Thermodynamic and hydrodynamic properties of the the systems polymer—tetrahydrofuran—water: 1. Solution properties of polystyrene

Spychal, T.; Lath, D.; Berek, Dušan

doi:10.1016/0032-3861(79)90067-3

Cited by 53 publications

(24 citation statements)

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“…Large scatter of experimental K and a values is attributed to presence of water in THF, which is highly hygroscopic [11]. The azeotropic mixture of THF and water contains about 5 wt.% of water and its boiling point differs less than 3 • C from the boiling point of dry THF (65.9 • C) at atmospheric pres- sure.…”

Section: Resultsmentioning

confidence: 92%

“…The azeotropic mixture of THF and water contains about 5 wt.% of water and its boiling point differs less than 3 • C from the boiling point of dry THF (65.9 • C) at atmospheric pres- sure. The a values for PS determined in dry THF lie around 0.73 [11]. It is supposed that THF is a good solvent also for PnBMA.…”

Section: Resultsmentioning

confidence: 99%

“…Tetrahydrofuran is a thermodynamically good solvent for polystyrene: a ranges from 0.64 to 0.768 at 25-30 • C [4,11]. Large scatter of experimental K and a values is attributed to presence of water in THF, which is highly hygroscopic [11].…”

Section: Resultsmentioning

confidence: 99%

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Evaluation of liquid chromatography column retentivity using macromolecular probes

Berek

2003

Journal of Chromatography A

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Section: Resultsmentioning

confidence: 92%

Section: Resultsmentioning

confidence: 99%

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Evaluation of liquid chromatography column retentivity using macromolecular probes

Berek

2003

Journal of Chromatography A

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“…Unfortuthe Kuhn-Mark-Houwink-Sakurada viscosity nately, narrow pore silica gels with large pore vollaw using constants K Å 11.6 1 10 03 mL/g and a ume are not available. Å 0.73 for PS in THF, 11 and K Å 7.5 1 10 03 mL/ The calibration curves of log M vs. V R for PS g and a Å 0.72 for PMMA in THF 12 at 25ЊC. and PMMA show a pronounced divergence toThe separation selectivity of the column set wards low molar mass region.…”

Section: Resultsmentioning

confidence: 97%

Liquid chromatography of macromolecules at the critical adsorption point. II. Role of column packing: Bare silica gel

Berek

Jančo

Meira

1998

J. Polym. Sci. A Polym. Chem.

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“…Macromolecules of PS are rather homogeneous as to their physical architecture, and appropriate samples are readily available. The constants K and a in the Kuhn‐Mark‐Houwink‐Sakurada viscosity law [ η ] = K · M a , where [ η ] is the intrinsic viscosity, were determined for PSs in several single and mixed solvents 23–26. The exponent a is a measure of thermodynamic quality of solvent for linear macromolecules23 though there exists some doubt about its universality,27 especially for concentrated polymer solutions.…”

Section: Experimental Partmentioning

confidence: 99%

Adsorption and Enthalpic Partition in Liquid Chromatography of Non‐Charged Synthetic Polymers, 3

Berek

2005

Macro Chemistry & Physics

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Summary: Two kinds of retention mechanisms of polystyrene (PS) macromolecules are considered in liquid chromatography (LC) applying alkane-bonded silica gel phases as column packings. They are based on non-polar interactions between polymer segments and alkane groups, which lead to adsorption of polymer species on the surface situated between bonded alkane groups and eluent on the one hand (interphase adsorption) and to partition of macromolecules between bonded phase volume and eluent (enthalpic partition) on the other hand. The roles of both retention mechanisms were assessed for PS species with different molar masses and several series of binary eluents. Bare silica and C-1, C-4, C-8, as well as C-18-bonded phases were compared. The results demonstrated that the eluent had to be a thermodynamically poor solvent for macromolecules to push them onto/into the bonded phase. However, no quantitative dependence between the eluent's thermodynamic quality for macromolecules and the extent of retention of polymer species was found. Similarly, no correlation was identified between eluent quality and prevailing retention mechanism -either interphase adsorption on the trimethylsilylated silica gel or interphase adsorption plus enthalpic partition in the case of C-4, C-8 and C-18-bonded phases. The explanation is to be sought in the actual ''composition'' of the preferentially solvated macromolecules and bonded alkane groups. The bonded phase probably has to be a slightly better ''solvent'' than the eluent for a polymer species to cause their retention. Enthalpic partition of PS plays an especially important role in DMF/THF mixed eluents. The results indicate, however, that only three to five terminal -CH 2 -groups plus the methyl end-group take part in the enthalpic partition process. This means that silica gel bonded with shorter alkane groups may be advantageous compared to the C-18 packings in some coupled high performance liquid chromatography methods for synthetic polymers, combining entropic and enthalpic retention mechanisms.log V h vs. V R for bare Kromasil (&), as well as for C-18 (^), C-8 (!), C-4 (~) and C-1 (*) phases.

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Thermodynamic and hydrodynamic properties of the the systems polymer—tetrahydrofuran—water: 1. Solution properties of polystyrene

Cited by 53 publications

References 35 publications

Evaluation of liquid chromatography column retentivity using macromolecular probes

Evaluation of liquid chromatography column retentivity using macromolecular probes

Liquid chromatography of macromolecules at the critical adsorption point. II. Role of column packing: Bare silica gel

Adsorption and Enthalpic Partition in Liquid Chromatography of Non‐Charged Synthetic Polymers, 3

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