U.S. patent application number 16/495890 was filed with the patent office on 2020-01-23 for fiber-reinforced composites, methods therefor, and articles comprising the same.
This patent application is currently assigned to Boston Materials, Inc.. The applicant listed for this patent is Boston Materials, Inc.. Invention is credited to Anvesh Gurijala, Michael Segal.
Application Number | 20200024795 16/495890 |
Document ID | / |
Family ID | 63585641 |
Filed Date | 2020-01-23 |
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United States Patent
Application |
20200024795 |
Kind Code |
A1 |
Gurijala; Anvesh ; et
al. |
January 23, 2020 |
FIBER-REINFORCED COMPOSITES, METHODS THEREFOR, AND ARTICLES
COMPRISING THE SAME
Abstract
Disclosed herein are fiber-reinforced composites. These
materials are useful in load-bearing components for mechanical
systems, and other applications. Also disclosed herein are methods
of making and using such composites, articles comprising the same,
and the like. For example, some embodiments of the invention are
generally directed to composites comprising discontinuous agents
such as fibers or platelets which are positioned within a
substrate, e.g., formed from a plurality of continuous fibers. In
some cases, the discontinuous agents may be substantially aligned,
for example, by attaching magnetic particles onto the agents and
using a magnetic field to manipulate the agents. Other embodiments
are generally directed to systems and methods for making or using
such composites, kits involving such composites, or the like.
Inventors: |
Gurijala; Anvesh;
(Lancaster, MA) ; Segal; Michael; (Needham,
MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Boston Materials, Inc. |
Bedford |
MA |
US |
|
|
Assignee: |
Boston Materials, Inc.
Bedford
MA
|
Family ID: |
63585641 |
Appl. No.: |
16/495890 |
Filed: |
March 12, 2018 |
PCT Filed: |
March 12, 2018 |
PCT NO: |
PCT/US2018/021975 |
371 Date: |
September 20, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62475667 |
Mar 23, 2017 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C08J 5/10 20130101; C08J
5/06 20130101; D06M 10/06 20130101; B29C 70/16 20130101 |
International
Class: |
D06M 10/06 20060101
D06M010/06 |
Claims
1. An article, comprising: a composite comprising a plurality of
continuous fibers defining a substrate, and a plurality of
discontinuous agents contained within at least a portion of the
substrate, wherein at least some of the plurality of discontinuous
agents have a plurality of magnetic particles adsorbed thereto.
2. The article of claim 1, wherein the plurality of discontinuous
agents are contained within and positioned substantially orthogonal
to the substrate.
3. The article of any one of claim 1 or 2, wherein the plurality of
continuous fibers define a fabric.
4. The article of any one of claims 1-3, wherein at least some of
the plurality of continuous fibers define a tow.
5. The article of any one of claims 1-4, wherein at least some of
the plurality of continuous fibers define a filament, a yarn, a
strand, a veil, or a mat.
6. The article of any one of claims 1-5, wherein at least some of
the plurality of continuous fibers are assembled together to define
the substrate.
7. The article of any one of claims 1-6, wherein at least some of
the plurality of continuous fibers are interwoven together to
define the substrate.
8. The article of claim 7, wherein at least some of the plurality
of woven continuous fibers are bi-directional.
9. The article of any one of claim 7 or 8, wherein at least some of
the plurality of woven continuous fibers are multi-directional.
10. The article of any one of claims 7-9, wherein at least some of
the plurality of woven continuous fibers are quasi-isotropic.
11. The article of any one of claims 1-10, wherein at least some of
the plurality of continuous fibers are not woven together.
12. The article of any one of claims 1-11, wherein at least some of
the plurality of continuous fibers are uni-directional.
13. The article of any one of claims 1-12, wherein at least some of
the continuous fibers comprise natural fibers.
14. The article of any one of claims 1-13, wherein at least some of
the continuous fibers comprise synthetic fibers.
15. The article of any one of claims 1-14, wherein at least some of
the continuous fibers comprise carbon, basalt, silicon carbide,
aramid, zirconia, nylon, boron, alumina, silica, borosilicate,
mullite, and/or cotton.
16. The article of any one of claims 1-15, wherein at least some of
the continuous fibers are substantially parallel.
17. The article of any one of claims 1-16, wherein the continuous
fibers have an average length of at least 5 millimeters.
18. The article of any one of claims 1-17, wherein the continuous
fibers have an average diameter of between 10 micrometers and 100
micrometers.
19. The article of any one of claims 1-18, wherein the continuous
fibers have an average aspect ratio of length to diameter that is
greater than or equal to 100.
20. The article of any one of claims 1-19, wherein the
discontinuous fibers have an average length of less than 5
millimeters.
21. The article of any one of claims 1-20, wherein the
discontinuous fibers have an average diameter of between 10
micrometers and 100 micrometers.
22. The article of any one of claims 1-21, wherein the substrate
has an average thickness of less than 10 cm.
23. The article of any one of claims 1-22, wherein at least some of
the plurality of discontinuous agents are randomly oriented.
24. The article of any one of claims 1-23, wherein at least some of
the plurality of discontinuous agents are substantially
aligned.
25. The article of any one of claims 1-24, wherein the plurality of
discontinuous agents comprises at least 3% by mass of the
composite.
26. The article of any one of claims 1-25, wherein the plurality of
discontinuous agents comprises no more than 97% by mass of the
composite.
27. The article of any one of claims 1-26, wherein at least some of
the discontinuous agents comprise discontinuous fibers.
28. The article of claim 27, wherein the discontinuous fibers have
an average length of between 5 nm and 15 mm.
29. The article of any one of claim 27 or 28, wherein the
discontinuous fibers have an average length of between 5 mm and 15
mm.
30. The article of any one of claims 27-29, wherein the
discontinuous fibers have an average aspect ratio of length to
diameter that is at least 5.
31. The article of any one of claims 27-30, wherein the
discontinuous fibers have an average aspect ratio of length to
diameter that is less than 100,000.
32. The article of any one of claims 27-31, wherein the
discontinuous fibers have an average aspect ratio of length to
diameter that is less than 100.
33. The article of any one of claims 1-32, wherein at least some of
the discontinuous fibers have an average length that substantially
spans the thickness of the substrate.
34. The article of any one of claims 1-33, wherein at least some of
the discontinuous agents comprise platelets.
35. The article of any one of claims 1-34, wherein at least some of
the discontinuous agents comprise ellipsoids.
36. The article of claim 35, wherein the platelets have a
characteristic dimension of between 5 nm and 15 mm.
37. The article of any one of claim 35 or 36, wherein the platelets
have a characteristic dimension of between 5 mm and 15 mm.
38. The article of any one of claims 35-37, wherein the platelets
have a maximum dimension of less than 1 mm.
39. The article of any one of claims 1-38, wherein at least some of
the discontinuous agents comprise a natural material.
40. The article of any one of claims 1-49, wherein at least some of
the discontinuous agents comprise a synthetic material.
41. The article of any one of claims 1-40, wherein at least some of
the discontinuous agents comprise glass.
42. The article of any one of claims 1-41, wherein at least some of
the discontinuous agents comprise carbon fibers.
43. The article of any one of claims 1-42, wherein at least some of
the discontinuous agents are non-magnetic.
44. The article of any one of claims 1-43, wherein at least some of
the discontinuous agents are magnetic.
45. The article of any one of claims 1-44, wherein at least some of
the discontinuous agents comprise basalt, silicon carbide, silicon
nitride, aramid, zirconia, nylon, boron, alumina, silica,
borosilicate, mullite, boron nitride, and/or graphite.
46. The article of any one of claims 1-45, wherein at least some of
the discontinuous agents are uncoated.
47. The article of any one of claims 1-46, wherein at least some of
the discontinuous agents are coated with a coating.
48. The article of claim 47, wherein the coating comprises a
surfactant, a silane coupling agent, epoxy, glycerine,
polyurethane, and/or an organometallic coupling agent.
49. The article of any one of claims 1-48, wherein at least 1 vol %
of the composite comprises the discontinuous agents.
50. The article of any one of claims 1-49, wherein at least 5 vol %
of the composite comprises the discontinuous agents.
51. The article of any one of claims 1-50, wherein at least 20 vol
% of the composite comprises the discontinuous agents.
52. The article of any one of claims 1-51, wherein no more than 85
vol % of the composite comprises the discontinuous agents.
53. The article of any one of claims 1-52, wherein at least some of
the magnetic particles comprise a ferromagnetic material, iron
oxide, nickel oxide, cobalt oxide, or an alloy comprising a rare
earth metal.
54. The article of any one of claims 1-53, wherein the magnetic
particles have an average diameter of less than 10 micrometers.
55. The article of any one of claims 1-54, wherein the composite
further comprises a binder binding the plurality of continuous
fibers and the plurality of discontinuous agents.
56. The article of claim 55, wherein the binder comprises a
resin.
57. The article of any one of claim 55 or 56, wherein the binder
comprises a thermoplastic.
58. The article of any one of claims 55-57, wherein the binder
comprises a thermoplastic melt.
59. The article of any one of claims 55-58, wherein the binder
comprises a thermoplastic resin.
60. The article of any one of claims 55-59, wherein the binder
comprises a thermoset.
61. The article of any one of claims 55-60, wherein the binder
comprises a volatile compound.
62. The article of any one of claims 55-61, wherein the binder
comprises an epoxy, polyester, vinyl ester, polyethylenimine,
polyetherketoneketone, polyaryletherketone, polyether ether ketone,
polyphenylene sulfide, polyethylene terephthalate, polycarbonates,
poly(methyl methacrylate), acrylonitrile butadiene styrene,
polyacrylonitrile, polypropylene, polyethylene, nylon, a silicone
rubber, polyvinylidene fluoride, and/or styrene butadiene
rubber.
63. The article of any one of claims 55-62, wherein the binder
comprises a pre-ceramic monomer.
64. The article of claim 63, wherein the pre-ceramic monomer
comprises a siloxane, a silazane, and/or a carbosilane.
65. A method, comprising: providing a liquid comprising a plurality
of discontinuous agents having a plurality of magnetic particles
adsorbed thereto; exposing the liquid to a plurality of continuous
fibers defining a substrate; applying a magnetic field to the
liquid to cause alignment of at least some of the plurality of
discontinuous agents within the plurality of continuous fibers; and
hardening the liquid to form a composite.
66. The method of claim 65, wherein the liquid further comprises a
solvent, and the method further comprises heating the liquid to
remove at least some of the solvent.
67. The method of claim 66, wherein the liquid comprises an organic
solvent.
68. The method of any one of claim 66 or 67, wherein the liquid
comprises isopropanol, butanol, ethanol, acetone, toluene, and/or
xylene.
69. The method of any one of claims 65-68, wherein the liquid
comprises a slurry.
70. The method of any one of claims 65-69, wherein the liquid
comprises a thermoset.
71. The method of any one of claims 65-70, wherein the liquid
comprises an oil.
72. The method of any one of claims 65-71, wherein the liquid
comprises water.
73. The method of any one of claims 65-72, wherein exposing the
liquid to a plurality of continuous fibers comprises coating the
plurality of continuous fibers with the liquid.
74. The method of any one of claims 65-73, wherein exposing the
liquid to a plurality of continuous fibers comprises immersing the
plurality of continuous fibers in the liquid.
75. The method of any one of claims 65-74, wherein the magnetic
field has a minimum field strength of at least 0.01 T.
76. The method of any one of claims 65-75, wherein the magnetic
field has a maximum field strength of no more than 10 T.
77. The method of any one of claims 65-76, wherein the magnetic
field is a time-varying magnetic field.
78. The method of claim 77, wherein the time-varying magnetic field
has a frequency of between 1 Hz and 500 Hz.
79. The method of any one of claims 65-78, wherein at least 5 vol %
of the liquid comprises the discontinuous agents.
80. The method of any one of claims 65-79, wherein no more than 85
vol % of the liquid comprises the discontinuous agents.
81. The method of any one of claims 65-,80 wherein hardening the
liquid to form a composite comprises causing the liquid to gel.
82. The method of any one of claims 65-81, wherein hardening the
liquid to form a composite comprises evaporating at least a portion
of the liquid.
83. The method of any one of claims 65-82, wherein hardening the
liquid to form a composite comprises freezing at least a portion of
the liquid.
84. The method of any one of claims 65-83, wherein hardening the
liquid to form a composite comprises removing at least a portion of
the liquid.
85. The method of any one of claims 65-84, further comprising
permeating a binder into the composite.
86. The method of claim 85, wherein at least some of the binder
permeates into the composite via capillary action.
87. The method of any one of claim 85 or 86, wherein at least some
of the binder permeates into the composite via gravity.
88. The method of any one of claims 85-87, wherein permeating a
binder into the composite comprises applying pressure to the binder
to cause the binder to permeate into the composite.
