers and Their Containing Homopolymer Components by Diffusion Ordered Spectroscopy

Quantitative Studies of Block Copolymers and Their Containing Homopolymer Components by Diffusion Ordered Spectroscopy

Advanced fractionation methods for the microstructure analysis of complex polymers

Medium Resolution ¹H‐NMR at 62 MHz as a New Chemically Sensitive Online Detector for Size‐Exclusion Chromatography (SEC–NMR)

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Molar Mass and Microstructure Analysis of PI‐b‐PMMA Copolymers by SEC‐NMR

Cited by 24 publications

References 28 publications

Quantitative Studies of Block Copolymers and Their Containing Homopolymer Components by Diffusion Ordered Spectroscopy

Quantitative Studies of Block Copolymers and Their Containing Homopolymer Components by Diffusion Ordered Spectroscopy

Advanced fractionation methods for the microstructure analysis of complex polymers

Medium Resolution 1H‐NMR at 62 MHz as a New Chemically Sensitive Online Detector for Size‐Exclusion Chromatography (SEC–NMR)

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Medium Resolution ¹H‐NMR at 62 MHz as a New Chemically Sensitive Online Detector for Size‐Exclusion Chromatography (SEC–NMR)