U.S. patent application number 15/671411 was filed with the patent office on 2019-02-14 for matrix-bonding abrasion resistant cnts (mbarcs) and employing same in fiber reinforced polymer composites.
The applicant listed for this patent is International Business Machines Corporation. Invention is credited to Sarah K. Czaplewski, Joseph Kuczynski, Jason T. Wertz, Jing Zhang.
Application Number | 20190048154 15/671411 |
Document ID | / |
Family ID | 65274634 |
Filed Date | 2019-02-14 |
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United States Patent
Application |
20190048154 |
Kind Code |
A1 |
Czaplewski; Sarah K. ; et
al. |
February 14, 2019 |
MATRIX-BONDING ABRASION RESISTANT CNTs (MBARCs) AND EMPLOYING SAME
IN FIBER REINFORCED POLYMER COMPOSITES
Abstract
A process of providing matrix-bonding abrasion resistant CNTs
(MBARCs) includes reacting functionalized carbon nanotubes (f-CNTs)
and Janus particles, wherein each of the Janus particles is a
silica particle having a surface with a first portion containing a
CNT-bonding functionality and a second portion containing a
matrix-bonding functionality. The CNT-bonding functionality may
include, for example, one or more hydroxyl groups. The
matrix-bonding functionality may be, for example, selected from a
group consisting of vinyl functionalities, amine functionalities,
epoxy functionalities, allyl functionalities, acrylate
functionalities, sulfur functionalities, isocyanate
functionalities, halogen functionalities, and combinations thereof.
In some embodiments, the MBARCs are processed to produce fibers
that, in turn, may be blended into a polymeric resin to produce a
fiber reinforced polymer composite.
Inventors: |
Czaplewski; Sarah K.;
(Rochester, MN) ; Kuczynski; Joseph; (North Port,
FL) ; Wertz; Jason T.; (Pleasant Valley, NY) ;
Zhang; Jing; (Poughkeepsie, NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
International Business Machines Corporation |
Armonk |
NY |
US |
|
|
Family ID: |
65274634 |
Appl. No.: |
15/671411 |
Filed: |
August 8, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C08J 5/06 20130101; C08J
5/042 20130101; C08J 5/005 20130101; C08J 5/04 20130101; C01B
32/174 20170801; C08J 2300/00 20130101; C01B 33/18 20130101 |
International
Class: |
C08J 5/06 20060101
C08J005/06; C01B 32/174 20060101 C01B032/174; C08J 5/04 20060101
C08J005/04 |
Claims
1. A method, comprising: providing a plurality of carbon nanotubes
(CNTs); functionalizing the plurality of CNTs to provide a
plurality of functionalized CNTs; providing a plurality of Janus
particles, wherein each of the plurality of Janus particles is a
silica particle having a surface with a first portion containing a
CNT-bonding functionality and a second portion containing a
matrix-bonding functionality; reacting the plurality of
functionalized CNTs and the plurality of Janus particles to produce
a plurality of matrix-bonding abrasion resistant CNTs (MBARCs).
2. The method as recited in claim 1, further comprising: processing
the plurality of MBARCs to produce at least one fiber.
3. The method as recited in claim 2, further comprising: blending
the at least one fiber into a polymeric resin to produce a fiber
reinforced polymer composite, wherein the matrix-bonding
functionality is tailored for blending and bonding into a polymer
matrix produced by the polymeric resin.
4. The method as recited in claim 1, wherein the silica particle is
a silica nanoparticle.
5. The method as recited in claim 1, wherein the CNT-bonding
functionality includes one or more hydroxyl groups.
6. The method as recited in claim 5, wherein the matrix-bonding
functionality is selected from a group consisting of vinyl
functionalities, amine functionalities, epoxy functionalities,
allyl functionalities, acrylate functionalities, sulfur
functionalities, isocyanate functionalities, halogen
functionalities, and combinations thereof.
7. The method as recited in claim 1, wherein the matrix-bonding
functionality is selected from a group consisting of vinyl
functionalities, amine functionalities, epoxy functionalities,
allyl functionalities, acrylate functionalities, sulfur
functionalities, isocyanate functionalities, halogen
functionalities, and combinations thereof.
8. The method as recited in claim 1, wherein the CNT-bonding
functionality includes residual hydroxyl groups that remain on the
first portion of the surface of the silica particle after surface
modification of the second portion of the surface of the silica
particle to include the matrix-bonding functionality.
9. The method as recited in claim 8, wherein the matrix-bonding
functionality is selected from a group consisting of vinyl
functionalities, amine functionalities, epoxy functionalities,
allyl functionalities, acrylate functionalities, sulfur
functionalities, isocyanate functionalities, halogen
functionalities, and combinations thereof.
10. A matrix-bonding abrasion resistant carbon nanotube (MBARC),
comprising: a carbon nanotube (CNT) having one or more silica
particles covalently bonded to a surface thereof, wherein each of
the one or more silica particles has a surface with a portion
containing a matrix-bonding functionality.
11. The matrix-bonding abrasion resistant carbon nanotube (MBARC)
as recited in claim 10, wherein the silica particle is a silica
nanoparticle.
12. The matrix-bonding abrasion resistant carbon nanotube (MBARC)
as recited in claim 11, wherein the matrix-bonding functionality is
selected from a group consisting of vinyl functionalities, amine
functionalities, epoxy functionalities, allyl functionalities,
acrylate functionalities, sulfur functionalities, isocyanate
functionalities, halogen functionalities, and combinations
thereof.
13. The matrix-bonding abrasion resistant carbon nanotube (MBARC)
as recited in claim 11, wherein the matrix-bonding functionality is
one or more vinyl functionalities.
14. The matrix-bonding abrasion resistant carbon nanotube (MBARC)
as recited in claim 10, wherein the MBARC is produced by a method,
comprising: providing a carbon nanotube (CNT); functionalizing the
CNT to provide a functionalized CNT; providing a plurality of Janus
particles, wherein each of the plurality of Janus particles is a
silica particle having a surface with a first portion containing a
CNT-bonding functionality and a second portion containing the
matrix-bonding functionality; reacting the functionalized CNT and
the plurality of Janus particles to produce the MBARC.
15. A fiber reinforced polymer composite, comprising: a polymeric
resin; a plurality of fibers blended into the polymeric resin,
wherein each of the plurality of fibers comprises matrix-bonding
abrasion resistant carbon nanotubes (MBARCs), wherein each of the
MBARCs comprises a carbon nanotube (CNT) having one or more silica
particles covalently bonded to a surface thereof, wherein each of
the one or more silica particles is covalently bonded to a polymer
matrix formed by the polymeric resin.
16. The fiber reinforced polymer composite as recited in claim 15,
wherein the silica particle is a silica nanoparticle.
