Controlled chemical stabilization of polyvinyl precursor fiber, and high strength carbon fiber produced therefrom

Patent metadata

Field	Value
Publication number	US-9528197-B2
Application number	US-201313860188-A
Country	US
Kind code	B2
Filing date	Apr 10, 2013
Priority date	Apr 10, 2013
Publication date	Dec 27, 2016
Grant date	Dec 27, 2016

Abstract

Method for the preparation of carbon fiber, which comprises: (i) immersing functionalized polyvinyl precursor fiber into a liquid solution having a boiling point of at least 60° C.; (ii) heating the liquid solution to a first temperature of at least 25° C. at which the functionalized precursor fiber engages in an elimination-addition equilibrium while a tension of at least 0.1 MPa is applied to the fiber; (iii) gradually raising the first temperature to a final temperature that is at least 20° C. above the first temperature and up to the boiling point of the liquid solution for sufficient time to convert the functionalized precursor fiber to a pre-carbonized fiber; and (iv) subjecting the pre-carbonized fiber produced according to step (iii) to high temperature carbonization conditions to produce the final carbon fiber. Articles and devices containing the fibers, including woven and non-woven mats or paper forms of the fibers, are also described.

First claim

What is claimed is:

1. A method for the preparation of carbon fiber from a sulfonated polyvinyl precursor fiber having sulfonic acid groups thereon, the method comprising:
(i) immersing the sulfonated polyvinyl precursor fiber into a liquid solution comprised of an ionic liquid solvent and a solute species capable of engaging in an elimination-addition equilibrium with said sulfonic acid groups, wherein said ionic liquid solvent has a boiling point of at least 350° C.;
(ii) heating said liquid solution, after said sulfonated polyvinyl precursor fiber has been immersed therein, to a first temperature of at least 25° C. at which said sulfonated polyvinyl precursor fiber engages in an elimination-addition equilibrium between said sulfonic acid groups and said liquid solution while the sulfonated polyvinyl precursor fiber is maintained at an applied tension of at least 0.1 MPa;
(iii) gradually raising said first temperature to a final temperature of at least 300° C. at an average temperature ramp rate of up to 50° C. per minute, wherein said final temperature is at least 20° C. above the first temperature and up to the boiling point of the liquid solution for sufficient time to convert said sulfonated polyvinyl precursor fiber to a pre-carbonized fiber; and
(iv) subjecting the pre-carbonized fiber produced according to step (iii) to a high temperature carbonization process to produce said carbon fiber, wherein said high temperature carbonization process is conducted at a temperature of at least 500° C.

2. The method of claim 1 , wherein said sulfonated polyvinyl precursor is sulfonated polyolefin precursor.

3. The method of claim 1 , wherein said first temperature at which said polyvinyl precursor fiber engages in said elimination-addition equilibrium is at least 50° C.

4. The method of claim 1 , wherein said first temperature at which said polyvinyl precursor fiber engages in said elimination-addition equilibrium is at least 120° C.

5. The method of claim 1 , wherein said first temperature at which said polyvinyl precursor fiber engages in said elimination-addition equilibrium is at least 150° C.

6. The method of claim 1 , wherein said applied tension is at least 1 MPa.

7. The method of claim 1 , wherein said applied tension is at least 2 MPa.

8. The method of claim 1 , wherein said applied tension is at least 5 MPa.

9. The method of claim 1 , wherein said first temperature is raised to said final temperature at an average temperature ramp rate of up to 20° C. per minute.

10. The method of claim 1 , wherein said first temperature is raised to said final temperature at an average temperature ramp rate of up to 10° C. per minute.

11. The method of claim 1 , wherein said first temperature is raised to said final temperature at an average temperature ramp rate of up to 5° C. per minute.

12. The method of claim 1 , wherein said final temperature is at least 40° C. above said first temperature and up to the boiling point of the liquid solution.

13. The method of claim 1 , wherein said final temperature is at least 70° C. above said first temperature and up to the boiling point of the liquid solution.

14. The method of claim 1 , wherein said pre-carbonized fiber is infusible and incombustible.

15. The method of claim 1 , wherein said liquid solution includes at least one free-radical scavenger.

16. The method of claim 15 , wherein said free-radical scavenger is selected from hindered phenols, thioesters, phosphites, and aromatic amines.

17. The method of claim 1 , wherein steps (i) to (iii) are conducted as a continuous process on a continuously fed precursor fiber.

18. The method of claim 1 , wherein steps (i) to (iii) are conducted as a batch process on batch-fed precursor fiber.

19. The method of claim 1 , wherein said sulfonated polyvinyl precursor fiber having sulfonic acid groups thereon is produced from non-functionalized precursor fiber in a separate step before step (i), or is produced from non-functionalized precursor fiber during step (i) or during steps (i) and (ii).

20. The method of claim 1 , wherein said high temperature carbonization process is conducted at a temperature of at least 1000° C.

21. The method of claim 1 , wherein said high temperature carbonization process is conducted at a temperature of at least 2000° C.

22. The method of claim 1 , wherein said high temperature carbonization process is conducted at a temperature of at least 2500° C.

23. The method of claim 1 , wherein said carbon fiber has a tensile strength of at least 200 ksi.

24. The method of claim 1 , wherein said carbon fiber has a modulus of at least 20 Msi.

25. The method of claim 1 , wherein said carbon fiber has an ultimate elongation of at least 0.5%.

26. The method of claim 1 , wherein said carbon fiber has an ultimate elongation of at least 0.8%.

27. The method of claim 1 , wherein said carbon fiber has a surface area of at least 1000 m 2 /g.

28. The method of claim 1 , wherein said carbon fiber is processed in spoolable filament web or mat form.

29. The method of claim 1 , wherein, directly prior to step (i), the sulfonated polyvinyl precursor fiber is produced by treating an unsulfonated precursor fiber in oleum.

30. The method of claim 1 , wherein said final temperature is at least 350° C.

31. The method of claim 1 , wherein said ionic liquid solvent has a boiling point of at least 400° C.

32. The method of claim 31 , wherein said final temperature is at least 400° C.

33. The method of claim 1 , wherein said solute is a salt of a strong mineral acid.

34. The method of claim 33 , wherein said salt is ammonium sulfate.

Assignees

• Ut Battelle Llc

Inventors

• Naskar Amit K

Classifications

• D01F9/20

  from polyaddition, polycondensation or polymerisation products (D01F9/145, D01F9/16, D01F9/18 take precedence) · CPC title

• D01F9/21 Primary

  from macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds · CPC title

• D01F9/12

  Carbon filaments; Apparatus specially adapted for the manufacture thereof · CPC title