U.S. patent application number 14/911110 was filed with the patent office on 2016-07-07 for nanocomposites containing layered nanoparticles and dispersant, composites, articles, and methods of making same.
The applicant listed for this patent is 3M INNOVATIVE PROPERTIES COMPANY. Invention is credited to Peter D. Condo, Steven C. Hackett, Neeraj Sharma, Jeremy O. Swanson, James E. Thorson, Kristin L. Thunhorst.
Application Number | 20160194479 14/911110 |
Document ID | / |
Family ID | 51392443 |
Filed Date | 2016-07-07 |
United States Patent
Application |
20160194479 |
Kind Code |
A1 |
Condo; Peter D. ; et
al. |
July 7, 2016 |
NANOCOMPOSITES CONTAINING LAYERED NANOPARTICLES AND DISPERSANT,
COMPOSITES, ARTICLES, AND METHODS OF MAKING SAME
Abstract
A nanocomposite is provided including layered nanoparticles and
a dispersant dispersed in a curable resin, where the nanocomposite
contains less than 2% by weight solvent. A composite is also
provided including from about 1 to 70 weight percent of layered
nanoparticles, and a dispersant, dispersed in a cured resin, and a
filler embedded in the cured resin. Further, a method of preparing
a nanoparticle-containing curable resin system is provided
including mixing from 1 to 70 weight percent of aggregated layered
nanoparticles with a curable resin and a dispersant to form a
mixture. The mixture contains less than 2% by weight solvent. The
method also includes milling the mixture in an immersion mill
containing milling media to form a milled resin system including
layered nanoparticles dispersed in the curable resin.
Inventors: |
Condo; Peter D.; (Lake Elmo,
MN) ; Swanson; Jeremy O.; (Woodbury, MN) ;
Thorson; James E.; (Hudson, WI) ; Sharma; Neeraj;
(Woodbury, MN) ; Hackett; Steven C.; (Oakdale,
MN) ; Thunhorst; Kristin L.; (Stillwater,
MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
3M INNOVATIVE PROPERTIES COMPANY |
Saint Paul |
MN |
US |
|
|
Family ID: |
51392443 |
Appl. No.: |
14/911110 |
Filed: |
August 12, 2014 |
PCT Filed: |
August 12, 2014 |
PCT NO: |
PCT/US2014/050663 |
371 Date: |
February 9, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61865308 |
Aug 13, 2013 |
|
|
|
61909575 |
Nov 27, 2013 |
|
|
|
61918302 |
Dec 19, 2013 |
|
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|
62018993 |
Jun 30, 2014 |
|
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Current U.S.
Class: |
523/443 |
Current CPC
Class: |
B05D 2601/02 20130101;
C08K 7/00 20130101; C08J 2333/08 20130101; C08K 9/06 20130101; C08K
2201/011 20130101; C08K 9/04 20130101; C08K 3/36 20130101; C08K
2201/003 20130101; C08J 2363/00 20130101; C08K 7/28 20130101; C08L
63/00 20130101; C08J 5/005 20130101; C08K 7/18 20130101; C08K 9/06
20130101; C08K 3/36 20130101; B05D 2601/22 20130101; C08K 9/06
20130101; C09D 7/20 20180101; C08J 5/24 20130101; C09D 7/40
20180101; C08J 2333/24 20130101; C08L 71/00 20130101; C08K 3/36
20130101; C08L 63/00 20130101; C08L 63/00 20130101; C08L 63/00
20130101; C08L 63/00 20130101; C08K 9/06 20130101 |
International
Class: |
C08K 7/00 20060101
C08K007/00; C08J 5/24 20060101 C08J005/24 |
Claims
1. A nanocomposite including layered nanoparticles and a dispersant
dispersed in a curable resin, wherein the nanocomposite contains
less than 2% by weight solvent, wherein the curable resin comprises
an epoxy resin, a curable imide resin, a vinyl ester resin, an
acrylic resin, a bisbenzocyclobutane resin, a polycyanate ester
resin, or a mixture thereof.
2. The nanocomposite of claim 1 wherein the layered nanoparticles
include a platelet shape, an acicular shape, an irregular shape, or
combinations thereof.
3. The nanocomposite of claim 1 wherein the platelet shaped
nanoparticles include talc, halloysite, hydrotalcite,
montmorillonite, kaolin, mica, or combinations thereof.
4. The nanocomposite of claim 1 wherein the dispersant includes an
anchoring group and a tail portion.
5. The nanocomposite of claim 1 further comprising a catalyst for
reacting silanol groups on the surface of the nanoparticles with
the curable resin system.
6. The nanocomposite of claim 1 further including a surface
treatment agent including an organosilane, a monohydric alcohol, a
polyol, or a combination thereof.
7. The nanocomposite of claim 1 further comprising at least one
diluent comprising a mono- or poly-functional glycidyl ether or
styrene.
8. The nanocomposite of claim 1 further comprising at least one
additive selected from the group consisting of curing agents, cure
accelerators, defoamers, air release agents, crosslinking agents,
dyes, flame retardants, pigments, impact modifiers, and flow
control agents.
9. (canceled)
10. The nanocomposite of claim 1 wherein the nanocomposite
comprises from about 15 to about 50 weight percent of the layered
nanoparticles.
11. The nanocomposite of claim 1 further comprising a filler
comprising at least one of reinforcing continuous fibers,
reinforcing discontinuous fibers, and hollow glass bubbles, wherein
the filler comprises carbon, glass, ceramic, boron, silicon
carbide, basalt, ceramic, polyimide, polyamide, polyethylene,
polypropylene, polyacrylnitrile, or a combination thereof.
12. A prepreg comprising the nanocomposite of claim 1.
13. A composite comprising from about 1 to 70 weight percent of
layered nanoparticles, and a dispersant, dispersed in a cured
resin; and a filler embedded in the cured resin, wherein the filler
comprises at least one of a reinforcing continuous fiber,
reinforcing discontinuous fibers, and hollow glass bubbles, wherein
the cured resin comprises an epoxy resin, a cured imide resin, a
vinyl ester resin, an acrylic resin, a bisbenzocyclobutane resin, a
polycyanate ester resin, or a mixture thereof.
14. The composite of claim 13, wherein the layered nanoparticles
include a platelet shape, an acicular shape, an irregular shape, or
combinations thereof.
15. An article comprising from about 1 to about 70 weight percent
of layered nanoparticles, and a dispersant, dispersed in a cured
resin, wherein the cured resin comprises an epoxy resin, a cured
imide resin, a vinyl ester resin, an acrylic resin, a
bisbenzocyclobutane resin, a polycyanate ester resin, or a mixture
thereof.
