Functional type separation of oligocarbonates by liquid chromatography under critical conditions

Abstract

The separation of linear oligocarbonates has been carried out by the type of functionality, namely the number and nature of terminal chloroanhydride and hydroxyl groups. The analysis was performed with the aid of a novel variant of HPLC — “separation in a critical region” (SCR), on the boundary of the exclusion and adsorption separation modes. The SCR method is characterised by practically complete disappearance of separation by molecular masses (sizes) while chromatograms obtained in the critical region give information only on the types of functionality of oligomers under study. The critical point for the oligocarbonates has been found on silicas “Silasorb 600” and “Lichrosphere Si 500” in a binary solvent carbon tetrachloride-chloroform. An effect of pore size on the retention volumes of macromolecules of different functionality under critical conditions is discussed.