Derivatives of native lignin from annual fibre feedstocks
One aspect of the invention relates to annual fiber lignin derivatives having an aliphatic hydroxyl content of about 3.75 mmol/g lignin or less, or about 1.5 mmol/g lignin or more, and the preparation method thereof. The lignin derivatives have a desired antioxidant activity characterized by radical scavenging index (RSI). Another aspect of the invention relates to compositions comprising the annual fiber lignin derivative. Another aspect of the invention relates to a use of the annual fiber lignin derivatives comprising incorporating the annual fiber lignin derivatives into polymer compositions.
1. An annual fibre lignin derivative wherein said lignin derivative has an aliphatic hydroxyl content of from about 1 mmol/g to 3.25 mmol/g, a normalized RSI of 15 or greater, and a weight average molecular weight of from about 500 g/mol to about 5000 g/mol.
2. The lignin derivative according to claim 1 wherein the derivative has an aliphatic hydroxyl content is from about 1.5 mmol/g to 3.25 mmol/g.
3. The lignin derivative according to claim 1 wherein the lignin is derived from biomass comprising flax, cereal straw, wheat, barley, oats, bagasse, corn, hemp, fruit pulp, alfa grass, or combinations/hybrids thereof.
4. The lignin derivative according to claim 1 wherein the lignin is derived from biomass comprising wheat straw, bagasse, corn cobs, or combinations/hybrids thereof.
5. The lignin derivative according to claim 1 having a normalized RSI of from 15 to 100.
6. The lignin derivative according to claim 1 wherein the derivative comprises alkoxy groups.
7. The lignin derivative according to claim 1 wherein the derivative comprises ethoxyl groups.
8. The lignin derivative according to claim 7 wherein the ethoxyl content is 1.4 mmol/g or less.
9. A composition comprising the lignin derivative of claim 1 and a polymer-forming component.
10. A thermoplastic composition comprising the lignin derivative according to claim 1 .
11. A polyolefin composition comprising the lignin derivative according to claim 1 .
12. The lignin derivative according to claim 1 having a normalized RSI of about 36.63 to about 55.32.