16. The article of claim 15 wherein the layered nanoparticles
include a platelet shape, an acicular shape, an irregular shape, or
combinations thereof.
17. The article of claim 15 wherein the article comprises a turbine
blade, a pressure vessel, an aerospace part, a cable, or sporting
goods equipment.
18. The article of claim 17, wherein the article comprises a
pressure vessel.
19. A method of preparing a nanoparticle-containing curable resin
system comprising: mixing from 1 to 70 weight percent of aggregated
layered nanoparticles with a curable resin, a first dispersant, and
optionally a catalyst, a surface treatment agent, and/or a diluent,
to form a first mixture, wherein the mixture comprises less than 2%
by weight solvent; and milling the first mixture in a first
immersion mill comprising milling media to form a milled resin
system comprising layered nanoparticles and the first dispersant
dispersed in the curable resin.
20. The method of claim 19 wherein the layered nanoparticles
include a platelet shape, an acicular shape, an irregular shape, or
combinations thereof.
21. The method of claim 19 wherein the platelet shaped
nanoparticles include talc, halloysite, hydrotalcite,
montmorillonite, kaolin, mica, or combinations thereof.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional Patent
Applications 61/918,302, filed on Dec. 19, 2013, 61/865,308, filed
on Aug. 13, 2013, 61/909,575, filed on Nov. 27, 2013 and
62/018,993, filed on Jun. 30, 2014, the disclosures of which are
incorporated by reference in their entireties.
TECHNICAL FIELD
[0002] The present disclosure relates to nanocomposites,
composites, and articles that contain layered nanoparticles and
dispersant, as well as methods of making the same.
BACKGROUND
[0003] A persistent issue for nanocomposites, and in turn
composites that contain nanoparticles, is cost, including cost
associated with the processing steps. One approach to processing
nanocomposites is a solvent-based approach where an aqueous
dispersion of nanoparticles is the raw material. The dispersion is
typically dilute, in which the nanoparticles are present in an
amount between about 15-40 weight percent. A solvent, typically a
water-miscible solvent, is added in a 1:1 ratio with the water in
the dispersion, further diluting the nanoparticles. The solvent is
typically chosen so that the dispersed state of the nanoparticles
is maintained. The solvent further serves to counteract the
thickening effect of, for instance, silica nanoparticles, on resin
systems. A surface treating agent is typically used to make the
nanoparticles more compatible with the matrix resin. The surface
treating agent is typically soluble in the
water:solvent:nanoparticle dispersion. After completion of the
surface treatment process, the modified nanoparticle dispersion is
mixed with resin. This is followed by removal of the water and
solvent to yield a nanocomposite.
[0004] There is a cost associated with the processes of preparing
the nanoparticle aqueous dispersion, addition of solvent, surface
treatment of the nanoparticles, compounding the nanoparticles into
a resin, and removal of the water and solvent to form the
nanocomposite. The removal of water and solvent is typically the
most expensive of these processes.
[0005] Another approach to processing nanocomposites is the
solvent-free approach where dry, aggregated particles are reduced
in size, surface treated, and compounded into a resin by a
mechanical grinding process (e.g., milling) without the aid of a
solvent.
SUMMARY
[0006] The present disclosure provides nanocomposites and articles
that contain layered nanoparticles, and methods of making the
nanocomposites and articles, which have decreased cost of materials
and processing, as compared to other preparation approaches.
[0007] In a first embodiment, the present disclosure provides a
nanocomposite including layered nanoparticles and a dispersant,
dispersed in a curable resin, wherein the nanocomposite contains
less than 2% by weight solvent.
[0008] In a second embodiment, the present disclosure provides a
composite including from about 1 to 70 weight percent of layered
nanoparticles, and a dispersant, dispersed in a cured resin, and a
filler embedded in the cured resin. The filler comprises at least
one of a reinforcing continuous fiber, reinforcing discontinuous
fibers, and hollow glass bubbles.
[0009] In a third embodiment, the present disclosure provides an
article including from about 1 to about 70 weight percent of
layered nanoparticles, and a dispersant, dispersed in a cured
resin.
[0010] In a fourth embodiment, the present disclosure provides a
method of preparing a nanoparticle-containing curable resin system
including mixing from 1 to 70 weight percent of aggregated layered
nanoparticles with a curable resin, a first dispersant, and
optionally a catalyst, a diluent, a surface treatment agent, and/or
a curing agent, to form a mixture. The mixture contains less than
2% by weight solvent. The method further includes milling the first
mixture in a first immersion mill containing milling media to form
a milled resin system comprising layered nanoparticles and the
dispersant dispersed in the curable resin.
[0011] Various unexpected results and advantages are obtained in
exemplary embodiments of the disclosure. One such advantage of
exemplary embodiments of the present disclosure is the ability to
produce low cost, high performance layered nanocomposites and
articles. Another potential advantage of exemplary embodiments of
the present disclosure is the ability to prepare dispersions of
layered nanoparticles in curable resin and/or in a curing agent at
high loading amounts without the use of solvents.
[0012] The above summary of the present disclosure is not intended
to describe each disclosed embodiment or every implementation of
the present disclosure. The description that follows more
particularly exemplifies illustrative embodiments. In several
places throughout the application, guidance is provided through
lists of examples, which examples can be used in various
combinations. In each instance, the cited list serves only as a
representative group and should not be interpreted as an exclusive
list.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a graph presenting the measured viscosity of each
of Comparative Example 1, Comparative Example 2, Example 1, Example
2, and Example 3.
[0014] FIG. 2 is a graph presenting the measured storage modulus in
the rubber plateau region and in the glassy region of each of
Comparative Example 1a, Comparative Example 2a, Example 1a, Example
2a, and Example 3a.
[0015] FIG. 3A is a scanning electron microscope (SEM) image of
Example 1a.
[0016] FIG. 3B is an SEM image of Example 1a, having a higher
magnification than the SEM image of FIG. 3A.
[0017] FIG. 4A is a scanning electron microscope (SEM) image of
Example 2a.
[0018] FIG. 4B is an SEM image of Example 2a, having a higher
magnification than the SEM image of FIG. 4A.
[0019] FIG. 5A is a scanning electron microscope (SEM) image of
Example 3a.
[0020] FIG. 5B is an SEM image of Example 3a, having a higher
magnification than the SEM image of FIG. 5A.
DETAILED DESCRIPTION
[0021] Nanocomposites, composites, and articles are provided that
contain layered nanoparticles, as well as methods of making the
nanocomposites, composites, and articles. There is a need for a
more efficient process for the incorporation of layered
nanoparticles into nanocomposites and articles.
