Process of making carbon fibers from compositions including esterified lignin and poly(lactic acid)

• US 9,340,425 B2
• Filed: 10/08/2013
• Issued: 05/17/2016
• Est. Priority Date: 10/09/2012
• Status: Active Grant

• Current Assignee: Iowa State University Research Foundation Incorporated (Iowa State University)
• Original Assignee: Iowa State University Research Foundation Incorporated (Iowa State University)
• Inventors: Thunga, Mahendra, Chen, Keke, Kessler, Michael Richard
• Primary Examiner(s): Tentoni, Leo B
• Application Number:
  US14/048,532
• Publication Number:
  US 20140099505A1
• Time in Patent Office: 952 Days
• Field of Search: 264/29.2, 264/29.6, 264/29.7, 264/42, 264/211.11, 264/211.12, 423/447.1, 423/447.4, 423/447.7, 423/447.8, 527/400, 530/500
• US Class Current: 1/1
• CPC Class Codes: C08H 6/00 Macromolecular compounds derived from lignin, e.g. tannins, humic acids
• CPC Class Codes: C08L 2203/12 used for fibers
• CPC Class Codes: C08L 67/04 Polyesters derived from hydroxycarboxylic acids, e.g. lactones C08L67/06 takes precedence
• CPC Class Codes: C08L 97/005 Lignin
• CPC Class Codes: D01F 6/625 derived from hydroxy-carboxylic acids, e.g. lactones
• CPC Class Codes: D01F 6/92 of polyesters
• CPC Class Codes: D01F 8/14 with at least one polyester as constituent
• CPC Class Codes: D01F 8/18 from other substances
• CPC Class Codes: D01F 9/00 Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments
• CPC Class Codes: D01F 9/17 from lignin
• CPC Class Codes: D01F 9/26 from polyesters
• CPC Class Codes: Y10T 428/2929 Bicomponent, conjugate, composite or collateral fibers or filaments [i.e., coextruded sheath-core or side-by-side type]
• CPC Class Codes: Y10T 428/298 Physical dimension

Abstract

The present invention relates to compositions comprising esterified lignin and poly(lactic acid). In various embodiments, the present invention provides fibers comprising the esterified lignin and poly(lactic acid) blend, carbon fibers made therefrom, and methods of making the fiber and the carbon fibers.

Claims

1. A method of making carbon fibers, the method comprising:

spinning fibers comprising an esterified lignin composition, to give spun fibers, the esterified lignin composition comprising

lignin comprising at least one esterified —

OH group, wherein the esterified —

OH group has the structure —

OC(O)R, wherein each R is independently a C₁-C₃₀ hydrocarbyl group, and

poly(lactic acid); and

heating the spun fibers to obtain the carbon fibers.

2. The method of claim 1, wherein heating the spun fibers to obtain carbon fibers comprises heating to a temperature of about 500°

C. to about 3000°

C. with a heating rate of about 10°

C./h to about 3000°

C./h, wherein the temperature of about 500 to about 3000°

C. is maintained in an oxygen atmosphere for about 1 min to about 30 h.

3. The method of claim 1, wherein spinning fibers comprises extruding the esterified lignin composition through a die and continuously spooling the extruded fiber.

4. The method of claim 1, wherein the method of making carbon fibers further comprises thermostabilizing the spun fibers prior to the heating step.

5. The method of claim 4, wherein thermostabilizing the spun fibers comprises at least one of a) heating to a temperature of about 120°

C. to about 500°

C. with a heating rate of about 0.01°

C./min to about 10°

C./min, and b) heating to about 100°

C. to about 120°

C. with a heating rate of about 0.1°

C./min to about 5°

C./min.

6. The method of claim 1, wherein in the esterified lignin composition the weight ratio of the esterified lignin to the poly(lactic acid) is about 1:

1 to about 9;

1.

7. The method of claim 1, wherein in the esterified lignin composition the weight ratio of the esterified lignin to the poly(lactic acid) is about 3:

1.

8. The method of claim 1, wherein in the esterified lignin composition about 50 mol % to about 100 mol % of the —

OH groups on the lignin are esterified.

9. The method of claim 1, wherein in the esterified lignin composition each R group is independently a C₁-C₁₀ alkyl group.

10. The method of claim 1, wherein each R group is a propyl group.

11. The method of claim 1, wherein the esterified lignin composition has a glass transition temperature of about 40°

C. to about 70°

C. and a melting temperature of about 150°

C. to about 170°

C.

12. The method of claim 1, wherein the fibers comprising the esterified lignin composition each independently have a diameter of about 1 μ

m to about 300 μ

m.

13. The method of claim 1, wherein the fibers comprising the esterified lignin each comprise a plurality of smaller fibers within a larger fiber, wherein each of the plurality of smaller fibers independently have a diameter that is about 1/10 to about 1/1,000,000 the diameter of the larger fiber.

14. The method of claim 13, wherein each of the plurality of smaller fibers independently has a diameter of less than about 1-2 μ

m.

15. The method of claim 1, wherein the carbon fibers have a diameter of about 1 μ

m to about 300 μ

m.

16. The method of claim 1, wherein the carbon fibers comprise pores occupying about 0.01% to about 50% of the volume of the carbon fibers, wherein the carbon fibers have an average pore volume of about 0.100 cm³/g to about 0.500 cm³/g.

17. The method of claim 1, wherein the carbon fibers have an average surface area of about 300 m²/g to about 700 m²/g, as determined using BET.

18. The method of claim 1, wherein the carbon fibers comprise:

an average surface area of about 300 m²/g to about 700 m²/g; and

an average pore volume of about 0.100 cm³/g to about 0.500 cm³/g.

19. A method of making carbon fibers, the method comprising:

spinning fibers comprising an esterified lignin composition, to give spun fibers, the esterified lignin composition comprising

lignin comprising at least one esterified —

OH group, wherein the esterified —

OH group has the structure —

OC(O)R, wherein each R is independently a C₁-C₃₀ hydrocarbyl group, and

poly(lactic acid); and

heating the spun fibers to obtain the carbon fibers, wherein the carbon fibers comprise

an average surface area of about 300 m²/g to about 700 m²/g; and

an average pore volume of about 0.100 cm³/g to about 0.500 cm³/g.

20. A method of making carbon fibers, the method comprising:

spinning fibers comprising an esterified lignin composition, to give spun fibers, the esterified lignin composition comprising

lignin comprising at least one esterified —

OH group, wherein the esterified —

OH group has the structure —

OC(O)R, wherein each R is independently a C₁-C₁₀ alkyl group, and

poly(lactic acid),

wherein the weight ratio of the esterified lignin to the poly(lactic acid) is about 3;

1; and

heating the spun fibers to obtain the carbon fibers.