17. The fiber reinforced polymer composite as recited in claim 15,
wherein each of the MBARCs is produced by a method, comprising:
providing a plurality of carbon nanotubes (CNTs); functionalizing
the plurality of CNTs to provide a plurality of functionalized
CNTs; providing a plurality of Janus particles, wherein each of the
plurality of Janus particles is a silica particle having a surface
with a first portion containing a CNT-bonding functionality and a
second portion containing a matrix-bonding functionality; reacting
the plurality of functionalized CNTs and the plurality of Janus
particles to produce a plurality of the MBARCs.
Description
BACKGROUND
[0001] The present invention relates in general to the field of
materials science. More particularly, the present invention relates
to matrix-bonding abrasion resistant CNTs (MBARCs) that may be
processed to produce fibers that, in turn, may be blended with a
polymeric resin to produce a fiber reinforce polymer composite.
SUMMARY
[0002] In accordance with an embodiment, a process of providing
matrix-bonding abrasion resistant CNTs (MBARCs) includes reacting
functionalized carbon nanotubes (f-CNTs) and Janus particles,
wherein each of the Janus particles is a silica particle having a
surface with a first portion containing a CNT-bonding functionality
and a second portion containing a matrix-bonding functionality. The
CNT-bonding functionality may include, for example, one or more
hydroxyl groups. The matrix-bonding functionality may be, for
example, selected from a group consisting of vinyl functionalities,
amine functionalities, epoxy functionalities, allyl
functionalities, acrylate functionalities, sulfur functionalities,
isocyanate functionalities, halogen functionalities, and
combinations thereof. In some embodiments, the MBARCs are processed
to produce fibers that, in turn, may be blended into a polymeric
resin to produce a fiber reinforced polymer composite.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0003] Embodiments of the present invention will hereinafter be
described in conjunction with the appended drawings, where like
designations denote like elements. Elements are not necessarily
scaled with respect to each other.
[0004] FIG. 1 is a flow diagram illustrating a process of producing
Janus particles, according to some embodiments.
[0005] FIG. 2 is a block diagram showing a particular embodiment of
a synthetic procedure for producing silica particles that may be
utilized in the process of FIG. 1.
[0006] FIG. 3 is a block diagram showing a particular embodiment of
a synthetic procedure for masking silica particles that may be
utilized in the process of FIG. 1.
[0007] FIG. 4 is a block diagram showing a particular embodiment of
a synthetic procedure for functionalizing masked silica particles
that may be utilized in the process of FIG. 1.
[0008] FIG. 5 is a block diagram showing a particular embodiment of
a synthetic procedure for de-masking functionalized silica
particles that may be utilized in the process of FIG. 1.
[0009] FIG. 6 is a block diagram illustrating a synthetic procedure
for functionalizing CNTs, according to some embodiments.
[0010] FIG. 7 is a block diagram illustrating a synthetic procedure
for preparing matrix-bonding abrasion resistant CNTs (MBARCs) by
reacting Janus particles and functionalized CNTs, according to some
embodiments.
[0011] FIG. 8 is a flow diagram illustrating a process of preparing
a fiber reinforced polymer composite, according to some
embodiments.
[0012] FIG. 9 is a partial, sectional view of a fiber reinforced
polymer composite, according to some embodiments.
DETAILED DESCRIPTION
[0013] The present disclosure describes matrix-bonding abrasion
resistant CNTs (MBARCs) provided by a process that includes
reacting functionalized carbon nanotubes (f-CNTs) and Janus
particles, wherein each of the Janus particles is a silica particle
having a surface with a first portion containing a CNT-bonding
functionality and a second portion containing a matrix-bonding
functionality. The CNT-bonding functionality may include, for
example, one or more hydroxyl groups. The matrix-bonding
functionality may be, for example, selected from a group consisting
of vinyl functionalities, amine functionalities, epoxy
functionalities, allyl functionalities, acrylate functionalities,
sulfur functionalities, isocyanate functionalities, halogen
functionalities, and combinations thereof. In some embodiments, the
MBARCs are processed to produce fibers that, in turn, may be
blended into a polymeric resin to produce a fiber reinforced
polymer composite.
[0014] In some embodiments, silica Janus particles are reacted with
functionalized carbon nanotubes (f-CNTs). The use of silica Janus
particles in accordance with some embodiments of the present
invention is advantageous because it simultaneously allows silica
particles to be bound to CNTs (via the CNT-bonding functionality of
the silica Janus particles) to impart abrasion resistance, while
also allowing for binding into a resin (via the matrix-bonding
functionality of the silica Janus particles) to improve modulus and
stiffness.
[0015] In an example application, MBARCs of the present disclosure
may be processed to produce fibers that may be blended into a
polymeric resin to produce a fiber reinforced polymer composite
that satisfies particular performance characteristics. For example,
MBARCs of the present disclosure may be used to produce a fiber
reinforced polymer composite that can withstand contact against
polyethylene terephthalate (PET) under high pressure and velocity
(e.g., 6 MPa and 50 m/min, respectively). Fiber reinforced polymer
composites produced using MBARC-containing fibers of the present
disclosure may, for example, exhibit a stiffness (flexural modulus)
of 30 GPa and an abrasion resistance substantially equivalent to
that of zinc. Fiber reinforced polymer composites produced by
blending MBARC-containing fibers of the present disclosure into a
polymeric resin may be, for example, injection molded with a
production cycle time of roughly 20 seconds.
[0016] In numerous applications, manufacturers seek to substitute
engineered plastic components for metal components. Typically, this
substitution reduces the weight and increases the productivity of
the component. Various manufacturers are attempting to develop
high-performance plastic materials, with a particular focus on
glass fiber reinforced polyamide composite materials, to achieve
the required stiffness and abrasion resistance performance for
successful replacement of metal components.
[0017] Several techniques may be used to increase the modulus of
polyamide resins. Most notable among these is the use of long glass
(or high aspect ratio) fiber. The benefits of long fiber or high
aspect ratio fiber (e.g., length:diameter=800:1) are well known to
those skilled in the art. Unfortunately, simply loading polyamide
resin with the maximum workable level of long glass fibers does not
achieve the desired properties. Consequently, an alternative
approach is required. Other approaches to increase the modulus of
polyamide resins include the use of braided CNTs, coating carbon
fiber with a non-conductive silica, and thermal spraying of ceramic
coatings on glass or carbon fiber. None of these approaches,
however, achieves the desired properties.
[0018] In accordance with some embodiments of the present
disclosure, high aspect ratio CNTs with a "hard coat" of silica
functionality are utilized. This silica functionality may be
provided by employing Janus particles, for example, that not only
have a CNT-bonding functionality for bonding to the high aspect
ratio CNT but, additionally, have a matrix-bonding functionality
for bonding to a polymer matrix.