[0022] For the following Glossary of defined terms, these
definitions shall be applied for the entire application, unless a
different definition is provided in the claims or elsewhere in the
specification.
GLOSSARY
[0023] Certain terms are used throughout the description and the
claims that, while for the most part are well known, may require
some explanation. It should be understood that, as used herein:
[0024] As used in this specification and the appended embodiments,
the singular forms "a", "an", and "the" include plural referents
unless the content clearly dictates otherwise. Thus, for example,
reference to "a compound" includes a mixture of two or more
compounds.
[0025] As used in this specification and the appended embodiments,
the term "or" is generally employed in its sense including "and/or"
unless the content clearly dictates otherwise. The term "and/or"
means either or both. For example, the expression "A and/or B"
means A, B, or a combination of A and B.
[0026] As used in this specification, the recitation of numerical
ranges by endpoints includes all numbers subsumed within that range
(e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.8, 4, and 5).
[0027] Unless otherwise indicated, all numbers expressing
quantities or ingredients, measurement of properties and so forth
used in the specification and embodiments are to be understood as
being modified in all instances by the term "about." Accordingly,
unless indicated to the contrary, the numerical parameters set
forth in the foregoing specification and attached listing of
embodiments can vary depending upon the desired properties sought
to be obtained by those skilled in the art utilizing the teachings
of the present disclosure. At the very least, and not as an attempt
to limit the application of the doctrine of equivalents to the
scope of the claimed embodiments, each numerical parameter should
at least be construed in light of the number of reported
significant digits and by applying ordinary rounding
techniques.
[0028] The term "comprises" and variations thereof do not have a
limiting meaning where these terms appear in the description and
claims.
[0029] The words "preferred" and "preferably" refer to embodiments
of the disclosure that may afford certain benefits, under certain
circumstances. However, other embodiments may also be preferred,
under the same or other circumstances. Furthermore, the recitation
of one or more preferred embodiments does not imply that other
embodiments are not useful, and is not intended to exclude other
embodiments from the scope of the disclosure.
[0030] The term "nanoparticle" refers to particles that are
submicron in size. The nanoparticles have an average particle size,
which refers to the average longest dimension of the particles,
that is no greater than 1000 nanometers, no greater than 500
nanometers, no greater than 200 nanometers, no greater than 100
nanometers, no greater than 75 nanometers, no greater than 50
nanometers, no greater than 40 nanometers, no greater than 25
nanometers, or no greater than 20 nanometers. The average particle
size is often determined using transmission electron microscopy but
various light scattering methods (e.g., laser diffraction) can be
used as well. The average particle size typically refers to the
average size of non-agglomerated and/or non-aggregated single
nanoparticles.
[0031] The term "agglomerated" refers to a weak association of
primary particles or aggregated particles usually held together by
charge or polarity. Agglomerated particles can typically be broken
down into smaller entities by, for example, shearing forces
encountered during dispersion of the agglomerated particles in a
liquid.
[0032] The terms "aggregated" and "aggregates" refer to a strong
association of primary particles often bound together by, for
example, residual chemical treatment, covalent chemical bonds, or
ionic chemical bonds. Further breakdown of the aggregates into
smaller entities is very difficult to achieve.
[0033] The term "spherical" means a round body whose surface is at
all points equidistant from the center. The term "nonspherical"
means any shape other than essentially spherical, including for
example and without limitation, platelet, acicular, conical,
diamond shaped, cubic, rhombohedral, pyramidal, and oval, and
including regular and/or irregular shapes. For instance, a shape
that is at least partially spherical but has portions missing from
the sphere is encompassed by the term nonspherical.
[0034] The term "acicular" encompasses shapes such as rods,
ellipsoids, needles, and the like. In certain embodiments, an
acicular shape may further be hollow, e.g., a hollow needle shape.
Certain nonspherical shapes have an aspect ratio of at least 2:1,
at least 3:1, at least 5:1, or at least 10:1. The term "aspect
ratio" refers to the ratio of the average longest dimension (e.g.,
of a nanoparticle) to the average shortest dimension.
[0035] As used herein, the term "silicate" refers to a compound
including at least one SiO.sub.2 or SiO.sub.4 group and at least
one metallic ion, and optionally including hydrogen. As used
herein, the term "layered silicate" refers to a silicate having a
structure that shears or cleaves into layers upon being subjected
to mechanical force (and optionally treatment with an intercalating
agent). The term "cationic clay" as used herein refers to a
material containing silicon, aluminum, or magnesium, as well as
oxygen and hydroxyl with various associated cations, and
encompasses layered silicates.
[0036] As used herein, the term "layered double hydroxide" refers
to a class of materials with positively charged layers and weakly
bound charge-balancing anions located in the interlayer region,
having a structure that shears or cleaves into layers upon being
subjected to mechanical force (and optionally treatment with an
intercalating agent). The term "anionic clay" as used herein refers
to a material containing silicon, aluminum, or magnesium, as well
as oxygen and hydroxyl with various associated anions, and
encompasses layered double hydroxides.
[0037] As used herein, the term "intercalate" refers to insertion
of a material between one or more layers of a layered nanoparticle.
As used herein, the term "intercalated" refers to a layered
nanoparticle containing at least two adjacent layers separated by a
material that is disposed between the layers.
[0038] As used herein, the term "intercalating agent" refers to a
material that is disposed between layers of layered nanoparticles
to assist in intercalating and/or exfoliating layered
nanoparticles.
[0039] As used herein, the term "exfoliate" refers to completely
separating at least one layer of a layered nanoparticle from the
one or more other layers of the layered nanoparticle. As used
herein, the term "exfoliated" refers to a layered nanoparticle that
has had at least one layer of a layered nanoparticle from the one
or more other layers of the layered nanoparticle. A completely
exfoliated layered nanoparticle has had all of its individual
layers separated from each other.
[0040] As used herein, the term "silica" refers to amorphous
silicon dioxide (SiO.sub.2). As used herein, the term "pyrogenic"
silica refers to silicon dioxide formed in flame or in sufficiently
high temperature to decompose organic materials.
[0041] As used herein, the term "silica nanoparticle" refers to a
nanoparticle having a silica surface. This includes nanoparticles
that are substantially, entirely silica, as well nanoparticles
comprising other inorganic (e.g., metal oxide) or organic cores
having a silica surface. In some embodiments, the core comprises a
metal oxide. Any known metal oxide may be used. Exemplary metal
oxides include silica, titania, alumina, zirconia, vanadia,
chromia, antimony oxide, tin oxide, zinc oxide, ceria, and mixtures
thereof.
[0042] The term "curable" as used herein means chemically or
physically crosslinkable to form a glassy, insoluble, non-flowable
network which is maintained under normal use conditions.