89. The method of claim 88, wherein applying pressure comprises
hot-pressing the binder into the composite.
90. The method of any one of claim 88 or 89, wherein applying
pressure comprises calendaring the binder into the composite.
91. The method of any one of claims 88-90, wherein applying
pressure comprises permeating the binder into the composite using
vacuum infusion.
92. The method of any one of claims 88-91, further comprising
causing the binder to harden.
93. The method of any one of claims 88-92, wherein the binder
comprises a resin.
94. The method of any one of claims 88-93, wherein the binder
comprises a thermoplastic.
95. The method of any one of claims 88-94, wherein the binder
comprises a thermoplastic melt.
96. The method of any one of claims 88-95, wherein the binder
comprises a thermoplastic resin.
97. The method of any one of claims 88-96, wherein the binder
comprises a thermoset.
98. The method of any one of claims 88-97, wherein the binder
comprises a volatile compound.
99. The method of any one of claims 88-98, further comprising
heating the composite after permeating the binder into the
composite.
100. An article, comprising: a composite comprising a fabric
defined by a plurality of continuous fibers, and a plurality of
aligned discontinuous agents contained within pores within the
fabric.
101. An article, comprising: a layered composite comprising a
plurality of plies, at least one ply comprising a plurality of
continuous fibers defining a substrate, and a plurality of
discontinuous agents contained within the substrate.
102. The article of claim 101, wherein the plurality of
discontinuous agents are contained within and positioned
substantially orthogonal to the substrate.
103. An article, comprising: a composite comprising a plurality of
continuous fibers defining a substrate, and a plurality of
discontinuous agents contained within the substrate, at least some
of the plurality of discontinuous agents having a plurality of
magnetic particles adsorbed thereto, wherein at least 20 vol % of
the composite comprises the discontinuous agents.
104. An article, comprising: a composite comprising a plurality of
continuous fibers defining a substrate, and a plurality of
discontinuous agents contained within at least a portion of the
substrate.
105. The article of claim 104, wherein at least some of the
plurality of discontinuous agents have a plurality of magnetic
particles adsorbed thereto.
Description
RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Patent Application Ser. No. 62/475,667, filed Mar. 23, 2017,
entitled "Fiber-Reinforced Composites, Methods Therefore And
Articles Comprising The Same," incorporated herein by reference in
its entirety.
FIELD
[0002] Disclosed herein are fiber-reinforced composites. These
materials are useful in load-bearing components for mechanical
systems, and other applications. Also disclosed herein are methods
of making and using such composites, articles comprising the same,
and the like.
BACKGROUND
[0003] Mechanical systems such as airplanes, spacecraft, cars,
trains, wind turbines, protective equipment, sporting equipment,
medical implants, and the like have become increasingly thinner and
lighter. The increasing performance requirements of such mechanical
systems are resulting in higher stresses on components. Sensitive
elements in a mechanical system may need to be maintained within a
prescribed deformation limit to avoid significant performance
degradation or even a catastrophic failure.
[0004] In this context, fiber-reinforced composites (FRC) have been
developed to effectively cope with high stresses with minimal
plastic deformation. In general, these FRCs are based on polymers,
including thermoset polymers, that contain reinforcing fibers. For
example, epoxy resins are some of the most popular thermoset
polymers in the art, owing to their good adhesive properties and
processability. Epoxy resins themselves, however, have relatively
low mechanical strength and, therefore, do not effectively
facilitate stress in high performance mechanical systems.
Consequently, mechanically reinforcing fiber materials such carbon,
glass, aramid, basalt, or boron are usually incorporated in the
polymer to achieve effective mechanical strength.
[0005] Generally, relatively high filler loadings, typically larger
than 40 volume percent, are required to achieve the desired
mechanical strength. Commonly, dense fiber loadings are achieved
through the orientation of long reinforcing fibers into a textile.
Long-fiber reinforced composites (LFRC) use a polymer matrix
reinforced by a dispersed phase in the form of continuous fibers.
LFRCs offer exceptional mechanical strength in planar directions.
Alternatively, dense fiber loadings can also be achieved with short
reinforcing fibers. Short-fiber reinforced composites (SFRC) use a
polymer matrix reinforced by a dispersed phase in the form of
discontinuous fibers. Discontinuous fibers are classified by a
general aspect ratio, defined as the ratio of fiber length to
diameter, of between 10 and 60. Discontinuous fibers can be
randomly or preferentially oriented to yield directionally varying
mechanical properties.
[0006] A high filler loading of reinforcing fiber is required to
observe a significant boost in mechanical strength. The continuous
fibers in LFRCs are oriented and constructed prior to the
dispersion into a polymer matrix. Conversely, the orientation of
discontinuous fibers in SFRCs is modulated after the dispersion
into a polymer matrix. Consequently, the high filler loading of
discontinuous fibers reduces the processability of the material
because the viscosity of the composite increases with the filler
volume fraction.
[0007] In the view of the above, there remains a need for
fiber-reinforced composites for mechanical systems that are easily
processable, possess improved homogenous and multidirectional, or
isotropic, material properties, or where improved mechanical
strength can increase resistance to plastic deformation and
catastrophic failure in high stress environments.
SUMMARY
[0008] Disclosed herein are fiber-reinforced composites. These
materials are useful in load-bearing components for mechanical
systems, and other applications. Also disclosed herein are methods
of making and using such composites, articles comprising the same,
and the like. The subject matter of the present invention involves,
in some cases, interrelated products, alternative solutions to a
particular problem, and/or a plurality of different uses of one or
more systems and/or articles.
[0009] In one aspect, the present invention is generally directed
to an article. For example, the article may be a fiber-reinforced
composite in certain embodiments.
[0010] The article, in one set of embodiments, comprises a
composite comprising a plurality of continuous fibers defining a
substrate, and a plurality of discontinuous agents contained within
at least a portion of the substrate. In one embodiment, at least
some of the plurality of discontinuous agents have a plurality of
magnetic particles adsorbed thereto.
[0011] The article, according to another set of embodiments, is
generally directed to a composite comprising a fabric defined by a
plurality of continuous fibers, and a plurality of aligned
discontinuous agents contained within pores within the fabric.
[0012] In yet another set of embodiments, the article comprises a
layered composite comprising a plurality of plies, at least one ply
comprising a plurality of continuous fibers defining a substrate,
and a plurality of discontinuous agents contained within the
substrate.
[0013] According to still another set of embodiments, the article
includes a composite comprising a plurality of continuous fibers
defining a substrate, and a plurality of discontinuous agents
contained within the substrate. In some cases, at least some of the
plurality of discontinuous agents have a plurality of magnetic
particles adsorbed thereto. In some embodiments, at least 20 vol %
of the composite comprises the discontinuous agents.
[0014] The article, in yet another set of embodiments, includes a
composite comprising a plurality of continuous fibers defining a
substrate, and a plurality of discontinuous agents contained within
at least a portion of the substrate.
[0015] In another aspect, the present invention is generally
directed to a method. In some cases, the method includes providing
a liquid comprising a plurality of discontinuous agents having a
plurality of magnetic particles adsorbed thereto, exposing the
liquid to a plurality of continuous fibers defining a substrate,
applying a magnetic field to the liquid to cause alignment of at
least some of the plurality of discontinuous agents within the
plurality of continuous fibers, and optionally, hardening the
liquid to form a composite.
[0016] In another aspect, the present invention encompasses methods
of making one or more of the embodiments described herein, for
example, a fiber-reinforced composite. In still another aspect, the
present invention encompasses methods of using one or more of the
embodiments described herein, for example, a fiber-reinforced
composite.
[0017] Other advantages and novel features of the present invention
will become apparent from the following detailed description of
various non-limiting embodiments of the invention when considered
in conjunction with the accompanying figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Non-limiting embodiments of the present invention will be
described by way of example with reference to the accompanying
figures, which are schematic and are not intended to be drawn to
scale. In the figures, each identical or nearly identical component
illustrated is typically represented by a single numeral. For
purposes of clarity, not every component is labeled in every
figure, nor is every component of each embodiment of the invention
shown where illustration is not necessary to allow those of
ordinary skill in the art to understand the invention. In the
figures:
[0019] FIGS. 1A-1B illustrate composites in accordance with some
embodiments of the invention; and
[0020] FIG. 2 is a schematic diagram in accordance with certain
embodiments of the invention.
DETAILED DESCRIPTION
[0021] Disclosed herein are fiber-reinforced composites. These
materials are useful in load-bearing components for mechanical
systems, and other applications. Also disclosed herein are methods
of making and using such composites, articles comprising the same,
and the like. For example, some embodiments of the invention are
generally directed to composites comprising discontinuous agents
such as fibers or platelets which are positioned within a
substrate, e.g., formed from a plurality of continuous fibers. In
some cases, the discontinuous agents may be substantially aligned,
for example, by attaching magnetic particles onto the agents and
using a magnetic field to manipulate the agents. Other embodiments
are generally directed to systems and methods for making or using
such composites, kits involving such composites, or the like.
[0022] For instance, certain aspects of the invention are generally
directed to fiber-reinforced composite ply with a matrix of
discontinuous fibers aligned in the through-plane direction that
are fixed in position with a binder and embed a planar fabric of
continuous fibers. Aligning particles transversely to the planar
fabric can enhance the mechanical, electrical, and/or thermal
properties in the transverse direction and interlaminar regions
between plies. The discontinuous fibers and similarly sized
particles are aligned using a magnetic alignment process in which
non-magnetic agents are surface-coated with magnetic particles,
allowing the originally non-magnetic particles to exhibit a
physical response to magnetic fields. The immediate focus is
implementing this alignment method with discontinuous carbon
fibers. However, other agents can also be aligned, including (but
not limited to) materials in fiber, platelet, and ellipsoid form,
etc.
[0023] Various embodiments of the invention are generally directed
to composite plies with a discontinuous fiber matrix that embed a
planar fabric of continuous fibers, regardless of orientation.
Other embodiments are generally directed to fiber-reinforced
composite plies that do not have oriented, magnetically
functionalized particles.
[0024] Particles typically used in composites are diamagnetic,
requiring extremely high magnetic fields for alignment (greater
than 1 Tesla). However, in some embodiments, discontinuous carbon
fibers and other similarly sized particles can be surface-coated
with magnetic nanoparticles make them more responsive to magnetic
fields.
[0025] In some embodiments, selection of the proper geometry of
particles leads to a magnetic response that may reduce the required
magnetic field strength for alignment by over one hundred-fold. For
example, sub-millimeter discontinuous carbon fibers can be
successfully magnetized to exhibit a suitable magnetic response.
The produced magnetically responsive particles can be controlled
with magnetic fields to produce composites with tunable orientation
and distribution of particles, e.g., as shown in FIG. 1.
[0026] Another aspect of the present invention is generally
directed to composites comprising substrates having a plurality of
discontinuous agents, such as fibers or platelets. The
discontinuous agents may be generally substantially aligned within
the substrate in some embodiments, for example, substantially
orthogonally aligned. The substrate itself may be defined by
generally continuous fibers, which may be woven or non-woven to
form the substrate. In certain instances, some of the holes or
pores created by the continuous fibers may be filled in by the
discontinuous agents. In addition, in some embodiments, the
composite may further comprise binders or other materials, such as
those discussed herein.
[0027] In certain embodiments, magnetic particles can be attached
to the discontinuous agents, and a magnetic field may then be used
to manipulate the magnetic particles. For instance, the magnetic
field may be used to move the magnetic particles into the
substrate, and/or to align the discontinuous agents within the
substrate. The magnetic field may be constant or time-varying
(e.g., oscillating), for instance, as is discussed herein. For
example, an applied magnetic field may have a frequency of 1 Hz to
500 Hz and an amplitude of 0.01 T to 10 T. Other examples of
magnetic fields are described in more detail below. The volume of
magnetic particles used to manipulate the magnetic particles may be
substantial in some cases.
[0028] As an illustrative non-limiting example, in FIG. 2, a
composite 10 may comprise a plurality of continuous fibers 15 (in
this example, woven together to form a substrate). Gaps 25 between
the fibers may be empty, or filled with discontinuous agents 30.
The discontinuous agents may be, for example, fibers 35 and/or
platelets 40, and/or may have other shapes such as those discussed
herein. In some embodiments, the agents may also be aligned, e.g.,
as is shown with fibers 35. Some of the discontinuous agents may
include magnetic particles 50 that are adsorbed or otherwise
attached to the discontinuous agents. An applied magnetic field 55
may in some embodiments be used to manipulate the magnetic
particles, e.g., to cause them to align the discontinuous agents,
and/or to move them into one or more of the gaps within the
substrate.
