Low density materials having high surface areas and articles formed therefrom
AssigneeAlliedSignal Inc.
InventorsPeter D. Unger, Ronald P. Rohrbach
Life of this patent
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Abstract
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.
Claims9
A completely crosslinked, highly porous body derived from a water-soluble hydrogel polymer, said porous body having an open-celled 3-dimensional lattice structure, a density of less than about 1.0 g/cm.sup.3, a surface area equal to or greater than about 30 m.sup.2 /g, a compression strength of equal to or less than about 75% yield at 300 psi, and an average pore diameter from about 50.ANG. to about 500.ANG., wherein said hydrogel polymer is 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.
A covalently crosslinked gel body made in accordance with a process comprising:
- 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, polyethylamine, 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.
A covalently crosslinked gel body made in accordance with the process comprising:
- 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
- f) 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.
Dependencies are inferred from the claim text.