[0001] The present application relates to fibers produced from mesophase pitch and related continuous production methods.

BACKGROUND

[0002] Carbon fibers are composed primarily of carbon atoms and typically have diameters of 5 microns to 20 microns. Carbon fibers are widely used to produce articles or parts for aerospace, civil engineering, military, and motorsports applications because of carbon fibers’ properties like light weight, high stiffness and tensile strength, high chemical resistance and temperature tolerance, and a low thermal expansion. However, compared to glass and plastic fibers, carbon fibers can be expensive to manufacture.

[0003] Most carbon fibers are made from polyacrylonitrile (PAN). The PAN is solution (wet) spun or otherwise formed into a fiber or web that is then treated to carbonize the PAN fiber or web. The resultant fibers have about 50% of the mass of the starting (non-carbonized) material. Petroleum products and coal oils are also used to produce carbon fibers. Melt spinning processes may be used to produce filaments or nonwoven webs from such petroleum products and coal oils, particularly petroleum pitch and coal tar pitch, that can be subsequently treated (e.g., heat treated and/or plasma treated) to yield carbonized and/or graphitized products containing greater than 80% of the mass of the starting material.

[0004] Mesophase pitch is an important member of the petroleum pitch family. Mesophase petroleum pitch and coal oil pitch forms a thermotropic liquid crystal where the molecules align at higher temperatures. This property is useful when forming carbon fibers. Because the molecules align during the fiber forming process, complex processing techniques that require maintaining filaments under tension during treatment processes including stabilization, carbonization, or graphitization are not needed. The alignment of the molecules during melt spinning further enhances the stiffness and tensile strength of the resultant carbon fibers. However, preparation of mesophase pitch generally requires a time-consuming and expensive batch process of heating at an elevated temperature for a number of hours, as shown by in US Pat. Nos. 3,967,729, 4,005,183, and 4,014,725. Further, improper heating can increase viscosity and softening point of mesophase pitch so much that it is rendered unsuitable for spinning. SUMMARY OF INVENTION

[0005] The present application relates to fibers produced from mesophase pitch and related continuous production methods.

[0006] The present disclosure includes a method comprising: producing a mesophase pitch melt by a continuous process, wherein the mesophase pitch has a softening point of about 175°C to about 400°C (ASTM D3104-14), a coking value of about 60 wt% to about 95 wt% (ASTM D2416-84(2004)), a mesophase content of about 5 vol% to 100 vol% (ASTM D4616- 95(2018)), and a quinoline-insoluble content from about 0 wt% to about 95 wt% (ASTM D2318-15); melt extruding the mesophase pitch melt into a green fiber; and carbonizing the green fiber into a carbonized fiber.

[0007] The present disclosure includes a method comprising: producing a mesophase pitch melt by a continuous process, wherein the mesophase pitch has a softening point of about 175°C to about 400°C (ASTM D3104-14), a coking value of about 60 wt% to about 95 wt% (ASTM D2416-84(2004)), a mesophase content of about 5 vol% to 100 vol% (ASTM D4616- 95(2018)), and a quinilone-insoluble content from about 0 wt% to about 95 wt%; melt blowing the mesophase pitch melt into a green fiber; and carbonizing the green fiber into a carbonized fiber. Melt blowing may comprise extruding the mesophase pitch melt through a plurality of die capillaries.

[0008] The present disclosure includes a method comprising: producing a mesophase pitch melt by a continuous process, wherein the mesophase pitch has a softening point of about 175°C to about 400°C (ASTM D3104-14), a coking value of about 60 wt% to about 95 wt% (ASTM D2416-84(2004)), a mesophase content of about 5 vol% to 100 vol% (ASTM D4616- 95(2018)), and a quinilone-insoluble content from about 0 wt% to about 95 wt%; spun bonding the mesophase pitch melt into a green fiber; and carbonizing the green fiber into a carbonized fiber. Spun bonding may comprise feeding the mesophase pitch melt to a gear pump and subsequently extruding the mesophase pitch melt through openings in a die.

[0009] The present disclosure includes a carbonized fiber having a carbon content of about 85 wt % to about 99 wt%, a Young’s modulus (ASTM C1557-20) of about 100 GPa to about 900 GPa, and a tensile strength (ASTM C1557-20) of about 1,500 MPa to about 3,500 MPa. Further, the carbonized fiber may have a (a) carbon content of about 85 wt % to about 99 wt% and/or (b) a diameter of about 0.5 microns to about 100 microns.