[0029] Such composites may find use in a wide variety of
applications. As non-limiting examples, such composites may be
useful for eliminating or reducing stress concentrations or
delamination within materials, stiffening materials, eliminating or
reducing surface wear, dissipating electrical shocks, transmitting
electrical signals, attenuating or transmitting electromagnetic
waves, dissipating thermal shocks, eliminating or reducing thermal
gradients, as components for energy storage applications, or as
components for carbon fibers or ceramic matrixes. Additional
examples are discussed in more detail below.
[0030] The above discussion is a non-limiting example of certain
embodiment of the present invention that are generally directed to
composites comprising continuous fibers and discontinuous agents,
e.g., that can be manipulated using magnetic particles in a
suitable magnetic field. However, other embodiments are also
possible. Accordingly, more generally, various aspects of the
invention are directed to fiber-reinforced composites, as well as
various systems and methods for producing such fiber-reinforced
composites.
[0031] Certain embodiments of the invention are generally directed
to composites comprising a plurality of continuous fibers defining
a substrate, and a plurality of discontinuous agents contained
within the substrate. For instance, at least some of the plurality
of discontinuous agents may be contained within holes or pores of
the substrate, e.g., created by spacing between the continuous
fibers that define the substrate. In some cases, the discontinuous
agents may be substantially aligned within the holes or pores. The
composite may, in some cases, also contain a plurality of
particles, such as magnetic particles, adsorbed onto the continuous
fibers and/or the discontinuous agents, which may be used to
manipulate the agents, e.g., with an applied magnetic field. In
some cases, a binder may be present, for example, to bind the
continuous fibers and/or the discontinuous agents within the
composite.
[0032] In some cases, the composite is generally planar. However,
it should be understood that such a substrate need not be a
mathematically-perfect planar structure (although it can be); for
instance, the substrate may also be deformable, curved, bent,
folded, rolled, creased, or the like. As examples, the substrate
may have an average thickness of at least about 0.1 micrometers, at
least about 0.2 micrometers, at least about 0.3 micrometers, at
least about 0.5 micrometers, at least about 1 micrometer, at least
about 2 micrometers, at least about 3 micrometers, at least about 5
micrometers, at least about 10 micrometers, at least about 30
micrometers, at least about 50 micrometers, at least about 100
micrometers, at least about 300 micrometers, at least about 500
micrometers, at least about 1 mm, at least about 2 mm, at least
about 3 mm, at least about 5 mm, at least about 1 cm, at least
about 3 cm, at least about 5 cm, at least about 10 cm, at least
about 30 cm, at least about 50 cm, at least about 100 cm, etc. In
certain instances, the average thickness may be less than 100 cm,
less than 50 cm, less than 30 cm, less than 10 cm, less than 5 cm,
less than 3 cm, less than 1 cm, less than 5 mm, less than 2 mm,
less than 3 mm, less than 1 mm, less than 500 micrometers, less
than 300 micrometers, less than 100 micrometers, less than 50
micrometers, less than 30 micrometers, less than 10 micrometers,
less than 5 micrometers, less than 3 micrometers, less than 1
micrometers, less than 0.5 micrometers, less than 0.3 micrometers,
or less than 0.1 micrometers. Combinations of any of these are also
possible in certain embodiments. For instance, the average
thickness may be between 0.1 and 5,000 microns, between 10 and
2,000 microns, between 50 and 1,000 microns, or the like. The
thickness may be uniform or non-uniform across the substrate. Also,
the substrate may be rigid (e.g., as discussed herein), or may be
deformable in some cases.
[0033] In some cases, the pores or holes that are created by the
continuous fibers may be relatively small. Some or all of the pores
or holes may contain discontinuous agents, which may be aligned in
some cases. The pores or holes may have an average size or
cross-sectional dimension of no more than 10 cm, no more than 5 cm,
no more than 3 cm, no more than 2 cm, no more than 1 cm, no more
than 5 mm, no more than 3 mm, no more than 2 mm, no more than 1 mm,
no more than 500 micrometers, no more than 300 micrometers, no more
than 200 micrometers, no more than 100 micrometers, no more than 50
micrometers, no more than 30 micrometers, no more than 20
micrometers, no more than 10 micrometers, etc. Composites may be
used in a wide variety of applications, including those discussed
in more detail herein. As non-limiting examples, composites may be
used in diverse applications such as reinforcement for pressure
vessels, components for wind turbines, shims used in jacking heavy
structures, sporting equipment, building or construction materials,
laminates or encapsulants for electronic devices, battery
components, or panels for vehicles such as automobiles, aircraft,
marine vehicles, or spacecraft.
[0034] As mentioned, one set of embodiments of the invention are
generally directed to composites comprising substrates formed from
continuous fibers, and containing a plurality of discontinuous
agents, e.g., fibers or platelets. The continuous fibers generally
have a length that on average is substantially longer than the
characteristic dimension of the discontinuous agents. For instance,
the continuous fibers may have an average length that is greater
than 10, greater than 30, greater than 50, greater than 100,
greater than 300, greater than 500, or greater than 1,000 times the
characteristic dimension of the discontinuous agents. In some
embodiments, the continuous fibers have an average aspect ratio
(e.g., of length to diameter or average cross-sectional dimension)
of at least 3, at least 5, at least 10, at least 30, at least 50,
at least 100, at least 300, at least 500, at least 1,000, etc.
Additionally, in certain cases, the continuous fibers may have an
average length of at least 1 nm, at least 3 nm, at least 5 nm, at
least 10 nm, at least 30 nm, at least 50 nm, at least 100 nm, at
least 300 nm, at least 500 nm, at least 1 micrometer, at least 3
micrometers, at least 5 micrometers, at least 10 micrometers, at
least 30 micrometers, at least 50 micrometers, at least 100
micrometers, at least 300 micrometers, at least 500 micrometers, at
least 1 mm, at least 3 mm, at least 5 mm, at least 1 cm, at least 3
cm, at least 5 cm, or at least 10 cm. Longer average lengths are
also possible in some instances.
[0035] The continuous fibers may be woven together (e.g.
bidirectional, multidirectional, quasi-isotropic, etc.), and/or
non-woven (e.g., unidirectional, veil, mat, etc.). In certain
embodiments, at least some of the continuous fibers are
substantially parallel, and/or orthogonally oriented relative to
each other, although other configurations of continuous fibers are
also possible. In certain embodiments, the continuous fibers may
together define a fabric or other substrate, e.g., a textile, a
tow, a filament, a yarn, a strand, or the like. In some cases, the
substrate may have one orthogonal dimension that is substantially
less than the other orthogonal dimensions (i.e., the substrate may
have a thickness).
[0036] The continuous fibers forming the substrate may comprise any
of a wide variety of materials, and one type or more than one type
of fiber may be present within the substrate. Non-limiting examples
include carbon, basalt, silicon carbide, aramid, zirconia, nylon,
boron, alumina, silica, borosilicate, mullite, cotton, or any other
natural or synthetic fibers.
[0037] The continuous fibers may have any suitable average
diameter. For example, the continuous fibers may have an average
diameter of at least 10 micrometers, at least 20 micrometers, at
least 30 micrometers, at least 50 micrometers, at least 100
micrometers, at least 200 micrometers, at least 300 micrometers, at
least 500 micrometers, at least 1 mm, at least 2 mm, at least 3 mm,
at least 5 mm, at least 1 cm, at least 2 cm, at least 3 cm, at
least 5 cm, at least 10 cm, etc. In certain embodiments, the
continuous fibers may have an average diameter of no more than 10
cm, no more than 5 cm, no more than 3 cm, no more than 2 cm, no
more than 1 cm, no more than 5 mm, no more than 3 mm, no more than
2 mm, no more than 1 mm, no more than 500 micrometers, no more than
300 micrometers, no more than 200 micrometers, no more than 100
micrometers, no more than 50 micrometers, no more than 30
micrometers, no more than 20 micrometers, no more than 10
micrometers, etc. Combinations of any of these are also possible.
For example, the continuous fibers may have an average diameter of
between 10 micrometers and 100 micrometers, between 50 micrometers
and 500 micrometers, between 100 micrometers and 5 mm, etc.
[0038] The continuous fibers may also have any suitable average
length. For example, the continuous fibers may have an average
length of at least about 0.5 cm, at least 1 cm, at least 2 cm, at
least 3 cm, at least 5 cm, at least 10 cm, etc. In certain
embodiments, the continuous fibers may have an average diameter of
no more than 10 cm, no more than 5 cm, no more than 3 cm, no more
than 2 cm, no more than 1 cm, no more than 0.5 cm, or the like.
Combinations of any of these are also possible; for example, the
continuous fibers may have an average length of between 1 cm and 10
cm, between 10 cm and 100 cm, etc.
[0039] In some instances, the continuous fibers may comprise a
relatively large portion of the composite. For example, in certain
embodiments, the continuous fibers may comprise at least 1%, at
least 2%, at least 3%, at least 4%, at least 5%, at least 7%, at
least 10%, at least 15%, at least 20%, at least 25%, at least 30%,
at least 35%, at least 40%, at least 45%, at least 50%, at least
55%, at least 60%, at least 65%, at least 70%, at least 75%, at
least 80%, at least 85%, at least 90%, at least 95%, or at least
97% of the mass of the composite. In some cases, the continuous
fibers comprise no more than 97%, no more than 95%, no more than
90%, no more than 85%, no more than 80%, no more than 70%, no more
than 60%, no more than 50%, no more than 40%, no more than 30%, no
more than 20%, or no more than 10% of the mass of the composite.
Combinations of any of these are also possible.
[0040] The composite may also contain one or more discontinuous
agents in certain embodiments. The agents may include agglomerated
agents or individual agents. The agents may have a variety of
shapes, including discontinuous fibers or platelets. Other shapes
include, but are not limited to, nanotubes, nanofibers, nanosheets,
or the like. In one set of embodiments, the discontinuous agents
are not spherical. Typically, a fiber has a shape such that one
orthogonal dimension (e.g., its length) is substantially greater
than its other two orthogonal dimensions (e.g., its width or
thickness). The fiber may be substantially cylindrical in some
cases. Similarly, a platelet may have a shape such that two
orthogonal dimensions (e.g., its diameter) are substantially
greater than its other orthogonal dimension (e.g., its width or
thickness). A platelet may be substantially cylindrical or
disc-shaped in some cases, although it may have other shapes as
well. In addition, it should be understood that both platelets and
fibers may be present in some cases, and/or that other shapes
besides platelets and/or fibers may be present in certain
embodiments (e.g., instead of or in addition to platelets and/or
fibers).
[0041] It should be understood that discontinuous agents such as
platelets and/or fibers may be relatively stiff, or may be curved
or flexible in some cases, or adopt a variety of other shapes. For
instance, a fiber need not be perfectly straight (e.g., its length
may still be determined along the fiber itself, even if it is
curved). Similarly, a platelet need not be perfectly
disc-shaped.
[0042] In one set of embodiments, the discontinuous agents may have
a dimension (e.g., a characteristic dimension) that is
substantially the same, or smaller, than the thickness of the
substrate. For example, at least some discontinuous fibers within a
composite may have an average length that substantially spans the
thickness of the substrate. However, in other cases, the dimension
may be greater than the thickness.
[0043] As mentioned, certain embodiments of the invention are
generally directed to composites comprising discontinuous fibers.
In some cases, the discontinuous fibers within a composite may have
an average length, or characteristic dimension, of at least 1 nm,
at least 3 nm, at least 5 nm, at least 10 nm, at least 30 nm, at
least 50 nm, at least 100 nm, at least 300 nm, at least 500 nm, at
least 1 micrometer, at least 3 micrometers, at least 5 micrometers,
at least 10 micrometers, at least 20 micrometers, at least 30
micrometers, at least 50 micrometers, at least 100 micrometers, at
least 200 micrometers, at least 300 micrometers, at least 500
micrometers, at least 1 mm, at least 2 mm, at least 3 mm, at least
5 mm, at least 1 cm, at least 1.5 cm, at least 2 cm, at least 3 cm,
at least 5 cm, at least 10 cm, etc. In certain embodiments, the
discontinuous fibers may have an average length, or characteristic
dimension, of no more than 10 cm, no more than 5 cm, no more than 3
cm, no more than 2 cm, no more than 1.5 cm, no more than 1 cm, no
more than 5 mm, no more than 3 mm, no more than 2 mm, no more than
1 mm, no more than 500 micrometers, no more than 300 micrometers,
no more than 200 micrometers, no more than 100 micrometers, no more
than 50 micrometers, no more than 30 micrometers, no more than 20
micrometers, no more than 10 micrometers, no more than 5
micrometers, no more than 3 micrometers, no more than 1
micrometers, no more than 500 nm, no more than 300 nm, no more than
100 nm, no more than 50 nm, no more than 30 nm, no more than 10 nm,
no more than 5 nm, etc. Combinations of any of these are also
possible. For example, the discontinuous fibers within a composite
may have an average length of between 5 mm and 15 mm, or between 1
mm and 5 mm, between 1 mm and 1 cm, etc.
