WHISKER-REINFORCED HYBRID FIBER BY METHOD OF BASE MATERIAL INFUSION INTO WHISKER YARN
A hybrid fiber consists of a continuous phase base material that permeates the length of the hybrid fiber and a plurality of fibrils or nanotubes that are dispersed throughout the hybrid fiber interior in the form of a yarn woven from the plurality of fibrils or nanotubes. The method of making the hybrid fiber involves coating the yarn with the continuous phase base material and infusing the continuous phase base material into the plurality of fibrils or nanotubes that form the yarn.
The present invention pertains to a hybrid fiber consisting of a conventional polymer or glass fiber that is reinforced with fibrils distributed throughout the fiber. More specifically, the invention pertains to a hybrid fiber consisting of a polymer or glass that is reinforced by fibrils woven into a yarn that extends through the hybrid fiber interior and is coated and infused with the polymer or glass.
BACKGROUNDGlass fibers, graphite fibers, silicon carbide fibers, and polymer fibers, among others, are used extensively in modern fiber composites. These composites have been used in a variety of different products, for example building materials such as deck planking and rails, in sporting goods such as golf clubs, and in structural components of automobiles and aircraft such as, for example, body panels and rotor blades.
The composite is generally formed by placing a plurality of the fibers in a liquefied polymer base material such as a thermoset or a thermoplastic. The polymer base material is then caused to solidify. The plurality of fibers reinforce the solidified polymer base material. Other potential base materials that are reinforced by fibers include glass, ceramic, and metals.
The placement of the plurality of fibers in the liquefied base materials can be in the form of layers of the fibers with the fibers in each layer being arranged in a uniaxial direction or substantially parallel, or layers of fibers with the fibers in each layer being formed by a weave geometry of the fibers.
Examples of thermoset base materials that are reinforced with fibers include polyester, vinylester, epoxy, bismalemide, polyimide, phenolicester and cyanateester. Examples of thermoplastic base materials that are reinforced with fibers include polycarbonate, polyphenylene sulfide, polyether-etherketone, polyether-ketone-ketone, and polyetherimide.
In general, there is evidence that incorporation of reinforcing fibers into a glass base material can provide both increases in tensile strength and elastic modulus. This is disclosed in the Brennan U.S. Pat. No. 4,314,852, incorporated herein by reference.
However, fibers, composed of a single material, have limited properties. Sometimes a second material is employed as a reinforcement on the outside of the fiber material. This method however results in limited improvement of desired fiber properties. Placing reinforcement inside of the fiber material has resulted in a small percentage of the fiber interior being occupied by the reinforcement and a minimal alignment of the reinforcement in a desired direction, for example along the fiber axis.
SUMMARYThe present invention provides a single base material fiber with reinforcement where the reinforcement is distributed throughout the interior of the fiber and is primarily aligned with the axis or length of the fiber. The present invention also provides a fiber having a high percentage of the fiber interior volume being occupied by the reinforcement within the fiber.
The present invention overcomes disadvantages associated with composite base material reinforced with fibers by providing a hybrid fiber to be used in reinforcing a composite base material where the hybrid fiber construction and the method of making the hybrid fiber are unique.
The hybrid fiber is basically comprised of a pure base material that permeates a length of the hybrid fiber. In a preferred embodiment the base material is glass. Alternative material could be polymer.
A plurality of fibrils or nanotubes are distributed throughout the base material. The nanotubes are interwoven into a yarn that extends the length of the hybrid fiber. Each nanotube has a length that is aligned with the length of the hybrid fiber. The length of each nanotube is a fraction of the length of the hybrid fiber. In a preferred embodiment the nanotubes are carbon nanotubes. Additionally, in the preferred embodiment the volume percentage of the plurality of nanotubes in the hybrid fiber is in a range of 10% to 90%, and preferably 30% to 80%.
The method of making the hybrid fiber involves aligning and overlapping a plurality of the nanotubes forming a continuous strand or yarn of the nanotubes having a strand length. In the strand of nanotubes, each nanotube of the plurality of nanotubes has a length that is aligned with the strand length and is a fraction of the strand length. In a preferred embodiment the plurality of nanotubes are twisted or woven into a length of yarn.
The strand or yarn length is then successively coated with a flowable base material that infuses into the plurality of nanotubes of the strand or yarn.
The coating of the strand or yarn length with the liquid base material can be accomplished by containing the liquid base material in a container having a nozzle opening, and then pulling the strand or yarn through the nozzle opening and into the liquid base material in the container. Pulling the strand or yarn through the liquid base material successively coats the strand or yarn with the liquid base material and infuses the liquid base material into the plurality of nanotubes forming the strand or yarn.
