Fractionation of functional polystyrenes, poly(ethylene oxide)s and poly(styrene)-b-poly(ethylene oxide) by liquid chromatography at the exclusion-adsorption transition point

The paper reports the fractionation of functional polystyrenes (PSs) and po ly(ethylene oxide)s (PEOs) as well as their block copolymers, by liquid chr omatography at the exclusion adsorption transition point (EATP-LC), also ca lled "critical conditions" mode. In this specific elution mode (EATP-LC), t he fractionation is only governed by the nature and the number of functions attached to the polymer backbone, independent of the molar mass distributi on of the whole sample. Functional polystyrenes (alpha- and/or alpha,omega -alcohol-, acetal-, aldehyde- and acidic-PS) could be readily separated fro m nan-functional polystyrenes under various chromatographic conditions. The technique also allowed the fractionation of poly(ethylene oxide)s and PS-P EO block copolymers. In the latter cases, moderately polar columns (grafted silica) and water-based polar eluents were required to obtain a satisfacto ry fractionation. (C) 2001 Elsevier Science B.V. All rights reserved.