Starch-based adhesives
Disclosed are starch-based cross-linked phenolic heteropolymer compositions and methods of synthesizing starch-based cross-linked phenolic heteropolymer compositions as well as their use as adhesives or adhesive additives.
1. A composition comprising:
a starch-based cross-linked phenolic heteropolymer;
a plurality of antimicrobial agents covalently bound to the starch-based cross-linked phenolic heteropolymer; and
a plurality of sugar units covalently bound to the starch-based cross-linked phenolic heteropolymer.
2. The composition of claim 1 , wherein the starch-based cross-linked phenolic heteropolymer is a sulfonated starch-based cross-linked phenolic heteropolymer.
3. The composition of claim 1 , wherein the starch-based cross-linked phenolic heteropolymer is selected from lignin, cellulose, hemicellulose, dextrin, a wood-derived cross-linked phenolic heteropolymer, or a combination thereof.
4. The composition of claim 1 , wherein the starch-based cross-linked phenolic heteropolymer comprises a plurality of pendent hydroxyl groups of formula —OH and a plurality of pendent carboxylic acid groups of formula —C(═O)OH and wherein the plurality of antimicrobial agents is covalently bound to about 1% to about 50% of the combination of the plurality of pendent hydroxyl groups and the plurality of pendent carboxylic acid groups.
5. The composition of claim 1 , wherein the plurality of antimicrobial agents comprises at least one of a phenol, a quaternary ammonium salt, 4-hydroxybenzoic acid, a hydroxytyrosol, an alkyl ester of gallic acid, an amino acid, a peptide, or combinations thereof.
6. The composition of claim 1 , wherein the starch-based cross-linked phenolic heteropolymer comprises a plurality of pendent hydroxyl groups of formula —OH and a plurality of pendent carboxylic acid groups of formula —C(═O)OH and wherein the plurality of sugar units is covalently bound to about 10% to about 90% of the combination of the plurality of pendent hydroxyl groups and the plurality of pendent carboxylic acid groups.
7. The composition of claim 1 , wherein the plurality of sugar units comprises at least one hexose sugar oligomer wherein multiple hexose sugar oligomers are linked together by either α-(1,4) or α-(1,6) glycosidic bonds.
8. The composition of claim 2 , wherein the sulfonated starch-based cross-linked phenolic heteropolymer is selected from sulfonated lignin, sulfonated cellulose, sulfonated hemicellulose, sulfonated dextrin, a sulfonated wood-derived cross-linked phenolic heteropolymer, or a combination thereof.
9. The composition of claim 5 , wherein the plurality of antimicrobial agents comprise a quaternary ammonium salt having a structure of the formula —O-alkyl-NR 1 R 2 R 3 X, wherein R 1 -R 3 are alkyl chains, and wherein X is a counterion.
10. The composition of claim 5 , wherein the counterion comprises a chloride, a fluoride, a bromide, an iodide, an astatide, a sulfate, a tosylate, a mesylate, or a combination thereof.
11. The composition of claim 5 , wherein the amino acid comprises histidine, lysine, serine, glycine, proline, alanine, isoleucine, leucine, phenylalanine, tryptophan, tyrosine, valine, or combinations thereof.
12. The composition of claim 11 , wherein the amino acid is covalently bound to the starch-based cross-linked phenolic heteropolymer via a molecular linker.
13. The composition of claim 12 , wherein the molecular linker is an alkyl chain of formula CH 3 —(CH 2 ) n —CH 2 — wherein n is an integer from 0 to 24 and wherein the alkyl chain is covalently bound to a plurality of pendent hydroxyl groups of formula —OH and a plurality of pendent carboxylic acid groups of formula —C(═O)OH on the starch-based cross-linked phenolic heteropolymer forming an alkoxy chain, an ester side chain or a combination thereof.
14. The composition of claim 13 , wherein the alkyl chain is a dodecyl straight alkyl chain.
15. The composition of claim 12 , wherein the molecular linker is a polyethylene glycol chain formula —[O—CH 2 —CH 2 ] n —O— where n is an integer from 2 to 24.
16. The composition of claim 5 , wherein the amino acid is a modified amino acid wherein at least one amine group is substituted with a quaternary amine of formula —NRMeX where R is an straight alkyl chain of formula CH 3 —(CH 2 ) n —CH 2 — wherein n is an integer from 0 to 124, Me is a methyl group, and wherein X is a counterion.
17. The composition of claim 1 , wherein the plurality of antimicrobial agents are covalently bound to the starch-based cross-linked phenolic heteropolymer by a polyethylene glycol chain of formula —[O—CH 2 —CH 2 ] n —O— where n is an integer from 2 to 18.
18. The composition of claim 1 , wherein the plurality of sugar units comprises at least one of α D-allose, α D-altrose, α D-mannose, α D-glucose, α D-gulose, α D-galactose, α D-idose, α D-talose, β D-allose, β D-altrose, β D-mannose, β D-glucose, β D-gulose, β D-galactose, β D-idose, β D-talose β-D-lactoside, α-L-flucoside, α-D-mannoside, or combinations thereof.
19. The composition of claim 1 , wherein the plurality of sugar units is covalently bound to the starch-based cross-linked phenolic heteropolymer via a polyethylene glycol chain of formula —[O—CH 2 —CH 2 ] n —O— where n is an integer from 2 to 24.
20. The composition of claim 1 , wherein the composition is suitable for use as a pressure sensitive adhesive.
21. The composition of claim 1 , wherein the composition is suitable for use as an adhesive additive.
22. The composition of claim 1 , wherein the starch-based cross-linked phenolic heteropolymer is selected from lignin, sulfonated lignin or a combination thereof.
23. The composition of claim 1 , wherein the starch-based cross-linked phenolic heteropolymer comprises a plurality of pendent hydroxyl groups of formula —OH and a plurality of pendent carboxylic acid groups of formula —C(═O)OH and wherein the plurality of antimicrobial agents is covalently bound to about 1% to about 5% of the combination of the plurality of pendent hydroxyl groups and the plurality of pendent carboxylic acid groups.
24. The composition of claim 1 , wherein the starch-based cross-linked phenolic heteropolymer comprises a plurality of pendent hydroxyl groups of formula —OH and a plurality of pendent carboxylic acid groups of formula —C(═O)OH and wherein the plurality of antimicrobial agents is covalently bound to about 5% to about 10% of the combination of the plurality of pendent hydroxyl groups and the plurality of pendent carboxylic acid groups.