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US 5,541,234 AGranted
Process for making low density hydrogel materials having high surface areas
AssigneeAlliedSignal Inc.
InventorsPeter D. Unger, Ronald P. Rohrbach
Life of this patent
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Abstract
A process for making a crosslinked, highly porous body derived from a water-soluble, hydrogel polymer, wherein the porous body is characterized in that it has an open-celled 3-dimensional lattice structure, a density of less than about 1.0 g/cm.sup.3, a surface area of equal to or greater than about 30 m.sup.2 /g, and a compression strength of equal to or less than about 75% yield at 300 psi.
Claims10
A process for making a crosslinked, highly porous body comprising the steps of:
- a) dissolving a hydrogel polymer in a gelling solvent, said hydrogel polymer selected from the group consisting of alginates, gums, starch, dextrins, agar, gelatins, casein, collagen, polyvinyl alcohol, polyethylenimine, acrylate polymers, starch/acrylate copolymers, and mixtures and copolymers thereof,
- b) forming a gel from the dissolved polymer solution into a desired configuration,
- c) gradually replacing said gelling solvent with a crosslinking solvent by employing a concentration gradient solvent exchange process,
- d) adding a crosslinking agent to crosslink said gel, and
- e) isolating the crosslinked gel from said crosslinking solvent,
- wherein said porous body is characterized in that it has an open-celled 3-dimensional lattice structure, a density of less than about 1.0 g/cm.sup.3, a surface area of equal to or greater than about 30 m.sup.2 /g, and a compression strength of equal to or less than about 75% yield at 300 psi.
3 more elements
A process for making a crosslinked, highly porous body comprising the steps of:
- a) dissolving a hydrogel polymer in a gelling solvent that contains an additive selected from the group consisting of surfactants, elastomeric additives, and polyols, said hydrogel polymer selected from the group consisting of alginates, gums, starch, dextrins, agar, gelatins, casein, collagen, polyvinyl alcohol, polyethylenimine, acrylate polymers, starch/acrylate copolymers, and mixtures and copolymers thereof,
- b) forming a gel from the dissolved polymer solution into a desired configuration,
- c) freeze-drying said gel,
- d) adding a crosslinking solvent to the freeze-dried gel,
- e) adding a crosslinking agent to said crosslinking solvent, and
- e) isolating the crosslinked gel from said crosslinking solvent,
- wherein said porous body is characterized in that it has an open-celled 3-dimensional lattice structure, a density of less than about 1.0 g/cm.sup.3, a surface area of equal to or greater than about 30 m.sup.2 /g, and a compression strength of equal to or less than about 75% yield at 300 psi.
4 more elements
Dependencies are inferred from the claim text.