Prophetic Preparation of Silica Janus Particles with CNT-Bonding
Functionality and Matrix-Bonding Functionality
[0019] FIG. 1 is a flow diagram illustrating a process 100 of
producing Janus particles with a CNT-bonding functionality and a
matrix-bonding functionality, according to some embodiments. In the
process 100, the steps discussed below (steps 105-120) are
performed. These steps are set forth in their preferred order. It
must be understood, however, that the various steps may occur
simultaneously or at other times relative to one another. Moreover,
those skilled in the art will appreciate that one or more steps may
be omitted.
[0020] A Janus particle is a microscopic particle, typically a
nanoparticle, having at least two distinct faces with different
chemical and/or physical properties. For example, a Janus particle
may be a spherical nanoparticle having a hydrophilic hemisphere and
a hydrophobic hemisphere. Janus particles are named after the
two-faced Roman god Janus. The synthesis of Janus nanoparticles
requires the ability to selectively generate each face of a
nanometer-sized particle with different chemical and/or physical
properties. Janus nanoparticles may be synthesized using any of
several competing methods including, but not limited to, masking,
self-assembly, and phase separation. Thus, while masking is used in
the process 100, one skilled in the art will appreciated that other
methods of producing Janus particles may be used in lieu of, or in
addition to, masking.
[0021] As noted above, masking is used in the process 100. Masking
involves the protection of one side of a nanoparticle (e.g., molten
paraffin wax is mixed into a solution containing silica
nanoparticles and the solution subsequently cooled to solidify the
wax, thereby trapping one half of each silica nanoparticle in the
wax surface and leaving the other half of each silica nanoparticle
exposed outside the wax surface), followed by the modification of
the unprotected side of the nanoparticle, and subsequent removal of
the protection. The mask is typically made of paraffin wax.
However, other suitable masking materials may be used in lieu of
paraffin wax. Other suitable masking materials include, but are not
limited to, polydimethylsiloxane (PDMS) polymer film.
[0022] The process 100 begins by providing silica particles (step
105). For example, silica particles may be synthesized by the
Stober process using, for example, tetraethyl orthosilicate (TEOS).
The Stober process is described in Stober et al., "Controlled
Growth of Monodisperse Silica Spheres in the Micron Size Range,"
Journal of Colloid and Interface Science, Vol. 26, 1968, pages
62-69, which is hereby incorporated herein by reference in its
entirety. One skilled in the art will appreciate, however, that the
silica particles may be synthesized by other processes or obtained
commercially. A particular embodiment of a synthetic procedure for
producing silica nanoparticles using a modified Stober process is
shown in FIG. 2.
[0023] The process 100 continues by masking the silica particles
(step 110). For example, silica nanoparticles may be masked using
paraffin wax. A particular embodiment of a synthetic procedure for
masking silica particles using paraffin wax is shown in FIG. 3.
[0024] The process 100 continues by functionalizing the masked
silica particles (step 115). For example, masked silica
nanoparticles may be functionalized using a silane coupling agent
to introduce reactive groups on the unprotected side of the masked
silica particles. In accordance with some embodiments, the reactive
groups introduced by the silane coupling agent include one or more
matrix-bonding functionalities that is/are capable of reacting with
a polymeric resin into which matrix-bonding abrasion resistant CNTs
(MBARCs) or MBARCs-containing fibers are to be blended. The
matrix-bonding functionality allows the MBARCs or MARCs-containing
fibers to be covalently bonded into a particular polymer matrix.
That is, the MBARCs or MARCs-containing fibers may be "tailored"
for blending and bonding into a given polymer matrix. The
matrix-bonding functionalities may be, for example, selected from a
group consisting of vinyl functionalities, amine functionalities,
epoxy functionalities, allyl functionalities, acrylate
functionalities, sulfur functionalities, isocyanate
functionalities, halogen functionalities, and combinations thereof.
A particular embodiment of a synthetic procedure for
functionalizing masked silica nanoparticles using
triethoxyvinylsilane as a silane coupling agent to introduce vinyl
groups as reactive groups on the unprotected side of the masked
silica nanoparticles is shown in FIG. 4.
[0025] Generally, silane coupling agents are organosilane compounds
having a silicon atom that is bonded to reactive groups of two
different types (i.e., one or more reactive groups of a first type
and one or more reactive groups of a second type). Reactive groups
of the first type (e.g., alkoxy groups) are reactive with various
inorganic materials (e.g., silica) to form a chemical bond with the
surface of the inorganic material. In some embodiments, these
reactive groups of the first type may be, for example, alkoxy
groups that react with hydroxyl groups on the surface of a silica
nanoparticle (or silica microparticle) to form a chemical bond with
the surface of the silica nanoparticle (or silica microparticle).
Reactive groups of the second type (e.g., vinyl, amine, epoxy,
allyl, acrylate, sulfur, isocyanate, and halogen groups) are
reactive with various kinds of organic materials (e.g., polymeric
resins) to form a chemical bond with the organic material. In some
embodiments, these reactive groups of the second type may be, for
example, amine, epoxy, and/or isocyanate groups that are capable of
reacting with various polyamide resins (or other polymeric resins
into which MARCs or MARCs-containing fibers are to be blended) to
form a chemical bond with a polymer matrix produced from the
polymeric resin.
[0026] One skilled in the art will appreciate that selection of the
silane coupling agent used to introduce the matrix-bonding
functionality on the unprotected side of the masked silica
particles may be based upon the particular polymeric resin into
which matrix-bonding abrasion resistant CNTs (MBARCs) or
MARCs-containing fibers are to be blended. For example, an epoxy
functionality may be selected as the matrix-bonding functionality
to provide MBARCs tailored for blending and bonding into polymer
matrices produced from acrylic-based resins, butyl-based resins,
cellulosic-based resins, epoxy-based resins, furan-based resins,
melamine-based resins, nitrile-based resins, phenolic-based resins,
polyamide-based resins, polyester-based resins, polyolefin-based
resins, polysulfide-based resins, polyurethane-based resins,
silicone-based resins, styrene-butadiene-based resins,
urea-formaldehyde-based resins, and vinyl (PVC)-based resins. An
epoxy functionality may be introduced on the unprotected side of
the masked silica particle using an epoxysilane, such as
Trimethoxy[2-(7-oxabicyclo[4.1.0]hept-3-yl)ethyl]silane (CAS Number
3388-04-3), (3-Glycidyloxypropyl)trimethoxysilane (CAS Number
2530-83-8), Diethoxy(3-glycidyloxypropyl)methylsilane (CAS Number
2897-60-1), and the like.
