High modulus, high strength carbon fibers produced from mesophase pitch

Claim 2

A fiber having a structure possessing the three-dimensional order characteristic of polycrystalline graphite, said fiber having a diameter no greater than 30 microns; an electrical resistivity less than 250 × 10 - 6 ohm centimeters; a tensile strength greater than 200 × 10 3 psi.; a Young's modulus of elasticity greater than 50 × 10 6 psi.; an X-ray diffraction pattern characterized by the presence of the (112) cross-lattice line, and resolved (100) and (101) lines; a preferred orientation of carbon crystallites parallel to the fiber axis such that the preferred orientation parameter for the fiber is no greater than 10° (determined by microdensitometer scanning of the (002) band of the exposed X-ray film of the fiber and expressed as the full width at half maximum of the azimuthal intensity distribution); an interlayer spacing d no greater than 3.37 A; and containing oriented elongated domains preferentially aligned parallel to the fiber axis, said domains characteristically being greater than 5000 A in diameter and visible under polarized light at a magnification of 1000 X.

Claim 3

The fiber as in claim 1 having an electrical resistivity of from 150 × 10 - 6 ohm centimeters to 200 × 10 - 6 ohm centimeters, a tensile strength greater than 250 × 10 3 psi., and a Young's modulus of elasticity greater than 75 × 10 6 psi.

Claim 4

The fiber as in claim 1 containing elongated domains from 10,000 A to 40,000 A in diameter.

Claim 5

The fiber as in claim 3 having an electrical resistivity of from 150 × 10 - 6 ohm centimeters to 200 × 10 - 6 ohm centimeters, a tensile strength greater than 250 × 10 3 psi., and a Young's modulus of elasticity greater than 75 × 10 6 psi.

Claim 6

The fiber as in claim 1 containing elongated domains from 10,000 A to 100,000 A in diameter.

Claim 7

A carbon fiber capable of being converted thermally to a fiber having a structure possessing the three-dimensional order characteristic of polycrystalline graphite, said carbon fiber having a diameter no greater than 30 microns; a preferred orientation of carbon crystallites parallel to the fiber axis such that the preferred orientation parameter for the fiber is less than 45° (determined by microdensitometer scanning of the (002) band of the exposed X-ray film of the fiber and expressed as the full width at half maximum of the azimuthal intensity distribution); and containing at least 40 per cent of oriented elongated domains preferentially aligned parallel to the fiber axis, said domains characteristically being greater than 5000 A in diameter and visible under polarized light at a magnification of 1000 X.

Claim 8

A carbon fiber capable of being converted thermally to a fiber having a structure possessing the three-dimensional order characteristic of polycrystalline graphite, said carbon fiber having a diameter no greater than 30 microns; a preferred orientation of carbon crystallites parallel to the fiber axis such that the preferred orientation parameter for the fiber is less than 45° (determined by microdensitometer scanning of the (002) band of the exposed X-ray film of the fiber and expressed as the full width at half maximum of the azimuthal intensity distribution); and containing at least 40 per cent of oriented elongated domains preferentially aligned parallel to the fiber axis, said domains characteristically being greater than 5000 A in diameter and visible under polarized light at a magnification of 1000 X.

Claim 9

The carbon fiber as in claim 6 containing essentially 100 per cent of oriented elongated domains preferentially aligned parallel to the fiber axis.

Claim 10

The carbon fiber as in claim 6 containing elongated domains from 10,000 A to 40,000 A in diameter.

Claim 11

The carbon fiber as in claim 6 containing elongated domains from 10,000 A to 100,000 A in diameter.

Claim 12

A carbonaceous pitch fiber capable of being thermoset and converted thermally to a fiber having a structure possessing the three-dimensional order characteristic of polycrystalline graphite, said pitch fiber having a mesophase content of from 40 per cent by weight to 90 per cent by weight, a diameter no greater than 30 microns, a preferred orientation of pitch molecules parallel to the fiber axis such that the preferred orientation parameter for the fiber is from 20° to 35° (determined by microdensitometer scanning of the (002) band of the exposed X-ray film of the fiber and expressed as the full width at half maximum of the azimuthal intensity distribution), and containing elongated domains of oriented molecules preferentially aligned parallel to the fiber axis, said domains characteristically being greater than 5000 A in diameter and visible under polarized light at a magnification of 1000 X.

Claim 13

A carbonaceous pitch fiber capable of being thermoset and converted thermally to a fiber having a structure possessing the three-dimensional order characteristic of polycrystalline graphite, said pitch fiber having a mesophase content of from 40 per cent by weight to 90 per cent by weight, a diameter no greater than 30 microns, a preferred orientation of pitch molecules parallel to the fiber axis such that the preferred orientation parameter for the fiber is from 20° to 35° (determined by microdensitometer scanning of the (002) band of the exposed X-ray film of the fiber and expressed as the full width at half maximum of the azimuthal intensity distribution), and containing elongated domains of oriented molecules preferentially aligned parallel to the fiber axis, said domains characteristically being greater than 5000 A in diameter and visible under polarized light at a magnification of 1000 X.

