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 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.
2 . The crosslinked lignin of claim 1 , wherein said number-average molecular weight is at least 100,000 g/mol.
3 . The crosslinked lignin polymer of claim 1 , wherein said number-average molecular weight is at least 150,000 g/mol.
4 . The crosslinked lignin polymer of claim 1 , wherein said number-average molecular weight is at least 200,000 g/mol.
5 . The crosslinked lignin polymer of claim 1 , wherein said glass transition temperature is at least 120° C.
6 . The crosslinked lignin polymer of claim 1 , wherein said glass transition temperature is at least 150° C.
7 . The crosslinked lignin polymer of claim 1 , wherein said glass transition temperature is at least 180° C.
8 . The crosslinked lignin polymer of claim 1 , wherein said glass transition temperature is at least 200° C.
9 . 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.
10 . The thermoplastic copolymer of claim 9 , wherein said thermoplastic copolymer is a block copolymer or multiphase copolymer.
11 . The thermoplastic copolymer of claim 9 , wherein said thermoplastic copolymer is a graft copolymer.
12 . The thermoplastic copolymer of claim 9 , wherein said thermoplastic copolymer has a glass transition temperature selected from a temperature in the range of −100° C. up to 200° C.
13 . The thermoplastic copolymer of claim 9 , wherein said non-lignin thermoplastic polymer segments contain unsaturated carbon-carbon bonds.
14 . The thermoplastic copolymer of claim 13 , 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.
15 . The thermoplastic copolymer of claim 14 , wherein said non-lignin thermoplastic polymer segments comprise polyisoprene units.
16 . The thermoplastic copolymer of claim 14 , wherein said non-lignin thermoplastic polymer segments comprise polybutadiene units.
17 . The thermoplastic copolymer of claim 9 , wherein said non-lignin thermoplastic polymer segments are alkyleneoxide polymer units.
18 . The thermoplastic copolymer of claim 17 , wherein said alkylene-oxide polymer units are ethyleneoxide polymer units.
19 . The thermoplastic copolymer of claim 9 , 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 R11, R 12, and R 13 are selected from hydrogen atom and saturated or unsaturated hydrocarbon groups having 1 to 4 carbon atoms, and n is an integer of at least 2, and said generic chemical structure can be a monomer or copolymer.
20 . The thermoplastic copolymer of claim 9 , 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 0 to 3, n is an integer of at least 5, and said generic structure can be a monomer or copolymer.
21 . The thermoplastic copolymer of claim 9 , 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.
22 . The thermoplastic copolymer of claim 9 , 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.
23 . The thermoplastic copolymer of claim 9 , wherein said thermoplastic copolymer exhibits a shear modulus of at least 100 Pa at an angular frequency of up to 10 rad/s.
24 . The thermoplastic copolymer of claim 9 , wherein said thermoplastic copolymer exhibits a shear modulus of at least 1000 Pa at an angular frequency of up to 10 rad/s.
25 . The thermoplastic copolymer of claim 9 , wherein said thermoplastic copolymer exhibits a shear modulus of at least 1200 Pa at an angular frequency of up to 10 rad/s.
26 . The thermoplastic copolymer of claim 9 , wherein said thermoplastic copolymer contains at least 10 weight percent and up to 60 weight percent of said crosslinked lignin.
27 . The thermoplastic copolymer of claim 26 , wherein said thermoplastic copolymer contains at least 15 weight percent and up to 50 weight percent of said crosslinked lignin.
28 . The thermoplastic copolymer of claim 26 , wherein said thermoplastic copolymer contains at least 20 weight percent and up to 50 weight percent of said crosslinked lignin.
29 . A method for preparing a crosslinked lignin, the process comprising treating a precursor lignin having a number-average molecular weight of up to 10,000 g/mol with formaldehyde and/or glyoxal, present in a concentration of up to 10 wt % of reaction volume, under condensation conditions to produce said crosslinked lignin, wherein said crosslinked lignin includes methylene and/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 or greater than 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.
30 . The method of claim 29 , wherein said formaldehyde and/or glyoxal is present in a concentration of up to 5 wt % of reaction volume.
31 . The method of claim 29 , wherein said formaldehyde and/or glyoxal is in a mole ratio to lignin phenolic groups of 1:10 to 1:100.
32 . The method of claim 29 , wherein said precursor lignin has a number-average molecular weight of at least 500 g/mol.
33 . The method of claim 29 , wherein said precursor lignin has a number-average molecular weight of up to 3,000 g/mol.
34 . 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.
35 . The method of claim 34 , wherein said lignin-reactive groups are selected from carboxylic acid, carboxylic acid ester, acyl chloride, epoxy, and isocyanate groups.
36 . The method of claim 34 , 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.
37 . The method of claim 36 , wherein said non-lignin thermoplastic polymer segments are comprised of polyisoprene units.
38 . The method of claim 36 , wherein said non-lignin thermoplastic polymer segments are comprised of polybutadiene units.
39 . The method of claim 34 , wherein said non-lignin thermoplastic polymer segments are alkyleneoxide polymer units, each containing at least two phenol-reactive groups.
40 . The method of claim 34 , 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 R11, R 12, and R 13 are selected from hydrogen atom and saturated or unsaturated hydrocarbon groups having 1 to 4 carbon 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.
41 . The method of claim 34 , 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 0 to 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.
42 . The method of claim 34 , 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.
43 . The method of claim 34 , wherein said thermoplastic copolymer exhibits a shear modulus of at least 100 Pa at an angular frequency of up to 10 rad/s.
44 . The method of claim 34 , wherein said thermoplastic copolymer contains at least 10 weight percent and up to 50 weight percent of said crosslinked lignin.
45 . The method of claim 34 , wherein said crosslinked lignin and non-lignin thermoplastic polymer segments are reacted under in situ melt mixing polymerization conditions.
46 . The method of claim 34 , wherein said crosslinked lignin and non-lignin thermoplastic polymer segments are reacted under free-radical grafting polymerization conditions.