	US 12,031,243 B2
	Methods to produce carbon fibers from carbon pitches
Alfred H. Stiller, Morgantown, WV (US)
Assigned to West Virginia University, Morgantown, WV (US)
Filed by West Virginia University, Morgantown, WV (US)
Filed on Dec. 11, 2020, as Appl. No. 17/119,997.
Claims priority of provisional application 62/946,643, filed on Dec. 11, 2019.
Prior Publication US 2021/0180217 A1, Jun. 17, 2021
Int. Cl. D01F 9/15 (2006.01); C01B 32/05 (2017.01); D01F 8/18 (2006.01); D01F 9/155 (2006.01)

CPC D01F 9/15 (2013.01) [C01B 32/05 (2017.08); D01F 8/18 (2013.01); D01F 9/155 (2013.01)]

13 Claims

1. A process for preparing carbon fibers, the process comprising:

(a) converting coal to a low-softening point carbon pitch;

(b) extruding the pitch into carbon fibers;

(d) calcining the carbon fibers;

wherein the coal is selected from bituminous, sub-bituminous, lignite, and combinations thereof;

wherein the pitch is an anisotropic mesophase carbon pitch;

wherein the converting the coal to a low-softening point carbon pitch comprises air oxidation until a softening point from about 295° C. to about 350° C. is achieved, thereby yielding a low-softening point carbon pitch having a softening point from about 295° C. to about 350° C.;

wherein the pitch is heated to a first temperature for extrusion;

wherein the first temperature is from about 295° C. to about 345° C.;

wherein the carbon fibers have a diameter from about 5 μm to about 10 μm;

wherein the graphite/graphene sheath comprises a layer on the outside of the carbon fibers having a thickness from about 1 μm to about 2 μm;

wherein the adding the graphite/graphene sheath to the carbon fibers comprises mixing graphite and/or graphene with the low-softening point carbon pitch prior to extrusion; and

wherein the graphite and/or graphene is added to the low-softening point carbon pitch in a ratio equal to the thickness of the graphite/graphene layer to the desired cross-sectional area of the carbon fiber.