Abstract: A method of separating organic materials is disclosed utilizing a chromatographic packing material. This packing material includes a coated support material which is a chromatographically suitable substrate. An immobilized butadiene acrylonitrile polymer coating is provided on the substrate. The copolymer can be crosslinked by gamma radiation, or by means of a crosslinking agent such as dicumyl peroxide. The support material can be silica, alumina, diatomaceous earth, zeolite, porous glass or carbon, but preferably is spherical lamellar shaped crystals of aluminum hydroxide. The aluminum hydroxide crystals are bonded together at a central core and extend radially outward from a central core with a particle density ranging from 0.3 to 2.5 g/cm.sup.3 and a diameter of 2 to 150 microns.

Abstract: High density polymers of ethylene are produced in improved yields employing a solid Ziegler type transition metal-containing catalyst component and an organoaluminum cocatalyst in the presence of a small amount of an aliphatic diene having at least 4 carbon atoms and a terminal double bond. The amount of diene is from about 0.01 to about 3000 mole per gram atom of transistion metal in the catalyst component. The catalyst component variously may be pretreated with the diene before using the component for homopolymerization, may be prepolymerized with ethylene in the presence of the diene, may be prereduced in the presence of the diene, or the diene may be added to the polymerization reaction. Preferred dienes are .alpha.-.omega.-dienes.