[0044] In addition, the discontinuous fibers may also have any
suitable average diameter. For instance, the discontinuous fibers
may have an average diameter of at least 10 micrometers, at least
20 micrometers, at least 30 micrometers, at least 50 micrometers,
at least 100 micrometers, at least 200 micrometers, at least 300
micrometers, at least 500 micrometers, at least 1 mm, at least 2
mm, at least 3 mm, at least 5 mm, at least 1 cm, at least 2 cm, at
least 3 cm, at least 5 cm, at least 10 cm, etc. In certain
embodiments, the discontinuous fibers may have an average diameter
of no more than 10 cm, no more than 5 cm, no more than 3 cm, no
more than 2 cm, no more than 1 cm, no more than 5 mm, no more than
3 mm, no more than 2 mm, no more than 1 mm, no more than 500
micrometers, no more than 300 micrometers, no more than 200
micrometers, no more than 100 micrometers, no more than 50
micrometers, no more than 30 micrometers, no more than 20
micrometers, no more than 10 micrometers, etc. Combinations of any
of these are also possible. For example, the discontinuous fibers
may have an average diameter of between 10 micrometers and 100
micrometers, between 50 micrometers and 500 micrometers, between
100 micrometers and 5 mm, etc.
[0045] In certain embodiments, the discontinuous fibers may have a
length that is at least 10 times or at least 50 times its thickness
or diameter, on average. In some cases, the fibers within a
composite may have an average aspect ratio (ratio of fiber length
to diameter or thickness) of at least 3, at least 5, at least 10,
at least 30, at least 50, at least 100, at least 300, at least 500,
at least 1,000, at least 3,000, at least 5,000, at least 10,000, at
least 30,000, at least 50,000, or at least 100,000. In some cases,
the average aspect ratio may be less than 100,000, less than
50,000, less than 30,000, less than 10,000, less than 5,000, less
than 3,000, less than 1,000, less than 500, less than 300, less
than 100, less than 50, less than 30, less than 10, less than 5,
etc. Combinations of any of these are also possible in some cases;
for instance, the aspect ratio may be between 5, and 100,000.
[0046] As mentioned, the composite is not limited to only
discontinuous fibers. In certain embodiments, a composite may
include platelets, e.g., instead of or in addition to discontinuous
fibers. Typically, a platelet may be disc-shaped, although other
shapes may be possible as well.
[0047] In some cases, the platelet may have a maximum dimension or
a characteristic dimension of at least 10 micrometers, at least 20
micrometers, at least 30 micrometers, at least 50 micrometers, at
least 100 micrometers, at least 200 micrometers, at least 300
micrometers, at least 500 micrometers, at least 1 mm, at least 2
mm, at least 3 mm, at least 5 mm, at least 1 cm, at least 1.5 cm,
at least 2 cm, at least 3 cm, at least 5 cm, at least 10 cm, etc.
In certain embodiments, the platelet have a maximum dimension or a
characteristic dimension of no more than 10 cm, no more than 5 cm,
no more than 3 cm, no more than 2 cm, no more than 1.5 cm, no more
than 1 cm, no more than 5 mm, no more than 3 mm, no more than 2 mm,
no more than 1 mm, no more than 500 micrometers, no more than 300
micrometers, no more than 200 micrometers, no more than 100
micrometers, no more than 50 micrometers, no more than 30
micrometers, no more than 20 micrometers, no more than 10
micrometers, etc. If the platelet does not have a substantially
circular face (for example, if the platelet has an oblong or an
irregular face), then the characteristic dimension may be taken as
a diameter of a perfect circle having the same area as the face of
the platelet. Combinations of any of these dimensions are also
possible. For example, the maximum dimension or a characteristic
dimension may be between 5 mm and 15 mm, or between 1 mm and 5 mm,
between 1 mm and 1 cm, etc.
[0048] In certain embodiments, the platelet may have an average
aspect ratio (ratio of largest dimension to smallest dimension or
thickness) of at least 3, at least 5, at least 10, at least 30, at
least 50, at least 100, at least 300, at least 500, at least 1,000,
etc. In some cases, the average aspect ratio may be less than
1,000, less than 500, less than 300, less than 100, less than 50,
less than 30, less than 10, less than 5, etc. Combinations of any
of these are also possible in some cases; for instance, the aspect
ratio may be between 5, and 1,000.
[0049] The discontinuous agents may be formed or include any of a
wide variety of materials, and one or more than one type of
material may be present. For example, the discontinuous agents may
comprise materials such as carbon (e.g., carbon fibers), basalt,
silicon carbide, silicon nitride, aramid, zirconia, nylon, boron,
alumina, silica, borosilicate, mullite, nitride, boron nitride,
graphite, glass, or the like. The discontinuous agents may include
any natural and/or any synthetic material, and may be magnetic
and/or non-magnetic.
[0050] In some instances, the discontinuous agents may comprise a
relatively large portion of the composite. For example, in certain
embodiments, the discontinuous agents may comprise at least 1%, at
least 2%, at least 3%, at least 4%, at least 5%, at least 7%, at
least 10%, at least 15%, at least 20%, at least 25%, at least 30%,
at least 35%, at least 40%, at least 45%, at least 50%, at least
55%, at least 60%, at least 65%, at least 70%, at least 75%, at
least 80%, at least 85%, at least 90%, at least 95%, or at least
97% of the mass of the composite. In some cases, the discontinuous
agents comprise no more than 97%, no more than 95%, no more than
90%, no more than 85%, no more than 80%, no more than 70%, no more
than 60%, no more than 50%, no more than 40%, no more than 30%, no
more than 20%, or no more than 10% of the mass of the composite.
Combinations of any of these are also possible.
[0051] The discontinuous agents, in some embodiments, may be at
least substantially aligned within the composite. Methods for
aligning discontinuous agents, such as fibers, are discussed in
more detail herein. Various alignments are possible, and in some
cases, can be determined optically or microscopically, e.g., as is
shown in FIG. 1B. Thus, in some cases, the alignment may be
determined qualitatively. However, it should be understood that the
alignment need not be perfect. In some cases, at least 50%, at
least 75%, at least 85%, at least 90%, or at least 95% of the
discontinuous agents within a composite may exhibit an alignment
that is within 20.degree., within 15.degree., within 10.degree., or
within 5.degree. of the average alignment of the plurality of the
discontinuous agents, e.g., within a sample of the composite.
[0052] In certain instances, the alignment of the discontinuous
particles is substantially orthogonal to the substrate. For
example, the average alignment may be oriented to be at least
60.degree., at least 65.degree., at least 70.degree., at least
75.degree., at least 85.degree., or at least 87.degree. relative to
the plane of the substrate at that location. As mentioned, the
substrate itself may not necessarily be planar, but may also be
curved, etc.
[0053] Without wishing to be bound by any theory, it is believed
that alignment of the discontinuous particles substantially
orthogonal to the substrate may serve to provide reinforcement of
the substrate. This may improve the strength of the substrate,
e.g., when subjected to forces in different directions. For
instance, fibers within the substrate may run in substantially
orthogonal directions in 3 dimensions, thereby providing strength
to the substrate regardless of the direction of force that is
applied. The discontinuous particles may also limit degradation of
the surface, e.g., with interlaminar micro-cracks, through-ply
fissures, or the like. In addition, in some embodiments, the
discontinuous particles may enhance other properties of the
substrate, e.g., electrical and/or thermal properties within the
composite, in addition to or instead of its mechanical
properties.
[0054] At least some of the discontinuous agents may be uncoated.
In some cases, however, some or all of the discontinuous agents may
be coated. The coating may be used, for example, to facilitate the
adsorption or binding of particles, such as magnetic particles,
onto the agents. As non-limiting examples, the agents may be coated
with a surfactant, a silane coupling agent, an epoxy, glycerine,
polyurethane, an organometallic coupling agent, or the like.
Non-limiting examples of surfactants include oleic acid, sodium
dodecyl sulfate, sodium lauryl sulfate, etc. Non-limiting examples
of silane coupling agents include amino-, benzylamino-,
chloropropyl-, disulfide-, epoxy-, epoxy/melamine-, mercapto-,
methacrylate-, tertasulfido-, ureido-, vinyl-, isocynate-, and
vinyl-benzyl-amino-based silane coupling agents. Non-limiting
examples of organometallic coupling agents include aryl- and
vinyl-based organometallic coupling agents
[0055] Particles such as magnetic particles may be adsorbed or
otherwise bound to at least some of the discontinuous agents. In
some cases, the particles may coat some or all of the discontinuous
agents and/or the continuous fibers. This may be facilitated by a
coating of material as discussed above, although a coating is not
necessarily required to facilitate the adsorption of the
particles.
[0056] If the particles are magnetic, the particles may comprise
any of a wide variety of magnetically susceptible materials. For
example, the magnetic materials may comprise one or more
ferromagnetic materials, e.g., containing iron, nickel, cobalt,
alnico, oxides of iron, nickel, cobalt, rare earth metals, or an
alloy including two or more of these and/or other suitable
ferromagnetic materials. In some cases, the magnetic particles may
have a relative permeability of at least 2, at least 5, at least
10, at least 20, at least 40, at least 100, at least 200, at least
500, at least 1,000, at least 2,000, at least 5,000, or at least
10,000.
[0057] However, it should be understood that not all of the
particles are necessarily magnetic. In some cases, non-magnetic
particles may be used, e.g., in addition to and/or instead of
magnetic particles. Non-limiting examples of nonmagnetic particles
include glass, polymer, metal, or the like.
[0058] The particles may be spherical or non-spherical, and may be
of any suitable shape or size. The particles may be relatively
monodisperse or come in a range of sizes. In some cases, the
particles may have a characteristic dimension, on average, of at
least 10 micrometers, at least 20 micrometers, at least 30
micrometers, at least 50 micrometers, at least 100 micrometers, at
least 200 micrometers, at least 300 micrometers, at least 500
micrometers, at least 1 mm, at least 2 mm, at least 3 mm, at least
5 mm, at least 1 cm, at least 1.5 cm, at least 2 cm, at least 3 cm,
at least 5 cm, at least 10 cm, etc. The particles within the
composite may also have an average characteristic dimension of no
more than 10 cm, no more than 5 cm, no more than 3 cm, no more than
2 cm, no more than 1.5 cm, no more than 1 cm, no more than 5 mm, no
more than 3 mm, no more than 2 mm, no more than 1 mm, no more than
500 micrometers, no more than 300 micrometers, no more than 200
micrometers, no more than 100 micrometers, no more than 50
micrometers, no more than 30 micrometers, no more than 20
micrometers, no more than 10 micrometers, etc. Combinations of any
of these are also possible. For example, the particles may exhibit
a characteristic dimension of or between 100 micrometer and 1 mm,
between 10 micrometer and 10 micrometer, etc. The characteristic
dimension of a nonspherical particle may be taken as the diameter
of a perfect sphere having the same volume as the nonspherical
particle.
[0059] In some embodiments, the particles (including magnetic
and/or non-magnetic particles) may comprise a relatively large
portion of the composite. For example, in certain embodiments, the
particles may comprise at least 1%, at least 2%, at least 3%, at
least 4%, at least 5%, at least 7%, at least 10%, at least 15%, at
least 20%, at least 25%, at least 30%, at least 35%, at least 40%,
at least 45%, at least 50%, at least 55%, at least 60%, at least
65%, at least 70%, at least 75%, at least 80%, at least 85%, at
least 90%, at least 95%, or at least 97% of the volume of the
composite. In some cases, the particles comprise no more than 97%,
no more than 95%, no more than 90%, no more than 85%, no more than
80%, no more than 70%, no more than 60%, no more than 50%, no more
than 45%, no more than 40%, no more than 35% no more than 30%, no
more than 25%, no more than 20%, no more than 15%, no more than
10%, no more than 7%, no more than 5%, no more than 4%, no more
than 3%, no more than 2%, or no more than 1% of the volume of the
composite. Combinations of any of these are also possible.
[0060] In certain embodiments, a binder is also present within the
composite, e.g., which may be used to bind the continuous fibers
and the discontinuous agents, e.g., within the composite. For
example, the binder may facilitate holding the continuous fibers
and the discontinuous agents in position within the composite.