[0010] The present disclosure includes a graphitized fiber having a carbon content of about 85 wt % to about 99 wt%, a Young’s modulus (ASTM C1557-20) of about 100 GPa to about 1,000 GPa, and a tensile strength (ASTM Cl 557-20) of about 1,000 MPa to about 4,000 MPa. Further, the graphitized fiber may have a (a) carbon content of about 85 wt % to about 99 wt% and/or (b) a diameter of about 0.5 microns to about 100 microns.

[0011] The present disclosure includes reinforced cements, reinforced epoxy-matrices, insulating materials, friction surface products, conductive materials, sporting goods, aerospace materials, medical devices, transportation materials, power generation materials, and the like, and any combination thereof that comprises the green fibers described herein, the carbonized fibers described herein, the graphitized fibers described herein, or any combination thereof.

[0012] The present disclosure includes a method comprising: producing a mesophase pitch melt by a continuous process, wherein the mesophase pitch has a softening point of about 175°C to about 400°C (ASTM D3104-14), a coking value of about 60 wt% to about 95 wt% (ASTM D2416-84(2004)), a mesophase content of about 5 vol% to 100 vol% (ASTM D4616- 95(2018)), and a quinoline-insoluble content from about 0 wt% to about 95 wt% (ASTM D2318-15); and melt extruding the mesophase pitch melt to produce at least one of a film, fibrillated film, sheet, or tapes.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The following figures are included to illustrate certain aspects of the disclosure, and should not be viewed as exclusive configurations. The subject matter disclosed is capable of considerable modifications, alterations, combinations, and equivalents in form and function, as will occur to those skilled in the art and having the benefit of this disclosure.

[0014] FIG. 1 is a nonlimiting example method for producing fibers described herein from mesophase pitch.

[0015] FIG. 2 is another nonlimiting example method for producing fibers described herein from mesophase pitch.

[0016] FIG. 3 is yet another nonlimiting example method for producing fibers described herein from mesophase pitch.

DETAILED DESCRIPTION

[0017] The present application relates to fibers produced from mesophase pitch and related continuous production methods. More specifically, the present application describes melt extrusion techniques (preferably melt spinning, spun bonding, or melt blowing) using mesophase pitches. Mesophase pitches described herein can be prepared from an aromatic feedstock using a continuous process, such as described in US Patent Nos. 9,376,626 and 10,731,084. Further, the melt extrusion techniques are preferably conducted as a continuous process. Advantageously, these continuous processes reduce the cost of the resultant fibers and can produce said fibers at a more commercially viable rate.

[0018] The melt extrusion techniques of petroleum pitches may also be used to produce sheets, films, tapes, fibrillated films, and the like that may be subsequently treated (e.g., with heat and/or plasma) to produce carbonized structures such as films, fibrillated films, tapes, or sheets.

Definitions

[0019] As used herein, the term “fiber” refers to strands having a longer length than diameter. The term “fiber” encompasses filaments and staple fibers. As used herein, the term “staple fiber” refers to a fiber having a length of 6 inches or less. As used herein, the term “filament” refers to a fiber having a length longer than 6 inches.

[0020] As used herein, the term “melt extrusion” and grammatical variations thereof refers to extrusion of a fluid through a die, frequently having a plurality of holes or orifices that may be of desired shapes, then removing the extrudate from the die by mechanical, aerodynamic, or other means and subsequently solidifying the extrudate. As used herein, “melt extrusion” encompasses melt spinning, melt blowing, and spun bonding techniques.

[0021] As used herein, the term “mesophase pitch” refers to pitch that is a structurally ordered optically anisotropic liquid crystal. Mesophase structure can be described and characterized by various techniques such as optical birefringence, light scattering, or other scattering techniques.

[0022] As used herein, the term “mesophase pitch melt” refers to mesophase pitch that is above the softening point and/or the melting point of the mesophase pitch.

[0023] As used herein, “green fiber” refers to fiber that has been extruded but has not been heat treated or otherwise treated, such as via the carbonization and graphitization methods described herein, to convert to a carbonized or graphitic state.

[0024] As used herein, the term “sizing” refers to a coating applied to the surface of a fiber to improve handling and/or improve mechanical strength and/or improve interaction with a matrix in a composite composition.

