Zwitterionic lignin derivatives
View Patent ↗Methods and compositions with anti-fouling properties that are derived from lignin are disclosed. The compositions include lignin with one or more zwitterionic functional groups. The lignin with one or more zwitterionic functional groups may be incorporated in paints and coatings to prepare biocidal coatings.
1. A method of making a biocidal coating, the method comprising:
contacting a lignin with a formaldehyde and an amino acid or an amino sulfonic acid in a solvent to incorporate one or more zwitterionic functional groups into the lignin; and
adding the lignin incorporated with the one or more zwitterionic functional groups to a coating composition.
2. The method of claim 1 , wherein adding the lignin incorporated with the one or more zwitterionic functional groups to the coating composition comprises adding the lignin incorporated with the one or more zwitterionic functional groups to the coating composition comprising a binder, a solvent, a pigment, a coalescing agent, a rheology modifier, a plasticizer, a surfactant, or any combination thereof.
3. The method of claim 1 , wherein contacting the lignin with the formaldehyde and the amino acid comprises contacting the lignin with the formaldehyde and the amino acid selected from arginine, leucine, lysine, glycine, glutamic acid, aspartic acid, alanine, phenylalanine, serine, threonine, tyrosine, glutamine, histidine, valine, isoleucine, tryptophan, and a combination thereof.
4. The method of claim 1 , wherein contacting the lignin with the formaldehyde and the amino sulfonic acid comprises contacting the lignin with the formaldehyde and the amino sulfonic acid selected from aminomethane sulphonic acid, aminoethane sulphonic acid (taurine), aminohexane sulphonic acid, aminoisopropyl sulphonic acid, aminododecyl sulphonic acid, aminobenzene sulfonic acid, aminotoulene sulfonic acid, sulfanilic acid, chlorosulfanilic acid, diamino benzene sulfonic acid, amino phenol sulfonic acid, amino propyl benzene sulfonicacid, amino hexyl benzene sulfonic acid, and a combination thereof.
5. The method of claim 1 , wherein the contacting the lignin with the formaldehyde and an amino acid or an amino sulfonic acid comprises refluxing the lignin with the formaldehyde and the amino acid or the amino sulfonic acid for about 15 minutes to about 2 hours at a temperature of about 50° C. to about 80° C.
6. The method of claim 1 , wherein contacting the lignin with the formaldehyde and the amino acid or the amino sulfonic acid comprises refluxing the lignin with the formaldehyde and the amino acid or the amino sulfonic acid for about 30 minutes at about 65° C.
7. The method of claim 1 , wherein contacting the lignin with the formaldehyde and the amino acid or the amino sulfonic acid in the solvent comprises contacting in the presence of the solvent selected from methanol, ethanol, dioxane, tetrahydrofuran, dimethylformamide, and a combination thereof.
8. The method of claim 1 , further comprising removing the solvent after the contacting step.
9. The method of claim 1 , wherein adding the lignin incorporated with the one or more zwitterionic functional groups to the coating composition comprises adding zwitterionic lignin derivatives to a concentration of about 0.5 to about 20 weight percent of the coating composition.