However, it should be understood that the binder is optional and
not required in all cases. In some cases, the binder may comprise a
resin. The binder may include a thermoset or a thermoplastic. In
certain embodiments, the binder may comprise a thermoplastic
solution, a thermoplastic melt, thermoplastic pellets, a thermoset
resin, a volatile compound such as a volatile organic compound,
water, or an oil. Additional non-limiting examples of binders
include an epoxy, polyester, vinyl ester, polyethylenimine,
polyetherketoneketone, polyaryletherketone, polyether ether ketone,
polyphenylene sulfide, polyethylene terephthalate, a
polycarbonates, poly(methyl methacrylate), acrylonitrile butadiene
styrene, polyacrylonitrile, polypropylene, polyethylene, nylon, a
silicone rubber, polyvinylidene fluoride, styrene butadiene rubber,
or a pre-ceramic monomer, such as a siloxane, a silazane, or a
carbosilane. The binder may also include mixtures including any one
or more of these materials and/or other materials, in certain
embodiments.
[0061] In some embodiments, the binder may comprise at least 1%, at
least 2%, at least 3%, at least 4%, at least 5%, at least 7%, at
least 10%, at least 15%, at least 20%, or at least 25% of the mass
of the composite, and/or no more than 25%, no more than 20%, no
more than 15%, no more than 10%, no more than 7%, no more than 5%,
no more than 4%, no more than 3%, no more than 2%, or no more than
1% of the mass of the composite.
[0062] Another aspect of the present invention is generally
directed to systems and methods for making composites such as those
described herein. In one set of embodiments, composites can be
prepared from a liquid, such as a slurry, containing a plurality of
discontinuous agents and a plurality of magnetic particles, to
which a suitable substrate is exposed to. The discontinuous agents
can include fibers, platelets, or the like, e.g., as discussed
herein. A magnetic field can be applied to manipulate the magnetic
particles and the discontinuous agents, for example, to move the
magnetic particles into the substrate, and/or to align the
discontinuous agents. Excess material can be removed. In some
cases, the composite can be set or hardened, e.g., with a binder,
which may be used to immobilize or fix the discontinuous agents
within the substrate. The binder may, in certain embodiments, be
infused or impregnated into the substrate.
[0063] In some cases, a liquid, such as a slurry, may be formed.
The slurry may include discontinuous agents and/or magnetic
particles. The liquid phase may include, for example, a
thermoplastic or a thermoset, e.g., a thermoplastic solution,
thermoplastic melt, thermoset, volatile organic compound, water, or
oil. Non-limiting examples of thermosets include polyethylenimine,
polyetherketoneketone, polyaryletherketone, polyether ether ketone,
polyphenylene sulfide, polyethylene terephthalate, a
polycarbonates, poly(methyl methacrylate), acrylonitrile butadiene
styrene, polyacrylonitrile, polypropylene, polyethylene, nylon,
polyvinylidene fluoride, phenolics, epoxies, bismaleimides, cyanate
esters, polyimides, etc. Non-limiting examples of elastomers
include silicone rubber and styrene butadiene rubber, etc.
Non-limiting examples of thermoplastics include epoxy, polyester,
vinyl ester, polycarbonates, polyamides (e.g., nylon, PA-6, PA-12,
etc.), polyphenylene sulfide, polyetherimide, polyetheretherketone,
polyetherketoneketone, etc. Non-limiting examples of ceramic
monomers include a siloxane, a silazane, or a carbosilane, etc. In
some cases, for example, one or more of these may be added to
assist in homogenously dispersing the discontinuous agents and/or
magnetic particles within the liquid. Examples of volatile organic
compounds include, but are not limited to, isopropanol, butanol,
ethanol, acetone, toluene, or xylenes.
[0064] In some cases, the magnetic particles may be adsorbed or
otherwise bound to the discontinuous agents within the liquid. As
non-limiting examples, the magnetic particles may be added to the
discontinuous agents prior to introduction into the liquid, or the
discontinuous agents and magnetic particles may be separately added
to the liquid and at least some of the magnetic particles may
spontaneously adsorb onto the discontinuous agents.
[0065] Any suitable amount of discontinuous agents and/or magnetic
particles may be present in the slurry or other liquid. For
instance, at least 10%, at least 15%, at least 20%, at least 25%,
at least 30%, at least 35%, at least 40%, at least 45%, at least
50%, at least 55%, at least 60%, at least 65%, at least 70%, at
least 75%, or at least 80% of the volume of the slurry may be
discontinuous agents and/or magnetic particles. In some cases, no
more than 85%, no more than 80%, no more than 75%, no more than
70%, no more than 65%, no more than 60%, no more than 55%, no more
than 50%, no more than 45%, no more than 40%, no more than 35%, no
more than 30%, no more than 25%, no more than 20%, no more than
15%, or no more than 10% may be discontinuous agents and/or
magnetic particles. Combinations of any of these are also possible
in some cases. For example, a slurry or other liquid may contain
between 70% and 80%, between 75% and 85%, between 50% and 90%, etc.
discontinuous agents and/or magnetic particles.
[0066] After preparation of the slurry or other liquid, it may be
applied to or exposed to the substrate, e.g., comprising the
continuous fibers. In some cases, the substrate may be placed on a
surface such as a polymer foil, metal foil, or paper, e.g., for
application of liquid, a magnetic field, mechanical vibration,
heating, and/or the like, e.g., as discussed herein.
[0067] Any suitable method may be used to apply the slurry or other
liquid to the substrate. As non-limiting examples, the liquid may
be poured, coated, sprayed, or painted onto the substrate, or the
substrate may be immersed partially or completely within the
liquid. The liquid may be used to wet, coat, and/or surround the
continuous fibers.
[0068] A magnetic field may be applied to manipulate the magnetic
particles. Without wishing to be bound by any theory, it is
believed that the magnetic field may also be used to manipulate the
discontinuous agents, e.g., due to the magnetic particles that are
adsorbed or otherwise bound to the discontinuous agents. For
instance, the magnetic field may be used to move the magnetic
particles into the substrate, e.g., into pores or holes within the
substrate. In addition, in some cases, the magnetic field may be
used to at least substantially align the discontinuous agents
within the substrate, e.g., as discussed herein. For example, the
magnetic field may be used to align at least 50%, at least 75%, at
least 85%, at least 90%, or at least 95% of the discontinuous
agents to within 20.degree., within 15.degree., within 10.degree.,
or within 5.degree. of the average alignment. The magnetic field,
in some embodiments, may be used to align the magnetic particles
and/or the discontinuous agents within the substrate, e.g., in the
direction of the magnetic field, and/or within the substrate in a
through-plane direction.
[0069] Any suitable magnetic field may be applied. In some cases,
the magnetic field is a constant magnetic field. In other cases,
the magnetic field may be time-varying; for example, the magnetic
field may oscillate or periodically change in amplitude and/or
direction, e.g., to facilitate manipulation of the discontinuous
agents. The oscillation may be sinusoidal or another repeating
waveform (e.g., square wave or sawtooth). The frequency may be, for
example, at least 0.1 Hz, at least 0.3 Hz, at least 0.5 Hz, at
least 1 Hz, at least 3 Hz, at least 5 Hz, at least 10 Hz, at least
30 Hz, at least 50 Hz, at least 100 Hz, at least 300 Hz, at least
500 Hz, etc., and/or no more than 1000 Hz, no more than 500 Hz, no
more than 300 Hz, no more than 100 Hz, no more than 50 Hz, no more
than 30 Hz, no more than 10 Hz, no more than 5 Hz, no more than 3
Hz, etc. For example, the frequency may be between 1 Hz to 500 Hz,
between 10 Hz and 30 Hz, between 50 Hz and Hz, or the like. In
addition, the frequency may be held substantially constant, or the
frequency may vary in some cases.
[0070] The magnetic field, whether constant or oscillating, may
have any suitable amplitude. For example, the amplitude may be at
least 0.001 T, at least 0.003 T, at least 0.005 T, at least 0.01 T,
at least 0.03 T, at least 0.05 T, at least 0.1 T, at least 0.3 T,
at least 0.5 T, at least 1 T, at least 3 T, at least 5 T, at least
10 T, etc. The amplitude in some cases may be no more than 20 T, no
more than 10 T, no more than 5 T, no more than 3 T, no more than 1
T, no more than 0.5 T, no more than 0.3 T, no more than 0.1 T, no
more than 0.05 T, no more than 0.03 T, no more than 0.01 T, no more
than 0.005 T, no more than 0.003 T, etc. The amplitude may also
fall within any combination of these values. For instance, the
amplitude may be between 0.01 T to 10 T, between 1 T and 3 T,
between 0.5 T and 1 T, or the like. The amplitude may be
substantially constant, or may vary in certain embodiments, e.g.,
within any range of these values.
[0071] In some embodiments, the magnetic field direction (i.e.,
direction of maximum amplitude) may vary by +/-90.degree.,
+/-85.degree., +/-80.degree., +/-75.degree., +/-70.degree.,
+/-65.degree., +/-60.degree., +/-55.degree., +/-50.degree.,
+/-45.degree., +/-40.degree., +/-35.degree., +/-30.degree.,
+/-25.degree., +/-20.degree., +/-15.degree., +/-10.degree.,
+/-5.degree. about a mean direction.
[0072] A variety of different devices for producing suitable
magnetic fields may be obtained commercially, and include permanent
magnets or electromagnets. In some cases, an oscillating magnetic
may be created by attaching a magnet to a rotating disc and
rotating the disc at an appropriate speed or frequency.
Non-limiting examples of permanent magnets include iron magnets,
alnico magnets, rare earth magnets, or the like.
[0073] In addition, in one set of embodiments, mechanical vibration
may be used to manipulate the particles, e.g., in addition to
and/or instead of magnetic manipulation. For example, mechanical
vibration can be used to move particles into the substrate, e.g.,
into pores or holes within the substrate, and/or at least
substantially align the discontinuous agents within the substrate,
e.g., as discussed herein. In some cases, vibration may be used to
align the particles within the substrate and/or move the particles
into holes or pores within the substrate, which may be used, for
example, to correspondingly manipulate the discontinuous agents
and/or eliminate voids.
[0074] In one set of embodiments, mechanical vibration may be
applied to cause motion of the particles and/or discontinuous
agents of at least 1 micrometer, at least 2 micrometers, at least 3
micrometers, at least 5 micrometers, at least 10 micrometers, at
least 20 micrometers, at least 30 micrometers, at least 50
micrometers, at least 100 micrometers, at least 200 micrometers, at
least 300 micrometers, at least 500 micrometers, at least 1,000
micrometers, at least 2,000 micrometers, at least 3,000
micrometers, at least 5,000 micrometers, or at least 10,000
micrometers.
[0075] In addition, in some cases, the mechanical vibrations may be
time-varying; for example, the mechanical vibrations may
periodically change in amplitude and/or direction, e.g., to
facilitate manipulation of the discontinuous agents. The
oscillation may be sinusoidal or another repeating waveform (e.g.,
square wave or sawtooth). The frequency may be, for example, at
least 0.1 Hz, at least 0.3 Hz, at least 0.5 Hz, at least 1 Hz, at
least 3 Hz, at least 5 Hz, at least 10 Hz, at least 30 Hz, at least
50 Hz, at least 100 Hz, at least 300 Hz, at least 500 Hz, etc.,
and/or no more than 1000 Hz, no more than 500 Hz, no more than 300
Hz, no more than 100 Hz, no more than 50 Hz, no more than 30 Hz, no
more than 10 Hz, no more than 5 Hz, no more than 3 Hz, etc. For
example, the frequency may be between 1 Hz to 500 Hz, between 10 Hz
and 30 Hz, between 50 Hz and Hz, or the like. In addition, the
frequency may be held substantially constant, or the frequency may
vary in some cases. If applied in conjunction with an oscillating
magnetic field, their frequencies may independently be the same or
different.
[0076] During and/or after alignment, the discontinuous agents
within the substrate may be set or fixed in some embodiments, e.g.,
to prevent or limit subsequent movement of the discontinuous agents
and form a relatively hard composite. Non-limiting examples of
techniques to form the composite include, but are not limited to
solidifying, hardening, gelling, melting, evaporating, freezing, or
lyophilizing the liquid or the slurry. In another set of
embodiments, a material, such as a thermosetting polymer, may be
cured to harden the composite. The substrate may thus form a
composite that is a solid, a gel, or the like.
[0077] In some cases, the liquid may comprise a relatively volatile
solvent, which can be removed by heating and/or evaporation (e.g.,
by waiting a suitable amount of time, or allowing the solvent to
evaporate, e.g., in a fume hood or other ventilated area).
Non-limiting examples of volatile solvents include isopropanol,
butanol, ethanol, acetone, toluene, or xylenes. Other examples of
methods of removing solvents include applying vacuum,
lyophilization, mechanical shaking, or the like.