[0025] As used herein, the term “surface treatment” refers to contacting a fiber with a substance such as an acid solution or an ionic solution or exposing the fiber to a physical effect such as a plasma or gamma radiation.

[0026] As used herein, the term “composites” refers to compositions comprising a continuous matrix material and a dispersed phase. The fibers described herein may be the dispersed phase. The matrix material may be a polymer and/or resins. Examples of matrix materials include, but are not limited to, polyacrylamides, polymethacrylamides, polyethylene oxides, polypropylene oxides, polyurethanes, polyesters, polyolefins, polyamides, polyimides, epoxy resins, silicone resins, biopolymers (e.g., cellulose), cements, mortars, and the like, and any blend thereof.

Test Methods

[0027] For purposes herein, glass transition temperature (Tg) is determined using the thermomechanical analysis technique by means of a dilatometer described on pages 664-665 of “The Measurement of the Glass Transition Temperature of Mesophpase Pitches using a Thermomechanical Device”, P.M. Khandare, J.W. Zondlo, and A.S. Pavlovic , Carbon, v34 issue 5, 1996, p.663-669.

[0028] As used herein, the “diameter” of a fiber is measured using optical microscopy.

[0029] As used herein, the “length” of a fiber is measured using calibrated linear scales

(e.g., rulers) or may be calculated from measurements of both processing speeds and duration. Fibers and Related Methods of Production

[0030] The mesophase pitch produced by the methods and systems described herein may have a softening point of about 175 °C to about 400°C (ASTM D3104-14), a coking value of about 60 wt% to about 95 wt% (or about 70 wt% to about 95 wt%) (ASTM D2416-84(2004)), a mesophase content of about 5 vol% to 100 vol% (or about 60 vol% to about 95 vol%) (ASTM D4616-95(2018)), and a quinoline-insoluble content from about 0 wt% to about 95 wt% (or about 25 wt % to about 80 wt%) (ASTM D2318-15). Further, the mesophase pitch produced by the methods and systems described herein may have a glass transition temperature of about 125°C to about 350°C (or about 230°C to about 280°C). Methods of producing such mesophase pitch and related systems are described further herein.

[0031] FIG. 1 is a nonlimiting example method 100 for producing fibers described herein from mesophase pitch. Mesophase pitch is first produced from a continuous production process 101. The continuous production process 101 produces a liquid product comprising mesophase pitch, which is used as a mesophase pitch melt 102 in a melt extrusion process 104.

[0032] The mesophase pitch melt 102 is liquid mesophase pitch at a temperature greater than the melting point of the mesophase pitch. The mesophase pitch melt 102 may be at a temperature of about 150°C to about 400°C (or about 150°C to about 300°C, or about 250°C to about 400°C). Preferably, the mesophase pitch melt 102 may be the liquid product from a continuous mesophase pitch production method and continuously melt extruded 102 directly in series with the mesophase production system.

[0033] In certain aspects, the mesophase pitch melt 102 may be melt extruded 104 by passing the melt 102 through an orifice (e.g., a die) and rapidly cooling the melt to below the melting point of the pitch to yield a green fiber 106. Alternatively, melt extrusion 104 may use tension and/or blowing methods for forming the green fiber 106. In tension methods, rollers or other suitable apparatuses are used to attenuate molten filaments exiting the die. Further processing of the green fiber 106 is typically performed by continuously passing the fiber through a series of treatment areas using rollers to convey the fiber through the processes. Generally, tension methods result in a spool of fiber or fibers that may be in the form of a yam, tow, or bundle.

[0034] In blowing methods, a high-speed gas jet is used to attenuate molten filaments and also to cool the mesophase pitch filaments exiting the die. The resultant fiber is collected on, for example, a moving belt as a web that can be further processed.

[0035] The green fibers 106 from the melt extrusion process 104 may be in the form of individual fibers (e.g., spools of filaments and the like) or a collection of fibers (e.g., a web of staple fibers, a web of filaments, a web of staple fibers and filaments, a yam of filaments, and the like).

[0036] The green fibers 106 are then treated to stabilize and/or carbonize and/or graphitize said fibers. Such treatments may be achieved with heat treatment, plasma treatment, or a combination thereof.

[0037] In the illustrated example method 100, the green fibers 106 are carbonized 108 and graphitized 112 in separate steps. More specifically, the green fibers 106 as individual fibers or a web of fibers are heat-treated to carbonize 108 the mesophase pitch of the green fibers 106 and yield carbonized fibers 110.

