U.S. patent application number 13/930637 was filed with the patent office on 2015-01-01 for whisker-reinforced hybrid fiber by method of base material infusion into whisker yarn.
The applicant listed for this patent is The Boeing Company. Invention is credited to John R. Hull, Mark S. Wilenski.
Application Number | 20150004392 13/930637 |
Document ID | / |
Family ID | 51842744 |
Filed Date | 2015-01-01 |
United States Patent
Application |
20150004392 |
Kind Code |
A1 |
Hull; John R. ; et
al. |
January 1, 2015 |
WHISKER-REINFORCED HYBRID FIBER BY METHOD OF BASE MATERIAL INFUSION
INTO WHISKER YARN
Abstract
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.
Inventors: |
Hull; John R.; (Sammamish,
WA) ; Wilenski; Mark S.; (Mercer Island, WA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
The Boeing Company |
Chicago |
IL |
US |
|
|
Family ID: |
51842744 |
Appl. No.: |
13/930637 |
Filed: |
June 28, 2013 |
Current U.S.
Class: |
428/292.1 ;
427/177; 428/367 |
Current CPC
Class: |
C03C 25/16 20130101;
C04B 41/009 20130101; C03C 25/26 20130101; C04B 35/62844 20130101;
Y10T 428/2918 20150115; C04B 2235/5268 20130101; C04B 2235/5252
20130101; C03C 25/42 20130101; C03C 25/18 20130101; Y10T 428/249924
20150401; C04B 2235/5244 20130101; D02G 3/182 20130101; C04B
2235/5284 20130101; C04B 41/48 20130101; D10B 2101/122 20130101;
D02G 3/404 20130101; C04B 41/5022 20130101; D02G 3/02 20130101;
C04B 2235/5288 20130101; C04B 41/009 20130101; C04B 14/386
20130101; C04B 30/02 20130101; C04B 41/48 20130101; C04B 41/4523
20130101; C04B 41/5022 20130101; C04B 41/4523 20130101 |
Class at
Publication: |
428/292.1 ;
428/367; 427/177 |
International
Class: |
D02G 3/36 20060101
D02G003/36; D02G 3/02 20060101 D02G003/02 |
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.
Description
FIELD
[0001] 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.
BACKGROUND
[0002] Glass 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.
[0003] 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.
[0004] 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.
[0005] 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.
[0006] 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.
[0007] 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.
SUMMARY
[0008] The 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.
[0009] 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.
[0010] 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.
[0011] 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%.
[0012] 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.
[0013] 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.
[0014] 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.
[0015] 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.
[0016] 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.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] 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.
[0018] FIG. 1 is a schematic representation of a longitudinal
cross-section of a portion of a fiber reinforced with whiskers
where the whiskers make up only a small volume fraction of the
hybrid fiber.
[0019] FIG. 2 is a schematic representation of a portion of the
yarn length of interwoven nanotubes.
[0020] FIG. 3 is a schematic representation of a portion of the
length of the hybrid fiber.
[0021] FIG. 4 is a schematic representation of a method of
producing the hybrid fiber.
[0022] FIG. 5 is a schematic representation of a method of
producing the hybrid fiber.
DETAILED DESCRIPTION
[0023] FIG. 1 is a representation of a basic embodiment of a hybrid
fiber. FIG. 1 shows a hybrid fiber of glass base material that is
fibril reinforced by a plurality of isolated fibrils.
[0024] FIG. 1 is a representation of a cross-section of a portion
of the hybrid fiber length. In the actual hybrid fiber 10, the
fiber is surrounded by a generally cylindrical exterior surface 14
having a center axis 16 that extends along the fiber length. The
hybrid fiber 10 is basically comprised of a base material 12 that
forms the overall fiber body. The base material 12 is a pure
material, for example a pure glass. In the example shown in FIG. 1
the base material is glass. Other known fiber base materials could
also be used in the hybrid fiber 10.
[0025] 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.
[0026] 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 FIG. 1, the fibrils 20 are carbon nanotubes, either single
wall or multi wall. The longest carbon nanotubes that have been
made to date are of the order of a centimeter in length, whereas
the fibers used in most fiber composites are continuous. Other
fibril materials include silicone carbide and boron nitride. The
material of the fibrils 20 must be chemically compatible with the
base material 12 of the hybrid fiber 10. The material of the
fibrils 20 must not degrade at temperatures at which the glass or
other base material 12 can flow to form the final shape of the
hybrid fiber 10.
[0027] 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.
[0028] FIG. 2 is a representation of a portion of a length of yarn
26. The yarn 26 is created from two or more individual fibrils 28.
In general, the length of yarn 26 has a center axis 30 when the
yarn is held straight, and the fibrils 28 have lengths that are
predominantly aligned with the yarn center axis 30. As represented
in FIG. 2, the fibrils 28 may twist around the yarn center axis 30
within the yarn 26. It should be understood that in FIG. 2, only a
segment of the yarn length 26 is shown. Some of the fibrils 28 have
been removed from the representation of the opposite ends of the
segment of yarn 26 to better show the twisted or interwoven
structure of the yarn. The yarn 26 formed from the fibrils 28 has a
similar structure to a conventional yarn composed of fibers, with
the primary difference being that the fibrils 28 have a smaller
diameter and length, compared to conventional fibers of a
conventional yarn. For example, conventional carbon fibers may have
a diameter of 3-50 microns, whereas carbon nanotube fibrils 28 may
have a diameter of 1-100 nanometers. For point of reference, the
diameter of an atom ranges from about 0.1-0.5 nanometer. The
diameter of the fibrils 28 could be as large as 5 microns if a
large diameter hybrid fiber were to be made.