[0078] In one set of embodiments, heating may be applied to the
substrate, for example, to remove a portion of the solvent. For
example, the substrate may be heated to a temperature of at least
about 30.degree. C., at least about 35.degree. C., at least about
40.degree. C., at least about 45.degree. C., at least about
50.degree. C., at least about 55.degree. C., at least about
60.degree. C., at least about 65.degree. C., at least about
70.degree. C., at least about 75.degree. C., at least about
80.degree. C., at least about 90.degree. C., at least about
100.degree. C., at least about 125.degree. C., at least about
150.degree. C., at least about 175.degree. C., at least about
200.degree. C., at least about 250.degree. C., at least about
300.degree. C., at least about 350.degree. C., at least about
400.degree. C., at least about 450.degree. C., at least about
500.degree. C., etc. Any suitable method of applying heat may be
used, for example, a thermoelectric transducer, an Ohmic heater, a
Peltier device, a combustion heater, or the like. In some cases,
the viscosity of the liquid may decrease as a result of heating.
The heating may be applied, for example, prior, concurrent or
subsequent to the application of magnetic field and/or mechanical
vibration. In some cases, heating may be used to prevent or
initiate cross-linking or curing of a thermosetting prepolymer.
[0079] A binder may also be applied in one set of embodiments,
e.g., before, during, and/or after hardening of the composite
and/or removal of at least a portion of the liquid. In some
embodiments, the binder may be used to produce a pre-impregnated
composite ply material, e.g., by wetting dry ply material. The
binder may be a liquid in some cases, and may be caused to harden
after application to the composite. In some cases, the binder is
permeated into at least a portion of the composite. Non-limiting
examples of permeation techniques include using gravitational and
capillary forces, by applying pressure to the binder to force it
into the composite, or the like. Other examples include, but are
not limited to, hot-pressing, calendaring, or vacuum infusion.
However, in some cases, the binder is used to coat all, or only a
portion of, the substrate, e.g., without necessarily requiring
permeation. Non-limiting examples of suitable binders include
resins or other materials such as those discussed herein. After
permeation, the binder may be hardened. In some cases, the binder
may harden spontaneously, e.g., upon evaporation of a solvent. In
certain embodiments, heat may be applied to harden the binder,
e.g., by exposing the composite to temperatures such as those
described above. In some embodiments, the binder may be hardened
upon exposure to light or a catalyst, e.g., to facilitate or
promote a chemical or polymerization reaction to cause the binder
to polymerize. For example, a thermosetting polymer may be cured
upon exposure to suitable temperatures. In another example, a
polymer may be exposed to ultraviolet light to cause polymerization
to occur.
[0080] Composites such as those discussed herein may be used in a
wide variety of applications, in various aspects. Composites such
as those described herein may exhibit a variety of different
features in various embodiments of the invention.
[0081] For example, composites such as those discussed herein may
be useful for reducing or eliminating stress concentrations,
reducing or eliminating delamination, increasing planar strength
and/or stiffness, reducing or eliminating surface wear, dissipating
electricity (e.g., in electrical shocks), transmitting electrical
signals, attenuating electromagnetic waves, transmitting
electromagnetic waves, dissipating heat (e.g., in thermal shocks),
reducing or eliminating thermal gradients, storing energy,
synthesizing ex-PAN carbon fibers, synthesizing ceramic matrix
composites (CMC), or the like.
[0082] For example, in one set of embodiments, a composite ply with
at least three-axes of fiber orientation may be produced. This
fiber structure may allow the composite ply to distribute stresses
between subsequent plies and adjacent components, which may reduce
or eliminate stress concentrations. This may significantly improve
the strength of a laminated composite structure under dynamic
loads, e.g., when a laminated composite structure is formed with
small features or mates with a material with drastically different
stiffness (e.g. metal alloys or plastics).
[0083] Another set of embodiments is generally directed to a
composite ply with through-plane reinforcement of the interlaminar
region. This fiber reinforcement allows the composite ply to
efficiently distribute stresses between adjacent layers to hinder
the formation of cracks and prevents a crack from propagating in
the interlaminar region. The targeted reinforcement of the
interlaminar region can significantly improve the strength of a
laminated composite structure under shock and cyclic loads. This
formulation may be useful when a laminated composite structure is
formed with long sheets of composite ply, for example, where a
single crack in the interlaminar region between the plies can
potentially compromise the structural integrity of the overall
structure.
[0084] Yet another set of embodiments is generally directed to a
composite ply with through-plane reinforcement, e.g., a
through-plane uni-directional fabric. This fiber reinforcement may
reinforce target through-plane loads (e.g. point loads and
high-pressure loads). The targeted through-plane reinforcement can
significantly improve the strength and stiffness of a laminated
composite structure under expected through-plane mechanical loads.
This may be useful for effectively handling a composite ply with
through-plane reinforcement that can easily deform during handling
in an un-cured state while forming an exterior shell for a
laminated composite structure.
[0085] Still another set of embodiments is generally directed to a
composite ply with through-plane oriented particles with hardness
and/or chemical stability. In some cases, the through-plane
reinforcement can significantly improve the polymer matrix's
resistance to damage from mechanical wear (e.g. abrasion) and/or
chemical corrosion (e.g. oxidization). This formulation may be
useful, for example, for forming surfaces that protect structures
from mechanical and chemical wear.
[0086] In one set of embodiments, a composite ply is provided
having enhanced through-plane electrical conductivity. This can
significantly improve the resistance to damage caused by localized
heat generation induced by charge accumulation upon rapid discharge
of electrical energy (e.g. lightning). This formulation is
particularly useful for forming surfaces that protect structures
from damage from electrical discharge. In another set of
embodiments, a composite ply with enhanced near-isotropic
electrical conductivity is provided. This may effectively conduct
electrical signals. In yet another set of embodiments, a composite
ply is provided with enhanced isotropic electrical conductivity.
This material may effectively attenuate incident electromagnetic
waves. In still another set of embodiments, a composite ply is
provide having low radio-frequency interference and enhanced
through-plane thermal conductivity to effectively transmit
electromagnetic waves without overheating.
[0087] Another set of embodiments is generally directed to a
composite ply with enhanced through-plane thermal conductivity for
sufficient structural integrity under heating. This may be useful
in some embodiments for increasing structural integrity under rapid
temperature fluctuations. Still another set of embodiments is
generally directed to a composite ply with through-plane thermal
conductivity and low electrical conductivity. This formulation may
be useful for effectively moving and distributing heat flux, e.g.,
in electronics.
[0088] Yet another set of embodiments is generally directed to a
carbon-based composite ply with through-plane electrical
conductivity. This may be useful for adsorbing ionic species from
an electrolyte and efficiently distributing electrical charge.
[0089] One set of embodiments is generally directed to a composite
ply with through-plane carbon fiber catalysts. At appropriate
temperatures, a PAN (polyacrylonitrile) matrix may be oxidized and
carbonized to form a carbon matrix. Another set of embodiments is
generally directed to a composite ply with through-plane carbon
fiber or silicon carbide catalysts. At appropriate temperatures,
the polymer matrix may be oxidized to form a ceramic matrix.
[0090] In addition, in some aspects, the present invention is
generally directed to the following:
1. A process for making a fiber-reinforced composite, comprising
providing continuous fibers, or a combination comprising at least
one of the foregoing: combining continuous fibers, or a combination
comprising at least one of the foregoing, in a dispersed phase
within discontinuous fibers, inorganic crystals or a combination
comprising at least one of the foregoing particulate filler
including, without limitation, uncoated, silane coupling agent
coated, organometallic coupling agent coated, ferromagnetic
material, specifically containing oxides of iron, nickel, cobalt,
an alloy of a rare earth metal, or a combination comprising at
least one of the foregoing coated discontinuous fibers and
inorganic crystals and compounds with a thermosetting prepolymer
and an optional volatile organic compound to provide a curable
mixture; forming the curable mixture with a dispersed phase in the
form of continuous fibers, or a combination comprising at least one
of the foregoing into a layer material comprising opposing first
and second layer surfaces; and applying a magnetic field in the
presence of a static electromagnet to the layer material;
mechanically vibrating the layer material in the parallel,
orthogonal, or a combination comprising at least one of the
foregoing directions relative to the plane of the opposing layer
surfaces; heating the layer material, optionally uniformly; and
partially or completely curing the layer material to form a
flexible or rigid fiber-reinforced composite. 2. The process of
sentence 1, wherein the application of a magnetic field and/or
mechanical vibration comprises dispersing the particulate fillers
within the voids of the continuous fiber matrix. 3. The process of
sentence 1 or 2, wherein the application of a magnetic field and/or
mechanical vibration comprises aligning the particulate fillers
exceedingly in the direction orthonormal to the planar orientation
of the continuous fiber matrix. 4. The process of any one or more
of sentences 1 to 3, wherein the application of a magnetic field
and/or mechanical vibration comprises aligning the particulate
fillers exceedingly in the direction orthonormal of the opposing
layer surfaces. 5. The process of any or more of sentences 1 to 4,
wherein the application of the magnetic field is concurrent or
subsequent to the application of mechanical vibration, preferably
concurrently. 6. The process of any one or more of sentences 1 to
5, wherein the application of magnetic field is with a magnetic
field strength of 1 to 5000 millitesla. 7. The process of any one
or more of sentences 1 to 6, wherein the application of a magnetic
field is with a standard deviation of the angle of the magnetic
field lines of 0.degree. to 30.degree.. 8. The process of any one
or more of sentences 1 to 7, wherein the application of mechanical
vibration comprises reciprocating motion of frequency 1 to 500
hertz. 9. The process of any one or more of sentences 1 to 8,
wherein the application of mechanical vibration comprises
reciprocating motion of amplitude 1 to 5,000 microns. 10. The
process of any one more of sentences 1 to 9, wherein the uniform
heating of the layer material of continuous fiber matrix in a
dispersed phase within the curable mixture in the presence of a
thermoelectric transducer including, without limitation, an Ohmic
heater, a Peltier device, or a combination comprising at least one
of the foregoing decreases the viscosity of the curable mixture.
11. The process of any one or more of sentences 1 to 10, wherein
the application of uniform heating to the layer material and
curable mixture is prior, concurrent or subsequent to the
application of magnetic field and/or mechanical vibration. 12. The
process of any one or more of sentences 1 to 11, wherein the
application of uniform heating to the layer material and curable
mixture prevents or initiates cross-linking or curing of the
prepolymer (e.g., the thermosetting prepolymer). 13. The process of
any one or more of sentences 1 to 12, wherein the application of
uniform heating comprises of temperature of 10.degree. C. to
300.degree. C. 14. The process of any one or more of sentences 1 to
13, wherein the application of magnetic field, mechanical
vibration, and/or uniform heating to the layer material of
continuous fiber matrix in a dispersed phase within the curable
mixture is implemented on substrates including, without limitation,
flexible polymer foil, flexible metal foil, flexible paper or a
combination comprising at least one of the foregoing. 15. The
process of any one or more of sentences 1 to 14 wherein the
continuous fiber matrix in a dispersed phase within the curable
mixture of the layer material is in a pattern form of
unidirectional, bidirectional, or a combination comprising at least
one of the foregoing. 16. The process of any one or more of
sentences 1 to 15, wherein the particulate fillers of the curable
mixture are in the form of discontinuous fibers, platelets,
nanotubes, nanofibers, nanosheets, or a combination comprising at
least one of the foregoing. 17. The process of any one or more of
sentences 1 to 16, wherein the particulate fillers of the curable
mixture of the layer material have an average particle size of 0.1
to 500 microns. 18. The process of any one or more of sentences 1
to 17, wherein the particulate fillers of the curable mixture of
the layer material are agglomerated particles or individual primary
particles. 19. The process of any one or more of sentences 1 to 18,
wherein the particulate fillers of the curable mixture of the layer
material possess a general aspect ratio, defined as the ratio of
fiber length to diameter, between 5 and 100,000. 20. The process of
any one or more of sentences 1 to 19, wherein the continuous fiber
matrix in a dispersed phase within the curable mixture of the layer
material. 21. The process of any one or more of sentences 1 to 20,
wherein the particulate fillers of the curable mixture of the layer
material. 22. The process of any one or more of sentences 1 to 21,
wherein the particulate fillers of the curable mixture of the layer
material exhibit a physical response to electromagnetic fields. 23.
The process of any one or more of sentences 1 to 22, wherein the
particulate fillers are aligned to a greater degree orthonormal to
the planar orientation of the continuous fiber matrix. 24. The
process of any one or more of sentences 1 to 23, wherein the
average thickness of the later material is 0.1 to 5,000 microns,
preferably 10 to 2,000 microns, most preferably 50 to 1,000
microns. 25. The process of any one or more of sentences 1 to 24,
wherein the continuous fiber matrix in a dispersed phase within the
curable mixture of the layer material comprises 5 to 75 volume
percent of the total volume of the layer material. 26. The process
of any one or more of sentences 1 to 25, wherein the particulate
fillers of the curable mixture of the layer material comprises 5 to
82 volume percent of the total volume of the layer material. 27.
