Hollow fiber with gradient properties and method of making the same

Patent metadata

Field	Value
Publication number	US-9683310-B2
Application number	US-201113316506-A
Country	US
Kind code	B2
Filing date	Dec 10, 2011
Priority date	Dec 10, 2011
Publication date	Jun 20, 2017
Grant date	Jun 20, 2017

Abstract

There is provided a hollow fiber and method of making. The hollow fiber has an inner-volume portion having a first-core portion and one or more hollow second-core portions. The first-core portion has nanostructures and one or more first polymers. The nanostructures act as an orientation template for orientation of the first polymers in a direction parallel to a longitudinal axis of the fiber. The first-core portion is in contact with and encompasses the hollow second-core portions. The hollow fiber further has an outer-volume portion having one or more second polymers. The outer-volume portion is in contact with and completely encompasses the inner-volume portion. The inner-volume portion has at least one of a tensile modulus and a strength that are higher than at least one of a tensile modulus and a strength of the outer-volume portion.

First claim

What is claimed is:

1. A continuous-filament hollow finished carbon fiber consisting of:
an inner-volume portion with a first-core portion having a plurality of carbon nanotubes and a first polymer selected from the group consisting of polyacrylonitrile (PAN), pitch, polyphenylene sulfide (PPS), viscose, cellulose, polyvinylidene chloride (PVDC), and polyvinyl alcohol (PVA), the carbon nanotubes substantially aligned along a longitudinal axis of the continuous-filament hollow finished carbon fiber and polymer chains of the first polymer oriented in a direction parallel to the longitudinal axis of the continuous-filament hollow finished carbon fiber; and, one or more hollow second-core portions, the first-core portion being in contact with and encompassing the one or more hollow second-core portions; and,
an outer-volume portion having a second polymer selected from the group consisting of polyacrylonitrile (PAN), pitch, polyphenylene sulfide (PPS), viscose, cellulose, polyvinylidene chloride (PVDC), and polyvinyl alcohol (PVA), the outer-volume portion being in contact with and completely encompassing the inner-volume portion,
wherein the inner-volume portion of the continuous-filament hollow finished carbon fiber has a greater tensile modulus and/or tensile strength than the outer-volume portion of the continuous-filament hollow finished carbon fiber, and further wherein the first polymer of the continuous-filament hollow finished carbon fiber and the second polymer of the continuous-filament hollow finished carbon fiber are the same.

2. The continuous-filament hollow finished carbon fiber of claim 1 wherein the polymer chains of the first polymer that are oriented in the direction parallel to the longitudinal axis of the continuous-filament hollow finished carbon fiber create a higher stiffness in the inner-volume portion and a lower stiffness at the outer surface of the outer-volume portion of the continuous-filament hollow finished carbon fiber.

3. The continuous-filament hollow finished carbon fiber of claim 1 wherein a plurality of continuous-filament hollow finished carbon fibers form a tow.

4. The continuous-filament hollow finished carbon fiber of claim 1 wherein the first polymer and the second polymer of the continuous-filament hollow finished carbon fiber are polyacrylonitrile (PAN).

5. The continuous-filament hollow finished carbon fiber of claim 1 wherein a percentage of carbon nanotube content in the inner-volume portion is in an amount of from about 0.01% by weight to about 10% by weight.

6. The continuous-filament hollow finished carbon fiber of claim 1 wherein the first polymer of the continuous-filament hollow finished carbon fiber and the second polymer of the continuous-filament hollow finished carbon fiber are melt-processable/spinnable polyacrylonitrile (PAN) or a solution spinnable polyacrylonitrile (PAN).

7. The continuous-filament hollow finished carbon fiber of claim 1 wherein the continuous-filament hollow finished carbon fiber has gradient properties that vary from the tensile modulus and the tensile strength that are higher in the inner-volume portion to the tensile modulus and the tensile strength that are lower at the outer-volume portion and that result in the continuous-filament hollow finished carbon fiber having an improved resistance to microfracture formation at a fiber-matrix interface between the continuous-filament hollow finished carbon fiber and a resin matrix, as compared to a continuous-filament hollow finished carbon fiber having an inner-volume portion with a first polymer and an outer-volume portion with a second polymer, each of the first polymer and the second polymer being the same, and the continuous-filament hollow finished carbon fiber not having carbon nanotubes in the inner-volume portion that act as a nucleating agent for orientation of the first polymer in the inner-volume portion.

