Coagulation map for fiber spinning

Patent metadata

Field	Value
Publication number	US-10633770-B2
Application number	US-201916240309-A
Country	US
Kind code	B2
Filing date	Jan 4, 2019
Priority date	Jan 4, 2018
Publication date	Apr 28, 2020
Grant date	Apr 28, 2020

Abstract

Disclosed are methods for preparing a lignin/poly(vinyl alcohol) (PVA) fiber and for preparing a lignin/polyacrylonitrile (PAN) fiber. The methods can comprise adding a dope of lignin and PVA or a dope of lignin and PAN to a coagulation bath containing a solvent comprising one or more components, wherein the one or more components are present in the solvent in concentrations based on the hydrogen bonding character (f H ) of the solvent, the polar character (f P ) of the solvent, and the dispersive character (f D ) of the solvent; and gel-spinning a lignin/PVA fiber or a lignin/PAN fiber from the coagulation bath.

First claim

What is claimed is:

1. A method for preparing a lignin/poly(vinyl alcohol) (PVA) fiber, the method comprising:
(a) adding a dope of lignin and PVA to a coagulation bath containing a solvent comprising one or more components, wherein the one or more components are present in the solvent in concentrations such that the hydrogen bonding character (f H ) of the solvent is between 20% and 30%, the polar character (f p ) of the solvent is between 25% and 35%, and the dispersive character (f D ) of the solvent is between 40% and 50%; and
(b) gel-spinning a lignin/PVA fiber from the coagulation bath,
wherein a lignin/PVA fiber is produced.

2. The method of claim 1 , wherein the dope is prepared at about 80° C. to about 85° C.

3. The method of claim 1 , wherein the dope comprises a weight ratio of 5-90% (w/w) lignin to PVA.

4. The method of claim 1 , wherein the dope comprises PVA at a molecular weight of about 100-500 kg/mol, and further wherein the PVA is characterized by at least about 85% hydrolysis.

5. The method of claim 1 , wherein the dope is provided in a solution of about 80% DMSO to about 100% DMSO (v/v) in distilled water at about 60° C. to about 85° C.

6. The method of claim 1 , further comprising conditioning the dope at room temperature for at least two hours prior to the adding step.

7. The method of claim 1 , wherein the coagulation bath is maintained at a pre-set temperature that is between about −15° C. and about −30° C., optionally wherein the pre-set temperature is about −25° C.

8. The method of claim 1 , wherein the lignin/PVA fiber has an as-spun draw ratio of at least 2×.

9. The method of claim 1 , wherein the lignin has a minimum molecular weight of at least 2 kiloDaltons (kDa).

10. The method of claim 1 , wherein the one or more components of the solvent include about 15% to about 50% methanol and about 50% to about 85% acetone.

11. A method for preparing a lignin/polyacrylonitrile (PAN) fiber, the method comprising:
(a) adding a dope of lignin and PAN to a coagulation bath containing a solvent comprising one or more components, wherein the one or more components are present in the coagulation bath in concentrations such that the hydrogen bonding character (f H ) of the solvent is between 40% and 60%, the polar character (f P ) of the solvent is between 15% and 30%, and the dispersive character (f D ) of the solvent is between 20% and 50%; and
(b) gel-spinning a lignin/PAN fiber from the coagulation bath,
wherein a lignin/PAN fiber is produced.

12. The method of claim 11 , wherein the PAN is present in the dope in an amount of about 10 to about 50 g/dL, optionally about 20 g/dL.

13. The method of claim 11 , wherein the dope comprises PAN at about 150 kDa and is prepared at about 80° C. to about 85° C. or comprises PAN at about 200-250 kDa and is prepared at about 60° C. to about 85° C.

14. The method of claim 11 , further comprising conditioning the dope at room temperature for at least two hours prior to the adding step.

