CHEMICAL-COMPOSITION SEPARATION OF SYNTHETIC-POLYMERS BY REVERSED-PHASE LIQUID-CHROMATOGRAPHY

Synthetic polymers present many unique separations challenges because, unlike small organic molecules, they consist of a distribution of str ucturally different chains. Each macromolecule can differ in chain len gth and end groups; stereochemical and structural isomers are possible along with unique branching architectures. Copolymers are further com plicated by the combination of these potential variables with varying ratios and sequence distributions of their comonomer units. Liquid chr omatography of individual synthetic polymers is limited by the solutio n properties of macromolecules to a narrow selection of solvents. In p articular the thermodynamic considerations of polymer dissolution are strongly influenced by entropic factors. The application of reversed-p hase liquid chromatography to the separation of synthetic polymers is characterized by the delicate balance between strong solvation interac tions and weak adsorption interactions and is often further complicate d by polymer solubility limitations in gradient elution separations.