[0027] As another example, a vinyl functionality (or allyl
functionality) may be selected as the matrix-bonding functionality
to provide MBARCs tailored for blending and bonding into polymer
matrices produced from polyamide-based resins, polyester-based
resins, polyolefin-based resins, polysulfide-based resins,
silicone-based resins, styrene-butadiene-based resins, and vinyl
(PVC)-based resins. A vinyl functionality may be introduced on the
unprotected side of the masked silica particle using a vinylsilane,
such as Trichlorovinylsilane (CAS Number 75-94-5),
Tris(2-methoxyethoxy)(vinyl)silane (CAS Number 1067-53-4),
Triethoxyvinylsilane (CAS Number 78-08-0), Vinyltrimethoxysilane
(CAS Number 2768-02-7), and the like. An allyl functionality may be
introduced on the unprotected side of the masked silica particle
using an allylsilane, such as 11-Allyloxyundecyltrimethoxysilane
(CAS Number 1196453-35-6), Allyltriethoxysilane (CAS Number
2550-04-1), Allyltrimethoxysilane (CAS Number 2551-83-9),
2-(chloromethyl)allyltrimethoxysilane (CAS Number 39197-94-9),
N-Allyl-aza-2,2-dimethoxysilacyclopentate (CAS Number 618914-49-1),
Allylmethyldimethoxysilane (CAS Number 67681-66-7), and the
like.
[0028] `As yet another example, an acrylate functionality may be
selected as the matrix-bonding functionality to provide MBARCs
tailored for blending and bonding into polymer matrices produced
from acrylic-based resins, butyl-based resins, polyester-based
resins, polyether-based resins, polyolefin-based resins,
polyurethane-based resins, silicone-based resins, and vinyl
(PVC)-based resins. An acrylate functionality may be introduced on
the unprotected side of the masked silica particle using an
acryloyloxysilane, such as 3-(Trimethoxysilyl)propyl acrylate (CAS
Number 4369-14-6), 3-(Trimethoxysilyl)propyl methacrylate (CAS
Number 2530-85-0), and the like.
[0029] As still another example, an amine functionality may be
selected as the matrix-bonding functionality to provide MBARCs
tailored for blending and bonding into polymer matrices produced
from acrylic-based resins, butyl-based resins, cellulosic-based
resins, epoxy-based resins, furan-based resins, melamine-based
resins, neoprene-based resins, nitrile-based resins,
nitrocellulose-based resins, phenolic-based resins, polyamide-based
resins, polyester-based resins, polyether-based resins,
polyolefin-based resins, polysulfide-based resins,
polyurethane-based resins, polyvinyl butyral-based resins,
silicone-based resins, urea-formaldehyde-based resins, and vinyl
(PVC)-based resins. An amine functionality may be introduced on the
unprotected side of the masked silica particle using an
aminosilane, such as N-[3-(Trimethoxysilyl)propyl]ethylenediamine
(CAS Number 1760-24-3),
3-(2-Aminoethylamino)propyldimethoxymethylsilane (CAS Number
3069-29-2), (3-Aminopropyl)triethoxysilane (CAS Number 919-30-2),
(3-Aminopropyl)trimethoxysilane (CAS Number 13822-56-5),
N-[3-(Trimethoxysilyl)propyl]aniline (CAS Number 3068-76-6), and
the like.
[0030] Still other functionalities may be selected as the
matrix-bonding functionality to provide MBARCs tailored for
blending and bonding into various polymer matrices. For example, a
sulfur functionality may be introduced on the unprotected side of
the masked silica particle using a mercaptosilane, such as
(3-Mercaptopropyl)trimethoxysilane (CAS Number 4420-74-0),
(3-Mercaptopropyl)methyldimethoxysilane (CAS Number 31001-77-1),
and the like, for acryic-based resins, butyl-based resins,
epoxy-based resins, neoprene-based resins, nitrile-based resins,
phenolic-based resins, polyolefin-based resins, polysulfide-based
resins, polyurethane-based resins, and styrene-butadiene-based
resins. An isocyanate functionality may be introduced on the
unprotected side of the masked silica particle using an
isocyanatesilane, such as 3-(Triethoxysilyl)propyl isocyanate (CAS
Number 24801-88-5) and the like, for acrylic-based resins,
cellulosic-based resins, melamine-based resins, polyamide-based
resins, polyurethane-based resins, silicone-based resins, and
urea-formaldehyde-based resins. A halogen functionality may be
introduced on the unprotected side of the masked silica particle
using a halogen functional silane, such as
(3-Chloropropyl)trimethoxysilane (CAS Number 2530-87-2) and the
like, for epoxy-based resins.
[0031] The process 100 ends by de-masking the functionalized silica
particles (step 120). For example, functionalized silica
nanoparticles may be de-masked using a solvent to dissolve away the
mask. A particular embodiment of a synthetic procedure for
de-masking the functionalized silica nanoparticles using a
hydrocarbon solvent, such as benzene, to dissolve away the paraffin
wax is shown in FIG. 5.
[0032] FIG. 2 is a block diagram showing a particular embodiment of
a synthetic procedure 200 for producing silica particles that may
be utilized in the process 100 of FIG. 1. The synthetic procedure
200 shown in FIG. 2 may correspond to step 105 in the process 100
of FIG. 1. Silica particles may be produced through the
polymerization of a suitable silica precursor, such as
tetralkoxysilane (e.g., Si(OR').sub.4, where R' is a methyl or
ethyl group). In accordance with some embodiments, synthetic
procedure 200 is performed via a polymerization reaction of a
tetralkoxysilane using a modified Stober process. The Stober
process, itself, and modifications thereof are well known in the
art. A modified Stober process is, for example, disclosed in U.S.
Pat. No. 7,777,176 B2, issued to Loy et al. on Aug. 17, 2010,
entitled "COMPOSITION AND METHOD TO CHARACTERIZE MEMBRANES'
DEFECTS", which is hereby incorporated herein by reference in its
entirety.
[0033] The modified Stober synthesis of monodisperse silica
particles illustrated in FIG. 2 is exemplary and non-limiting. One
skilled in the art will appreciate that the silica particles may be
synthesized by other processes or obtained commercially. The silica
precursor utilized in synthetic procedure 200 may be, for example,
a tetralkoxysilane. Utilizing a silica precursor (e.g., TEOS in the
prophetic example, described below), ammonia, water and a solvent
gives the ability to afford monodispersed particles that have
diameters in the nanometer size range up to the micron size range.
In accordance with some embodiments, the silica particle is a
nanoparticle approximately 15 to 1000 nm in diameter. Particle size
can be controlled using chemical concentration. For example, in the
modified Stober process, the concentration of water can be used to
vary particle size.
[0034] After synthesis, the silica particles are removed from their
mother liquor solution to halt the growth of the particles and
obtain the desired particle size. Through the process of
centrifugation and solvent washes, particles are removed from any
residual catalyst and precursor monomer. Particles are then removed
from solution in vacuo for ease of processing further tasks.
Prophetic Example of Silica Nanoparticle Synthesis
[0035] A prophetic example of the synthetic procedure 200 depicted
in FIG. 2 is described below. In this prophetic example, silica
particles are prepared through a modified Stober process using
ammonia, deionized water, tetraethoxysilane (TEOS), and ethanol.
TEOS is commercially available from chemical suppliers, such as
Sigma-Aldrich, St. Louis, Mo. One skilled in the art will
appreciate that other silica precursors may be used in lieu of, or
in addition to, TEOS.
