Adsorption of Linear Polyethylene and Isotactic Polypropylene from 1,1,2,2-Tetrachloroethane and 1,2,3-Trichloropropane on to Polar Adsorbents

Linear polyethylene and isotactic polypropylene samples were dissolved in 1,1,2,2-tetrachloroethane or 1,2,3-trichloropropane and injected at 135 °C into columns packed with porous particles of hydroxyapatite, aluminium oxide, zirconium oxide, Florisil, or silica gel. Both polymers were retained, to different extents, within the columns. It is hypothesized that the polymers interact with the surfaces of the adsorbents and are adsorbed. Retention of isotactic polypropylene from 1,1,2,2-tetrachloroethane was in the order aluminium oxide > hydroxyapatite ≈ zirconium oxide ≈ Florisil ≈ silica gel. Recovery of polyethylene from 1,1,2,2-tetrachloroethane was almost the same on aluminium oxide, hydroxyapatite, zirconium oxide, and Florisil; it was more retained by silica gel. Polyethylene was usually more retained than polypropylene. Recovery of polyethylene from both chlorinated solvents was similar whereas recovery of polypropylene was better from 1,2,3-trichloropropane than from 1,1,2,2-tetrachloroethane. Both chlorinated solvents are toxic and may attack seals in a Waters 150C chromatograph. Moreover, the polymers may be chlorinated in these solvents. For these reasons they are not optimum solvents for routine analysis. This is the first time polyethylene and polypropylene have been found to be retained by adsorbents with pore diameters in the range 60–300 Å. Desorption of the retained polymers is possible with some polar solvents.