[0043] The term "cured" as used herein means chemically or
physically crosslinked in the form of a glassy, insoluble,
non-flowable network which is maintained under normal use
conditions.
[0044] The term "resin" as used herein means one polymer or at
least two polymers blended together, in either solid or molten
form.
[0045] The term "matrix" as used herein in the term "matrix resin"
refers to a curable or cured resin into which additional components
may be included (e.g., particles, fibers, etc.).
[0046] The term "nanocomposite" as used herein refers to a material
comprising a curable or cured resin and nanoparticles.
[0047] The term "microcomposite" as used herein refers to a
material comprising a curable or cured resin and microparticles,
which is inclusive of microparticles and agglomerates and/or
aggregates of nanoparticles.
[0048] The term "composite" as used herein refers to a cured
nanocomposite comprising a cured resin, layered nanoparticles, and
a filler comprising at least one of a continuous fiber,
discontinuous fibers, and hollow glass bubbles. Continuous fibers
include for example and without limitation, glass, carbon, basalt,
ceramic (e.g., NEXTEL ceramic oxide fibers available from 3M
Company (St. Paul, Minn.)), and organic fibers (e.g., aromatic
polyamide (e.g., KEVLAR available from DuPont (Wilmington, Del.)),
polypropylene, and polyacrylnitrile).
[0049] The term "article" as used herein refers to an object
comprising a cured nanocomposite comprising a cured resin and
layered nanoparticles, and optionally a filler comprising at least
one of a reinforcing continuous fiber, reinforcing discontinuous
fibers, and hollow glass bubbles (i.e., a composite).
[0050] The term "neat" as used herein in the term "neat resin"
refers to a curable or cured resin which does not include a
macroscopic filler (e.g., continuous or discontinuous fibers,
hollow glass bubbles, etc.).
[0051] The term "(co)polymer" is inclusive of both homopolymers
containing a single monomer and copolymers containing two or more
different monomers.
[0052] The term "(meth)acrylic" or "(meth)acrylate" is inclusive of
both acrylic and methacrylic (or acrylate and methacrylate).
[0053] The term "aliphatic group" means a saturated or unsaturated
linear or branched hydrocarbon group. This term is used to
encompass alkyl, alkenyl, and alkynyl groups, for example.
[0054] The term "alkyl group" means a saturated linear or branched
hydrocarbon group including, for example, methyl, ethyl, isopropyl,
t-butyl, heptyl, dodecyl, octadecyl, amyl, 2-ethylhexyl, and the
like. The term "alkylene group" refers to a divalent alkyl
group.
[0055] The term "heteroalkyl group" means an alkyl group having at
least one --CH.sub.2-- replaced with a heteroatom such as O or S.
In many embodiments, the heteroalkyl group is a monovalent
polyether group. The term "heteroalkylene group" refers to a
divalent heteroalkyl group. In many embodiments, the heteroalkylene
group is a divalent polyether group.
[0056] The term "alicyclic group" means a cyclic hydrocarbon group
having properties resembling those of aliphatic groups. The term
"aromatic group" or "aryl group" means a mono- or polynuclear
aromatic hydrocarbon group.
[0057] The term "unsaturation" means either a double bond between
two atoms (e.g., C.dbd.C), or a triple bond between two atoms
(e.g., C.ident.C).
[0058] When a group is present more than once in a formula
described herein, each group is "independently" selected, whether
specifically stated or not. For example, when more than one R group
is present in a formula, each R group is independently
selected.
[0059] The term "component" refers to any compound (e.g., any
reactant), heterogeneous catalyst, solvent, or other material,
which is present in a reactor.
[0060] Reference throughout this specification to "one embodiment,"
"certain embodiments," "one or more embodiments" or "an
embodiment," whether or not including the term "exemplary"
preceding the term "embodiment," means that a particular feature,
structure, material, or characteristic described in connection with
the embodiment is included in at least one embodiment of the
certain exemplary embodiments of the present disclosure. Thus, the
appearances of the phrases such as "in one or more embodiments,"
"in certain embodiments," "in one embodiment," "in many
embodiments" or "in an embodiment" in various places throughout
this specification are not necessarily referring to the same
embodiment of the certain exemplary embodiments of the present
disclosure. Furthermore, the particular features, structures,
materials, or characteristics may be combined in any suitable
manner in one or more embodiments.
[0061] Various exemplary embodiments of the disclosure will now be
described. Exemplary embodiments of the present disclosure may take
on various modifications and alterations without departing from the
spirit and scope of the disclosure. Accordingly, it is to be
understood that the embodiments of the present disclosure are not
to be limited to the following described exemplary embodiments, but
are to be controlled by the limitations set forth in the claims and
any equivalents thereof.
[0062] Thus, in a first exemplary embodiment, the disclosure
provides a nanocomposite comprising layered nanoparticles and a
dispersant, dispersed in a curable resin; wherein the nanocomposite
comprises less than 2% by weight solvent. Preferably, the
nanocomposite comprises less than 0.5% by weight solvent, or even
more preferably the nanocomposite comprises essentially no
solvent.
[0063] In a second exemplary embodiment, the disclosure provides a
composite comprising from about 1 to 70 weight percent of layered
nanoparticles, and a dispersant, dispersed in a cured resin, and a
filler embedded in the cured resin. The filler comprises at least
one of a reinforcing continuous fiber, reinforcing discontinuous
fibers, and hollow glass bubbles. In certain embodiments, an
article is provided comprising the composite.
[0064] In a third exemplary embodiment, the present disclosure
provides an article comprising from about 1 to about 70 weight
percent of layered nanoparticles, and a dispersant, dispersed in a
cured resin.
[0065] In a fourth exemplary embodiment, the present disclosure
provides a method of preparing a nanoparticle-containing curable
resin system comprising mixing from 1 to 70 weight percent of
aggregated layered nanoparticles with a curable resin, a first
dispersant, and optionally a catalyst, a diluent, a surface
treatment agent, and/or a curing agent, to form a mixture
comprising less than 2% by weight solvent; and milling the first
mixture in a first immersion mill containing milling media to form
a milled resin system comprising layered nanoparticles and the
dispersant dispersed in the curable resin.
[0066] Accordingly, in a third exemplary embodiment, an article is
provided comprising a nanocomposite comprising from about 1 to
about 70 weight percent of layered nanoparticles and a dispersant
dispersed in a cured resin. In certain aspects, the article
contains from about 1 to about 3 weight percent, or from about 10
to about 70 weight percent, or from about 1 to about 5 weight
percent, or from about 15 to about 50 weight percent, or from about
20 to about 50 weight percent, or from about 25 to about 50 weight
percent, or from about 15 to about 70 weight percent, or from about
25 to about 70 weight percent, or from about 35 to about 70 weight
percent, or from about 50 to about 70 weight percent of the layered
nanoparticles.