Alternatively, the strand or yarn could be pulled over a rotating cylindrical surface while pouring the liquid base material onto the surface and the strand or yarn. This successively coats the strand or yarn length with the liquid base material and infuses the liquid base material into the plurality of nanotubes forming the strand or yarn.
The strand or yarn coated and infused with the liquid base material is then caused to solidify, thereby completing the method of making the hybrid fiber of the invention.
Further features of the hybrid fiber of the invention and its method of construction are set forth in the following description of the fiber and method and in the drawing figures.
A plurality of individual isolated fibrils 20 is distributed throughout the base material 12. The fibrils 20 can be small filaments, nanotubes such as carbon nanotubes, boron nitride nantotubes, whiskers such as silicon carbide or others. The fibrils 20 are primarily distributed through the interior 22 of the hybrid fiber 10, but some of the fibrils 20 could also be distributed along and around the fiber exterior surface 14. The plurality of fibrils 20 each have a length that is substantially aligned with the length or axis 16 of the hybrid fiber 10.
The fibrils 20 are materials that have better properties, such as tensile strength, compressive strength, elastic modulus (mechanical stiffness), electrical conductivity, and dielectric coefficient, among others, than the base material 12 of the hybrid fiber 10. However, the materials of the fibrils 20 cannot be grown in the length or size desired for the fibrils 20 to be used in a fiber composite. An example of such a material of the fibrils 20 is a nanotube. In the exemplary embodiment of the hybrid fiber 10 shown in
The basic technology for spinning short lengths of filaments into a longer length of yarn has been known for some time in the textile industry. In general, the length of a piece of yarn can be greater than the lengths of any individual filament woven into and composing the yarn. In the present invention, this basic technology is employed to create yarns from very small diameter fibrils, such as carbon nanotubes.
In the present invention, one or more yarns 26, composed of the fibrils 28 or nanotubes 28, are embedded in a cylindrical form of a conventional fiber base material 32 to create the hybrid fiber 34. In the example to follow, glass is the conventional fiber base material 32. However, it should be understood that any of the conventional fiber base materials may also be used, such as polyethylene or other polymers, including thermoset base materials and thermoplastic base materials.
The base material 32 covers the plurality of fibrils or nanotubes 28 and permeates or is infused into the fibrils or nanotubes 28 along the length of the hybrid fiber 34. The plurality of fibrils or nanotubes 28 are primarily contained in the interior of the base material 32 that makes up the hybrid fiber 34. However, it is possible that at least some of the fibrils or nanotubes 28 would be positioned on the generally cylindrical exterior surface 38 of the hybrid fiber 34. Although the terminal ends of some of the fibrils are shown at uniform locations in
It should be appreciated that composing or interweaving the plurality of fibrils or nanotubes 28 in a yarn 26 enables a much greater density of the fibrils or nanotubes than if a collection of fibrils or nanotubes 28 were individually embedded in the yarn 26, for example in the embodiment represented in
In
The hybrid fiber 34 is then wound on a take up reel 52. To form a quasi-continuous process, a hopper 54 may add extra base material 32, either in molten form or as solid pellets that are melted by the heat of the bath of base material 32.
The inner diameter of the nozzle 44 on the container 46 must be large enough to allow the yarn 26 to easily pass through the nozzle 44, but must not be so large that the molten bath of base material 32 can drip out through the nozzle 44. In general, the surface tension of the molten bath of base material 32 would be enough to prevent the unwanted dripping of the base material 32 through the nozzle 44 if the diameter of the nozzle 44 is between 1-2 mm. This will allow easy passage of yarns of diameters up to almost 1 mm. Most yarn diameters of interest will be 5-20 microns.
The method represented in
In
The portion of the yarn 72 that has been coated and infused with the base material 32 then leaves the combining wheel exterior surface 60 and passes through an optional ring 74. The ring 74 scrapes excess base material 32 from the portion of yarn 72 and gives the cylindrical exterior surface shape to the hybrid fiber 34. The resulting hybrid fiber 34 then passes onto a take up reel 78.
The combining wheel 62 may be heated to prevent the base material dropped onto the portion of the yarn 72 from beginning to solidify until the portion of yarn 72 coated and infused with the base material leaves the combining wheel exterior surface 60.
In a quasi-continuous process, the supply reel 58 and the take up reel 78 rotate synchronously so that the yarn travels at a constant speed throughout the process.
The method represented in
Other methods of infusing the yarn with base material could also be employed, such as chemical vapor deposition (CVD) or physical vapor deposition (PVD).
