Lignin-derived thermoplastic co-polymers and methods of preparation
The present invention relates to a crosslinked lignin comprising a lignin structure having methylene or ethylene linking groups therein crosslinking between phenyl ring carbon atoms, wherein said crosslinked lignin is crosslinked to an extent that it has a number-average molecular weight of at least 10,000 g/mol, is melt-processible, and has either a glass transition temperature of at least 100° C., or is substantially soluble in a polar organic solvent or aqueous alkaline solution. Thermoplastic copolymers containing the crosslinked lignin are also described. Methods for producing the crosslinked lignin and thermoplastic copolymers are also described.
1. A thermoplastic copolymer, wherein said thermoplastic copolymer has a two-phase morphology and is comprised of crosslinked lignin copolymerized with non-lignin thermoplastic polymer segments, wherein said crosslinked lignin is comprised of a lignin structure having methylene or ethylene linking groups therein crosslinking between phenyl ring carbon atoms, and said crosslinked lignin is crosslinked to an extent that it has a number-average molecular weight of at least 10,000 g/mol, is melt-processible, and has a glass transition temperature of at least 100° C., or is substantially soluble in a polar organic solvent or aqueous alkaline solution.
2. The thermoplastic copolymer of claim 1 , wherein said thermoplastic copolymer is a block copolymer or multiphase copolymer.
3. The thermoplastic copolymer of claim 1 , wherein said thermoplastic copolymer is a graft copolymer.
4. The thermoplastic copolymer of claim 1 , wherein said thermoplastic copolymer has a glass transition temperature selected from a temperature in the range of −100° C. up to 200° C.
5. The thermoplastic copolymer of claim 1 , wherein said non-lignin thermoplastic polymer segments contain unsaturated carbon-carbon bonds.
6. The thermoplastic copolymer of claim 5 , wherein said non-lignin thermoplastic polymer segments are derived from monomer units having a chemical structure within the following generic chemical structure:
wherein R 1 , R 2 , R 3 , R 4 , R 5 , and R 6 are independently selected from hydrogen atom, a saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms, and halogen atoms.
7. The thermoplastic copolymer of claim 6 , wherein said non-lignin thermoplastic polymer segments comprise polyisoprene units.
8. The thermoplastic copolymer of claim 6 , wherein said non-lignin thermoplastic polymer segments comprise polybutadiene units.
9. The thermoplastic copolymer of claim 1 , wherein said non-lignin thermoplastic polymer segments are alkyleneoxide polymer units.
10. The thermoplastic copolymer of claim 9 , wherein said alkylene-oxide polymer units are ethyleneoxide polymer units.
11. The thermoplastic copolymer of claim 1 , wherein said non-lignin thermoplastic polymer segments possess a saturated backbone and have a chemical structure within the following generic chemical structure:
wherein R 7 , R 8 , R 9 , and R 10 are independently selected from hydrogen atom, saturated or unsaturated hydrocarbon groups having 1 to 4 carbon atoms, nitrile, halogen atoms, and groups having formulas —C(O)R 11 , C(O)OR 12 , and —OR 13 , wherein R 11 , R 12 , and R 13 are selected from hydrogen atom and saturated or unsaturated hydrocarbon groups having 1 to 4carbon atoms, and n is an integer of at least 2, and said generic chemical structure can be a monomer or copolymer.
12. The thermoplastic copolymer of claim 1 , wherein said non-lignin thermoplastic polymer segments are comprised of a polyhydroxyalkanoate structure within the following generic chemical structure:
wherein R 14 is selected from a hydrogen atom or hydrocarbon group, t is an integer from 0to 3, n is an integer of at least 5, and said generic structure can be a monomer or copolymer.
13. The thermoplastic copolymer of claim 1 , wherein said thermoplastic copolymer exhibits an angular shear rate viscosity of at least 500 Pa/s at an angular frequency of up to 1000 rad/s at room temperature.
14. The thermoplastic copolymer of claim 1 , wherein said thermoplastic copolymer exhibits an angular shear rate viscosity of at least 1000 Pa/s at an angular frequency of up to 1000 rad/s at room temperature.
15. The thermoplastic copolymer of claim 1 , wherein said thermoplastic copolymer exhibits a shear modulus of at least 100 Pa at an angular frequency of up to 10 rad/s.