[0067] In certain embodiments, the nanocomposite or article further
comprises one or more additional components (e.g., additives), for
example and without limitation, catalysts, surface treatment
agents, reactive diluents, curing agents, cure accelerators,
defoamers, air release agents, crosslinking agents, dyes, flame
retardants, pigments, impact modifiers, and flow control
agents.
[0068] Layered nanoparticles often have an average width (smallest
dimension) equal to at least 1 nanometer, at least 2 nanometers, or
at least 5 nanometers. The average width of layered nanoparticles
is often no greater than 250 nanometers, no greater than 100
nanometers, no greater than 50 nanometers, no greater than 25
nanometers, or no greater than 15 nanometers. The layered
nanoparticles will have a different length than width, and can have
an average length D1 measured by dynamic light scattering methods
that is, for example, at least 25 nanometers, at least 50
nanometers, at least 75 nanometers, or at least 100 nanometers. The
average length D1 (e.g., longer dimension) can be up to 200
nanometers, up to 400 nanometers, or up to 500 nanometers. Acicular
layered particles may have an elongation ratio D1/D2 in a range of
5 to 30, wherein D2 means a diameter in nanometers calculated by
the equation D2=2720/S and S means specific surface area in meters
squared per gram (m.sup.2/gram) of the nanoparticle, as described
in U.S. Pat. No. 5,221,497 (Watanabe et al.).
[0069] In certain embodiments, the layered nanoparticles are
selected to have an average specific surface area equal to at least
20 m.sup.2/gram, at least 50 m.sup.2/gram, at least 100
m.sup.2/gram, at least 150 m.sup.2/gram, at least 200 m.sup.2/gram,
at least 250 m.sup.2/gram, at least 300 m.sup.2/gram, or at least
400 m.sup.2/gram. Nanoparticles having average specific surface
areas equal to at least 150 m.sup.2/gram often have an average
diameter (e.g., longest dimension) less than 40 nanometers, less
than 30 nanometers, less than 25 nanometers, or less than 20
nanometers.
[0070] Various sizes and/or various shapes of layered a
nanoparticles may be used in combination. In certain embodiments,
bimodal distributions of particle sizes may be used. For example,
nanoparticles having an average particle size (i.e., of the length
of the longest dimension) of at least 50 nanometers (e.g., in the
range of 50 to 200 nanometers or in the range of 50 to 100
nanometers) can be used in combination with nanoparticles having an
average particle size no greater than 40 nanometers. The weight
ratio of the larger to smaller nanoparticles can be in the range of
2:98 to 98:2, in the range of 5:95 to 95:5, in the range of 10:90
to 90:10, or in the range of 20:80 to 80:20. Nanocomposites having
a bimodal distribution of layered nanoparticles can include 2 to 20
weight percent layered nanoparticles having an average particle
size of 40 nanometers or less and 2 to 40 weight percent layered
nanoparticles having an average particle size of 50 nanometers or
greater. The amount is based on a total weight of the
nanocomposite. In an aspect, the layered nanoparticles comprise a
bimodal particle size distribution. In another aspect, the layered
nanoparticles comprise a unimodal particle size distribution. In
some embodiments, the layered nanoparticle cores have a narrow
particle size distribution.
[0071] The layered nanoparticles typically comprise an average
particle size of the longest dimension in the range from about 1
nanometer to about 1000 nanometers, or from about 1 nanometer to
about 500 nanometers, or from about 1 nanometer to about 100
nanometers, or from about 1 nanometer to about 50 nanometers, or
from about 100 nanometers to about 400 nanometers, or from about
500 nanometers to about 1000 nanometers. In certain embodiments,
the layered nanoparticles include a population of clusters of
primary nanoparticles (e.g., an aggregate of layered
nanoparticles), wherein the cluster is defined to have an irregular
shape and is submicron in size. The population of clusters (i.e.,
the clusters within the population) has a mean size, which refers
to the average longest dimension of the clusters of primary
nanoparticles, that is no greater than 1000 nanometers, no greater
than 500 nanometers, no greater than 200 nanometers, no greater
than 100 nanometers, no greater than 75 nanometers, no greater than
50 nanometers, or no greater than 40 nanometers. In some
embodiments, the layered nanoparticles are substantially
non-agglomerated.
[0072] The layered particles to be included in a nanocomposite are
typically commercially available in the form of a layered
microparticle powder, for example and without limitation, talc,
halloysite, hydrotalcite, montmorillonite, kaolin, and mica.
Example layered silicate powder is available as talc (e.g.,
magnesium silicate) under the trade designation JETFINE (e.g.,
JETFINE 3 cc) from Emerys Talc America (San Jose, Calif.), and as
halloysite (e.g., aluminosilicate) under the trade designation
DRAGONITE XR from Applied Materials, Inc. (New York, N.Y.). Example
layered double hydroxide powder is available as hydrotalcite (e.g.,
hydrous aluminum and magnesium hydroxide with carbonate) under the
trade designation PURAL MG 63 HT from Sasol Germany GmbH (Hamburg,
Germany).
[0073] In certain embodiments, the nanocomposite or composite
comprises from about 1 to about 70 weight percent of the layered
nanoparticles, or from about 3 to about 30 weight percent, or from
about 5 to about 30 weight percent, or from about 10 to about 50
weight percent, or from about 10 to about 70 weight percent, or
from about 15 to about 30 weight percent, or from about 15 to about
50 weight percent, or from about 20 to about 50 weight percent, or
from about 25 to about 50 weight percent, or from about 15 to about
70 weight percent, or from about 25 to about 70 weight percent, or
from about 35 to about 70 weight percent, or from about 50 to about
70 weight percent of the layered nanoparticles. In an aspect, the
nanocomposite consists essentially of the layered nanoparticles and
a dispersant dispersed in the curable resin. In an aspect, the
article consists essentially of the layered nanoparticles and a
dispersant dispersed in the cured resin.
[0074] Nanoparticles, including surface-modified nanoparticles,
have been compounded into curable resins to alter the properties of
the resulting cured resin system. For example, U.S. Pat. No.
5,648,407 (Goetz et al.) describes, among other things, curable
resins comprising colloidal microparticles in curable resin, and
the use of such particle-containing resins in combination with
reinforcing fibers. International Patent Publication No.
WO2008/027979 (Goenner et al.) describes, among other things, resin
systems comprising one or more crosslinkable resins, one or more
reactive diluents, and a plurality of reactive, surface-modified
nanoparticles.