15. The method of claim 11 , wherein the coagulation bath is maintained at about −5° C.

16. The method of claim 11 , wherein the lignin/PAN fiber has an as-spun draw ratio of at least 3×.

17. The method of claim 11 , wherein the dope comprises up to 30% PAN, a concentration of up to 20% g/dL PAN, and a weight ratio of up to 90% (w/w) lignin to PAN.

18. The method of claim 11 , wherein the dope comprises PAN at a molecular weight of about 150 kDa to about 300 kDa.

19. The method of claim 11 , wherein the dope is provided in a solution comprising DMSO, dimethyl acetamide (DMAc), dimethylforamide (DMF), and/or an alkanolamine.

20. The method of claim 19 , wherein the solution comprises 5-10% (w/w) alkanolamine, optionally monoethanolamine (MEA) or triethanolamine, to DMSO.

21. The method of claim 11 , wherein the dope is provided in an 80-100% (v/v) solution of DMSO in distilled water at about 80° C. to about 85° C.

22. The method of claim 11 , wherein the lignin has a minimum molecular weight of at least 2 kDa.

23. The method of claim 11 , wherein the solvent comprises about 25% isopropyl alcohol, about 50% methanol, and about 25% water.

24. The method of claim 11 , wherein the dope comprises a weight ratio of 10-90% (w/w) lignin to PAN.

25. The method of claim 11 , wherein the adding step comprises extruding the dope through an orifice above the top surface of the solvent present in the coagulation bath.

26. The method of claim 11 , wherein the solvent is maintained at a temperature of about −15° C. to about 5° C.

27. A method for preparing a lignin/poly(vinyl alcohol) (PVA) fiber, the method comprising:
(a) aging a dope of lignin and PVA in an aging bath, optionally for 12 hours to 30 days, wherein the aging bath contains a solvent comprising one or more components, and further wherein the one or more components are present in the solvent in concentrations such that the hydrogen bonding character (fH) of the solvent is between 20% and 40%, the polar character (fP) of the solvent is between 25% and 35%, and the dispersive character (fD) of the solvent is between 35% and 50%; and
(b) gel-spinning a lignin/PVA fiber from the aging bath.

28. A method for preparing a lignin/polyacrylonitrile (PAN) fiber, the method comprising:
(a) heating a dope of lignin and PAN to a desired temperature in a first solvent, optionally wherein the first solvent is DMSO, until the lignin and PAN are dissolved in the first solvent;
(b) aging the dope of lignin and PAN by allowing the dope to cool, optionally to about 18° C. to 25° C., further optionally allowing the dope to remain at about 18° C. to 25° C. for at least about two hours;
(c) adding the dope of lignin and PAN to a coagulation bath that contains a solvent comprising one or more components, and further wherein the one or more components are present in the solvent in concentrations such that the hydrogen bonding character (f H ) of the solvent is between 40% and 60%, the polar character (f P ) of the solvent is between 15% and 30%, and the dispersive character (f D ) of the solvent is between 20% and 50%; and
(d) gel-spinning a lignin/PAN fiber from the bath,
wherein a lignin/PAN fiber is produced.

29. The method of claim 28 , wherein the dope is aged for at least about 2 hours at 18° C. to 25° C., optionally 18° C. to 22° C.

30. The method of claim 29 , wherein the desired temperature is about 85° C.

31. The method of claim 29 , further comprising transferring the dope to a pump after the lignin and the PAN are completely dissolved in the solvent and the dope is at the desired temperature.

Assignees

• Univ North Carolina State

Inventors

• Ford Ericka
• Blackwell Charles
• Lu Chunhong

Classifications

• D01D5/06

  Wet spinning methods {(D01D5/0046 takes precedence)} · CPC title

• C08L2203/12

  used for fibers · CPC title

• D01F9/22

  from polyacrylonitriles · CPC title

• D01F6/54

  of polymers of unsaturated nitriles · CPC title

• C08L29/04

  Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids · CPC title