Identification Method of Synthetic Polymers by High-Performance Liquid Chromatography

Abstract

Polyvinyl chloride (PVC), polyvinyl acetate (PVAc), and their copolymers and blends, polystyrene, poly(methyl, ethyl, and butyl) acrylates and methacrylates were dissolved in tetrahydrofu-ran (THF), respectively, and the solutions were injected into a column of silica gel having a pore diameter of 30 A and eluted with the mobile phases of THF, chloroform, ethyl acetate, methanol, methylethylketone, acetonitrile and 1, 2-dichloroethane (DCE). Some polymers eluted from the column and the rest were retained in the column. The identification of the polymers was not based on the difference in the retention volumes of the polymers, but the elution of the polymers from or the retention in the column were a measure of the identification. This technique was termed as “On-Off Elution Method”. Two retention mechanisms were proposed: hydrogen bonding between silica gel and the sample polymers, and the precipitation of polymers in the column. In case of the former, some polymers were retained in the column even though a good solvent to the polymers was used as the mobile phase. When poor solvents to the polymers were used as the mobile phases, the polymers were precipated in the column, except PVC with DCE. The physical blond of PVC and PVAc could be discriminated from the copolymer having the sane composition by this procedure.