[0038] Carbonizing 108 can include heating the green fibers 106 in an inert atmosphere to a temperature of about 750°C to about l,500°C (or about 750°C to about l,000°C, or about 900°C to about l,350°C, or about l,000°C to about l,500°C). Inert atmospheres may include, but are not limited to, argon, nitrogen, helium, and the like, and any combination thereof. Carbonizing 108 may occur for about 5 minutes to about 2 hours (or about 15 minutes to about 1 hour).

[0039] Carbonizing 108 can also include exposing the green fibers 106 to plasma (e.g., from a plasma plume or torch) and electromagnetic radiation (e.g., between about 3 KHz and about 300 GHz, or between about 0.5 GHz and about 300 GHz) in an inert atmosphere. Additional details regarding said methods are described in US Patent No. 6,372,192, which is incorporated herein by reference.

[0040] The carbonized fibers 110 may be used as is or further treated to graphitize 112 the carbon and yield a graphitized fiber 114. Graphitizing 112 can include heating the carbonized fibers 110 in an inert atmosphere to a temperature of about l,500°C to about 3,000°C (or about l,500°C to about 2,225°C, or about 2,000°C to about 2,500°C, or about 2,225°C to about 3,000°C). Inert atmospheres may include, but are not limited to, argon, nitrogen, helium, and the like, and any combination thereof. Graphitizing 112 the carbonized fibers 110 may occur for about 5 minutes to about 2 hours (or about 15 minutes to about 1 hour).

[0041] FIG. 2 is a nonlimiting example method 200 for producing fibers described herein from mesophase pitch. Mesophase pitch is first produced from a continuous production process 201. Examples of continuous production processes are described further herein. The continuous production process 201 produces a liquid product comprising mesophase pitch, which is used as a mesophase pitch melt 202 in a melt blowing process 204. The mesophase pitch melt 202 may preferably be the same as the mesophase pitch melt 102 in FIG 1.

[0042] The melt blowing process 204 preferably includes extruding the mesophase pitch melt 202 through a plurality of fine die capillaries to form molten fibers (not illustrated). The molten fibers typically emerge into a high velocity (e.g., 500 m/s or higher gas velocity) gas (e.g. air, nitrogen) stream to attenuate the fibers of the molten material to reduce the molten fiber diameter. Said attenuation may be to a very fine diameter (e.g., about 50 microns or less, about 0.5 microns to about 50 microns, about 0.5 microns to about 3 microns, or about 1 microns to about 10 microns, or about 5 microns to about 25 microns, or about 10 microns to about 40 microns, or about 25 microns to about 50 microns).

[0043] The fibers are generally carried by the high velocity gas stream to a collecting surface to form a web 206 of randomly or semi-randomly disbursed green meltblown fibers on a moving surface such as a rotating drum or a conveyor belt. The green meltblown fibers may be staple fibers, filaments, or a combination thereof. The web 206 may undergo various processes to modify the web’s 206 characteristics and/or green meltblown fiber’s characteristics.

[0044] Processes to modify the characteristics of the green meltblown fibers include, but are not limited to, heat treatment, plasma treatment, or a combination thereof as described above with reference to FIG. 1 to produce graphitized fibers and/or carbonized fibers. Processes to modify the characteristics of the web 206 include, but are not limited to, mechanical and/or hydraulic entanglement of fibers. Additional details regarding meltblown processes are described in US Patent Nos. 3,849,241 and 6,268,203; and Z. Leweandowski, A. Ziabicki, L. Jarecki “The Nonwovens Formation in the Melt-Blown Process,” Fibers & Textiles in Eastern Europe, v 15, No. 5-6, January / December 2007, p 64-65, each of which are incorporated herein by reference.

[0045] FIG. 3 is yet another nonlimiting example method 300 for producing fibers described herein from mesophase pitch. Mesophase pitch is first produced from a continuous production process 301. Examples of continuous production processes are described further herein. The continuous production process 301 produces a liquid product comprising mesophase pitch, which is used as a mesophase pitch melt 302 in a spun bonding process 304 to produce green spunbond fibers 306. The mesophase pitch melt 302 may preferably be the same as the mesophase pitch melt 102 in FIG 1.

