Abstract: A composite marine structure comprises a marine substrate having adhered to at least a portion of its surface a layer of a water-permeable composite article comprising a non-woven fibrous web having entrapped therein active particulate to provide said marine substrate with protection against at least one of fouling and corrosion. Underwater surfaces such as ship hulls, buoys, docks, intake pipes, etc., can be protected against marine growth and corrosion by adhering thereto the composite sheet article of the invention.

Abstract: A composite article having controlled void volume and mean pore size comprises:(a) polytetrafluoroethylene (PTFE) fibril matrix, and(b) insoluble, non-swellable sorptive particles enmeshed in said matrix, the ratio of non-swellable sorptive particles to PTFE is in the range of 40:1 to 1:4 by weight, the composite article having a porosity in the range of 30 to 80 percent void volume and a mean pore size in the range of 0.3 to 5 micrometers, preferably with at least 90 percent of pores having a size less than 3.6 micrometers.The article is prepared by incorporating lubricant in the precursor admixture in an amount sufficient to exceed the lubricant sorptive capacity of the particles by at least 3 weight percent and up to an amount at which the mass loses its integrity.

Abstract: A composite article having controlled void volume and mean pore size comprises:(a) polytetrafluoroethylene (PTFE) fibril matrix, and(b) insoluble, non-swellable sorptive particles enmeshed in said matrix, the ratio of non-swellable sorptive particles to PTFE is in the range of 40:1 to 1:4 by weight, the composite article having a porosity in the range of 30 to 80 percent void volume and a mean pore size in the range of 0.3 to 5 micrometers, preferably with at least 90 percent of pores having a size less than 3.6 micrometers.The article is prepared by incorporating lubricant in the precursor admixture in an amount sufficient to exceed the lubricant sorptive capacity of the particles by at least 3 weight percent and up to an amount at which the mass loses its integrity.

Abstract: A composite article having controlled void volume and mean pore size comprises:(a) polytetrafluoroethylene (PTFE) fibril matrix, and(b) insoluble, non-swellable sorptive particles enmeshed in said matrix, the ratio of non-swellable sorptive particles to PTFE is in the range of 40:1 to 1:4 by weight, the composite article having a porosity in the range of 30 to 80 percent void volume and a mean pore size in the range of 0.3 to 5 micrometers, preferably with at least 90 percent of pores having a size less than 3.6 micrometers.The article is prepared by incorporating lubricant in the precursor admixture in an amount sufficient to exceed the lubricant sorptive capacity of the particles by at least 3 weight percent and up to an amount at which the mass loses its integrity.

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: Articles which are composite structure are prepared which comprise a fibrillated polytetrafluoroethylene (PTFE) matrix containing enmeshed and immobilized therein viable cells capable of their usual and continuous biochemical and biological performances. The viable cells cells can be animal, bacterial, fungal or yeast. Almost all cells entrapped within said matrix are separated from each other and are unbound within said matrix such that when said matrix is cut the cells of the cut edge are free to escape from the matrix.

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.

Abstract: A polytetrafluoroethylene (PTFE) fibril matrix is prepared containing entrapped viable cells such as animal, bacterial, fungal or yeast cells. Cells are blended with surfactant and soap-free PTFE in aqueous dispersion to form a damp paste. Water is added to the paste and a resultant stiff dough is biaxially calendered between calendering rolls to cause fibrillation and form the PTFE fibril matrix. Calendering is preferably carried out at a temperature of 5.degree. to 70.degree. C. and a pressure of 1000 to 3000 MPa. The fibril matrix may be dried.

Abstract: A method of preparing a tear-resistant composite sheet material having hydrophilic, absorptive particles enmeshed in a network of interlaced microfibrous polytetrafluoroethylene forming a fibril matrix, the hydrophilic absorptive particles having absorptive particles with absorptive capacity greater than 1.0 gram of water per gram of dry particle, wherein the method comprises:(1) dry blending one or more hydrophilic, absorptive particulate materials;(2) admixing water to particulate to form a damp mixture;(3) adding gradually, with stirring, to the mixture an equal weight of an aqueous emulsion of polytetrafluoroethylene;(4) mixing the mass to cause initial fibrillation of the polytetrafluoroethylene particles;(5) biaxially calendering the mass to produce a tear-resistant sheet having a tensile strength of at least 0.5 megapascal; and(6) drying the resultant sheet to remove water.

Abstract: A composite sheet material is highly absorbent toward aqueous fluids including blood and exudate and comprises a polytetrafluoroethylene fibril matrix and hydrophilic absorptive particles enmeshed in the matrix. The composite sheet material is useful as a wound dressing, as a drying material for non-aqueous solvents, and as a chromatographic material.

Abstract: A composite wound dressing, optionally having controlled permeability, is highly absorbent toward blood and exudate and comprises a polytetrafluoroethylene fibril matrix, hydrophilic absorptive particles enmeshed in the matrix, and, optionally, a partially occlusive film coated on one surface of the matrix.

Abstract: A plant nourishment delivery device having a variable flux capability and comprising a water-permeable membrane having a conditioned flux capability in the range of about 0.005 to 10 cubic centimeters per minute per square centimeter at an applied hydrostatic pressure of about 1 atmosphere, and an exaltation of said conditioned flux capability in the range of about 30% to 10,000%.

Abstract: A polytetrafluoroethylene composite sheet having a tensile strength of at least one megapascal and comprising particulate material distributed in a matrix of interentangled polytetrafluoroethylene fibrils. The composite sheet is prepared by blending the particulate material with polytetrafluoroethylene aqueous dispersion in the presence of sufficient lubricant water to exceed the absorptive capacity of the solids yet maintain a putty-like consistency, subjecting the putty-like mass to intensive mixing at a temperature between 50.degree. C. and 100.degree. C. to cause initial fibrillation of the polytetrafluoroethylene particles, biaxially calendering the putty-like mass to cause additional fibrillation of the polytetrafluoroethylene particles while maintaining the same water content and drying the resultant sheet.

Abstract: A black sorbent thermoset foam which has been prepared by the pyrolysis of a composition comprising at least one aromatic nitrogen-containing compound having the general formula:X -- Ar -- Yin which Ar represents an aromatic nucleus on which X and Y are substituents directly attached to the nucleus, X represents a substituent having a negative Hammett sigma constant and attached to the aromatic nucleus by a nitrogen, oxygen or sulphur atom, and Y represents a substituent having a positive Hammett sigma constant and attached to the aromatic nucleus by a nitrogen atom, the substituents X and/or Y optionally forming part of a ring fused onto the aromatic nucleus, in an effective sorbtive substance for polar molecules and materials.