[0036] To a glass vial, 2M ammonia (3.75 mL) and water (0.63 mL)
are added to generate a catalyst (ammoniacal) solution 205. To a
second glass vial, TEOS (0.38 mL, 1.70.times.10.sup.-3 mol) and 200
proof ethanol (5.24 mL) are then added to generate a monomer
solution 210. In this prophetic example, TEOS is used as the
suitable tetralkoxysilane (e.g., Si(OR').sub.4, where R' is a
methyl or ethyl group). Next, the catalyst (ammoniacal) solution
205 is added to the monomer solution 210 and stirred vigorously for
24 hours to generate silica particles in solution 215. The silica
particles are then centrifuged, washed, and dried to remove any
unreacted silane. ***End of the prophetic example of silica
nanoparticle synthesis.***
[0037] FIG. 3 is a block diagram showing a particular embodiment of
a synthetic procedure 300 for masking silica particles that may be
utilized in the process of FIG. 1. The synthetic procedure 300
shown in FIG. 3 may correspond to step 110 in the process 100 of
FIG. 1. In preparation of "two-faced" particles in accordance with
some embodiments, a Pickering emulsion is fabricated in synthetic
procedure 300. This emulsion facilitates a
liquid-liquid/liquid-solid hybrid interface method that is used in
the synthetic procedure 300 to mask silica particles. The emulsion
contains silica particles, a water/ethanol solution, cetyl
trimethylammonium bromide (CTAB), and molten paraffin wax. The
silica particles are adsorbed onto the liquid-liquid interface of
the emulsion formed by the molten paraffin wax and the
water/ethanol solution. Cooling the emulsion traps the silica
particles at the liquid-solid interface between the water/ethanol
solution and the solidified wax.
[0038] The synthetic procedure 300 for masking silica particles
illustrated in FIG. 3 is exemplary and non-limiting. One skilled in
the art will appreciate, for example, that the silica particles may
be masked using other synthetic procedures and/or other masking
materials, such as polydimethylsiloxane (PDMS) polymer film.
Prophetic Example of Silica Nanoparticle Masking
[0039] A prophetic example of the synthetic procedure 300 depicted
in FIG. 3 is described below. In this prophetic example, silica
particles are masked through a liquid-liquid/liquid-solid hybrid
interface method using an emulsion that contains silica particles,
a water/ethanol solution, cetyl trimethylammonium bromide (CTAB),
and molten paraffin wax. CTAB is a cationic surfactant that is
commercially available from chemical suppliers, such as
Sigma-Aldrich, St. Louis, Mo. Paraffin wax is commercially
available from chemical suppliers, such as Sigma-Aldrich, St.
Louis, Mo.
[0040] Silica particles (0.27 g) (e.g., prepared via synthetic
procedure 200) are dispersed in an ethanol/water solution (7.0%
w/w, 130 mL) at an elevated temperature (76-84.degree. C.) (to melt
the wax that will be added later) and then mixed. The particle
mixture 305 is then mixed with cetyl trimethylammonium bromide
(CTAB) (0.027 g) 310, to partially hydrophobize the surface of the
silica particles. A low concentration of CTAB is used to avoid the
creation of a bilayer at the surface of the particle. The CTAB also
allows for the particle to favor adsorption at the oil-water
interface (i.e., the interface between the molten paraffin wax and
the ethanol/water solution). One skilled in the art will appreciate
that other suitable surfactants may be used in lieu of, or in
addition to, CTAB. Other suitable surfactants include, but are not
limited to, dodecyltrimethylammonium bromide (DTAB) and
didodecyldimethylammonium bromide (DDAB). Paraffin wax 320 (8.9 g)
(mp=58 to 62.degree. C.) is then deposited on top of the particle
suspension and the mixture 315 is vigorously stirred (1800 rpm for
45 min) at the elevated temperature (76-84.degree. C.) to form an
emulsion 325. After cooling to room temperature, the paraffin wax
solidifies into solid droplets 330 with the silica particles 340
partially protruding from the surface 345 of the solidified
paraffin wax 350. The solidified wax droplets 330 are also referred
to as "colloidosomes." The silica particles 340 are trapped at the
liquid-solid interface between the water/ethanol solution 335 and
the solidified paraffin wax 350. The colloidosomes 330 are then
washed with an acid to remove CTAB and expose an unprotected (bare)
side of each of the silica particles 340. A protected (i.e.,
embedded in the solidified paraffin wax 350) side of each of the
silica particles 340 is masked by the solidified paraffin wax 350.
***End of the prophetic example of silica nanoparticle
masking.***
[0041] FIG. 4 is a block diagram showing a particular embodiment of
a synthetic procedure 400 for functionalizing masked silica
particles that may be utilized in the process of FIG. 1. The
synthetic procedure 400 shown in FIG. 4 may correspond to step 115
in the process 100 of FIG. 1. In order to attach silica particles
to the resin, the particles must first be partially functionalized.
The matrix-bonding functionalization of a silica Janus particle
illustrated in FIG. 4 is exemplary and non-limiting. One skilled in
the art will appreciate that the silica Janus particle may be
partially functionalized using other processes.
[0042] In synthetic procedure 400, masked silica nanoparticles are
functionalized using a silane coupling agent to introduce reactive
groups on the unprotected side of the masked silica particles. As
illustrated in FIG. 4, a masked silica nanoparticle 405 (e.g., one
of the silica particles 340 partially extruding from the surface
345 of the solidified paraffin wax 350 of one of the colloidosomes
330 prepared via synthetic procedure 300) is functionalized using
triethoxyvinylsilane 410 as the silane coupling agent to introduce
vinyl groups 415 as reactive groups on the unprotected side of the
masked silica nanoparticle 405 to produce a
partially-functionalized, masked silica nanoparticle 420 (i.e., a
partially-functionalized silica nanoparticle 440 partially
extruding from the surface 345 of the solidified paraffin wax 350).
The partially-functionalized silica nanoparticle 440 is also
referred to herein as a "silica Janus particle." Only five vinyl
groups 415 are shown in FIG. 4 on the partially-functionalized
silica nanoparticle 440 as not to unnecessarily complicate the
drawing. However, one skilled in the art will appreciate that many
more vinyl groups 415 are typically introduced on the unprotected
side of the masked silica nanoparticle 405 by the silane coupling
agent. The vinyl groups 415 are introduced only on the exposed
surface (i.e., unprotected side) of the masked silica particle 405.
This functionalizes the particle's exposed surface yielding
particles having resin bonding characteristics. Other
functionalities (for bonding to resins) outside the described vinyl
include, but are not limited to, amines, epoxies, allyls,
acrylates, mercapto (or other sulfur-containing groups),
isocyanates, and halogens.