The process of any one or more of sentences 1 to 26, wherein the
curable mixture of the layer material comprises an organic volatile
compound. 28. The process of any one or more of sentences 1 to 27,
wherein the curable mixture of the layer material comprises a
hardener and a curing catalyst. 29. The process of any one or more
of sentences 1 to 28, wherein the thermosetting prepolymer of the
curable mixture of the layer material. 30. A fiber-reinforced
composite layer material made by the process of any one or more of
sentences 1 to 29. 31. A mechanical system subassembly comprising
of a single layer or multiple layers of a fiber-reinforced
composite, comprising providing continuous fibers; combined the
continuous fibers, in a dispersed phase within discontinuous
fibers, inorganic crystals or a combination comprising at least one
of the foregoing particulate filler including, without limitation,
uncoated, silane coupling agent coated, organometallic coupling
agent coated, ferromagnetic material, specifically containing
oxides of iron, nickel, cobalt, an alloy of a rare earth metal, or
a combination comprising at least one of the foregoing coated
discontinuous fibers and inorganic crystals and compounds with a
thermosetting prepolymer and an optional volatile organic compound
to provide a curable mixture; forming the curable mixture with a
dispersed phase in the form of continuous fibers into a layer
material comprising opposing first and second layer surfaces;
applying a magnetic field in the presence of a static electromagnet
to the layer material; mechanically vibrating the layer material in
the parallel, orthogonal, or a combination comprising at least one
of the foregoing directions relative to the plane of the opposing
layer surfaces; uniformly heating the layer material; and partially
or completely curing the layer material to form a flexible or rigid
fiber-reinforced composite.
[0091] U.S. Provisional Patent Application Ser. No. 62/475,667,
filed Mar. 23, 2017, entitled "Fiber-Reinforced Composites, Methods
Therefore And Articles Comprising The Same," is hereby incorporated
herein by reference in its entirety.
[0092] The following examples are intended to illustrate certain
embodiments of the present invention, but do not exemplify the full
scope of the invention.
Example 1
[0093] Fiber-reinforced composites (e.g. carbon fiber composites)
are typically constructed with continuous fibers that are bundled
into tows, assembled into woven or non-woven fabrics, and encased
in a resin matrix. Specifically, carbon fiber composites formed
into layers or plies offer exceptional strength in the direction of
the strong-axis of the carbon fibers (e.g. in-plane) but are
drastically weaker when loads are applied perpendicular to the
fibers (e.g. through-plane). While, these composite plies are
laminated to create a structure with excellent bulk in-plane
properties, the lack of through-thickness reinforcement makes the
laminated composite structure especially prone to interlaminar
micro-cracks and through-ply fissures. These cracks and fissures
degrade the integrity of the component and can eventually result in
the delamination and catastrophic failure of the carbon fiber
composite structure.
Example 2
[0094] This prophetic example illustrates a solvent dispersion
method useful for making a composite according to certain
embodiments of the invention. Magnetized particles (e.g.
discontinuous fibers of carbon, basalt, silicon carbide, silicon
nitride, aramid, zirconia, nylon, boron, alumina, silica,
borosilicate, or mullite or platelets of alumina, boron nitride, or
graphite with at least one long axis less than 1 millimeter) can be
dispersed in a liquid-phase solvent of volatile organic compound
(e.g. isopropanol, butanol, ethanol, acetone, toluene, or xylenes),
and/or water to form a slurry. The magnetized particles account for
at most 85 percent by volume of the slurry in this example.
[0095] The slurry is deposited onto a woven (e.g. bi-directional,
multi-directional, or quasi-isotropic) or non-woven (e.g.,
uni-directional, veil, or mat) fabric of carbon, basalt, silicon
carbide, aramid, zirconia, nylon, boron, alumina, silica,
borosilicate, mullite, cotton, or any natural or synthetic
long-fibers. The slurry wets, coats, and/or surrounds the
continuous fibers of the fabric.
[0096] The fabric containing the slurry is then exposed to a
magnetic field of at most 10 teslas in field strength in this
example. The magnetic field aligns the magnetized particles within
the fabric in the direction of the magnetic field. After alignment,
the fabric is heated to evaporate the bulk solvent of the slurry,
resulting in dry ply material with through-plane aligned particles
embedding and/or coating the fabric.
[0097] Subsequently, the dry ply material is coated with a
liquid-phase binder (e.g. epoxy, polyester, vinyl ester,
polyethylenimine, polyetherketoneketone, polyaryletherketone,
polyether ether ketone, polyphenylene sulfide, polyethylene
terephthalate, polycarbonates, poly(methyl methacrylate),
acrylonitrile butadiene styrene, polyacrylonitrile, polypropylene,
polyethylene, nylon, silicone rubbers, polyvinylidene fluoride,
styrene butadiene rubber, or pre-ceramic polymer). The liquid-phase
binder effectively wets the dry ply material to produce a
pre-impregnated composite ply material.
[0098] This process may result in a high aligned particle content
(up to 85 percent of total composite ply volume). Additionally, the
solvent of the slurry can be removed prior to application of the
liquid-phase binder, which may avoid issues with chemical
incompatibility between the binder and the solvent. In some cases,
this process may be useful for certain types of precursor dry ply
material that is weak and brittle prior to the application of the
liquid-phase binder.
Example 3
[0099] This prophetic example illustrates a resin dispersion method
useful for making a composite according to certain embodiments of
the invention. Magnetized particles (e.g. discontinuous fibers of
carbon, basalt, silicon carbide, silicon nitride, aramid, zirconia,
nylon, boron, alumina, silica, borosilicate, or mullite or
platelets of alumina, boron nitride, or graphite with at least one
long axis less than 1 millimeter) are dispersed in a liquid-phase
binder (e.g. epoxy, polyester, vinyl ester, polyethylenimine,
polyetherketoneketone, polyaryletherketone, polyether ether ketone,
polyphenylene sulfide, polyethylene terephthalate, polycarbonates,
poly(methyl methacrylate), acrylonitrile butadiene styrene,
polyacrylonitrile, polypropylene, high-density polyethylene, nylon,
silicone rubbers, polyvinylidene fluoride, styrene butadiene
rubber, or pre-ceramic polymer). The magnetized particles account
for at most 80 percent by volume of the slurry in this example.
[0100] For slurries with magnetic particle content exceeding 10
percent by volume of the slurry, an additional solvent thinner
comprised of liquid-phase of volatile organic compound (e.g.
isopropanol, butanol, ethanol, acetone, toluene, or xylenes), oil
and/or water can be introduced to the slurry to assist in
homogenously dispersing the magnetized particles into the
liquid-phase binder.
[0101] The slurry is deposited onto a woven (e.g. bi-directional,
multi-directional, or quasi-isotropic) or non-woven (e.g.,
uni-directional, veil, or mat) fabric of carbon, basalt, silicon
carbide, aramid, zirconia, nylon, boron, alumina, silica,
borosilicate, mullite, cotton, or any natural or synthetic
long-fibers. The slurry wets, coats, and surrounds the continuous
fibers of the fabric.
[0102] The fabric containing the slurry is then exposed to a
magnetic field of at most 10 teslas in field strength in this
example. The magnetic field aligns the magnetized particles within
the fabric in the through-plane direction.
[0103] During and/or after alignment, the fabric is heated to
evaporate the bulk solvent thinner, resulting in a composite ply
material with a liquid-phase binder. The composite ply material is
either further heated or cooled to consolidate the composite ply
material by solidifying, hardening, gelling, or freezing the
liquid-phase binder to produce a pre-impregnated composite ply
material.
[0104] This process may result in a low aligned particle content
(up to 20 percent of total composite ply volume). Additionally, the
lack of a solvent during processing of low particle loading
slurries may allow streamlined manufacturing with minimal solvent
fume management and lower emissions. A solvent thinner may be used
to disperse particles into the liquid-phase binder. This process
also may use heating of the produced material after the
liquid-phase binder has been added to remove the solvent.
Example 4
[0105] This prophetic example illustrates various formulations for
eliminating or reducing stress concentrations. Particles (e.g.
discontinuous fibers of carbon, borosilicate, or nylon with at
least one long axis less than 1 millimeter) coat and/or embed a
woven (e.g. bi-directional, multi-directional, or quasi-isotropic)
fabric comprised of carbon, borosilicate, or nylon and embedded in
a matrix of epoxy, polyester, vinyl ester, polyether ether ketone
(PEEK), acrylonitrile butadiene styrene (ABS), high-density
polyethylene (HDPE), or nylon. The particles are transversely
oriented to the continuous fibers of the fabric.
[0106] This formulation may be used to provide a composite ply with
at least three axes of fiber orientation. This fiber structure
allows the composite ply to efficiently distribute stresses between
subsequent plies and adjacent components, which may reduce or
eliminate the accumulations of stress concentrations. The reduction
or elimination of stress concentrations can significantly improve
the strength of a laminated composite structure under dynamic
loads. This formulation may be useful when a laminated composite
structure is formed with small features or mates with a material
with drastically different stiffness (e.g. metal alloys or
plastics). Example applications include dome reinforcement for Type
III, IV, and V pressure vessels, wing tips and trailing/leading
edges for wind turbines, hydrofoils for marine vehicles,
aerodynamic winglets for automobiles, and aerostructure bolt/rivet
fastener attachments for aircrafts.
Example 5
[0107] This prophetic example illustrates various formulations for
eliminating or reducing delamination. Particles (e.g. discontinuous
fibers of carbon, borosilicate, or nylon with at least one long
axis less than 1 millimeter) coat and/or embed a non-woven (e.g.
uni-directional, veil, or mat) fabric comprised of carbon,
borosilicate, or nylon and embedded in a matrix of epoxy,
polyester, vinyl ester, polyether ether ketone (PEEK),
acrylonitrile butadiene styrene (ABS), high-density polyethylene
(HDPE), or nylon. The particles are transversely oriented to the
continuous fibers of the fabric.
[0108] This formulation may provide a composite ply with
through-plane reinforcement of the interlaminar region. This fiber
reinforcement allows the composite ply to efficiently distribute
stresses between adjacent layers to hinder the formation of cracks
and prevents a crack from propagating in the interlaminar region.
The targeted reinforcement of the interlaminar region can
significantly improve the strength of a laminated composite
structure under shock and cyclic loads. This formulation may be
useful when a laminated composite structure is formed with long
sheets of composite ply, for example, where a single crack in the
interlaminar region between the plies can compromise the structural
integrity of the overall structure. Example applications include
over-wraps for Type III, IV, and V pressure vessels, spars for wind
turbines, hulls for marine vehicles, chassis panels for
automobiles, and wings, and turbine fan blades for aircrafts.
Example 6
[0109] This prophetic example illustrates various formulations for
through-plane strength and stiffness. Particles (e.g. discontinuous
fibers of carbon or borosilicate with at least one long axis less
than 1 millimeter) coat and/or embed a woven (e.g. bi-directional
scrim) fabric comprised of borosilicate or nylon and embedded in a
matrix of epoxy, polyester, vinyl ester, polyether ether ketone
(PEEK), acrylonitrile butadiene styrene (ABS), high-density
polyethylene (HDPE), or nylon. The particles comprise over 50
percent by volume of the overall composite and are transversely
oriented to the continuous fibers of the fabric in this
example.
[0110] This formulation provides a composite ply with through-plane
reinforcement, e.g., as a through-plane uni-directional fabric.
This fiber reinforcement targets through-plane loads (e.g. point
loads and high-pressure loads) and the scrim fabric offers minimal
in-plane reinforcement. The targeted through-plane reinforcement
can significantly improve the strength and stiffness of a laminated
composite structure under expected through-plane mechanical
loads.
[0111] This formulation may be useful for effectively handling a
composite ply with through-plane reinforcement that can easily
deform during handling in an un-cured state while forming an
exterior shell for a laminated composite structure. Example
applications include repairs to the interior features of tooling
for injection molding, shims used in jacking heavy structures, and
surfaces of bats and sticks for sports.
Example 7
[0112] This prophetic example illustrates various formulations for
eliminating or reducing surface wear. Particles (e.g. discontinuous
fibers of silicon carbide, silicon nitride, zirconia, boron,
alumina, silica, or micro-platelets of alumina, boron nitride with
at least one long axis less than 1 millimeter) coat and/or embed a
woven (e.g. bi-directional, multi-directional, or quasi-isotropic)
fabric comprised of carbon, borosilicate, or nylon and embedded in
a matrix of epoxy, polyester, vinyl ester, polyether ether ketone
(PEEK), acrylonitrile butadiene styrene (ABS), high-density
polyethylene (HDPE), or nylon. The particles are transversely
oriented to the continuous fibers of the fabric.
[0113] This formulation provides a composite ply with through-plane
oriented particles with excellent hardness and/or chemical
stability. The through-plane reinforcement can significantly
improve the polymer matrix's resistance to damage from mechanical
wear (e.g. abrasion) and/or chemical corrosion (e.g. oxidization).
