Methods for the preparation of mixed polymer superabsorbent fibers containing cellulose
View Patent ↗A method for making mixed polymer composite fibers containing cellulose fibers in which cellulose fibers are dispersed in an aqueous solution comprising a carboxyalkyl cellulose and a galactomannan polymer or a glucomannan polymer in water to provide an aqueous fiber dispersion; the aqueous dispersion treated with a first crosslinking agent to provide a gel; the gel mixed with a water-miscible solvent to provide composite fibers; and the composite fibers treated with a second crosslinking agent to provide crosslinked fibers.
1. A method for making crosslinked fibers, comprising:
(a) dispersing cellulose fibers in an aqueous solution comprising a carboxyalkyl cellulose and a galactomannan polymer or a glucomannan polymer in water to provide an aqueous fiber dispersion;
(b) treating the aqueous dispersion with a first crosslinking agent to provide a gel;
(c) mixing the gel with a water-miscible solvent to provide composite fibers; and
(d) treating the composite fibers with a second crosslinking agent to provide crosslinked fibers.
2. The method of claim 1 further comprising fiberizing the crosslinked fibers to provide fiberized crosslinked fibers.
3. The method of claim 2 further comprising drying the fiberized crosslinked fibers to provide dried crosslinked fibers.
4. The method of claim 1 , wherein the carboxyalkyl cellulose has a degree of carboxyl group substitution of from about 0.3 to about 2.5.
5. The method of claim 1 , wherein the carboxyalkyl cellulose is carboxymethyl cellulose.
6. The method of claim 1 , wherein the galactomannan polymer is selected from the group consisting of guar gum, locust bean gum, and tara gum.
7. The method of claim 1 , wherein the glucomannan polymer is konjac gum.
8. The method of claim 1 , wherein the aqueous dispersion comprises from about 60 to about 99 percent by weight carboxyalkyl cellulose based on the total weight of crosslinked fibers.
9. The method of claim 1 , wherein the aqueous dispersion comprises from about 1 to about 20 percent by weight galactomannan polymer or glucomannan polymer based on the total weight of crosslinked fibers.
10. The method of claim 1 , wherein the aqueous dispersion comprises from about 2 to about 15 percent by weight cellulose fibers based on the total weight of crosslinked fibers.
11. The method of claim 1 , wherein the first crosslinking agent is a crosslinking agent reactive toward carboxyl groups.
12. The method of claim 1 , wherein the first crosslinking agent is a crosslinking agent reactive toward hydroxyl groups.
13. The method of claim 1 , wherein the first crosslinking agent is selected from the group consisting of aluminum (III) compounds, titanium (IV) compounds, bismuth (III) compounds, boron (III) compounds, and zirconium (IV) compounds.
14. The method of claim 1 , wherein the first crosslinking agent is present in an amount from about 0.1 to about 20 percent by weight based on the total weight of cross linked fibers.
15. The method of claim 1 , wherein the water-miscible solvent is an alcohol.
16. The method of claim 1 , wherein the water-miscible solvent is selected from the group consisting of methanol, ethanol, isopropanol, and mixtures thereof.
17. The method of claim 1 , wherein the volume of water-miscible solvent to water is from about 1:1 to about 1:5.
18. The method of claim 1 , wherein mixing the gel with the water-miscible solvent comprises stirring to provide fibers.
19. The method of claim 1 , wherein the second crosslinking agent is selected from the group consisting of aluminum (III) compounds, titanium (IV) compounds, bismuth (III) compounds, boron (III) compounds, and zirconium (IV) compounds.
20. The method of claim 1 , wherein the second crosslinking agent is present in an amount from about 0.1 to about 20 percent by weight based on the total weight of crosslinked fibers.