摘要:
A process for the preparation of a microporous polymeric membrane is provided which includes polymerizing a polymerizable fluorine-containing monomer in the presence of a microporous polymeric membrane substrate such that the fluorine-containing monomer forms a polymeric superstrate that is permanently chemically bonded to all surfaces of the membrane. A device is also provided for processing fluids which incorporates a microporous polymeric membrane having a CWST of less than about 28 dynes/cm and includes a microporous polymeric membrane substrate formed from a material such as a fluoropolymer and, permanently chemically bonded to all portions of the surface thereof is a superstrate, which may be a polymer or copolymer derived from a monomer(s), having an ethylenically unsaturated group and a perfluoroalkyl group. A gas filtration/drying process, a method of venting a gas from a vessel and a method of separating a gas from a liquid in a gas/liquid mixture using a microporous polymeric membrane having a CWST less than about 28 dynes/cm which includes a microporous polymeric membrane substrate and a superstrate fluoropolymer permanently chemically bonded to all portions of the membrane substrate are also provided.
摘要:
A self-supporting structure comprising an inorganic sorbent and method for preparing is described in which the self-supporting structure is substantially free of sorbent fines and the sorption characteristics of the sorbent particles is retained. The process for immobilizing the sorbent particles in the self-supporting structure comprises the steps of:(a) preheating inorganic sorbent particles to an elevated temperature;(b) mixing the sorbent particles with particles of a polymeric binding material to form a mixture comprising the particles of polymeric binding material adhered to the sorbent particles; and(c) heating the mixture to about the solid-liquid transition temperature of the polymeric binding material with or without pressure to form a structure which upon cooling is self supporting.
摘要:
A supported microporous membrane comprising a composite of a microporous membrane and a synthetic thermoplastic web of microfibers secured to the membrane without the use of added adhesive components and having an ASTM D903 peel strength of at least about 2 grams per centimeter, the composite having a modulus of flexure at leasts 10 percent greater than that of the membrane, and the method of manufacturing such supported membranes by contacting thermplastic microfibers with the membrane while the microfibers are at an elevated temperature.
摘要:
Polymeric microfibrous structures comprised of normally hydrophobic microfibers coated with a cured, precipitated, cationic, thermosetting binder resin or polymer and characterized by being hydrophilic and having a positive zeta potential with enhanced capability for the removal of negatively-charged particulate material in a fluid medium are prepared by a process comprising the steps:(1) combining in a controlled manner a first solution of a water-soluble, non-colloidal, cationic, thermosetting binder resin or polymer and a second solution or dispersion of a precipitating agent to form a stable emulsion or suspension;(2) impregnating the microfibrous structure of normally hydrophobic microfibers with the stable emulsion or suspension to form a fibrous structure wetted with the stable emulsion or suspension; and(3) drying the wetted microfibrous structure and curing the binder resin or polymer.
摘要:
Microporous membranes having positive zeta potentials in alkaline pH are provided by radiation grafting diallyldimenthylammonium dimethyl ammonium chloride to the surraces of a microporous, polyamide membrane using ionizing radiation. The membranes have particular use in microelectronics manufacture where quick rinse up times with ultrapure water are required.
摘要:
Surface modified, skinless, hydrophilic, microporous, polyamide membranes with controlled surface properties are prepared by the steps of preparing a casting solution comprised of (A) a casting resin system comprised of (a) an alcohol-insoluble polyamide resin, and (b) a water-soluble membrane surface modifying polymer having functional polar groups and a molecular weight of 10,000 or greater, and (B) a solvent system in which the casting resin system is soluble; inducing nucleation of the casting solution by controlled addition of a nonsolvent for the casting resin system under controlled conditions to obtain a visible precipitate of casting resin system particles, thereby forming a casting composition; spreading the casting composition on a substrate to form a thin film; contacting and diluting the film of the casting composition with a liquid nonsolvent system for the casting resin system, thereby precipitating the casting resin system from the casting composition in the form of a thin, skinless, hydrophilic, surface modified, microporous, polyamide membrane; and washing and drying the membrane. The membranes of this invention are characterized by having fine pore ratings, the surface properties thereof being substantially controlled by functional polar groups of a membrane surface modifying polymer and having the capability, through the functional polar groups of the modifying polymer, of reacting or interacting with particulates and/or nonparticulates in a fluid.
摘要:
Microfibrous, polymeric filter sheets and filter elements prepared therefrom comprised of a normally hydrophobic, microfibrous, polymeric web, wherein the surfaces of the microfibers making up the web are coated with a cured, precipitated, cationic, thermosetting binder resin or polymer. The filter sheet is further characterized by being hydrophilic and having a positive zeta potential.The process for preparing such filter sheets comprises four steps:(1) applying a first solution or dispersion of a precipitating agent to a hydrophobic web to at least partially wet the web;(2) applying a second solution of the binder resin or polymer to the wetted web of step (1);(3) working the wetted web of step (2) to mix the first and second solutions, thereby facilitating the precipitation of the binder resin or polymer and the distribution of the precipitated binder resin or polymer as a coating on the surface of the microfibers making up the worked web; and(4) drying and curing the coated web of step (3) to form the desired filter sheets.The filter sheets have enhanced mechanical strength, are hydrophilic, have positive zeta potentials over the pH range of from about 3 to about 10 and typically have absolute pore ratings of from about 0.5 to about 80 micrometers.
摘要:
A process for cleaning porous metal filters, particularly stainless steel filters, comprising the steps of:(1) electrolyzing the filter in an electrolyte bath using the filter as one of the electrodes, preferably as the cathode of the electrolytic system, and subjecting the system to an imposed or applied current, highly preferably a DC current; and(2) rinsing the filter to remove electrolytic solution from the filter and flush any residual contaminants from the filter.When organic material is to be removed, a baking step prior to the electrolysis step is used.
摘要:
A porous medium having a positive surface change removes heparin from a heparin-containing liquid, without removing other proteinaceous components from the liquid. Methods and devices are disclosed.
摘要:
A porous chemically activated medium having a low affinity for peptide group-containing materials is provided comprising a porous polymeric medium having a low affinity for peptide group-containing materials covalently bound to a residue of an activating agent which is capable of reacting with an acceptor molecule.