[0043] The alkoxy groups bonded to the silicon atom of the
triethoxysilane 410 hydrolyze to silanols, either through the
addition of water (e.g., a solvent) or from residual water on the
surface of the particle's exposed surface. Subsequently, the
silanols react with hydroxyl groups 425 on the particle's exposed
surface via a condensation reaction to form a siloxane bond
(Si--O--Si) and eliminate water. Only five hydroxyl groups 425 on
the silica particle 340 are shown in FIG. 4 as not to unnecessarily
complicate the drawing. However, one skilled in the art will
appreciate that many more hydroxyl groups 425 are typically present
on the particle's surface, both on the exposed surface (i.e.,
unprotected side) and on the unexposed surface (i.e., masked side).
Hydroxyl groups on the particle's unexposed surface are not shown
in FIG. 4 as not to unnecessarily complicate the drawing.
Prophetic Example of Masked Silica Nanoparticle
Functionalization
[0044] A prophetic example of the synthetic procedure 400 depicted
in FIG. 4 is described below. In this prophetic example, masked
silica particles are functionalized using a water/ethanol solution
and triethoxyvinylsilane. Triethoxyvinylsilane is a silane coupling
agent that is commercially available from chemical suppliers, such
as Sigma-Aldrich, St. Louis, Mo.
[0045] Masked silica particles (0.27 g) (e.g., colloidosomes
prepared via synthetic procedure 300) are dispersed in an
ethanol/water solution (7.0% w/w, 130 mL). Triethoxyvinylsilane
(2.8 mL) is then added into the prepared solution. The surface
modification reaction is allowed to continue for 24 h with
stirring. Alternatively, the triethoxyvinylsilane may be added to
the masked silica particles (colloidosomes) in their original
emulsion. Once the surface modification reaction is complete, the
masked silica particles (colloidosomes) are separated by
centrifugation and washed with ethanol. One skilled in the art will
appreciate the masked silica particles (colloidosomes) may be
functionalized using a gas-phase method in lieu of, or in addition
to, the described solution-based method. ***End of the prophetic
example of masked silica nanoparticle functionalization.***
[0046] FIG. 5 is a block diagram showing a particular embodiment of
a synthetic procedure 500 for de-masking functionalized silica
particles that may be utilized in the process of FIG. 1. The
synthetic procedure 500 shown in FIG. 5 may correspond to step 120
in the process 100 of FIG. 1. After the silane functionalization
synthesis step (e.g., synthetic procedure 400), the particles must
be removed from their wax confines to yield Janus-type particles.
To remove the wax, a hydrocarbon solvent (e.g., benzene, kerosene,
xylene or other petroleum derivative) is used, which will dissolve
away the paraffin wax.
Prophetic Example of Wax Removal to Yield Partially-Modified
Particles
[0047] The partially-functionalized, masked silica particles 505
(e.g., colloidosomes comprising solidified paraffin wax 350 having
a surface 345 on which partially-functionalized silica
nanoparticles 440 are embedded that were partially functionalized
via synthetic procedure 400) are dissolved in excess benzene or
other hydrocarbon solvent to release the partially-functionalized
silica particles 510 (e.g., the partially-functionalized silica
particles 440 released from the solidified paraffin wax 350 of the
colloidosomes). The benzene or other hydrocarbon solvent removes
the paraffin wax by dissolution. The partially-functionalized
silica particles 510 then are centrifuged and decanted numerous
times to yield Janus particles free of wax. ***End of the prophetic
example of wax removal to yield partially-modified
particles.***
[0048] As illustrated in FIG. 5, hydroxyl groups are bonded onto
the surface of the unmodified hemisphere of the
partially-functionalized silica particles 440; whereas, vinyl
groups are bonded onto the surface of the modified hemisphere of
the partially-functionalized silica particles 440. In accordance
with some embodiments, the vinyl groups on the surface of the
modified hemisphere of the partially-functionalized silica
particles are intended to function as a matrix-bonding
functionality for bonding the silica Janus particles 440 to a
polymeric matrix. In accordance with some embodiments, the hydroxyl
groups on the surface of the unmodified hemisphere of the
partially-functionalized silica particles are intended to function
as a CNT-bonding functionality for bonding the silica Janus
particles 440 to CNTs. One skilled in the art will appreciate that
the unmodified hemisphere of the silica Janus particles 440 may be
surface modified via an optional, additional step. The type of
surface modification performed in such an optional, additional step
is primarily dependent on the route of coupling used for bonding
the resulting Janus particles to CNTs.
[0049] Starting with a Janus particle that includes a CNT-bonding
functionality and a matrix-bonding functionality (e.g., the silica
Janus particle 440 synthesized above), several procedures may be
used to generate functionalized CNTs to which the Janus particle
will be bonded. Numerous routes to functionalize CNTs are described
in Wu et al., "Chemistry of carbon nanotubes in biomedical
applications," Journal of Materials Chemistry, 2010, Vol. 20, pp.
1036-1052, which is hereby incorporated herein by reference in its
entirety.
[0050] Typically, the CNT-bonding functionality and the
matrix-bonding functionality of the Janus particle are different
from each other. One skilled in the art will appreciate, however,
that the CNT-bonding functionality and the matrix-bonding
functionality of the particle may be the same. Further, the Janus
particle may be a fully modified Janus particle of only CNT-bonding
functionality such that bonding between CNTs is possible. In this
document, reference to a "Janus particle" additionally includes
such a fully modified Janus particle.
[0051] The CNTs may be processed by the following three methods,
wherein the "process CNTs" step includes, but is not limited to,
braiding, twisting, and the like. [0052] 1) Functionalize CNTs,
then process CNTs, and then bind Janus particle; or [0053] 2)
Functionalize CNTs, then bind Janus particle, and then process
CNTs; or [0054] 3) Process CNTs, then functionalize processed CNTs,
and then bind Janus particle.
[0055] Some embodiments of the present disclosure are described
below in terms of the second method (i.e., functionalize CNTs, then
bind Janus particle, and then process CNTs). In the second method,
the "functionalize CNTs" step may be accomplished via the synthetic
procedure 600 illustrated in FIG. 6 to produce functionalized CNTs
(f-CNTs), then the "bind Janus particle" step may be accomplished
via the synthetic procedure 700 illustrated in FIG. 7 using the
f-CNTs and Janus particles to produce MBARCs, and finally the
"process CNTs" step may be accomplished via the synthetic procedure
800 illustrated in FIG. 8 using the MBARCs to produce a
MBARCs-containing product (e.g., a fiber containing MBARCs, a fiber
reinforced polymer composite, etc.). More generally, however, the
techniques described herein with respect to the second method are
also applicable, albeit in a different order, to the first method
(i.e., functionalize CNTs, then process CNTs, and then bind Janus
particle) and the third method (i.e., process CNTs, then
functionalize processed CNTs, and then bind Janus particle).