[0075] Traditionally, nanoparticles have been compounded into
resins using a combination of solvent exchange and solvent
stripping processes. In addition to being time-consuming and
requiring the use of multiple solvents, such processes often expose
the curable resins to high temperatures. Such high temperatures can
lead to oligomerization and other undesirable reactions during the
compounding process with a resultant increase in viscosity. In
addition, low-boiling-temperature components (e.g., volatile
reactive diluents) may be lost during these compounding steps.
[0076] Moreover, prior to solvent stripping, silica nanoparticle
dispersions typically contain only about 20% by weight
nanoparticles, thus to make a concentrated (e.g., 50 wt. %)
nanocomposite is difficult, particularly when employing a batch
process requiring a large volume stripping unit to contain the
feed, 80 vol. % of which is waste (e.g., water and solvent).
[0077] Alternatively, layered nanoparticles have been compounded
into resins using layered nanoparticles that are pretreated with
intercalating agents to intercalate the layered nanoparticles prior
to dispersion. For instance, common intercalating agents include
tertiary and quaternary ammonium salts (e.g., trimethyl octadecyl
ammonium chloride, dimethyl dioctadecyl ammonium chloride, dimethyl
benzyl octadecyl ammonium chloride, and tetraethyl ammonium
chloride), octadecylamine, w-aminododecanoic acid, methyl
cocodipolyethylene glycol, protonated alkyl amines (e.g., butyl,
hexyl, octyl, dodecyl, hexadecyl, or octadecyl),
2-phenylethylamine, methyl tallow dihydroxy ethyl ammonium
chloride, quaternary phosphonium bromides (e.g., tributyl hexadecyl
phosphonium bromide), 1,2-dimethyl-3-n-hexadecyl imidazolium
bromide, bis(aminopropyl)-terminated oligo(propylene glycol),
1-methyl-2-norstearyl-3-stearinoacid amidoethyldihydroimidazolinium
methyl sulfate, hydroxyethyl dihydroimidazolinium chloride, ricinyl
dihydroimidazolinium chloride, and a dimethyl isophthalate
substituted with a triphenylphosphonium group.
[0078] Further, layered nanoparticles have been intercalated in
situ using liquid monomers, such as monomers of thermoplastic
polymers, or melt-intercalated by molten polymers. In such methods
the layered nanoparticles are typically swollen with liquid monomer
or molten polymer prior to curing.
[0079] The present disclosure provides alternative procedures for
combining layered nanoparticles, including agglomerated layered
nanoparticles, into a curable resin. These procedures do not
require the use of solvents or pretreatments and may be used to
compound curable resins without causing premature cure.
[0080] Layered particles have been included in resin systems as
thickeners; generally, the larger the aspect ratio, the greater the
increase in viscosity of the layered particle-containing resin.
Such thickening effects can be observed at layered particle
loadings of as little as 5 weight percent (wt. %), 3 wt. %, or even
2 wt. %. Typically, a loading of about 10 weight percent or more
layered microparticles or layered nanoparticles in resin poses
challenges with respect to effective dispersion of the particles
within the resin. For example, high resin system viscosities (e.g.,
greater than about 1,000 centipoises (cP), or greater than about
5,000 cP) inhibits dispersion of layered particles into a resin
system according to usual methods. Moreover, a decrease in tensile
strength, impact strength, fracture toughness, and strain at break
of polymer clay composites has been reported as clay content
increases, believed to be due to agglomeration of clay particles at
higher concentrations higher viscosity, and nanovoid formation from
entrapped air bubbles during sample preparation. (See Azeez A A et
al. Epoxy clay nanocomposites--processing, properties and
applications: A review. Composites: Part B, volume 45, issue 1,
February 2013, pp. 308-320.)
[0081] In contrast to prior systems, certain embodiments of the
nanocomposites, articles, and methods of the present disclosure
achieve dispersion of layered particles at high loadings (e.g., at
least 4 wt. %, at least 6 wt. %, at least 8 wt. %, at least 10 wt.
%, at least 12 wt. %, at least 15 wt. %, at least 20 wt. %, at
least 25 wt. %, at least 30 wt. %, at least 35 wt. %, at least 40
wt. %, at least 45 wt. %, at least 50 wt. %, at least 55 wt. %, at
least 60 wt. %, or at least 65 wt. %) without requiring the use of
solvents to decrease the viscosity of the resin system. Similarly,
embodiments of the nanocomposites, articles, and methods of the
present disclosure achieve dispersion of layered nanoparticles at
high loadings without requiring a pretreatment of the layered
nanoparticles with surface treatment agents to improve the
compatibility of the layered nanoparticles with the specific
resin(s) of the resin system or to intercalate the layered
nanoparticles before dispersion.
[0082] Generally, curable resin systems are used in a wide variety
of applications, e.g., as a protective layer (e.g., gel coats) and
as the impregnation resin in composites. Advanced structural
composites, for example, are high modulus, high strength materials
useful in many applications requiring high strength to weight
ratios, e.g., applications in the automotive, sporting goods, and
aerospace industries. Exemplary composites include for example and
without limitation, a turbine blade, golf club, a baseball bat, a
fishing rod, a racquet, a bicycle frame, a pressure vessel (e.g., a
container having pressurized contents), an aerospace part (e.g., an
exterior panel of an airplane), and a cable (e.g., a hoist cable,
an underwater tether, an umbilical cable, and the like). Such
composites typically comprise reinforcing fibers (e.g., carbon or
glass) embedded in a cured matrix resin. Resin systems are often
selected based on the desired mechanical properties of the final
product including, e.g., hardness, toughness, fracture resistance,
and the like. In some applications, the optical appearance of the
finished product may be important such that properties like clarity
and haze must be considered. In addition, process conditions may
lead to preferred ranges for properties such as viscosity. Finally,
the desired end use of the product often leads to additional
requirements, e.g., erosion resistance or anti-blistering.
[0083] Curable resins suitable for use in the nanocomposites of the
invention are those resins, e.g., thermosetting resins and
radiation-curable resins, which are capable of being cured to form
a glassy network polymer. Suitable resins include, e.g., epoxy
resins, curable imide resins (especially maleimide resins, but also
including, e.g., commercial K-3 polyimides (available from DuPont)
and polyimides having a terminal reactive group such as acetylene,
diacetylene, phenylethynyl, norbornene, nadimide, or
benzocyclobutane), vinyl ester resins and acrylic resins (e.g.,
(meth)acrylic esters or amides of polyols, epoxies, and amines),
bisbenzocyclobutane resins, polycyanate ester resins, and mixtures
thereof. The resins can be utilized in the form of either monomers
or prepolymers. Preferred curable resins include epoxy resins,
maleimide resins, polycyanate ester resins, and mixtures thereof.
