Phase distribution chromatography (PDC) as a method for the investigation of polymers in solution 1. Thermodynamics and transport

Greschner, Georg S.

doi:10.1002/macp.1980.021810708

Cited by 9 publications

(2 citation statements)

References 15 publications

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“…The temperature of operation is below the -temperature of the solute, and separation efficiency increases sharply with decreasing temperature. A fully automated chromatograph has been designed (247), and applications have been reported (248)(249)(250).…”

Section: Chromatography the Determination Of Molecular Weight Distributionmentioning

confidence: 99%

Molecular Weight Determination

Cooper

2004

Encyclopedia of Polymer Science and Technology

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Methods to determine molecular weight averages and distributions of polymeric and oligomeric materials have been devised and developed over many decades. Most of the early classical techniques were primary methods which usually yield only a single molecular weight average, based on theory and measurable constants. Of the classical methods only ultracentrifugation can determine a molecular weight distribution. Secondary methods, which depend on the availability of calibration materials, have largely supplanted the older classical techniques. Methods based on fractionation, with molecular weight characterization of the fractions, or chromatography, with continuous determination of molecular weight, are currently used to generate molecular weight distributions. Newer methods based on dynamic light scattering and viscoelastic measurements are available to determine the molecular weight distribution of difficulty soluble materials. Development of methods to describe the molecular weight and compositional distribution of multimer polymers continues to be a vibrant research area.

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Section: Chromatography the Determination Of Molecular Weight Distributionmentioning

confidence: 99%

Molecular Weight Determination

Cooper

2004

Encyclopedia of Polymer Science and Technology

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“…However, temperatures lower than this are used for better separation results, due to the solubility of UHPS and the low resolution near to this region 15. The theoretical background of PDC was extensively investigated and explained by Greschner 16–20 including the thermodynamics of molecular transport, the flow equilibrium and the deformation concept.…”

Section: Introductionmentioning

confidence: 99%

Separation of linear and star‐shaped polystyrenes by phase distribution chromatography

Boye

Scharfenberg

Lederer

2010

J of Separation Science

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The phase distribution chromatographic technique was optimized and applied for the separation of linear and star-shaped polystyrene (PS). For this purpose non-crosslinked, ultra high molecular weight PS coated on different supporting materials was used. The stability of the coating under chromatographic conditions was tested by thermo gravimetric analysis and microscopic techniques. The modification of different column packing materials was tested. Separation according to branching was indicated for different molecular weights of linear and star-shaped PS. The resolution of the separation was improved by changing the density of the stationary phase and the temperature. The separation results were supported by cloud point measurements and the determination of the critical conditions for linear and star-polymers at the same molecular weight.

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Phase distribution chromatography (PDC) as a method for the investigation of polymers in solution, 2. Flow‐equilibrium

Greschner

1981

Makromol. Chem.

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The dynamical region of the measured calibration curves is investigated using the results of the theory published previously. The kinetic constants of the flow-equilibrium are calculated from the measurements according to two different models for a spontaneous polymer diffusion of the transported P-mer from sol into gel of the Phase Distribution Chromatography (PDC)-column. The corresponding lateral concentration profiles in the gel are found by analytical integration of Fick's second law under the corresponding boundaries. An energetic model of this flow-equilibrium is stated, giving the activation enthalpy and -entropy of the rediffusion of the polymer from gel into sol after some retardation time in the gel. The influence of the gel mass of the column on its resolution is briefly investigated. Since the measurements show that the resolution of the PDC-column vanishes in the vicinity of the theta point, spreading phenomena in the column can be investigated by means of analysis of the corresponding PDC elution curves. The results give a basis for the numerical computation of the molecular weight distribution of narrowly distributed polystyrenes from PDC elution curves at sufficiently low column temperatures. The PDC-separation effect is opposite to that of gel permeation chromatography (GPC).

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Phase distribution chromatography (PDC) as a method for the investigation of polymers in solution 1. Thermodynamics and transport

Cited by 9 publications

References 15 publications

Molecular Weight Determination

Molecular Weight Determination

Separation of linear and star‐shaped polystyrenes by phase distribution chromatography

Phase distribution chromatography (PDC) as a method for the investigation of polymers in solution, 2. Flow‐equilibrium

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