Resilient foams and uses thereof
Disclosed is a resilient foam and methods of making the foam. The resilient foam includes a derivatized polyanionic polysaccharide and has an open-cell structure. When the resilient foam is contacted with water, the foam forms a thixotropic hydrogel.
1. A resilient foam comprising:
(a) a derivatized polyanionic polysaccharide; and
(b) an open-cell structure, wherein
(i) the resilient foam, when contacted with water, is capable of forming a thixotropic hydrogel, and
(ii) the derivatized polyanionic polysaccharide has a degree of substitution of less than 0.6 derivatives per monomer unit.
2. The resilient foam of claim 1 , wherein the derivatized polyanionic polysaccharide is dissolvable in water.
3. The resilient foam of claim 1 , wherein the derivatized pdyamomc polysaccharide is carboxymethyl cellulose, cellulose ethyl sulfonate, carboxymethyl amylose, chondroitin-6-sulfate, chondroitin-4-sulfate, demiatan sulfate, alginate, heparin, or heparin sulfate, or any combination thereof.
4. The resilient foam of claim 3 , wherein the derivatized polyanionic polysaccharide is carboxymethyl cellulose.
5. The resilient foam of claim 4 , wherein the carboxymethyl cellulose has a non-uniform distribution of carboxymethvl groups.
6. The resilient foam of claim 4 , wherein the carboxymethyl cellulose has a consistent weight per unit length of polymer.
7. The resilient foam of claim 4 , wherein the carboxymethyl cellulose compound has a molecular weight of 50 to 400 kilodaltons.
8. The resilient foam of claim 4 , wherein the carboxymethyl cellulose is derived from cotton or cotton linters.
9. The resilient foam of claim 1 , wherein the derivatized polyanionic polysaccharide is cellulose ethyl sulfonate.
10. The resilient foam of claim 1 , further comprising water, wherein a weight ratio of the water to the derivatized polyanionic polysaccharide ranges from about 0.04 to about 0.6.
11. The resilient foam of claim 1 , further comprising water, wherein an amount of the water ranges from 20 to about 60 wt. % based on the total weight of the resilient foam.
12. The resilient foam of claim 1 . Wherein the resilient foam comprises 40 wt. % or more of the derivatized polyanionic polysaccharide.
13. The resilient foam of claim 1 , wherein the resilient foam is obtained from a hydrogel comprising the derivatized polyanionic polysaccharide, wherein the hydrogel has a yield stress of 200 Pa or more.
14. The resilient foam of elhim 13 , wherein the hydrogel comprises the derivatized polyanionic polysaccharide in an amount of about 3 to 15 wt. % of the hydrogel.
15. The resilient foam of claim 1 , wherein the resilient foam is flexible.
16. The resilient foam of claim 1 , wherein the resilient foam is capable of absorbing 60 wt. % of less of water and remain resilient.
17. The resilient foam of claim 1 , wherein the resilient foam is a nonliquid, non-flowable foam.
18. The resilient foam of claim 1 , wherein the derivatized polyanionic polysaccharide 1% or less of cross-linked polyanionic polysaccharide.
19. The resilient foam of claim 1 , wherein the derivatized polyanionic polysaccharide and/or resilient foam has not been subjected to cross-linking conditions.
20. The resilient foam of claim 1 , wherein the resilient foam is non-deliquescent when exposed to water vapor.
21. The resilient foam of claim 1 , the degree of substitution is between 0.2 to 0.55 derivatives per monomer unit.
22. The resilient foam of claim 21 , the degree of substitution is between 0.3 to 0.45 derivatives per monomer unit.
23. The resilient foam of claim 1 , wherein the resilient foam is hygroscopic and the resilient foam is capable of retaining resiliency after absorbing water in vapor form.