A rapid technique for measuring copolymer composition as a function of molecular weight using gel permeation chromatography and infrared detection

Mirabella, Francis M.; Barrall, Edward M.; Johnson, Julian F.

doi:10.1002/app.1975.070190807

Cited by 25 publications

(3 citation statements)

References 5 publications

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“…When necessary, elution in the LC LCD column was interrupted to let the analyte ''wait'' before its introduction into the SEC column. Both the band broadening of a static zone of the polymer solution [16] and the diffusion rate within a pulsing liquid [17] are surprisingly low in packed beds.…”

Section: Chromatographymentioning

confidence: 99%

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Liquid Chromatography of Polymers under Limiting Conditions of Desorption, 3

Šnauko

Berek

2005

Macro Chemistry & Physics

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Summary: Liquid chromatography under limiting conditions of desorption (LC LCD) enables the elution of adsorbing macromolecules independent of their size in solution. In this way, polymer species with different adsorptivities can be separated without mutual interference. It is shown on systems of bare silica gel, a tetrahydrofuran/toluene‐mixed eluent and poly(methyl methacrylate)s (PMMA) that LC LCD produces narrow, focused peaks with retention volumes independent of not only polymer molar mass but also, to a large extent, the concentration and volume of the injected sample. Sample capacity of LC LCD is very high, and sample volume can reach as much as 80% of the column pore volume. Reduced sample dilution or even its re‐concentration within the column is important for two‐dimensional separations. Changes in temperature as large as 40 °C only slightly affected retention volumes of the LC LCD‐eluted PMMA. Consequently, the LC LCD method is rather robust and user‐friendly. A practical application of LC LCD for the separation of model polymer blends has been demonstrated. Polystyrene and PMMA of similar molar masses were easily separated in less than four minutes using a small LC LCD column of low efficiency. The LC LCD fractions were successively transported into an on‐line SEC column either directly or after storage in the LC LCD column. The SEC system was equipped with a refractive index detector and a multi‐angle light scattering (MALS) detector. The MALS detector proved a good reproducibility of the molar masses for polymer blend components determined with a combination of LC LCD and SEC. Storage of the fractions within the LC LCD column even for several hours exhibited only a negligible effect on the determined molar mass averages.Scheme of the two‐dimensional chromatograph used. The capillary resistor had a flow resistance similar to that of the SEC column. For further details, see text.imageScheme of the two‐dimensional chromatograph used. The capillary resistor had a flow resistance similar to that of the SEC column. For further details, see text.

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Section: Chromatographymentioning

confidence: 99%

“…We have chosen to store PMMA within the LC LCD column. The interrupted elution mode, originally proposed for SEC by Mirabella et al, [16] was performed here. Elution in the low-efficiency LC LCD column, No.…”

Section: Practical Application Of Lc Lcdmentioning

confidence: 99%

Liquid Chromatography of Polymers under Limiting Conditions of Desorption, 3

Šnauko

Berek

2005

Macro Chemistry & Physics

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“…Copolymers of methyl acrylate and methyl N-vinylcarbamate [4], styrene and vinyl stearate [6,52], styrene and t-butyl methacrylate [53], styrene and acrylonitrile, and styrene and methyl methacrylate [54] can use a wavenumber around 1730cm-1 for the carbonyl group. Poly(styrene-t-butyl methacrylate) block copolymer was measured at three different wavenumbers: 1724 cm -1 for a carbonyl group, 697 cm -1 for an aromatic group.…”

Section: An Irifrared Detectormentioning

confidence: 99%