Derivatives of native lignin
The present invention provides derivatives of native lignin having a certain aliphatic hydroxyl content. Surprisingly, it has been found that consistent and predictable antioxidant activity may be provided by selecting for derivatives of native lignin having a certain aliphatic hydroxyl content.
1. A lignin derivative recovered from a pulping process of a lignocellulosic biomass, wherein said lignin derivative has an aliphatic hydroxyl content of from 0.001 mmol/g to 2.35 mmol/g, and an alkoxy content of from 0.1 mmol/g to 2 mmol/g.
2. The lignin derivative according to claim 1 , wherein the derivative has an aliphatic hydroxyl content of about 2.25 mmol/g or less.
3. The lignin derivative according to claim 1 , wherein the derivative has an aliphatic hydroxyl content of about 1.75 mmol/g or less.
4. The lignin derivative according to claim 1 , wherein the derivative has an aliphatic hydroxyl content of about 0.1 mmol/g or greater.
5. The lignin derivative according to claim 1 , wherein the derivative has a normalized RSI of 15 or greater.
6. The lignin derivative according to claim 1 , wherein the lignin is derived from softwood biomass.
7. The lignin derivative according to claim 1 , wherein the lignin is derived from annual fibre biomass.
8. The lignin derivative according to claim 1 , wherein the lignin is derived from hardwood biomass.
9. The lignin derivative according to claim 1 , wherein the pulping process is selected from the group consisting of steam explosion, dilute acid hydrolysis, ammonia fiber expansion, autohydrolysis, kraft and modifications thereof, soda pulping and modifications thereof, sulphite pulping, and organosolv processes.
10. The lignin derivative according to claim 1 , wherein the pulping process is a kraft process or a modification thereof.
11. The lignin derivative according to claim 1 , wherein the pulping process is an organosolv process.
12. A composition comprising the lignin derivative according to claim 1 and a polymer-forming component.