[0046] In the spun bonding process 304, the mesophase pitch melt 302 is fed, often through a gear pump to control pressure and material delivery, to a die (also referred to as a spinneret). The mesophase pitch melt 302 is extruded through fine openings, which are frequently circular, in the die to produce molten fibers (not illustrated). The fibers in the molten state may be attenuated or drawn from the die by a variety of methods including routing over mechanical rollers. However, it is more common for the molten fibers to be attenuated and drawn from the die by passing through a pneumatic system (e.g., aspirator). The molten fibers are usually cooled and solidified by flowing high velocity, e.g., up to 100 m/s or up to 150 m/s, gas (e.g., air or nitrogen) onto the fibers. The resultant green spunbond fibers 306 are then deposited on a moving collector, such as a drum or conveyor belt. Additional details regarding spun bonding processes are described in US Patent Nos. 4,340,563, 3,692,618, 3,802,817, 3,338,992, 3,341,394, 3,502,763, 3,542,615, 4,820,142, and 6,918,750, US Patent Appl. Pub. Nos. 2012/0116338A1 and US 2010/0233928 Al, and European Patent Appl. Pub. No. 1 340843A1, each of which are incorporated herein by reference.

[0047] The green spunbond fibers 306 may be further treated by processes that include, but are not limited to, heat treatment, plasma treatment, or a combination thereof as described above with reference to FIG. 1 to produce graphitized fibers and/or carbonized fibers.

[0048] The carbonized fibers produced by the methods described herein may have a carbon content of about 85 wt % to about 99 wt% (or about 85 wt% to about 95 wt%, or about 90 wt% to about 99 wt%, or about 95 wt% to about 99 wt%, or about 98 wt% to about 99 wt%). [0049] The carbonized fibers produced by the methods described herein may have a Young’s modulus (ASTM C1557-20) of about 100 GPa to about 900 GPa (or about 100 GPa to about 500 GPa, or about 150 GPa to about 300 GPa, or about 500 GPa to about 900 GPa).

[0050] The carbonized fibers produced by the methods described herein may have a tensile strength (ASTM C1557-20) of about 1,000 MPa to about 3,500 MPa (or about 1,500 MPa to about 2,000 MPa, or about 2,000 MPa to about 2,500 MPa, or about 2,500 MPa to about 3,500 MPa).

[0051] The graphitized fibers produced by the methods described herein may have a carbon content of about 85 wt % to about 99 wt% (or about 85 wt% to about 95 wt%, or about 90 wt% to about 99 wt%, or about 95 wt% to about 99 wt%, or about 98 wt% to about 99 wt%).

[0052] The graphitized fibers produced by the methods described herein may have a Young’s modulus (ASTM C1557-20) of about 100 GPa to about 1,000 GPa (or about 100 GPa to about 500 GPa, or about 150 GPa to about 300 GPa, or about 500 GPa to about 1,000 GPa). [0053] The graphitized fibers produced by the methods described herein may have a tensile strength (ASTM C1557-20) of about 1,000 MPa to about 4,000 MPa (or about 1,500 MPa to about 2,500 MPa, or about 2,000 MPa to about 3,000 MPa, or about 2,500 MPa to about 4,000 MPa).

[0054] The fibers described herein (e.g., green fibers, carbonized fibers, and graphitized fibers) may be produced to have any suitable diameter. Preferably, the fibers described herein (e.g., green fibers, carbonized fibers, and graphitized fibers) have a diameter of about 0.5 microns to about 100 microns (or about 0.5 microns to about 50 microns, about 0.5 microns to about 3 microns, or about 1 micron to about 10 microns, or about 5 microns to about 25 microns, or about 10 microns to about 50 microns, or about 25 microns to about 75 microns, or about 50 microns to about 100 microns). Generally, melt extrusion techniques (preferably melt spinning, spun bonding, or melt blowing) produce fibers with low variability in diameter. However, fibers of various diameters can be produced simultaneously and/or mixed post production. Therefore, composite materials, webs, and the like that comprise a plurality of fibers described herein may have at least one fiber having a diameter of about 0.5 microns to about 100 microns (or about 0.5 microns to about 50 microns, about 0.5 microns to about 3 microns, or about 1 micron to about 10 microns, or about 5 microns to about 25 microns, or about 10 microns to about 50 microns, or about 25 microns to about 75 microns, or about 50 microns to about 100 microns). [0055] The carbonized fibers and graphitized fibers produced by the methods described herein may be used as-is or further treated. Examples of additional treatments include, but are not limited to, chopping, applying a surface treatment, applying a sizing, and the like, and any combination thereof. In methods where the carbonized fibers are graphitized, the carbonized fibers can be chopped and then graphitized, or graphitized and then chopped. However, surface treatments and/or sizing should be added after the final stage of carbonizing or graphitizing. Preferably, chopping is performed subsequent to any surface treatments and/or sizing, but these three steps of chopping, surface treating, and sizing may alternatively be performed in any order and in any combination.

