Molecular characterization of statistical copolymers: 1. Potential and limitations of full adsorption-desorption procedure in separation of statistical copolymers

Berek, Dušan; Nguyen, Son Hoai; Pavlineč, J.

doi:10.1002/(sici)1097-4628(20000214)75:7<857::aid-app1>3.0.co;2-f

Cited by 9 publications

(4 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The concentration potential of the FAD procedure, already anticipated in the separation of statistical copolymers, [18] was confirmed during this work. For each crude reaction mixture, at least 10 mg was injected into the column for every separation run.…”

Section: Resultssupporting

confidence: 76%

Liquid Adsorption Chromatography Separation of Star Poly(methyl methacrylate)s

Lazzari

Jančo

Kitayama

et al. 2003

Macromol. Rapid Commun.

View full text Add to dashboard Cite

Liquid adsorption chromatography, in combination with full adsorption–desorption and precipitation–redissolution techniques, is a powerful procedure for the fractionation of mixtures in the synthesis of star polymers. An easy separation of 4‐ and 6‐arm star poly(methyl methacrylate)s from their single arm precursors could be carried out by both procedures, with differences of separation efficiency also depending on the molecular weight of the precursor and the number of arms.Size exclusion chromatograms of retained and eluted fractions obtained by liquid adsorption chromatography/full adsorption–desorption separation with a tetrahydrofuran/cyclohexane eluent system (53:47 wt.‐%) for a crude reaction mixture (dotted line) containing a 4‐arm star PMMA polymer and a single‐arm precursor (solid lines a and b, respectively).magnified imageSize exclusion chromatograms of retained and eluted fractions obtained by liquid adsorption chromatography/full adsorption–desorption separation with a tetrahydrofuran/cyclohexane eluent system (53:47 wt.‐%) for a crude reaction mixture (dotted line) containing a 4‐arm star PMMA polymer and a single‐arm precursor (solid lines a and b, respectively).

show abstract

Section: Resultssupporting

confidence: 76%

Liquid Adsorption Chromatography Separation of Star Poly(methyl methacrylate)s

Lazzari

Jančo

Kitayama

et al. 2003

Macromol. Rapid Commun.

View full text Add to dashboard Cite

show abstract

Section: Introductionmentioning

confidence: 81%

“…The proposed hypothesis is indirectly supported by the following experimental observations: (i) wide pore LAC column packings afforded molar mass dependent retention for smaller (nonexcluded) macromolecules of copolymers that were eluted without molar mass effects from narrow pore packings; 7,8 (ii) nonporous packings allowed practically no gradient LAC separation; 11 and (iii) elution of random copolymers depended on both the composition and the molar mass of macromolecules when the full adsorption-desorption procedure with a nonporous column packing was applied. 12 In the above cases, the acceleration of macromolecules due to their exclusion was either diminished (i) or practically absent (ii and iii), and the progress of polymer species was exclusively governed by their adsorption. In turn, the best molar mass independent elution was attained if the LAC column was packed with a very narrow pore (3 nm) material.…”

Section: Introductionmentioning

confidence: 99%

Liquid Adsorption Chromatography of Copolymers: Molar Mass (In)dependent Retention

Berek

1999

Macromolecules

View full text Add to dashboard Cite

Liquid adsorption chromatography with a continuous solvent gradient elution has been shown by several authors to often separate random and graft copolymers according to their chemical composition whereas their molar masses do not play an important role. A tentative explanation of this finding is presented. It is assumed that the copolymer species travel along the column with a velocity which exactly corresponds with that of the eluent composition, exhibiting a displacing power just necessary to prevent a fast progress of the macromolecules due to their exclusion. Under specific circumstances, retention of macromolecules at this adsorption promoting “barrier” depends almost exclusively on the copolymer composition and not on its molar mass. This hypothesis is based on the mechanism of the recently proposed and tested liquid chromatographic elution of homopolymers under limiting conditions of desorption and takes into account the simultaneous effect of adsorption and exclusion of macromolecules onto/from the column packing.

show abstract

“…Statistical P(S-MMA) [15] and tri-block PGMA-PMMA-PGMA [16] copolymers have also been used to test the selectivity of the FAD ap- Berek proach in terms of chemical composition separation. Our preliminary results indicate that this procedure can be used to fractionate copolymers according to chemical composition (Figures 6 and 7).…”

Section: Separation and Characterization Of Multicomponent Polymer Symentioning

confidence: 99%

Separation and Characterization of Polymers Applying Full Adsorption/Desorption Approaches

Nguyen

Berek

2002

International Journal of Polymer Analysis and Characterization

View full text Add to dashboard Cite

The present contribution is a review of the recent progress in combining a full adsorption=desorption procedure with size exclusion chromatography (FAD=SEC) for the separation and characterization of (co)polymers. FAD includes complete and selective adsorption of the polymer sample to be separated from an adsorption promoting-liquid (adsorli) onto an appropriate adsorbent, which is packed in an especially designed LC-like (micro)column. In the following steps, macromolecules are successively displaced from the adsorbent by different eluents with increasing desorbing strength. Adsorption and desorption of macromolecules are generally governed by their molecular characteristics, primarily by their molar mass (MM) and their chemical nature, that is, by their chemical composition (CC). Therefore, fractionation of polymers according to these parameters can be reached in the course of the FAD process. In this respect, a coupling of an SEC instrument with the FAD column has turned out to be very advantageous. The on-line SEC enables monitoring the amount, molar mass and molar mass distribution of macromolecules leaving the FAD column. In this way, constituents of polymer blends can be discriminated and independently characterized.Advantages and problems associated with the applications of FAD approaches are outlined. The assessment of dynamic adsorption=desorption of macromolecules onto=from solid surfaces as part of the optimization procedure is discussed as well.Polymer science and technology is required to meet product and market needs. The effectiveness of R & D should be carried out with a strong regard to product quality, as well as to safety, health and environmental values like waste reduction and energy conservation. Recently, we have witnessed rapid development of high-performance polymeric materials, e.g., polymer blends, copolymers, sequenced and functionalized polymers, i.e., complex polymer systems. Complex polymers exhibit multiple distributions, namely molar mass distribution, chemical composition distribution, distribution of functionalities, distribution of sequence lengths and possibly also physical, structural and topological distributions. These distributions are well known to affect both the processing ability and the end-use properties of polymeric materials. Therefore, the establishment of relationships between structure, processing and properties is of great importance for the development of novel polymeric materials. As a result, measurement of average properties is often inadequate to fully characterize and elucidate the nature of such materials. In other words, methods that do not involve any separation, such as osmometry, light scattering, viscometry, NMR or FT-IR and classical methods for end-group determination, can yield only average values, e.g., molar mass, chemical composition and functionality, but not their distribution(s). A combination of separation and characterization techniques or multidimensional approaches represents one of the options to fulfill the complicated task of analys...

show abstract

Molecular characterization of statistical copolymers: 1. Potential and limitations of full adsorption-desorption procedure in separation of statistical copolymers

Cited by 9 publications

References 24 publications

Liquid Adsorption Chromatography Separation of Star Poly(methyl methacrylate)s

Liquid Adsorption Chromatography Separation of Star Poly(methyl methacrylate)s

Liquid Adsorption Chromatography of Copolymers: Molar Mass (In)dependent Retention

Separation and Characterization of Polymers Applying Full Adsorption/Desorption Approaches

Contact Info

Product

Resources

About