[0029] 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.
[0030] FIG. 3 is a representation of a possible structure of the
portion of the overall length of a hybrid fiber 34. The hybrid
fiber 34 basically consists of a continuous phase of the fiber base
material 32, in which one or more of the reinforcing yarns 26
comprised of fibrils or nanotubes 28 are embedded. The continuous
phase base material 32 is represented as being transparent in FIG.
3 for clarity in showing the interior of the hybrid fiber 34. It is
not necessary that the base material 32 be transparent.
[0031] 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 FIG. 3, in reality
the terminal end locations would be random.
[0032] 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 FIG. 1. The
intertwining of the fibrils or nanotubes 28 within the yarn 26
keeps the fibrils or nanotubes in relatively tight geometry,
although there is sufficient space between adjacent fibrils or
nanotubes 28 for the continuous phase base material 32 to infuse
within the yarn 26 and make intimate contact with all of the
fibrils or nanotubes 28. Appropriate surface energetics (i.e.,
wetting) will aid this. 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%.
[0033] FIG. 4 is a representation of a method of making the hybrid
fiber 34 of the invention. In the method of FIG. 4, the fibrils or
nanotube 28 reinforcement of the hybrid fiber 34 consists of a
single yarn 26 formed from a plurality of nanotubes. The yarn 26 is
pulled through a "molten" bath of the continuous phase base
material 32. By "molten", it is intended that the base material 32
be flowable like a liquid, although it may have a high viscosity.
It is therefore intended that the base material 32 described with
reference to FIG. 4 cover any type of known base material including
glass, thermoset base materials and thermoplastic base
materials.
[0034] In FIG. 4, the yarn 26 passes from a supply reel 42 through
a nozzle 44 and into the interior of a container 46 that contains a
molten bath of continuous phase base material 32. A heater 48
controls the temperature of the bath of base material 32. While in
the bath of base material, the yarn 26 is infused by the continuous
phase base material 32, which wets the fibrils or nanotubes 28
composing the yarn 26. Upon exiting the bath of base material 32
from the top surface of the bath, the fibrils or nanotubes 28 in
the yarn 26 and the infused base material 32 pass through an
optional ring 50. The ring 50 scrapes off any excess continuous
phase base material 32. The fibrils or nanotubes 28 and the infused
base material 32 are then allowed to cool below the solidification
temperature of the base material 32 and to solidify. This forms the
hybrid fiber 34.
[0035] 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.
[0036] 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.
[0037] The method represented in FIG. 4 may also be used with
multiple yarns that are gathered together in a tow. Additionally,
the method could proceed in the opposite direction to that
described above, i.e., from reel 52 to reel 42. In such a method
the optional ring 50 would be moved below the nozzle 44.
[0038] FIG. 5 is a representation of a further method of making the
hybrid fiber 34 of the invention. In the method of FIG. 5, the
fibril or nanotube 28 reinforcement of the hybrid fiber 34 consists
of a single yarn 26 formed from a plurality of the nanotubes. The
yarn 26 is pulled over a surface of a heated roller and "molten"
continuous phase base material 32 is poured onto the roller and is
infused into the yarn. Again, by "molten", it is intended that the
base material 32 be flowable like a liquid, although it may have a
high viscosity. It is therefore intended that the base material 32
described with reference to FIG. 5 cover any type of known base
material including glass, thermoset base materials and
thermoplastic base materials.
[0039] In FIG. 5, the yarn 26 leaves a supply reel 58 and travels
over part of a cylindrical exterior surface 60 of a combining wheel
62 which is rotating in a clockwise direction as viewed in FIG. 5.
A container 64 holding the molten base material 32 is positioned
above the combining wheel exterior surface 60. The container 64 has
a spout 66 that extends downwardly from the container to a nozzle
68 at the distal end of the spout. The nozzle 68 is positioned just
above the combining wheel exterior surface 60 and a portion 72 of
the yarn on the surface. The molten base material 32 passes through
the spout 66 and the nozzle 68 and drops onto the portion of yarn
72 on the combining wheel exterior surface 60. The base material 32
dropped onto the portion of yarn 72 coats the portion of yarn and
is infused into the plurality of fibrils or nanotubes 28 that form
the yarn.
[0040] 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.
[0041] 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.
[0042] 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.
[0043] The method represented in FIG. 5 may also be used with
multiple yarns that are gathered together in a tow.
[0044] Other methods of infusing the yarn with base material could
also be employed, such as chemical vapor deposition (CVD) or
physical vapor deposition (PVD).
[0045] 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.
* * * * *