[0056] Chopping may be performed to yield fibers so that at least some of the resultant chopped fibers (e.g., resultant chopped green fibers, resultant chopped carbonized fibers, or resultant chopped graphitized fibers) have a lengths of about 0.1 cm to about 6 cm (or about 0.3 cm to about 1 cm, or about 0.5 cm to about 2 cm, or about 1 cm to about 3 cm, or about 2 cm to about 6 cm).

[0057] Examples of surface treatments include, but are not limited to, acid oxidation, plasma treatment, rare earth treatment, gamma irradiation, and the like, and any combination thereof.

[0058] Examples of suitable sizing agents include polymers and resins. More specifically, examples of suitable sizing agents include, but are not limited to, polyacrylamides, polymethacrylamides, polyethylene oxides, polypropylene oxides, polyurethanes, polyesters, polyamides, polyimides, epoxy resins, silicone resins, and the like, and any blend thereof. Articles Comprising Fibers Described Herein

[0059] The fibers described herein (e.g., carbonized fibers and/or graphitized fibers each with or without further treatment like sizing, surface treatment, and/or chopping) may be used as composites and/or fabrics. Such composites and/or fabrics may be useful in end products that include, but are not limited to, reinforced cements, reinforced epoxy-matrices, insulating materials, friction surface products (e.g., brake pads), conductive materials, sporting goods, aerospace materials, medical devices, transportation materials, power generation materials (e.g., materials used to produce wind turbines), and the like, and any combination thereof.

[0060] Composites may be formed by blending the matrix material, the dispersed phase (e.g., the fibers described herein), and any other optional components into a compound. The compound may be mold injected, melt extruded, compression molded, or the like into a desired shape that is suitable for a desired article or suitable for further processing to produce the desired article (e.g., a billet, a sheet, or the like).

[0061] Tapes may be formed by embedding continuous fibers side by side in a matrix, for example epoxy or polyester, with a very high aspect ratio. Sections of such tapes can be placed by various means, for example over a mold, to build up a part. Depending on the matrix used, such parts may be treated by heat, pressure, and/or ultra violet light, for example, to set the matrix.

[0062] Articles formed using composites comprising the fibers described herein (e.g., carbonized fibers and/or graphitized fibers each with or without further treatment like sizing, surface treatment, and/or chopping) may include, but are not limited to, molded vehicle parts, wing spars, fuselage components, building materials, sports equipment (e.g., tennis racquets, bicycle frames, hockey sticks, fishing rods, surf boards, basketball sneakers, golf clubs, and the like), musical instruments, dentistry posts, electronics housings, protective cases for electronics, layers in cables, civil engineering blankets, civil engineering pads, civil engineering wrappers, civil engineering reinforcement bars, civil engineering beams, and the like.

[0063] Fabrics can be woven or nonwoven fabrics. Woven fabrics may use the fibers described herein that are not chopped. Nonwoven fabrics may use the fibers described herein that are chopped or produced directly from a melt spinning nonwoven process such as melt blowing or spun bonding processes. Examples of articles that may comprise the fibers described herein (e.g., carbonized fibers and/or graphitized fibers each with or without further treatment like sizing, surface treatment, and/or chopping) may include, but are not limited to, fabrics, scrims, nets, knitted or woven fabrics, braided filaments, ropes or cables, and the like. Example Embodiments

[0064] A first nonlimiting example embodiment of the present disclosure is a method comprising: producing a mesophase pitch melt by a continuous process, wherein the mesophase pitch has a softening point of about 175°C to about 400°C (ASTM D3104-14), a coking value of about 60 wt% to about 95 wt% (ASTM D2416-84(2004)), a mesophase content of about 5 vol% to 100 vol% (ASTM D4616-95(2018)), and a quinoline-insoluble content from about 0 wt% to about 95 wt% (ASTM D2318-15); melt extruding the mesophase pitch melt into a green fiber; and carbonizing the green fiber into a carbonized fiber.