Claim 14

The carbonaceous pitch fiber as in claim 10 containing elongated domains from 10,000 A to 40,000 A in diameter.

Claim 15

The carbonaceous pitch fiber as in claim 10 having a mesophase content of from 45 per cent by weight to 65 per cent by weight.

Claim 16

The carbonaceous pitch fiber as in claim 12 containing elongated domains from 10,000 A to 40,000 A in diameter.

Claim 17

A process for producing a carbon fiber capable of being converted thermally to a fiber having a structure possessing the three-dimensional order characteristic of polycrystalline graphite, said carbon fiber having a diameter no greater than 30 microns and a preferred orientation of carbon crystallites parallel to the fiber axis such that the preferred orientation parameter for the fiber is less than 45° (determined by microdensitometer scanning of the (002) band of the exposed X-ray film of the fiber and expressed as the full width at half maximum of the azimuthal intensity distribution), which comprises spinning a carbonaceous fiber having a diameter no greater than 30 microns from a carbonaceous pitch containing from 40 per cent by weight to 90 per cent by weight mesophase, which mesophase, under quiescent conditions, forms a homogeneous bulk mesophase which when examined under polarized light exhibits large coalesced domains in excess of 200 microns in size, said pitch being nonthixotropic and having a viscosity of 10 poises to 200 poises at the temperature of spinning; heating the spun fiber in an oxygen-containing atmosphere at a temperature of from 250° C. to 400° C. for a time sufficient to render it infusible; and then heating the infusible fiber so produced in an inert atmosphere to a temperature of at least 1000° C.

Claim 18

A process for producing a carbon fiber capable of being converted thermally to a fiber having a structure possessing the three-dimensional order characteristic of polycrystalline graphite, said carbon fiber having a diameter no greater than 30 microns and a preferred orientation of carbon crystallites parallel to the fiber axis such that the preferred orientation parameter for the fiber is less than 45° (determined by microdensitometer scanning of the (002) band of the exposed X-ray film of the fiber and expressed as the full width at half maximum of the azimuthal intensity distribution), which comprises spinning a carbonaceous fiber having a diameter no greater than 30 microns from a carbonaceous pitch containing from 40 per cent by weight to 90 per cent by weight mesophase, which mesophase, under quiescent conditions, forms a homogeneous bulk mesophase which when examined under polarized light exhibits large coalesced domains in excess of 200 microns in size, said pitch being nonthixotropic and having a viscosity of 10 poises to 200 poises at the temperature of spinning; heating the spun fiber in an oxygen-containing atmosphere at a temperature of from 250° C. to 400° C. for a time sufficient to render it infusible; and then heating the infusible fiber so produced in an inert atmosphere to a temperature of at least 1000° C.

Claim 19

The process as in claim 14 wherein the fiber is heated in an oxygen-containing atmosphere at a temperature of from 300° C. to about 390° C.

Claim 20

The process as in claim 15 wherein the oxygen-containing atmosphere is selected from the group consisting of air and oxygen.

Claim 21

The process as in claim 14 wherein the carbonaceous fiber is spun at a temperature at which the pitch has a viscosity of 30 poises to 60 poises.

Claim 22

The process as in claim 17 wherein the fiber is heated in an oxygen-containing atmosphere at a temperature of from 300° C. to about 390° C.

Claim 23

The process as in claim 18 wherein the oxygen-containing atmosphere is selected from the group consisting of air and oxygen.

Claim 24

The process as in claim 17 wherein the pitch contains from 45 per cent by weight to about 65 per cent by weight mesophase.

Claim 25

The process as in claim 20 wherein the fiber is heated in an oxygen-containing atmosphere at a temperature of from 300° C. to about 390° C.

Claim 26

The process as in claim 21 wherein the oxygen-containing atmosphere is selected from the group consisting of air and oxygen.

Claim 27

A process for producing a fiber having a structure possessing the three-dimensional order characteristic of polycrystalline graphite, said fiber having a diameter no greater than 30 microns and a preferred orientation of carbon crystallites parallel to the fiber axis such that the preferred orientation parameter for the fiber is no greater than 10° (determined by microdensitometer scanning of the (002) band of the exposed X-ray film of the fiber and expressed as the full width at half maximum of the azimuthal intensity distribution), which comprises spinning a carbonaceous fiber having a diameter no greater than 30 microns from a carbonaceous pitch containing from 40 per cent by weight to 90 per cent by weight mesophase, which mesophase, under quiescent conditions, forms a homogeneous bulk mesophase which when examined under polarized light exhibits large coalesced domains in excess of 200 microns in size, said pitch being nonthixotropic and having a viscosity of 10 poises to 200 poises at the temperature of spinning; heating the spun fiber in an oxygen-containing atmosphere at a temperature of from 250° C. to 400° C. for a time sufficient to render it infusible; and then heating the infusible fiber so produced in an inert atmosphere first to a temperature of at least 1000° C., and then to a higher temperature of at least 2500° C.

