Superabsorbent foams, and method for producing the same
First Claim
1. A method for producing a microporous, absorbent foam, comprising the steps of:
- (a) mixing a cross-linkable polymer and a first solvent to form a stable solution, wherein said stable solution can be induced to phase separate;
(b) inducing said stable solution to phase separate into a polymer-concentrated phase and a polymer-dilute phase;
(c) inducing chemical crosslinking of said polymer, so that said polymer will crosslink in said concentrated phase during said phase separation to thereby form a microporous material; and
(d) drying said microporous material to produce said absorbent foam.
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Abstract
An absorbent, microporous foam comprising a crosslinked polymer having interconnected fluid cells distributed throughout its mass, wherein the fluid cells have a diameter of between about 0.1 and about 100 μm, and wherein the foam can rapidly absorb at least about twice its dry weight in fluid, is disclosed.
A method for producing a microporous, absorbent foam is also disclosed. This method comprises the steps of:
(a) mixing a cross-linkable polymer and a first solvent to form a stable solution, wherein the stable solution can be induced to phase separate;
(b) inducing the stable solution to phase separate into a polymer-concentrated phase and a polymer-dilute phase after a predetermined period of time;
(c) inducing crosslinking of said polymer, so that the polymer will crosslink in said concentrated phase for a predetermined period of time during phase separation to thereby form a microporous material; and
(d) drying the microporous material to produce the absorbent foam.
108 Citations
37 Claims
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1. A method for producing a microporous, absorbent foam, comprising the steps of:
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(a) mixing a cross-linkable polymer and a first solvent to form a stable solution, wherein said stable solution can be induced to phase separate; (b) inducing said stable solution to phase separate into a polymer-concentrated phase and a polymer-dilute phase; (c) inducing chemical crosslinking of said polymer, so that said polymer will crosslink in said concentrated phase during said phase separation to thereby form a microporous material; and (d) drying said microporous material to produce said absorbent foam. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A method for producing a microporous, open-celled foam, comprising the steps of:
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(a) mixing hydroxypropyl cellulose (HPC) and water to form a substantially homogeneous, single-phase solution; (b) inducing crosslinking of said HPC by adding a suitable crosslinking agent to said single-phase solution; (c) inducing phase separation of said single-phase solution into a polymer-concentrated phase and a polymer-dilute phase, wherein said phase separation is induced by increasing the temperature of said single-phase solution to above the lower consolute solution temperature of said single-phase solution; (d) permitting said crosslinking to continue, so that said HPC will crosslink in said concentrated phase during said phase separation to thereby form a microporous material; and (e) drying said microporous material to produce said foam. - View Dependent Claims (26, 27, 28, 29, 30)
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31. A method for producing a microporous, open-celled foam, comprising the steps of:
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(a) mixing hydroxyethyl cellulose (HEC), water and a phase-separation enhancer to form a substantially homogeneous, single-phase solution, wherein said phase-separation enhancer is chosen from the group consisting of;
a salt, a water-soluble organic solvent, and a combination of a salt and a water-soluble organic solvent;(b) inducing crosslinking of said HEC by adding a suitable crosslinking agent to said single-phase solution; (c) inducing phase separation of said single-phase solution into a polymer-concentrated phase and a polymer-dilute phase, wherein said phase separation is induced by increasing the temperature of said single-phase solution to above the lower consolute solution temperature of said single-phase solution; and (d) permitting said crosslinking to continue, so that said HEC will crosslink in said concentrated phase during said phase separation to thereby form a microporous material; and (e) drying said microporous material to produce said foam. - View Dependent Claims (32, 33, 34, 35, 36, 37)
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Specification