Chromatographische eigenschaften von kieselgelen unterschiedlicher poren-struktur

Fractionation of Polymers by Thin-Layer Chromatography. III. Phase Separation and Thin-Layer Gel Permeation Chromatography

“…In adsorption mechanisms, the main considerations are the well-known dependencies of adsorption and desorption rates and equilibrium coverage on polymer molecular weight.10-12 While the energy per attachment between the polymer molecule and the substrate is invariant for homopolymers, the number of attachments per molecule increases with molecular weight, thereby providing the separation mechanism. In addition to the postulated adsorptive action, several investigators employing porous adsorbents have claimed to observe gel permeation effects modified by adsorptive interaction.5, 13 In this report we wish to describe several experiments which indicate that Inagaki's precipitation fractionation mechanism is largely correct. Several additional experiments show that while conventional adsorptive action plays a minor role in the fractionating action of tic, macroporous adsorbents exhibit definite size fractionation when solubility effects are circumvented.…”