[0056] In the first method (i.e., functionalize CNTs, then process
CNTs, and then bind Janus particle), the "functionalize CNTs" step
may be accomplished via the synthetic procedure 600 illustrated in
FIG. 6 to produce functionalized CNTs (f-CNTs), then the "process
CNTs" step may be accomplished via techniques described below with
respect to the synthetic procedure 800 illustrated in FIG. 8 (e.g.,
braiding, twisting, and the like) using the f-CNTs to produce
processed f-CNTs (e.g., a fiber containing f-CNTs), and finally the
"bind Janus particle" step may be accomplished via techniques
described below with respect to the synthetic procedure 700
illustrated in FIG. 7 using the processed f-CNTs to produce a
MBARCs-containing product (e.g., a fiber containing MBARCs).
[0057] In the third method (i.e., process CNTs, then functionalize
processed CNTs, and then bind Janus particle), the "process CNTs"
step may be accomplished via techniques described below with
respect to the synthetic procedure 800 illustrated in FIG. 8 (e.g.,
braiding, twisting, and the like) to produce processed CNTs (e.g.,
a fiber containing CNTs), then the "functionalize processed CNTs"
step may be accomplished via the synthetic procedure 600
illustrated in FIG. 6 using the processed CNTs to produce processed
f-CNTs (e.g., a fiber containing f-CNTs), and finally the "bind
Janus particle" step may be accomplished via techniques described
below with respect to the synthetic procedure 700 illustrated in
FIG. 7 using the processed f-CNTs to produce a MBARCs-containing
product (e.g., a fiber containing MBARCs).
[0058] FIG. 6 is a block diagram illustrating a synthetic procedure
600 for functionalizing CNTs, according to some embodiments. The
synthetic procedure 600 utilizes a two-step reaction scheme. In the
first step of the reaction scheme illustrated in FIG. 6, the
surface of a CNT is brominated via a photobromination process.
Preferably, the CNT is a high aspect ratio CNT (e.g.,
length:diameter=800:1). The CNT may, for example, be a high aspect
ratio CNT having a length in the range of hundreds of microns to
one or more millimeters. In the second step of the reaction scheme
illustrated in FIG. 6, the brominated CNT is modified with a silane
through a Grignard reaction. One skilled in the art will appreciate
that other surface modifications may be deployed with consideration
to the particular matrix-bonding functionality of the silica Janus
particle that will be used to bond into the matrix polymer. It
should be well understood that the matrix-bonding functionality of
the silica Janus particle can play no part in the coupling reaction
between the CNT and the silica Janus particle.
[0059] One skilled in the art will appreciate that other carbon
nanomaterials may be used in lieu of, or in addition to, the
single-walled carbon nanotube (SWNT) illustrated in FIG. 6. For
example, a multi-walled carbon nanotube (MWNT), a carbon nanofiber
(CNF), and the like may be used in lieu of, or in addition to, the
SWNT illustrated in FIG. 6. Also, one skilled in the art will
appreciate that in lieu of producing a brominated CNT in the first
step of the reaction scheme illustrated in FIG. 6, a fluorinated
CNT may be produced by, for example, chemical fluorination at
temperatures between 250 and 400.degree. C. The covalently bonded
fluorine may be subsequently replaced by alkyl groups through an
alkylation reaction. Either an alkyllithium or Grignard reagent may
be used in the alkylation reaction as an alkylation reagent.
Prophetic Example of Functionalized CNT Synthesis
[0060] In the first step of the reaction scheme illustrated in FIG.
6, the surface of a CNT is brominated via a photobromination
process. A SWNT suspension is prepared by sonication of SWNTs (27
mg) in dichloromethane (20 mL) for 20 min. The SWNT suspension is
then poured into a round bottom flask. To this SWNT suspension is
added N-bromosuccinimide (CAS Number 128-08-5) (15 mg). The
dispersion that results is dark-orange in color. A conventional
incandescent light bulb (100 W) is positioned approximately 4-6 mm
below the bottom of the flask to irradiate the dispersion while the
dispersion is refluxed. The photonic radiation emitted by the light
bulb through the flask promotes the formation of free bromine
radicals in the dispersion. After allowing the reaction to proceed
for about 15 min, more N-bromosuccinimide (28 mg) is added. The
additional N-bromosuccinimide further drives the reaction. The
reaction is allowed to proceed for another 90 min. The dispersion
that results is bright yellow in color. To reduce the rate of
reaction, the light bulb is then lowered to approximately 38-42 mm
below bottom of the flask. After allowing the reaction to proceed
at the reduced rate for another 24 h, the dispersion is cooled.
Once cooled, the dispersion may then be filtered through a PTFE
membrane (0.45 .mu.m, 25 mm). The precipitate that results may then
be washed consecutively with chloroform and diethyl ether. The
resulting product (brominated SWNTs) may then be dried in vacuo
overnight at 60.degree. C.
[0061] In the second step of the reaction scheme illustrated in
FIG. 6, the brominated CNT is modified with a silane through a
Grignard reaction. A suspension of brominated SWNTs is prepared by
sonication of the brominated SWNTs (prepared in the first step of
the reaction scheme illustrated in FIG. 6) in dry tetrahydrofuran
(20 mL) for 20 min. Added dropwise to the suspension of brominated
SWNTs is [(Triethoxysilyl)methyl]magnesium chloride (CAS Number
148599-37-5) as the Grignard Reagent, and the mixture is stirred
under nitrogen for 5 h. As illustrated in FIG. 6,
[(Triethoxysilyl)methyl]magnesium chloride will react (as the
Grignard Reagent) with the brominated (or fluorinated) SWNTs to
form silylated SWNTs. Excess Grignard Reagent is then quenched with
a saturated aqueous solution of ammonium chloride. The material
that results is then washed thoroughly with water. Removal of any
residual magnesium salts may be accomplished by re-suspending the
material in aqueous 5% HCl solution, followed by washing the
material consecutively with water, ethanol and dichloromethane. The
resulting product (silylated SWNTs) may then be dried in vacuo
overnight at 60.degree. C. ***End prophetic example of
functionalized CNT synthesis.***
[0062] FIG. 7 is a block diagram illustrating a synthetic procedure
700 for preparing matrix-bonding abrasion resistant CNTs (MBARCs)
by reacting Janus particles and functionalized CNTs, according to
some embodiments. Janus particles illustrated in FIG. 7 may
correspond to the silica Janus particles 440 illustrated in FIG. 5.
The functionalized CNT illustrated in FIG. 7 may correspond to the
silylated SWNT illustrated in FIG. 6.
[0063] The Janus particles and the functionalized CNT are reacted
through a condensation reaction that covalently binds the Janus
particles to the CNT using the CNT-bonding functionality (hydroxyl
groups in the example illustrated in FIG. 7) on the surface of the
Janus particles, while leaving the matrix-bonding functionality
(vinyl groups in the example illustrated in FIG. 7) on the surface
of the Janus particles available for bonding into a polymeric
matrix. The alkoxy groups on the functionalized CNTs hydrolyze to
silanols, through the addition of water. Subsequently, the silanols
react with the CNT-bonding functionality on the Janus particles via
the condensation reaction to form a siloxane bond (Si--O--Si) and
eliminate water. Only a few of these reactive groups are shown in
FIG. 7, along with only a few of the Janus particles, so as not to
unnecessarily complicate the drawing.