[0065] A second nonlimiting example embodiment is a method comprising: producing a mesophase pitch melt by a continuous process, wherein the mesophase pitch has a softening point of about 175°C to about 400°C (ASTM D3104-14), a coking value of about 60 wt% to about 95 wt% (ASTM D2416-84(2004)), a mesophase content of about 5 vol% to 100 vol% (ASTM D4616-95(2018)), and a quinilone-insoluble content from about 0 wt% to about 95 wt%; melt blowing the mesophase pitch melt into a green fiber; and carbonizing the green fiber into a carbonized fiber. Melt blowing may comprise extruding the mesophase pitch melt through a plurality of die capillaries.

[0066] A third nonlimiting example embodiment is a method comprising: producing a mesophase pitch melt by a continuous process, wherein the mesophase pitch has a softening point of about 175°C to about 400°C (ASTM D3104-14), a coking value of about 60 wt% to about 95 wt% (ASTM D2416-84(2004)), a mesophase content of about 5 vol% to 100 vol% (ASTM D4616-95(2018)), and a quinilone-insoluble content from about 0 wt% to about 95 wt%; spun bonding the mesophase pitch melt into a green fiber; and carbonizing the green fiber into a carbonized fiber. Spun bonding may comprise feeding the mesophase pitch melt to a gear pump and subsequently extruding the mesophase pitch melt through openings in a die.

[0067] The first, second, or third nonlimiting example embodiments may further include one or more of: Element 1: the method further comprising: graphitizing the carbonized fiber into a graphitized fiber; Element 2: Element 1 and wherein the graphitizing is conducted at about l,500°C to about 3,000°C for about 5 minutes to about 2 hours; Element 3: Element 1 and the method further comprising: chopping the graphitized fiber, wherein at least some of the chopped graphitized fibers have a fiber length of about 0.1 cm to about 6 cm; Element 4: Element 1 and the method further comprising: applying a surface treatment and/or sizing to a surface of the graphitized fiber; Element 5: Element 1 and wherein the graphitized fiber has a Young’s modulus (ASTM C1557-20) of about 100 GPa to about 1,000 GPa; Element 6: Element 1 and wherein the graphitized fiber has a tensile strength (ASTM C1557-20) of about 1,000 MPa to about 4,000 MPa; Element 7: Element 1 and wherein the graphitized fiber has a carbon content of about 85 wt % to about 99 wt%; Element 8: wherein the green fiber is in the form of a web; Element 9: wherein the carbonizing is conducted at about 750°C to about l,500°C for about 5 minutes to about 2 hours; Element 10: the method further comprising: chopping the carbonized fiber, wherein at least some of the chopped carbonized fibers have a fiber length of about 0.1 cm to 6 cm; Element 11: the method further comprising: applying a surface treatment and/or sizing to a surface of the carbonized fiber; Element 12: wherein the carbonized fiber has a Young’s modulus (ASTM C1557-20) of about 100 GPa to about 900 GPa; Element 13: wherein the carbonized fiber has a tensile strength (ASTM C1557-20) of about 1,500 MPa to about 3,500 MPa; Element 14: wherein the carbonized fiber has a carbon content of about 85 wt % to about 99 wt%; and Element 15: wherein at least some of the carbonized fibers have a diameter of about 0.5 microns to about 100 microns. Examples of combinations include, but are not limited to, Element 1 in combination with one or more of Elements 2-7; Element 1 (optionally in combination with one or more of Elements 2-7) in combination with one or more of Elements 8-15; and two or more of Elements 8-15 in combination.

[0068] A fourth nonlimiting example embodiment is a carbonized fiber having a carbon content of 85 wt % to about 99 wt%, a Young’s modulus (ASTM C1557-20) of about 100 GPa to about 900 GPa, and a tensile strength (ASTM C1557-20) of about 1,500 MPa to about 3,500 MPa. Further, the carbonized fiber may have a (a) carbon content of about 85 wt % to about

99 wt% and/or (b) a diameter of about 0.5 microns to about 100 microns.