8. The continuous-filament hollow finished carbon fiber of claim 1 wherein the one or more hollow second-core portions of the continuous-filament hollow finished carbon fiber is a single hollow second-core portion configuration extending through a length of the continuous-filament hollow finished carbon fiber.

9. The continuous-filament hollow finished carbon fiber of claim 1 wherein the one or more hollow second-core portions of the continuous-filament hollow finished carbon fiber are a plurality of hollow second-core portions extending through a length of the continuous-filament hollow finished carbon fiber to form an islands-in-a-sea configuration.

10. The continuous-filament hollow finished carbon fiber of claim 1 wherein the one or more hollow second-core portions of the continuous-filament hollow finished carbon fiber are formed from a fugitive polymer that disappears during conversion of a precursor fiber to the continuous-filament hollow finished carbon fiber.

11. A continuous-filament hollow finished carbon fiber consisting of:
an inner core portion with a first-core portion having a plurality of carbon nanotubes and a first polymer selected from the group consisting of polyacrylonitrile (PAN), pitch, polyphenylene sulfide (PPS), viscose, cellulose, polyvinylidene chloride (PVDC), and polyvinyl alcohol (PVA), the carbon nanotubes substantially aligned along a longitudinal axis of the continuous-filament hollow finished carbon fiber and polymer chains of the first polymer oriented in a direction parallel to the longitudinal axis of the continuous-filament hollow finished carbon fiber; and, a single hollow second-core portion configuration extending through a length of the continuous-filament hollow finished carbon fiber, the first-core portion being in contact with and encompassing the hollow second-core portion; and,
an outer shell portion having a second polymer selected from the group consisting of polyacrylonitrile (PAN), pitch, polyphenylene sulfide (PPS), viscose, cellulose, polyvinylidene chloride (PVDC), and polyvinyl alcohol (PVA), the outer shell portion being in contact with and completely encompassing the inner core portion,
wherein the inner core portion has at least one of a tensile modulus and a strength that are higher than at least one of a tensile modulus and a strength of the outer shell portion, and
wherein the inner core portion of the continuous-filament hollow finished carbon fiber has a greater tensile modulus and/or tensile strength than the outer shell portion of the continuous-filament hollow finished carbon fiber, and further wherein the first polymer and the second polymer are the same.

12. The continuous-filament hollow finished carbon fiber of claim 11 wherein the first polymer of the continuous-filament hollow finished carbon fiber and the second polymer of the continuous-filament hollow finished carbon fiber are polyacrylonitrile (PAN) fiber.

13. A continuous-filament hollow finished carbon fiber consisting of:
an inner core portion with a first-core portion having a plurality of carbon nanotubes and a first polymer selected from the group consisting of polyacrylonitrile (PAN), pitch, polyphenylene sulfide (PPS), viscose, cellulose, polyvinylidene chloride (PVDC), and polyvinyl alcohol (PVA), the carbon nanotubes substantially aligned along a longitudinal axis of the continuous-filament hollow finished carbon fiber and polymer chains of the first polymer oriented in a direction parallel to the longitudinal axis of the continuous-filament hollow finished carbon fiber; and, a plurality of hollow second-core portions configuration extending through a length of the continuous-filament hollow finished carbon fiber to form an islands-in-a-sea configuration, the first-core portion being in conta

Assignees

• Tsotsis Thomas Karl
• Boeing Co

Inventors

• Tsotsis Thomas Karl

Classifications

• D01D5/0046

  the fibre formed by coagulation, i.e. wet electro-spinning · CPC title

• D01D5/003

  the material being a polymer solution or dispersion (D01D5/0053 takes precedence) · CPC title

• B29C48/18

  the components being layers · CPC title

• Y10T428/2975

  Tubular or cellular · CPC title

• B29C48/21

  the layers being joined at their surfaces · CPC title