Claim 28

A process for producing a fiber having a structure possessing the three-dimensional order characteristic of polycrystalline graphite, said fiber having a diameter no greater than 30 microns and a preferred orientation of carbon crystallites parallel to the fiber axis such that the preferred orientation parameter for the fiber is no greater than 10° (determined by microdensitometer scanning of the (002) band of the exposed X-ray film of the fiber and expressed as the full width at half maximum of the azimuthal intensity distribution), which comprises spinning a carbonaceous fiber having a diameter no greater than 30 microns from a carbonaceous pitch containing from 40 per cent by weight to 90 per cent by weight mesophase, which mesophase, under quiescent conditions, forms a homogeneous bulk mesophase which when examined under polarized light exhibits large coalesced domains in excess of 200 microns in size, said pitch being nonthixotropic and having a viscosity of 10 poises to 200 poises at the temperature of spinning; heating the spun fiber in an oxygen-containing atmosphere at a temperature of from 250° C. to 400° C. for a time sufficient to render it infusible; and then heating the infusible fiber so produced in an inert atmosphere first to a temperature of at least 1000° C., and then to a higher temperature of at least 2500° C.

Claim 29

The process as in claim 23 wherein the fiber is heated in an oxygen-containing atmosphere at a temperature of from 300° C. to about 390° C.

Claim 30

The process as in claim 24 wherein the oxygen-containing atmosphere is selected from the group consisting of air and oxygen.

Claim 31

The process as in claim 23 wherein the carbonaceous fiber is spun at a temperature at which the pitch has a viscosity of 30 poises to 60 poises.

Claim 32

The process as in claim 26 wherein the fiber is heated in an oxygen-containing atmosphere at a temperature of from 300° C. to about 390° C.

Claim 33

The process as in claim 27 wherein the oxygen-containing atmosphere is selected from the group consisting of air and oxygen.

Claim 34

The process as in claim 26 wherein the pitch contains from 45 per cent by weight to about 65 per cent by weight mesophase.

Claim 35

The process as in claim 29 wherein the fiber is heated in an oxygen-containing atmosphere at a temperature of from 300° C. to about 390° C.

Claim 36

The process as in claim 30 wherein the oxygen-containing atmosphere is selected from the group consisting of air and oxygen.

Claim 37

A process for producing a carbonaceous pitch fiber capable of being thermoset and converted thermally to a fiber having a structure possessing the three-dimensional order characteristic of polycrystalline graphite, said pitch fiber having a mesophase content of from 40 per cent by weight to 90 per cent by weight, a diameter no greater than 30 microns, a preferred orientation of pitch molecules parallel to the fiber axis such that the preferred orientation parameter for the fiber is from 20° to 35° (determined by microdensitometer scanning of the (002) band of the exposed X-ray film of the fiber and expressed as the full width at half maximum of the azimuthal intensity distribution), and containing elongated domains of oriented molecules preferentially aligned parallel to the fiber axis, said domains characteristically being greater than 5000 A in diameter and visible under polarized light at a magnification of 1000 X, which comprises spinning a carbonaceous fiber having a diameter no greater than 30 microns from a carbonaceous pitch containing from 40 per cent by weight to 90 percent by weight mesophase, which mesophase, under quiescent conditions, forms a homogeneous bulk mesophase which when examined under polarized light exhibits large coalesced domains in excess of 200 microns in size, said pitch being nonthixotropic and having a viscosity of 10 poises to 200 poises at the temperature of spinning.

Claim 38

A process for producing a carbonaceous pitch fiber capable of being thermoset and converted thermally to a fiber having a structure possessing the three-dimensional order characteristic of polycrystalline graphite, said pitch fiber having a mesophase content of from 40 per cent by weight to 90 per cent by weight, a diameter no greater than 30 microns, a preferred orientation of pitch molecules parallel to the fiber axis such that the preferred orientation parameter for the fiber is from 20° to 35° (determined by microdensitometer scanning of the (002) band of the exposed X-ray film of the fiber and expressed as the full width at half maximum of the azimuthal intensity distribution), and containing elongated domains of oriented molecules preferentially aligned parallel to the fiber axis, said domains characteristically being greater than 5000 A in diameter and visible under polarized light at a magnification of 1000 X, which comprises spinning a carbonaceous fiber having a diameter no greater than 30 microns from a carbonaceous pitch containing from 40 per cent by weight to 90 percent by weight mesophase, which mesophase, under quiescent conditions, forms a homogeneous bulk mesophase which when examined under polarized light exhibits large coalesced domains in excess of 200 microns in size, said pitch being nonthixotropic and having a viscosity of 10 poises to 200 poises at the temperature of spinning.

Claim 39

A carbonaceous pitch fiber produced by the process of claim 32.

Claim 40

A carbon fiber produced by the process of claim 14.

Claim 41

A fiber produced by the process of claim 23.