Dissolution of oxidized cellulose
View Patent ↗A process for dissolving modified cellulose is disclosed. The process includes contacting modified cellulose with a solvent in a mixture to form swelled modified cellulose and then contacting the mixture with a salt to dissolve the swelled modified cellulose.
1. A process comprising:
forming a mixture by contacting an oxidized cellulose with a solvent under an inert atmosphere to form a swelled oxidized cellulose;
adjusting the mixture to a first temperature from about 115° C. to 145° C.;
contacting the swelled oxidized cellulose with a salt under the inert atmosphere to form an oxidized cellulose solution; and
adjusting the oxidized cellulose solution to a second temperature below the first temperature, the second temperature being from about 90° C. to about 120° C.
2. The process according to claim 1 , wherein the first temperature is from about 120° C. to about 140° C.
3. The process according to claim 1 , wherein the first temperature is from about 130° C. to about 135° C.
4. The process according to claim 1 , wherein the second temperature is from about 100° C. to about 110° C.
5. The process according to claim 1 , wherein the solvent is selected from the group consisting of N,N-Dimethylacetamide, N-methyl-2-pyrrolidinone, and combinations thereof.
6. The process according to claim 1 , wherein the salt is selected from the group consisting of lithium halides, sodium halides, potassium halides, and combinations thereof.
7. The process according to claim 1 , wherein the oxidized cellulose solution includes dissolved oxidized cellulose having a degree of oxidation from about 80% to about 120% of a degree of oxidation of the predissolved oxidized cellulose.
8. The process according to claim 1 , wherein the oxidized cellulose solution includes dissolved oxidized cellulose having a molecular weight from about 80% to about 120% of the molecular weight of the predissolved oxidized cellulose.
9. A process comprising:
forming a mixture by contacting an oxidized cellulose with a solvent under an inert atmosphere to form a swelled oxidized cellulose, the oxidized cellulose having a degree of oxidation of from about 0.2 to about 1.0;
adjusting the mixture to a first temperature from about 115° C. to 145° C.;
contacting the swelled oxidized cellulose with a salt under the inert atmosphere to form an oxidized cellulose solution; and
adjusting the oxidized cellulose solution to a second temperature below the first temperature, the second temperature being from about 90° C. to about 120° C., wherein the dissolved oxidized cellulose has a degree of oxidation from about 80% to about 120% of the degree of oxidation of the predissolved oxidized cellulose.
10. The process according to claim 9 , wherein the first temperature is from about 120° C. to about 140° C.
11. The process according to claim 9 , wherein the second temperature is from about 100° C. to about 110° C.
12. The process according to claim 9 , wherein the solvent is selected from the group consisting of N,N-Dimethylacetamide, N-methyl-2-pyrrolidinone, and combinations thereof.
13. The process according to claim 9 , wherein the salt is selected from the group consisting of lithium halides, sodium halides, potassium halides, and combinations thereof.
14. The process according to claim 9 , wherein the salt is present in an amount of from about 0.1% by weight to 3% by weight of the oxidized cellulose.
15. A process comprising:
forming a mixture by contacting an oxidized cellulose with a solvent under an inert atmosphere to form a swelled oxidized cellulose;
adjusting the mixture to a first temperature from about 115° C. to 145° C.;
contacting the swelled oxidized cellulose with a salt under the inert atmosphere to form an oxidized cellulose solution under the inert atmosphere; and
adjusting the oxidized cellulose solution to a second temperature below the first temperature, the second temperature being from about 90° C. to about 120° C., wherein the dissolved oxidized cellulose has a molecular weight from about 80% to about 100% of the molecular weight of the predissolved oxidized cellulose.
16. The process according to claim 15 , wherein the solvent is selected from the group consisting of N,N-Dimethylacetamide, N-methyl-2-pyrrolidinone, and combinations thereof.
17. The process according to claim 15 , wherein the salt is selected from the group consisting of lithium halides, sodium halides, potassium halides, and combinations thereof.
18. The process according to claim 15 , wherein the first temperature is from about 120° C. to about 140° C.
19. The process according to claim 15 , wherein the second temperature from about 100° C. to about 110° C.
20. The process according to claim 15 , wherein the salt is present in an amount of from about 0.1% by weight to 3% by weight of the oxidized cellulose.