Epoxy resins are especially preferred due to their processing
characteristics, high temperature properties, and environmental
resistance.
[0084] Epoxy resins are well-known in the art and comprise
compounds or mixtures of compounds which contain one or more epoxy
groups of the structure
##STR00001##
[0085] The compounds can be saturated or unsaturated, aliphatic,
alicylic, aromatic, or heterocyclic, or can comprise combinations
thereof. Compounds which contain more than one epoxy group (i.e.,
polyepoxides) are preferred.
[0086] Polyepoxides which can be utilized in the nanocomposites of
the invention include, e.g., both aliphatic and aromatic
polyepoxides, but aromatic polyepoxides are preferred for high
temperature applications. The aromatic polyepoxides are compounds
containing at least one aromatic ring structure, e.g. a benzene
ring, and more than one epoxy group. Preferred aromatic
polyepoxides include the polyglycidyl ethers of polyhydric phenols
(e.g., bisphenol A derivative resins, epoxy cresol-novolac resins,
bisphenol F derivative resins, epoxy phenol-novolac resins),
glycidyl esters of aromatic carboxylic acids, and glycidyl amines
of aromatic amines. The most preferred aromatic polyepoxides are
the polyglycidyl ethers of polyhydric phenols.
[0087] Representative examples of aliphatic polyepoxides which can
be utilized in the nanocomposites of the invention include
3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate,
3,4-epoxycyclohexyloxirane,
2-(3',4'-epoxycyclohexyl)-5,1''-spiro-3'',4''-epoxycyclohexane-1,3-dioxan-
e, bis(3,4-epoxycyclohexylmethyl)adipate, the diglycidyl ester of
linoleic dimer acid, 1,4-bis(2,3-epoxypropoxy)butane,
4-(1,2-epoxyethyl)-1,2-epoxycyclohexane,
2,2-bis(3,4-epoxycyclohexyl)propane, polyglycidyl ethers of
aliphatic polyols such as glycerol or hydrogenated
4,4'-dihydroxydiphenyl-dimethylmethane, and mixtures thereof.
[0088] Representative examples of aromatic polyepoxides which can
be utilized in the nanocomposites of the invention include glycidyl
esters of aromatic carboxylic acids, e.g., phthalic acid diglycidyl
ester, isophthalic acid diglycidyl ester, trimellitic acid
triglycidyl ester, and pyromellitic acid tetraglycidyl ester, and
mixtures thereof; N-glycidylaminobenzenes, e.g.,
N,N-diglycidylbenzeneamine,
bis(N,N-diglycidyl-4-aminophenyl)methane,
1,3-bis(N,N-diglycidylamino)benzene, and
N,N-diglycidyl-4-glycidyloxybenzeneamine, and mixtures thereof; and
the polyglycidyl derivatives of polyhydric phenols, e.g.,
2,2-bis-[4-(2,3-epoxypropoxy)phenyl]propane, the polyglycidyl
ethers of polyhydric phenols such as
tetrakis(4-hydroxyphenyl)ethane, pyrocatechol, resorcinol,
hydroquinone, 4,4'-dihydroxydiphenyl methane,
4,4'-dihydroxydiphenyl dimethyl methane,
4,4'-dihydroxy-3,3'-dimethyldiphenyl methane,
4,4'-dihydroxydiphenyl methyl methane, 4,4'-dihydroxydiphenyl
cyclohexane, 4,4'-dihydroxy-3,3'-dimethyldiphenyl propane,
4,4'-dihydroxydiphenyl sulfone, and tris-(4-hydroxyphenyl)methane,
polyglycidyl ethers of novolacs (reaction products of monohydric or
polyhydric phenols with aldehydes in the presence of acid
catalysts), and the derivatives described in U.S. Pat. No.
3,018,262 (Schoeder) and U.S. Pat. No. 3,298,998 (Coover et al.),
the descriptions of which are incorporated herein by reference, as
well as the derivatives described in the Handbook of Epoxy Resins
by Lee and Neville, McGraw-Hill Book Co., New York (1967) and in
Epoxy Resins, Chemistry and Technology, Second Edition, edited by
C. May, Marcel Dekker, Inc., New York (1988), and mixtures thereof.
A preferred class of polyglycidyl ethers of polyhydric phenols for
use in the nanocomposites of the invention is the diglycidyl ethers
of bisphenol that have pendant carbocyclic groups, e.g., those
described in U.S. Pat. No. 3,298,998 (Coover et al.), the
description of which is incorporated herein by reference. Examples
of such compounds include
2,2-bis[4-(2,3-epoxypropoxy)phenyl]norcamphane and
2,2-bis[4-(2,3-epoxypropoxy)phenyl]decahydro-1,4,5,8-dimethanonaphthalene-
. A preferred compound is
9,9-bis[4-(2,3-epoxypropoxy)phenyl]fluorene.
[0089] Suitable epoxy resins can be prepared by, e.g., the reaction
of epichlorohydrin with a polyol, as described, e.g., in U.S. Pat.
No. 4,522,958 (Das et al.), the description of which is
incorporated herein by reference, as well as by other methods
described by Lee and Neville and by May, supra. Many epoxy resins
are also commercially available.
[0090] Maleimide resins suitable for use in the nanocomposites of
the invention include bismaleimides, polymaleimides, and
polyaminobismaleimides. Such maleimides can be conveniently
synthesized by combining maleic anhydride or substituted maleic
anhydrides with di- or polyamine(s). Preferred are
N,N'-bismaleimides, which can be prepared, e.g., by the methods
described in U.S. Pat. No. 3,562,223 (Bargain et al.), U.S. Pat.
No. 3,627,780 (Bonnard et al.), U.S. Pat. No. 3,839,358 (Bargain),
and U.S. Pat. No. 4,468,497 (Beckley et al.) (the descriptions of
which are incorporated herein by reference) and many of which are
commercially available.
[0091] Representative examples of suitable N,N'-bismaleimides
include the N,N'-bismaleimides of 1,2-ethanediamine,
1,6-hexanediamine, trimethyl-1,6-hexanediamine, 1,4-benzenediamine,
4,4'-methylenebisbenzenamine, 2-methyl-1,4-benzenediamine,
3,3'-methylenebisbenzenamine, 3,3'-sulfonylbisbenzenamine,
4,4'-sulfonylbisbenzenamine, 3,3'-oxybisbenzenamine,
4,4'-oxybisbenzenamine, 4,4'-methylenebiscyclohexanamine,
1,3-benzenedimethanamine, 1,4-benzenedimethanamine,
4,4'-cyclohexanebisbenzenamine, and mixtures thereof.