Prophetic Example of Preparation of MBARCs
[0064] A solution containing a dispersion of silica Janus particles
(prepared via the synthetic procedures illustrated in FIGS. 2-5)
and deionized water is combined with silylated SWNTs (prepared via
the synthetic procedure illustrated in FIG. 6). The mixture is
sonicated for 15 min and stirred for 12 h. The deionized water
causes the alkoxy groups on the silylated SWNTs to hydrolyze to
silanols. Subsequently, the silanols react with hydroxyl groups
(CNT-bonding functionality) on the unmodified face of the silica
Janus particles via a condensation reaction to form a siloxane bond
(Si--O--Si) and eliminate water. Hence the silica Janus particles
are covalently bonded to the silylated SWNTs. The vinyl groups
(matrix-bonding functionality) on the modified face of the silica
Janus particle are available for bonding into a polymeric matrix.
Removal of any residual Janus particles is accomplished by rinsing
the material consecutively with benzene and distilled water. The
resulting product (MBARCs) may then be filtered and dried in vacuo
overnight at 60.degree. C. ***End prophetic example of preparation
of MBARCs.***
[0065] FIG. 8 is a flow diagram illustrating a process 800 of
preparing a fiber reinforced polymer composite, according to some
embodiments. In the process 800, the steps discussed below (steps
805-815) are performed. These steps are set forth in their
preferred order. It must be understood, however, that the various
steps may occur simultaneously or at other times relative to one
another. Moreover, those skilled in the art will appreciate that
one or more steps may be omitted.
[0066] The process 800 begins by providing matrix-bonding abrasion
resistant carbon nanotubes (MBARCs) (step 805). For example, MBARCs
may be prepared using the synthetic procedure 700 illustrated in
FIG. 7.
[0067] After the MBARCs are provided, the process 800 continues by
processing the MBARCs (step 810). For example, the MBARCs may be
processed to form fibers (or nonwoven fabrics, as described below)
using known techniques in the art to braid, twist, etc. the MBARCs.
The resulting MBARCs-containing fibers may be the final product,
may be further processed (e.g., the MBARCs-containing fibers may be
further processed to form MBARCs-containing cloth (e.g., 902 in
FIG. 9) using known techniques in the art to weave the
MBARCs-containing fibers), or may be blended into polymeric resin
to produce a fiber reinforced polymer composite (e.g., as
exemplified in step 815, described below).
[0068] The MBARCs-containing fibers may then be blended into
polymeric resin to produce a fiber reinforced polymer composite
(FRPC), wherein the MBARCs of the MBARCs-containing fibers can
covalently bind into the polymer matrix (step 815). The newly
formed fiber reinforced polymer composite has improved stiffness
and abrasion resistance by virtue of the MBARCs of the
MBARC-containing fibers. The use of silica Janus particles in the
construction of the MBARCs, in accordance with some embodiments of
the present invention, simultaneously allows silica particles to be
bound to CNTs (via the CNT-bonding functionality of the silica
Janus particles) to impart abrasion resistance, while also allowing
for binding into a resin (via the matrix-bonding functionality of
the silica Janus particles) to improve modulus and stiffness.
[0069] Preferably, the MBARCs of the MBARCs-containing fibers are
tailored to the polymeric resin. That is, the MBARCs-containing
fibers preferably contain MBARCs tailored for blending and bonding
into the polymer matrix produced by the polymeric resin. For
example, MBARCs having vinyl functionalities (or allyl
functionalities) as the matrix-bonding functionality are tailored
for blending and bonding into polymer matrices produced from
polyamide-based resins, polyester-based resins, polyolefin-based
resins, polysulfide-based resins, silicone-based resins,
styrene-butadiene-based resins, and vinyl (PVC)-based resins.
Depending on the desired polymeric resin, the matrix-bonding
functionality of the MBARCs may be, for example, selected from a
group consisting of vinyl functionalities, amine functionalities,
epoxy functionalities, allyl functionalities, acrylate
functionalities, sulfur functionalities, isocyanate
functionalities, halogen functionalities, and combinations
thereof.
[0070] In lieu of forming MBARCs-containing fibers in step 810, the
MBARCs may be processed to form nonwoven MBARCs-containing fabrics
using known techniques in the art. Both wet and dry CNT fabric
formation processes known in the art may be used to process the
MBARCs to form nonwoven MBARCs-containing fabrics.
[0071] FIG. 9 is a partial, cross-sectional view of a fiber
reinforced polymer composite 900, according to some embodiments. In
the embodiment shown in FIG. 9, fiber reinforced polymer composite
900 includes a MBARCs-containing cloth 902 impregnated with a
polymeric resin 904. Preferably, the MBARCs of the
MBARCs-containing cloth 902 are tailored to the polymeric resin
904. The polymeric resin 904 may be impregnated into the
MBARCs-containing cloth 902 using techniques well known to those
skilled in the art.
[0072] The MBARCs-containing cloth 902 may be constructed of a
number of MBARCs-containing fiber bundles 906 (or individual
MBARCs-containing fibers) that are woven together in an orthogonal
fashion. The MBARCs-containing fiber bundles 906 may be woven to
form the MBARCs-containing cloth 902 using techniques well known to
those skilled in the art. From the perspective illustrated in FIG.
9, the MBARCs-containing fiber bundles 906 extend within the
MBARCs-containing cloth 902 in a transverse direction (these
MBARCs-containing fiber bundles extend between left and right, one
such MBARCs-containing fiber bundle 906 is denoted with
hidden-lines in FIG. 9) and a normal direction (these
MBARCs-containing fiber bundles extend into the page, three such
MBARCs-containing fiber bundles 906 are shown in FIG. 9).
[0073] Each MBARCs-containing fiber bundle 906 includes two or more
individual MBARCs-containing fibers 908 that are typically braided
or twisted around one another (e.g., in the example shown in FIG.
9, each MBARCs-containing fiber bundle 906 consists of seven
individual MBARCs-containing fibers 908--six outer
MBARCs-containing fibers braided or twisted around a single central
MBARCs-containing fiber). The MBARCs-containing fibers 908 may be
braided or twisted to form the MBARCs-containing fiber bundles 906
using techniques well known to those skilled in the art.
[0074] Those skilled in the art will appreciate that many
variations are possible within the scope of the present invention.
Thus, while the present invention has been particularly shown and
described with reference to some embodiments thereof, it will be
understood by those skilled in the art that these and other changes
in form and detail may be made therein without departing from the
spirit and scope of the present invention.
* * * * *