Abstract: A layered filter composite comprises a filter medium, and on the upstream surface thereof a homogeneous or graded layer of nonporous spherical glass microbeads as a filter aid. A method for filtering or prefiltering a liquid mixture is disclosed wherein a layer of glass microbeads is used as a filter or filter aid. The layered filter composite is useful in analytical applications as well as in large scale industrial and remedial (clean-up) applications.

Abstract: A composite chromatographic sheet-like article is prepared by the steps comprising blending one or more non-swellable sorptive hydrophobic particulate materials in the presence of an amount of polar organic masking agent sufficient to allow rapid wetting of the surface of the particulate and in the presence of sufficient lubricant water to exceed the sorptive capacity of the particulate, provided that the volume ratio of water to masking agent does not exceed 3:1, adding with stirring an aqueous emulsion of polytetrafluoroethylene so that the resulting mass has a dough-like consistency, mixing the mass in an intensive mixer at a temperature between 50 C. and 100 C. for a time sufficient to cause fibrillation of the polytetrafluoroethylene particles, biaxially calendering the mass, while maintaining water at a level near the absorptive capacity of the particulate, between a gap in the calendering rolls maintained at about 50 C. to about 100 C.

Abstract: A composite chromatographic article comprising: (a) a polytetrafluoroethylene fibril matrix, and(b) non-swellable sorptive particles enmeshed in said matrix, the ratio of non-swellable sorptive particles to polytetrafluoroethylene being in the range of 19:1 to 4:1 by weight, said composite article having a net surface energy in the range of 20 to 300 milliNewtons per meter.

Abstract: A composite chromatographic article comprising:(a) a polytetrafluoroethylene fibril matrix, and(b) non-swellable sorptive particles enmeshed in said matrix, the ration of non-swellable sorptive particles to polytetrafluoroethylene being in the range of 19:1 to 4:1 by weight, said composite article having a net surface energy in the range of 20 to 300 milliNewtons per meter.