# US 2018/0023244 A1 · Composite carbon fibers

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- Number: US 2018/0023244 A1
- Document ID: US20180023244A1
- Status: Published application
- Kind: A1
- Application number: 15/213,564
- Filed: 2016-07-19
- Published: 2018-01-25
- Earliest claimed: 2016-07-19
- Applicants: Hexcel Corporation
- Inventors: Michael Yurchenko
- Web page: https://patentgrep.com/patent/US20180023244A1

## CPC

- D06M 14/36: on to carbon fibres
- C08J 5/042: {with carbon fibres}
- C08J 5/06: using pretreated fibrous materials
- D01F 11/14: with organic compounds, e.g. macromolecular compounds
- D06M 10/10: Macromolecular compounds
- D06M 15/3562: {containing nitrogen}
- D06M 15/55: Epoxy resins
- D06M 15/59: Polyamides; Polyimides
- D06M 15/61: Polyamines {polyimines}
- D06M 23/12: Processes in which the treating agent is incorporated in microcapsules (making microcapsules B01J13/02)
- D06M 2101/40: Fibres of carbon
- D06M 2400/01: Creating covalent bondings between the treating agent and the fibre
- D10B 2505/12: Vehicles (D10B2505/08 takes precedence)
- D06M: TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)
- D01F: CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
- D10B: INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES

## Abstract

A composite carbon fiber having a carbon fiber to which an amine-functionalized polymer is electro-grafted onto a surface thereof is provided. Electro-grafting the amine-functionalized polymer onto the surface of the carbon fiber results in a composite carbon fiber in which the polymer is covalently bonded to the fiber, and in which a significant number of reactive amine groups are available for subsequent reactions, such as for reacting with a resin matrix in the production of a fiber reinforced composite. As a result, the composite carbon fibers may be particularly useful in producing fibers reinforced composites that exhibit improved interlaminar strength. Fiber reinforced composites are also provided.

## Claims

### Claim at position 1

-56. (canceled)

### Claim 57

A composite carbon fiber comprising a carbon fiber having an amine-functionalized polymer electro-grafted onto a surface thereof.

### Claim 58 (depends on 57)

The composite carbon fiber of claim 57, wherein the composite carbon fiber has a nitrogen/carbon (N/C) ratio that is at least 0.125.

### Claim 59 (depends on 57)

The composite carbon fiber of claim 57, wherein the composite carbon fiber has a N/C ratio that is from about 0.15 to 0.3.

### Claim 60 (depends on 57)

The composite carbon fiber of claim 57, wherein the composite carbon fiber exhibits an increase in nitrogen surface concentration that is at least 50% in comparison to the original carbon fiber that does not include an amine-functionalized polymer electro-grafted onto the surface of the carbon fiber.

### Claim 61 (depends on 57)

The composite carbon fiber of claim 57, wherein the composite carbon fiber exhibits an increase in nitrogen surface concentration that is from about 50 to 500% in comparison to the original carbon fiber that does not include an amine-functionalized polymer electro-grafted onto the surface of the carbon fiber.

### Claim 62 (depends on 57)

The composite carbon fiber of claim 57, wherein the composite carbon fiber exhibits an increase in nitrogen surface concentration that is from about 150 to 500% in comparison to the original carbon fiber that does not include an amine-functionalized polymer electro-grafted onto the surface of the carbon fiber.

### Claim 63 (depends on 57)

The composite carbon fiber of claim 57, wherein the amine-functionalized polymer is selected from the group consisting of linear polyethyleneimines (PEI), branched polyethyleneimines (PEI), branched polypropyleneimine, linear poly(allylamine) (PAA), polyamidoamine (PAMAM) dendrimer, branched poly(allylamine) prepared by branching of poly(allylamine) with divinylbenzene (PAADVB), and block-copolymers, core-shell particles, and combinations thereof.

### Claim 64 (depends on 57)

The composite carbon fiber of claim 57, wherein the amine-functionalized polymer comprises a branched polyethyleneimine.

### Claim 65 (depends on 57)

The composite carbon fiber of claim 57, wherein the carbon fiber has a tensile strength of at least 400 ksi.

### Claim 66 (depends on 57)

The composite carbon fiber of claim 57, wherein the carbon fiber has a tensile strength from about 600 to 1,050 ksi.

### Claim 67 (depends on 57)

The composite carbon fiber of claim 57, wherein the amine-functionalized polymer has a weight average molecular weight ranging from about 5,000 to 35,000.

### Claim 68 (depends on 57)

A fiber reinforced composite comprising the composite carbon fiber of claim 57.

### Claim 69

A composite carbon fiber comprising a carbon fiber having an amine-functionalized polymer electro-grafted onto a surface thereof, and wherein the composite carbon fiber is characterized by:
a) a nitrogen/carbon (N/C) ratio that is at least 0.125; and
b) an increase in nitrogen surface concentration that is from about 50 to 3,000% in comparison to the original carbon fiber that does not include an amine-functionalized polymer electro-grafted onto the surface of the carbon fiber.

### Claim 70 (depends on 69)

The composite carbon fiber of claim 69, wherein the composite carbon fiber exhibits a nitrogen/carbon (N/C) ratio that is from about 0.15 to 0.3, and an increase in surface of nitrogen concentration of any one or more of at least 75%, at least 100%, at least 125%, at least 150%, at least 175%, at least 200%, at least 225%, at least 250%, at least 275%, at least 300%, at least 325%, at least 350%, at least 375%, at least 400%, at least 425%, at least 450%, at least 475%, or at least 500%, in comparison to the original carbon fiber that has not had an amine-functionalized polymer electro-grafted onto its surface.