As various modifications could be made in the constructions of the hybrid fiber and the methods of making the hybrid fiber described herein and illustrated without departing from the scope of the invention, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative rather than limiting. Thus, the breadth and scope of the present invention should not be limited by any of the above described exemplary embodiments, but should be defined only in accordance with the following claims appended hereto and their equivalents.
Claims
1. A hybrid fiber comprising:
- a base material permeating an interior of the hybrid fiber and a length of the hybrid fiber; and,
- a plurality of fibrils distributed throughout the base material, each fibril of the plurality of fibrils having a length that is a fraction of the hybrid fiber length and is aligned with the hybrid fiber length; and
- the plurality of fibrils being formed into a yarn with the base material being infused into the yarn.
2. The hybrid fiber of claim 1, further comprising:
- each fibril of the plurality of fibrils being a nanotube.
3. The hybrid fiber of claim 1, further comprising:
- each fibril of the plurality of fibrils being a carbon nanotube.
4. The hybrid fiber of claim 1, further comprising:
- each fibril of the plurality of fibrils being silicon carbide.
5. The hybrid fiber of claim 1, further comprising:
- the base material being a polymer.
6. The hybrid fiber of claim 1, further comprising:
- the base material being glass.
7. The hybrid fiber of claim 1, further comprising:
- a volume percentage of the plurality of fibrils in the hybrid fiber being in a range of 10 percent to 90 percent.
8. The hybrid fiber of claim 1, further comprising:
- a volume percentage of the plurality of fibrils in the hybrid fiber being in a range of 30 percent to 80 percent.
9. The hybrid fiber of claim 1, further comprising:
- the hybrid fiber being one of a plurality of hybrid fibers that are imbedded in a composite material.
10. A hybrid fiber comprising:
- a base material permeating a length of the hybrid fiber; and,
- a plurality of nanotubes distributed throughout the base material and interwoven into a yarn that extends the length of the hybrid fiber, each nanotube of the plurality of nanotubes having a length that is aligned with the length of the hybrid fiber and is a fraction of the length of the hybrid fiber.
11. The hybrid fiber of claim 10, further comprising:
- the plurality of nanotubes being carbon nanotubes.
12. The hybrid fiber of claim 10, further comprising:
- a volume percentage of the plurality of nanotubes in the hybrid fiber being in a range of 30 percent to 80 percent.
13. A method of making a hybrid fiber comprising:
- aligning and overlapping a plurality of fibrils forming a continuous strand having a strand length where each fibril of the plurality of fibrils has a fibril length that is aligned with the strand length and is a fraction of the strand length;
- successively coating the strand with a liquid base material and infusing the liquid base material into the plurality of fibrils forming the strand; and,
- allowing the liquid base material coating the strand and infused in the plurality of fibrils forming the strand to solidify resulting in the hybrid fiber.
14. The method of claim 13, further comprising:
- twisting the plurality of fibrils together and forming the strand as a yarn.
15. The method of claim 13, further comprising:
- using a plurality of nanotubes as the plurality of fibrils.
16. The method of claim 13, further comprising:
- using a plurality of carbon nanotubes as the plurality of fibrils.
17. The method of claim 13, further comprising:
- using a glass as the base material.
18. The method of claim 13, further comprising:
- pulling the strand through a bath of the liquid base material.
19. The method of claim 18, further comprising:
- containing the liquid base material in a container having a nozzle opening;
- pulling the strand through the nozzle opening and into the liquid base material in the container and thereby successively coating the strand with the liquid base material and infusing the liquid base material into the plurality of fibrils forming the strand;
- pulling the strand from the liquid base material; and,
- allowing the liquid base material coating the strand and infused in the plurality of fibrils forming the strand to solidify resulting in the hybrid fiber.
20. The method of claim 13, further comprising:
- pulling the strand over a surface;
- pouring the liquid base material onto the surface and the strand and thereby successively coating the strand with the liquid base material and infusing the liquid base material into the plurality of fibrils forming the strand;
- pulling the strand from the surface; and,
- allowing the liquid base material coating the strand and infused in the plurality of fibrils forming the strand to solidify resulting in the hybrid fiber.
21. The method of claim 20, further comprising:
- using a rotating cylindrical surface as the surface.
Type: Application
Filed: Jun 28, 2013
Publication Date: Jan 1, 2015
Inventors: John R. Hull (Sammamish, WA), Mark S. Wilenski (Mercer Island, WA)
Application Number: 13/930,637
International Classification: D02G 3/36 (20060101); D02G 3/02 (20060101);