16. The thermoplastic copolymer of claim 1 , wherein said thermoplastic copolymer exhibits a shear modulus of at least 1000 Pa at an angular frequency of up to 10 rad/s.
17. The thermoplastic copolymer of claim 1 , wherein said thermoplastic copolymer exhibits a shear modulus of at least 1200 Pa at an angular frequency of up to 10 rad/s.
18. The thermoplastic copolymer of claim 1 , wherein said thermoplastic copolymer contains at least 10 weight percent and up to 60 weight percent of said crosslinked lignin.
19. The thermoplastic copolymer of claim 18 , wherein said thermoplastic copolymer contains at least 15 weight percent and up to 50 weight percent of said crosslinked lignin.
20. The thermoplastic copolymer of claim 18 , wherein said thermoplastic copolymer contains at least 20 weight percent and up to 50 weight percent of said crosslinked lignin.
21. A method for preparing a thermoplastic copolymer, the method comprising reacting a crosslinked lignin with non-lignin thermoplastic polymer segments containing lignin-reactive groups thereon, wherein said crosslinked lignin is comprised of a lignin structure having methylene or ethylene linking groups therein crosslinking between phenyl ring carbon atoms, and said crosslinked lignin is crosslinked to an extent that it has a number-average molecular weight of at least 10,000 g/mol, is melt-processible, and has either a glass transition temperature of at least 100° C., or is substantially soluble in a polar organic solvent or aqueous alkaline solution.
22. The method of claim 21 , wherein said lignin-reactive groups are selected from carboxylic acid, carboxylic acid ester, acyl chloride, epoxy, and isocyanate groups.
23. The method of claim 21 , wherein said non-lignin thermoplastic polymer segments are derived from monomer units having a chemical structure within the following generic chemical structure:
wherein R 1 , R 2 , R 3 , R 4 , R 5 , and R 6 are independently selected from hydrogen atom, a saturated or unsaturated hydrocarbon group having 1 to 4 carbon atoms, and halogen atoms, and wherein each of said non-lignin thermoplastic polymer segments according to formula (1) includes at least two lignin-reactive groups.
24. The method of claim 23 , wherein said non-lignin thermoplastic polymer segments are comprised of polyisoprene units.
25. The method of claim 23 , wherein said non-lignin thermoplastic polymer segments are comprised of polybutadiene units.
26. The method of claim 21 , wherein said non-lignin thermoplastic polymer segments are alkyleneoxide polymer units, each containing at least two phenol-reactive groups.
27. The method of claim 21 , wherein said non-lignin thermoplastic polymer segments possess a saturated backbone and have a chemical structure within the following generic chemical structure:
wherein R 7 , R 8 , R 9 , and R 10 are independently selected from hydrogen atom, saturated or unsaturated hydrocarbon groups having 1 to 4 carbon atoms, nitrile, halogen atoms, and groups having formulas —C(O)R 11 , C(O)OR 12 , and —OR 13 , wherein R 11 , R 12 , and R 13 are selected from hydrogen atom and saturated or unsaturated hydrocarbon groups having 1 to 4carbon atoms, and n is an integer of at least 2, wherein said generic chemical structure can be a monomer or copolymer and includes at least two lignin-reactive groups.
28. The method of claim 21 , wherein said non-lignin thermoplastic polymer segments are comprised of polyhydroxyalkanoate structure within the following generic chemical structure:
wherein R 14 is selected from a hydrogen atom or hydrocarbon group, t is an integer from 0to 3, n is an integer of at least 5, and said generic structure can be a monomer or copolymer and includes at least two lignin-reactive groups.
29. The method of claim 21 , wherein said thermoplastic copolymer exhibits an angular shear rate viscosity of at least 500 Pa/s at an angular frequency of up to 1000 rad/s at room temperature.
30. The method of claim 21 , wherein said thermoplastic copolymer exhibits a shear modulus of at least 100 Pa at an angular frequency of up to 10 rad/s.
31. The method of claim 21 , wherein said thermoplastic copolymer contains at least 10 weight percent and up to 50 weight percent of said crosslinked lignin.
32. The method of claim 21 , wherein said crosslinked lignin and non-lignin thermoplastic polymer segments are reacted under in situ melt mixing polymerization conditions.
33. The method of claim 21 , wherein said crosslinked lignin and non-lignin thermoplastic polymer segments are reacted under free-radical grafting polymerization conditions.