### Claim 71 (depends on 69)

The composite carbon fiber of claim 69, wherein the composite carbon fiber exhibits an increase in surface of nitrogen concentration ranging from about 100 to 500% in comparison to the original carbon fiber that has not had an amine-functionalized polymer electro-grafted onto its surface.

### Claim 72 (depends on 69)

The composite carbon fiber of claim 69, wherein the amine-functionalized polymer is selected from the group consisting of linear polyethyleneimines (PEI), branched polyethyleneimines (PEI), branched polypropyleneimine, linear poly(allylamine) (PAA), polyamidoamine (PAMAM) dendrimer, branched poly(allylamine) prepared by branching of poly(allylamine) with divinylbenzene (PAADVB), and a combination thereof.

### Claim 73 (depends on 69)

The composite carbon fiber of claim 69, wherein the carbon fiber has a tensile strength from about 600 to 1,050 ksi, and the amine-functionalized polymer has a weight average molecular weight ranging from about 5,000 to 35,000.

### Claim 74

A fiber reinforced composite comprising a carbon fiber having an amine-functionalized polymer electro-grafted onto a surface thereof, and a resin matrix infused into the carbon fiber, wherein the fiber reinforced composite exhibits an interlaminar strength of about 17 to 25 ksi as characterized by Short Beam Shear (SBS) testing.

### Claim 75 (depends on 74)

The fiber reinforced composite of claim 74, wherein the interlaminar strength of the fiber reinforced composite is about 20 to 22 ksi as characterized by SBS.

### Claim 76 (depends on 74)

The fiber reinforced composite claim 74, wherein the fiber reinforced composite exhibits an increase in SBS ranging from about 5 to 25% in comparison to a similar fiber reinforced composite in which the carbon fibers are identical with the exception that the surfaces of the carbon fibers do not include an amine-functionalized polymer.

### Claim 77 (depends on 74)

The fiber reinforced composite claim 74, wherein a surface of the composite carbon fiber has a nitrogen/carbon (N/C) ratio that is from about 0.15 to 0.3.

### Claim 78 (depends on 77)

The fiber reinforced composite of claim 77, wherein the composite carbon fiber exhibits an increase in surface of nitrogen concentration of any one or more of least 25%, at least 50%, at least 75%, at least 100%, at least 125%, at least 150%, at least 175%, at least 200%, at least 225%, at least 250%, at least 275%, at least 300%, at least 325%, at least 350%, at least 375%, at least 400%, at least 425%, at least 450%, at least 475%, or at least 500%, in comparison to the original carbon fiber that has not had an amine-functionalized polymer electro-grafted onto its surface.

### Claim 79 (depends on 77)

The fiber reinforced composite of claim 77, wherein the composite carbon fiber exhibits an increase in surface of nitrogen concentration ranging from about 100 to 500%, in comparison to the original carbon fiber that has not had an amine-functionalized polymer electro-grafted onto its surface.

### Claim 80 (depends on 74)

The fiber reinforced composite of claim 74, wherein the resin is selected from the group consisting of epoxy based resins, bismaleimide based resins, cyanate ester based resins, and phenolic based resins.

### Claim 81 (depends on 74)

The fiber reinforced composite of claim 74, wherein the carbon fiber has a tensile strength from about 600 to 1,050 ksi.

### Claim 82 (depends on 74)

The fiber reinforced composite of claim 74, wherein the amine-functionalized polymer is selected from the group consisting of linear polyethyleneimines (PEI), branched polyethyleneimines (PEI), branched polypropyleneimine, linear poly(allylamine) (PAA), polyamidoamine (PAMAM) dendrimer, branched poly(allylamine) prepared by branching of poly(allylamine) with divinylbenzene (PAADVB), and a combination thereof.

### Claim 83 (depends on 74)

An aerospace part comprising the fiber reinforced composite of claim 74.

### Claim 84

A method of preparing a composite carbon fiber comprising
passing a carbon fiber through a bath comprising an amine-functionalized polymer;
applying an electro-potential to the cell;
electro-grafting the amine-functionalized polymer onto the carbon fiber to produce a composite carbon fiber having an amine-functionalized polymer electro-grafted onto a surface thereof, and wherein the composite carbon fiber is characterized by:
a) a carbon/nitrogen (N/C) ratio that is at least 0.125; and/or
b) an increase in nitrogen surface concentration that is from about 50 to 500% in comparison to the original carbon fiber that does not include an amine-functionalized polymer electro-grafted onto the surface of the carbon fiber.

### Claim 85 (depends on 84)

The method of claim 84, wherein the composite carbon fiber exhibits a nitrogen/carbon (N/C) ratio that is from about 0.15 to 0.3, and wherein the composite carbon fiber exhibits an increase in surface of nitrogen concentration of any one or more at least 100%, in comparison to the original carbon fiber that has not had an amine-functionalized polymer electro-grafted onto its surface.

### Claim 86 (depends on 84)

The method of claim 84, wherein the step of electro-grafting the amine-functionalized polymer onto the carbon fiber lasts for a period of time between 30 seconds and two minutes.

### Claim 87 (depends on 84)

The method of claim 84, wherein the step of electro-grafting the amine-functionalized polymer onto the carbon fiber lasts for a period of time between 45 seconds and 90 seconds.