This formulation may be useful for forming surfaces that protect
structures from mechanical and chemical wear. Example applications
include Class A surfaces for automobiles, skins for aircrafts, and
panels for buildings.
Example 8
[0114] This prophetic example illustrates various formulations for
dissipating electrical shocks. Particles (e.g. discontinuous fibers
of carbon or micro-platelets of graphite with at least one long
axis less than 1 millimeter) coat and/or embed a woven (e.g.
bi-directional, multi-directional, or quasi-isotropic) fabric
comprised of carbon and embedded in a matrix of epoxy, polyester,
vinyl ester, polyether ether ketone (PEEK), acrylonitrile butadiene
styrene (ABS), high-density polyethylene (HDPE), or nylon. The
particles are transversely oriented to the fibers of the fabric.
The particles comprise over 50 percent by volume of the overall
composite and are transversely oriented to the continuous fibers of
the fabric.
[0115] This formulation provides a composite ply with enhanced
through-plane electrical conductivity and can significantly improve
the resistance to damage caused by localized heat generation
induced by charge accumulation upon rapid discharge of electrical
energy (e.g. lightning). This formulation may be useful for forming
surfaces that protect structures from damage from electrical
discharge. Example applications are skins and leading/trailing
edges for aircrafts and wind turbines.
Example 9
[0116] This prophetic example illustrates various formulations for
transmitting electrical signals. Particles (e.g. discontinuous
fibers of carbon or micro-platelets of graphite with at least one
long axis less than 1 millimeter) coat and/or embed a non-woven
(e.g. uni-directional, veil, or mat) fabric comprised of carbon and
embedded in a matrix of epoxy, polyester, vinyl ester, polyether
ether ketone (PEEK), acrylonitrile butadiene styrene (ABS),
high-density polyethylene (HDPE), or nylon. The particles are
transversely oriented to the continuous fibers of the fabric.
[0117] This formulation provides a composite ply with enhanced
near-isotropic electrical conductivity and can effectively conduct
electrical signals across long and through thick composite
structures. Example applications are aircraft and wind turbine
de-icing systems that implement ohmic heating to prevent
accumulation of ice and composite health monitoring systems that
implement electrical signals to detect delamination within thick
and/or long laminated composite structures.
Example 10
[0118] This prophetic example illustrates various formulations for
attenuating electromagnetic waves. Particles (e.g. discontinuous
fibers of carbon or micro-platelets of graphite with at least one
long axis less than 1 millimeter) coat and/or embed a woven (e.g.
bi-directional, multi-directional, or quasi-isotropic) fabric
comprised of carbon and embedded in a matrix of epoxy, polyester,
vinyl ester, polyether ether ketone (PEEK), acrylonitrile butadiene
styrene (ABS), high-density polyethylene (HDPE), or nylon. The
particles are transversely oriented to the continuous fibers of the
fabric.
[0119] This formulation provides a composite ply with enhanced
isotropic electrical conductivity and can effectively attenuate
incident electromagnetic waves. Example applications are skins for
aircrafts that absorb radar signals for stealth.
Example 11
[0120] This prophetic example illustrates various formulations for
transmitting electromagnetic waves. Particles (e.g. micro-platelets
of alumina or boron nitride with at least one long axis less than 1
millimeter) coat and/or embed a woven (e.g. bi-directional,
multi-directional, or quasi-isotropic) fabric comprised of
borosilicate and embedded in a matrix of polypropylene (PP) and
polyethylene (PE). The particles are transversely oriented to the
continuous fibers of the fabric.
[0121] This formulation provides a composite ply with low
radio-frequency interference and enhanced through-plane thermal
conductivity to effectively transmit electromagnetic waves without
overheating. Example applications include radomes for
telecommunications.
Example 12
[0122] This prophetic example illustrates various formulations for
dissipating thermal shocks. Particles (e.g. e.g. discontinuous
fibers of carbon, silicon carbide, silicon nitride, alumina, or
micro-platelets of alumina, boron nitride, or graphite with at
least one long axis less than 1 millimeter) coat and/or embed a
woven (e.g. bi-directional, multi-directional, or quasi-isotropic)
fabric comprised of carbon and embedded in a matrix of epoxy,
polyester, vinyl ester, polyether ether ketone (PEEK),
acrylonitrile butadiene styrene (ABS), polypropylene (PP),
polyethylene (PE), nylon. The particles are transversely oriented
to the continuous fibers of the fabric.
[0123] This formulation provides a composite ply with enhanced
through-plane thermal conductivity sufficient structural integrity.
This formulation may be useful to increase structural integrity
under rapid temperature fluctuations. Example applications are
skins for spacecraft during atmospheric re-entry and brake discs
for vehicles.
Example 13
[0124] This prophetic example illustrates various formulations for
eliminating or reducing thermal gradients. Particles (e.g. e.g.
micro-platelets of alumina or boron nitride with at least one long
axis less than 1 millimeter) coat and/or embed a woven (e.g.
bi-directional, multi-directional, or quasi-isotropic) fabric
comprised of carbon and embedded in a matrix of epoxy, polyester,
vinyl ester, polyether ether ketone (PEEK), acrylonitrile butadiene
styrene (ABS), high-density polyethylene (HDPE), nylon, or silicone
rubbers. The particles are transversely oriented to the continuous
fibers of the fabric. The particles comprise over 50 percent by
volume of the overall composite
[0125] This formulation provides a composite ply with excellent
through-plane thermal conductivity and low electrical conductivity.
This formulation may be useful for effectively moving and
distributing heat flux, e.g., in electronics. Example applications
include printed circuit board laminates, gap fillers, and
encapsulants for electronic devices.
Example 14
[0126] This prophetic example illustrates various formulations for
energy storage. Particles (e.g. discontinuous fibers of carbon or
micro-platelets of graphite with at least one long axis less than 1
millimeter) coat and/or embed a non-woven (e.g. uni-directional,
veil, or mat) fabric comprised of carbon embedded in a matrix of
polyvinylidene fluoride (PVDF) or styrene butadiene rubber (SBR).
The particles are transversely oriented to the continuous fibers of
the fabric. The particles comprise over 50 percent by volume of the
overall composite.
[0127] This formulation provides a carbon-based composite ply with
excellent through-plane electrical conductivity. This formulation
may be useful for adsorbing ionic species from an electrolyte
and/or efficiently distributing electrical charge. Example
applications include anodes for electrochemical batteries (e.g.
lithium-ion and sodium-ion cells) and electrodes for
supercapacitors.
Example 15
[0128] This prophetic example illustrates formulations for ex-PAN
carbon fiber synthesis. Particles (e.g. discontinuous fibers of
carbon with at least one long axis less than 1 millimeter) coat
and/or embed a fabric comprised of carbon embedded in a matrix of
polyacrylonitrile (PAN). The particles are transversely oriented to
the continuous fibers of the fabric.
[0129] This formulation provides a precursory composite ply with
through-plane carbon fiber catalysts. At appropriate temperatures,
the PAN matrix may oxidize and carbonize into a carbon matrix. This
formulation may be useful for creating ex-PAN carbon-carbon
composites with isotropic grains.
Example 16
[0130] This prophetic example illustrates formulations for ceramic
matrix composites (CMCs). Particles (e.g. discontinuous fibers of
carbon and silicon carbide with at least one long axis less than 1
millimeter) coat and/or embed a fabric comprised of carbon or
silicon carbide embedded in a matrix of preceramic monomers (e.g.
siloxane, silazane, or carbosilane) with thiol, vinyl, acrylate,
methacrylate, or epoxy R-groups. The particles are transversely
oriented to the fibers of the fabric.
[0131] This formulation may provide a precursory composite ply with
through-plane carbon fiber or silicon carbide catalysts. At
appropriate temperatures, the polymer matrix can oxidize into a
ceramic matrix. This formulation may be useful for creating ceramic
matrix composites with isotropic grains.
[0132] While several embodiments of the present invention have been
described and illustrated herein, those of ordinary skill in the
art will readily envision a variety of other means and/or
structures for performing the functions and/or obtaining the
results and/or one or more of the advantages described herein, and
each of such variations and/or modifications is deemed to be within
the scope of the present invention. More generally, those skilled
in the art will readily appreciate that all parameters, dimensions,
materials, and configurations described herein are meant to be
exemplary and that the actual parameters, dimensions, materials,
and/or configurations will depend upon the specific application or
applications for which the teachings of the present invention
is/are used. Those skilled in the art will recognize, or be able to
ascertain using no more than routine experimentation, many
equivalents to the specific embodiments of the invention described
herein. It is, therefore, to be understood that the foregoing
embodiments are presented by way of example only and that, within
the scope of the appended claims and equivalents thereto, the
invention may be practiced otherwise than as specifically described
and claimed. The present invention is directed to each individual
feature, system, article, material, kit, and/or method described
herein. In addition, any combination of two or more such features,
systems, articles, materials, kits, and/or methods, if such
features, systems, articles, materials, kits, and/or methods are
not mutually inconsistent, is included within the scope of the
present invention.
[0133] In cases where the present specification and a document
incorporated by reference include conflicting and/or inconsistent
disclosure, the present specification shall control. If two or more
documents incorporated by reference include conflicting and/or
inconsistent disclosure with respect to each other, then the
document having the later effective date shall control.
[0134] All definitions, as defined and used herein, should be
understood to control over dictionary definitions, definitions in
documents incorporated by reference, and/or ordinary meanings of
the defined terms.
[0135] The indefinite articles "a" and "an," as used herein in the
specification and in the claims, unless clearly indicated to the
contrary, should be understood to mean "at least one."
[0136] The phrase "and/or," as used herein in the specification and
in the claims, should be understood to mean "either or both" of the
elements so conjoined, i.e., elements that are conjunctively
present in some cases and disjunctively present in other cases.
Multiple elements listed with "and/or" should be construed in the
same fashion, i.e., "one or more" of the elements so conjoined.
Other elements may optionally be present other than the elements
specifically identified by the "and/or" clause, whether related or
unrelated to those elements specifically identified. Thus, as a
non-limiting example, a reference to "A and/or B", when used in
conjunction with open-ended language such as "comprising" can
refer, in one embodiment, to A only (optionally including elements
other than B); in another embodiment, to B only (optionally
including elements other than A); in yet another embodiment, to
both A and B (optionally including other elements); etc.
[0137] As used herein in the specification and in the claims, "or"
should be understood to have the same meaning as "and/or" as
defined above. For example, when separating items in a list, "or"
or "and/or" shall be interpreted as being inclusive, i.e., the
inclusion of at least one, but also including more than one, of a
number or list of elements, and, optionally, additional unlisted
items. Only terms clearly indicated to the contrary, such as "only
one of" or "exactly one of," or, when used in the claims,
"consisting of," will refer to the inclusion of exactly one element
of a number or list of elements. In general, the term "or" as used
herein shall only be interpreted as indicating exclusive
alternatives (i.e. "one or the other but not both") when preceded
by terms of exclusivity, such as "either," "one of," "only one of,"
or "exactly one of."
[0138] As used herein in the specification and in the claims, the
phrase "at least one," in reference to a list of one or more
elements, should be understood to mean at least one element
selected from any one or more of the elements in the list of
elements, but not necessarily including at least one of each and
every element specifically listed within the list of elements and
not excluding any combinations of elements in the list of elements.
This definition also allows that elements may optionally be present
other than the elements specifically identified within the list of
elements to which the phrase "at least one" refers, whether related
or unrelated to those elements specifically identified. Thus, as a
non-limiting example, "at least one of A and B" (or, equivalently,
"at least one of A or B," or, equivalently "at least one of A
and/or B") can refer, in one embodiment, to at least one,
optionally including more than one, A, with no B present (and
optionally including elements other than B); in another embodiment,
to at least one, optionally including more than one, B, with no A
present (and optionally including elements other than A); in yet
another embodiment, to at least one, optionally including more than
one, A, and at least one, optionally including more than one, B
(and optionally including other elements); etc.
[0139] When the word "about" is used herein in reference to a
number, it should be understood that still another embodiment of
the invention includes that number not modified by the presence of
the word "about."
[0140] It should also be understood that, unless clearly indicated
to the contrary, in any methods claimed herein that include more
than one step or act, the order of the steps or acts of the method
is not necessarily limited to the order in which the steps or acts
of the method are recited.
[0141] In the claims, as well as in the specification above, all
transitional phrases such as "comprising," "including," "carrying,"
"having," "containing," "involving," "holding," "composed of," and
the like are to be understood to be open-ended, i.e., to mean
including but not limited to. Only the transitional phrases
"consisting of" and "consisting essentially of" shall be closed or
semi-closed transitional phrases, respectively, as set forth in the
United States Patent Office Manual of Patent Examining Procedures,
Section 2111.03.
* * * * *