[0069] A fifth nonlimiting example embodiment is a graphitized fiber having a carbon content of about 85 wt % to about 99 wt%, a Young’s modulus (ASTM C1557-20) of about

100 GPa to about 1,000 GPa, and a tensile strength (ASTM C1557-20) of about 1,000 MPa to about 4,000 MPa. Further, the graphitized fiber may have a (a) carbon content of about 85 wt % to about 99 wt% and/or (b) a diameter of about 0.5 microns to about 100 microns.

[0070] The green fibers, the carbonized fibers, the graphitized fibers, or any combination thereof produced by the first, second, or third nonlimiting example embodiment or of the fourth or fifth nonlimiting example embodiments may be incorporated into reinforced cements, reinforced epoxy-matrices, insulating materials, friction surface products, conductive materials, sporting goods, aerospace materials, medical devices, transportation materials, power generation materials, and the like, and any combination thereof.

[0071] A sixth nonlimiting example embodiment is a method comprising: producing a mesophase pitch melt by a continuous process, wherein the mesophase pitch has a softening point of about 175°C to about 400°C (ASTM D3104-14), a coking value of about 60 wt% to about 95 wt% (ASTM D2416-84(2004)), a mesophase content of about 5 vol% to 100 vol% (ASTM D4616-95(2018)), and a quinoline-insoluble content from about 0 wt% to about 95 wt% (ASTM D2318-15); melt extruding the mesophase pitch melt to produce at least one of a film, fibrillated film, sheet, or tapes.

[0072] Unless otherwise indicated, all numbers expressing quantities of ingredients, properties such as molecular weight, reaction conditions, and so forth used in the present specification and associated claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the incarnations of the present inventions. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claim, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. [0073] One or more illustrative incarnations incorporating one or more invention elements are presented herein. Not all features of a physical implementation are described or shown in this application for the sake of clarity. It is understood that in the development of a physical embodiment incorporating one or more elements of the present invention, numerous implementation-specific decisions must be made to achieve the developer's goals, such as compliance with system-related, business-related, government-related and other constraints, which vary by implementation and from time to time. While a developer's efforts might be time-consuming, such efforts would be, nevertheless, a routine undertaking for those of ordinary skill in the art and having benefit of this disclosure.

[0074] While compositions and methods are described herein in terms of “comprising” various components or steps, the compositions and methods can also “consist essentially of’ or “consist of’ the various components and steps.

[0075] To facilitate a better understanding of the embodiments of the present invention, the following examples of preferred or representative embodiments are given. In no way should the following examples be read to limit, or to define, the scope of the invention.

EXAMPLES

[0076] Mesophase pitch produced by the method described in US Patent 9,376,626 was melt spun into green fibers that were then carbonized at l,300°C and graphitized at 2,200°C. Table 1 includes the properties of the resultant fibers and also reports the properties of other commercially available fibers. Table 1

¹ Reported values in the literature. Lavin, J G. (2001) Carbon Fibres. In J.W.S. Hearle’s High- Performance Fibres, (1 ^st edition, page 157) (Elsevier).

[0077] Table 1 illustrates that the fibers described herein exhibit satisfactory Young’s Modulus and tensile strength properties for commercial applications. For instance, the fibers described herein provide comparable tensile strength to existing pitch-based fibers and outperform at least one existing pitch-based fiber in Young’s modulus. Accordingly, the methods described herein may advantageously provide a continuous production, and therefore lower cost and more commercially viable, means to produce fibers having comparable or better properties than those currently commercially available.

[0078] Therefore, the present invention is well adapted to attain the ends and advantages mentioned as well as those that are inherent therein. The particular examples and configurations disclosed above are illustrative only, as the present invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular illustrative examples disclosed above may be altered, combined, or modified and all such variations are considered within the scope and spirit of the present invention. The invention illustratively disclosed herein suitably may be practiced in the absence of any element that is not specifically disclosed herein and/or any optional element disclosed herein. While compositions and methods are described in terms of “comprising,” “containing,” or “including” various components or steps, the compositions and methods can also “consist essentially of’ or “consist of’ the various components and steps. All numbers and ranges disclosed above may vary by some amount. Whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range falling within the range is specifically disclosed. In particular, every range of values (of the form, “from about a to about b,” or, equivalently, “from approximately a to b,” or, equivalently, “from approximately a-b”) disclosed herein is to be understood to set forth every number and range encompassed within the broader range of values. Also, the terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee. Moreover, the indefinite articles “a” or “an,” as used in the claims, are defined herein to mean one or more than one of the element that it introduces.