Alpha-1,3-glucan graft copolymers
Compositions are disclosed herein comprising a graft copolymer that comprises: (i) a backbone comprising an alpha-1,3-glucan ether or ester compound, and (ii) one or more alpha-1,3-glucan side chains comprising at least about 50% alpha-1,3 glycosidic linkages. Further disclosed are reactions for producing such graft copolymers, as well as their use in various applications.
1. A composition comprising a graft copolymer, wherein the graft copolymer comprises:
(i) a backbone consisting of an alpha-1,3-glucan ether or ester compound that has a degree of substitution (DoS) of 0.001 to 3.0, wherein the alpha-1,3-glucan ether or ester compound comprises at least 90% alpha-1,3 glycosidic linkages, and
(ii) one or more alpha-1,3-glucan side chains comprising at least 90% alpha-1,3 glycosidic linkages, wherein the one or more side chains branch from said backbone.
2. The composition of claim 1 , wherein the alpha-1,3-glucan ether or ester compound comprises at least 95% alpha-1,3 glycosidic linkages.
3. The composition of claim 2 , wherein the one or more alpha-1,3-glucan side chains comprise at least 95% alpha-1,3 glycosidic linkages.
4. The composition of claim 2 , wherein the backbone consists of the alpha-1,3-glucan ether compound.
5. The composition of claim 4 , wherein the alpha-1,3-glucan ether compound comprises an ether-linked carboxymethyl group.
6. The composition of claim 1 , wherein the weight-average degree of polymerization (DPw) of the alpha-1,3-glucan ether or ester compound is at least 15.
7. The composition of claim 1 , wherein the backbone consists of the alpha-1,3-glucan ether compound.
8. The composition of claim 7 , wherein the alpha-1,3-glucan ether compound comprises an ether-linked group that is anionic or cationic when the compound is comprised in an aqueous composition.
9. The composition of claim 7 , wherein the alpha-1,3-glucan ether compound comprises an ether-linked carboxymethyl group.
10. The composition of claim 1 , wherein the one or more alpha-1,3-glucan side chains comprise at least 95% alpha-1,3 glycosidic linkages.
11. The composition of claim 1 , wherein the composition is an aqueous composition.
12. The composition of claim 11 , wherein the aqueous composition is a dispersion of the graft copolymer.
13. The composition of claim 12 , wherein the dispersion comprises less than 1.5 w/v % of the graft copolymer.
14. The composition of claim 1 , wherein the graft copolymer is produced in a reaction composition comprising at least water, sucrose, said alpha-1,3-glucan ether or ester compound, and a glucosyltransferase enzyme that synthesizes alpha-1,3-glucan with at least 90% alpha-1,3 glycosidic linkages.
15. The composition of claim 1 , wherein the degree of polymerization (DP) or weight-average degree of polymerization (DPw) of said one or more alpha-1,3-glucan side chains is at least 100.
16. The composition of claim 1 , wherein the graft copolymer is aqueous insoluble.
17. The composition of claim 1 , wherein the alpha-1,3-glucan ether or ester compound comprises at least 99% alpha-1,3 glycosidic linkages.
18. The composition of claim 1 , wherein the graft copolymer comprises 1 to 60 mole percent of the backbone.
19. A method of producing a graft copolymer, said method comprising:
(a) contacting, in a reaction composition, at least (i) water, (ii) sucrose, (iii) an alpha-1,3-glucan ether or ester compound that has a degree of substitution (DoS) of 0.001 to 3.0, and (iv) a glucosyltransferase enzyme that synthesizes alpha-1,3-glucan comprising at least 90% alpha-1,3 glycosidic linkages,
whereby a graft copolymer according to the composition of claim 1 is produced; and
(b) optionally, isolating the graft copolymer produced in step (a).
20. A method of providing an aqueous composition, said method comprising:
(a) providing a graft copolymer according to the composition of claim 1 , and
(b) dispersing or dissolving the graft copolymer into an aqueous liquid, thereby producing the aqueous composition.
21. The method of claim 20 , wherein the graft copolymer provided in step (a) is insoluble in aqueous conditions, and wherein the graft copolymer is dispersed into the aqueous liquid in step (b).