Two-step sulfonation process for the conversion of polymer fibers to carbon fibers

Patent metadata

Field	Value
Publication number	US-9816207-B2
Application number	US-201314413454-A
Country	US
Kind code	B2
Filing date	Jul 3, 2013
Priority date	Jul 12, 2012
Publication date	Nov 14, 2017
Grant date	Nov 14, 2017

Abstract

Disclosed herein are processes for preparing carbon fibers, comprising: sulfonating a polymer fiber with a sulfonating agent that is fuming sulfuric acid, sulfuric acid, chlorosulfonic acid, or a combination thereof; treating the sulfonated polymer with a heated solvent, wherein the temperature of the heated solvent is at least 95° C.; and carbonizing the resulting product by heating it to a temperature of 501-3000° C. Carbon fibers prepared according to these methods are also disclosed herein.

First claim

What is claimed is:

1. Processes for preparing carbonized polymers, comprising
a) treating a polymer in a first vessel with a solution comprising a sulfonating agent that is fuming sulfuric acid, -chlorosulfonic acid, or a combination thereof at a temperature below the boiling temperature of the sulfonating agent to form a sulfonated polymer, wherein the concentration of the sulfonating agent is from 0.1 to 30 percent;
b) treating the sulfonated polymer in a second vessel with a heated solvent comprising sulfuric acid, wherein the temperature of the heated solvent is from 95° C. to 180° C.; and
c) carbonizing the resulting product by heating it to a temperature of 500-3000° C.

2. Processes according to claim 1 , wherein the sulfonating agent comprises chlorosulfonic acid.

3. Processes according to claim 1 , wherein the sulfonating agent comprises fuming sulfuric acid.

4. Processes according to claim 3 , wherein the fuming sulfuric acid is 0.1-70% fuming sulfuric acid.

5. Processes according to claim 1 , wherein the polymer consists of polyethylene or comprises a copolymer of ethylene.

6. Processes according to claim 5 , wherein the copolymer of ethylene is an ethylene/octene copolymer, an ethylene/hexene copolymer, an ethylene/butene copolymer, or a combination of two or more thereof.

7. Processes according to claim 1 , wherein the heated solvent is at a temperature of at least 100° C.

8. Processes according to claim 1 , wherein the heated solvent is sulfuric acid at 100-180° C.

9. Processes according to claim 1 , wherein the sulfonation reaction is performed at a temperature of 0-140° C.

10. Processes according to claim 1 , wherein the sulfonation is conducted while the polymer is a polymer fiber, and the polymer fiber is under a tension of 0-35.5 MPa, the treatment with a heated solvent is conducted while the polymer fiber under a tension of 0-25 MPa, or carbonization is conducted while the polymer fiber is under a tension of 0-8.8 MPa.

11. Processes according to claim 1 , wherein the sulfonation, the treatment with a heated solvent, and the carbonization are performed while the polymer is under a tension greater than 1 MPa.

12. Processes according to claim 10 , wherein the tension during the carbonization step differs from that in the sulfonation step.

13. Processes according to claim 1 , wherein the carbonization step is performed at temperatures of from 700-1,500° C.

14. Processes according to claim 1 , comprising:
a) sulfonating a polyethylene containing polymer in a first vessel with fuming sulfuric acid, wherein the sulfonation reaction is performed at a temperature of from 35-140° C. to form a sulfonated polymer;
b) treating the sulfonated polymer in a second vessel with a protic and/or polar solvent, wherein the temperature of the solvent is 100-180° C.; and
c) carbonizing the resulting product by heating it to a temperature of 500-3000° C.;

wherein at least one of steps a), b) and c) is performed while the polymer fibers are under tension.

15. Processes according to claim 14 , wherein the protic and/or polar solvent is a mineral acid.

16. Processes according to claim 14 , wherein the polyethylene containing polymers are polyethylene homopolymers or polyethylene copolymers that comprise an ethylene/octene copolymers, ethylene/hexene copolymers, ethylene/butene copolymers, ethylene/propylene copolymers, ethylene/styrene copolymers, ethylene/butadiene copolymers, a mixture of one or more homopolymers and one or more polyethylene copolymers, or a combination of two or more polyethylene homopolymers.

17. Processes according to claim 14 , wherein the protic and/or polar solvent is sulfuric acid at a temperature of 115-160° C.

18. Processes according to claim 14 , wherein steps a), b) and c) are performed while the polymer is under a tension greater than 1 MPa.

19. Processes for preparing carbonized polymers, comprising
a) treating a polymer in a first vessel with a sulfonating agent that is fuming sulfuric acid, -chlorosulfonic acid, or a combination thereof to form a sulfonated polymer;
b) treating the sulfonated polymer in a second vessel with a heated solvent consisting of sulfuric acid, wherein the temperature of the heated solvent is at least 95° C.; and
c) carbonizing the resulting product by heating it to a temperature of 500-3000° C.

Assignees

• Dow Global Technologies Llc

Inventors

• Barton Bryan E
• Patton Jasson T
• Hukkanen Eric J
• Bernius Mark T

Classifications

• D06M11/55

  with sulfur trioxide; with sulfuric acid or thiosulfuric acid or their salts · CPC title

• D01F9/21 Primary

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

• D06M2101/20

  Polyalkenes, polymers or copolymers of compounds with alkenyl groups bonded to aromatic groups · CPC title

• D01F11/16

  by physicochemical methods · CPC title

• C01B32/05

  Preparation or purification of carbon not covered by groups C01B32/15, C01B32/20, C01B32/25, C01B32/30 · CPC title