Characterization of swollen polymer gels using size exclusion chromatography

Application of micropellicular poly-styrene/divinylbenzene stationary phases for high-performance reversed-phase liquid chromatography electrospray-mass spectrometry of proteins and peptides

“…Ethyl groups originate from the ethylstyrene monomer present in technical divinylbenzene preparations and vinyl groups come from the second vinyl groups of divinylbenzene which have not been incorporated into the polymer [32]. The core of highly crosslinked PS/DVB beads is not permeable for eluant or analyte molecules [33], the surface of the particles, however, is not totally smooth but is built up by linear and branched polymer chains resulting in a swollen polymer network, especially when hydroorganic mobile phases are used [33]. These inherent chemical properties of a polymer surface give rise to contributions to the retention and band broadening of solutes small enough to be trapped in the chains of the swollen polymer surface [34,35].…”

Towards porous polymer monoliths for the efficient, retention-independent performance in the isocratic separation of small molecules by means of nano-liquid chromatography

“…Also we found the strongly enhanced performance for monoliths derived from incomplete conversion to be less affected by specific surface areas when studying the isocratic separation of small molecules [15]. Therefore we suggested that the gel porosity, porosity only present in the solvated and swollen polymer [32], becomes the limiting factor for their performance including a retention-dependent efficiency in the separation of small molecules [15]. Such gel-porosity may be ascribed to the presence of varying cross-linking degrees originating from non-ideal reactivity ratios persisting between typically used mono-and di-vinyl precursors in the preparation of macroporous copolymer networks [33].…”

Catalytic Activity and Accessibility of Acidic Ion-Exchange Resins in Liquid Phase Etherification Reactions

“…Isobutene is slightly bigger than ethanol. To quantify the ease of penetration of a molecule into a porous domain of a certain density, in relation to its quantity in the free solution, the Ogston distribution coefficient, K O , estimated by [7,28] Table 2 agree with the fact that transport through gradually denser domains is more hindered for longer alcohols than for shorter ones. It is also noticeable that K O values for a given polymer density decrease progressively as the alcohol size increases.…”

“…the ion-exchanger, as the stationary phase in a liquid chromatography column, and measures elution volumes of solutes with a characteristic molecular size. Then, under the considered assumptions: (a) a simple geometric model can describe the pore system, and (b) the pore system can be treated as a discrete set of fractions with simple pores of a single size, the mathematical treatment of the data provided by the ISEC analysis provides information on pore volume distributions [6,7,32].…”

“…Up to date, the only procedure employed to characterize the morphology of ion-exchangers in the swollen state is the Inverse Steric Exclusion Chromatography (ISEC), based on modeling the microporous structure as a set of discrete volume fractions with different characteristic polymer chain densities [6,7]. The ISEC technique is appropriate to assess the catalytic behavior in chemical reactions, since it is based upon the swelling of ion-exchangers in water, for water was found to be the most suitable solvent in terms of reducing enthalpic interactions between polymer and solute [8], despite a number of industriallyinteresting reactions take place in water-free environment.…”