[0092] Co-reactants for use with the bismaleimides can include any
of a wide variety of unsaturated organic compounds, particularly
those having multiple unsaturation, either ethylenic, acetylenic,
or both. Examples include acrylic acids and amides and the ester
derivatives thereof, e.g., acrylic acid, methacrylic acid,
acrylamide, methacrylamide, and methylmethacrylate;
dicyanoethylene; tetracyanoethylene; allyl alcohol;
2,2'-diallylbisphenol A; 2,2'-dipropenylbisphenol A;
diallylphthalate; triallylisocyanurate; triallylcyanurate;
N-vinyl-2-pyrrolidinone; N-vinyl caprolactam; ethylene glycol
dimethacrylate; diethylene glycol dimethacrylate;
trimethylolpropane triacrylate; trimethylolpropane trimethacrylate;
pentaerythritol tetramethacrylate; 4-allyl-2-methoxyphenol;
triallyl trimellitate; divinyl benzene; dicyclopentadienyl
acrylate; dicyclopentadienyloxyethyl acrylate; 1,4-butanediol
divinyl ether; 1,4-dihydroxy-2-butene; styrene; .alpha.-methyl
styrene; chlorostyrene; p-phenylstyrene; p-methylstyrene;
t-butylstyrene; and phenyl vinyl ether. Of particular interest are
resin systems employing a bismaleimide in combination with a
bis(alkenylphenol). Descriptions of a typical resin system of this
type are found in U.S. Pat. No. 4,100,140 (Zahir et al.), the
descriptions of which are incorporated herein by reference.
Particularly preferred components are
4,4'-bismaleimidodiphenylmethane and o,o'-diallylbisphenol A.
[0093] Polycyanate ester resins suitable for use in the
nanocomposites of the invention can be prepared by combining
cyanogen chloride or bromide with an alcohol or phenol. The
preparation of such resins and their use in polycyclotrimerization
to produce polycyanurates are described in U.S. Pat. No. 4,157,360
(Chung et al.), the descriptions of which are incorporated herein
by reference. Representative examples of suitable polycyanate ester
resins include 1,2-dicyanatobenzene, 1,3-dicyanatobenzene,
1,4-dicyanatobenzene, 2,2'-dicyanatodiphenylmethane,
3,3'-dicyanatodiphenylmethane, 4,4'-dicyanatodiphenylmethane, and
the dicyanates prepared from biphenol A, bisphenol F, and bisphenol
S. Tri- and higher functionality cyanate resins are also
suitable.
[0094] In some embodiments, the curable resin may be an
ethylenically-unsaturated curable resin. For example, in some
embodiments, an unsaturated polyester resin may be used. In some
embodiments, the unsaturated polyester resin is the condensation
product of one or more carboxylic acids or derivatives thereof
(e.g., anhydrides and esters) with one or more alcohols (e.g.,
polyhydric alcohols).
[0095] In other embodiments, vinyl ester resins are used. As used
herein, the term "vinyl ester" refers to the reaction product of
epoxy resins with ethylenically-unsaturated monocarboxylic acids.
Exemplary epoxy resins include bisphenol A digycidyl ether (e.g.,
EPON 828, available from Hexion Specialty Chemicals, Columbus,
Ohio). Exemplary monocarboxylic acids include acrylic acid and
methacrylic acid. Although such reaction products are acrylic or
methacrylic esters, the term "vinyl ester" is used consistently in
the gel coat industry. (See, e.g., Handbook of Thermoset Plastics
(Second Edition), William Andrew Publishing, page 122 (1998).)
[0096] In still other embodiments, (meth)acrylate resins,
including, e.g., urethane (meth)acrylates, polyethyleneglycol
(multi)(meth)acrylates, and epoxy (multi)(meth)acrylates may be
used. In other embodiments, direct milling into epoxy resins may be
achieved. Epoxy resins may contain diluents such as
hexanedioldiglycidyl ether.
[0097] Depending on the selection of the curable resin, in some
embodiments, the resin system may also include a reactive diluent.
Exemplary reactive diluents include styrene, alpha-methylstyrene,
vinyl toluene, divinylbenzene, triallyl cyanurate, methyl
methacrylate, diallyl phthalate, ethylene glycol dimethacrylate,
hydroxyethyl methacrylate, hydroxyethyl acrylate, and other mono-
and multi-functional (meth)acrylates.
[0098] In certain embodiments of the nanocomposite, the curable
resin comprises an epoxy resin, a curable imide resin, a vinyl
ester resin, an acrylic resin, a bisbenzocyclobutane resin, a
polycyanate ester resin, or a mixture thereof. In an embodiment,
the curable resin comprises an epoxy resin, a maleimide resin, a
polycyanate ester resin, or a mixture thereof. In an embodiment,
the curable resin comprises an epoxy resin or a mixture of epoxy
resins. In an embodiment, the curable resin comprises a digycidyl
ether of bisphenol A, a diglycidyl ether of bisphenol F, ethylidene
bis-4,1-phenylene dicyanate, N,N'-4,4'-diphenylmethanebismaleimide,
4,4'-(1-methylethylidene)bis(2-(2-propenyl)phenol), or a mixture
thereof.
[0099] Similarly, in certain embodiments of the article, the cured
resin comprises an epoxy resin, a cured imide resin, a vinyl ester
resin, an acrylic resin, a bisbenzocyclobutane resin, a polycyanate
ester resin, or a mixture thereof. Such resins are discussed in
detail above. In an embodiment, the cured resin comprises an epoxy
resin, a maleimide resin, a polycyanate ester resin, or a mixture
thereof. In an embodiment, the cured resin comprises an epoxy resin
or a mixture of epoxy resins. In an embodiment, the cured resin
comprises a digycidyl ether of bisphenol A, a diglycidyl ether of
bisphenol F, ethylidene bis-4,1-phenylene dicyanate,
N,N'-4,4'-diphenylmethanebismaleimide,
4,4'-(1-methylethylidene)bis(2-(2-propenyl)phenol), or a mixture
thereof.
[0100] The nanocomposite or article further includes one or more
dispersants. The dispersant acts to stabilize the nanoparticle in
the matrix material during and after milling. Without dispersant,
the nanoparticles may reaggregate, thus adversely affecting the
benefit of the nanoparticle in the matrix material. Preferred
dispersants according to this disclosure are free of solvent and
typically referred to as dispersant that are "100% solids" or
"solvent-free." The dispersants typically have an anchoring (or
binding) group that interacts with the nanoparticle and a tail (or
extender) portion that is compatible with the matrix material.
Additional functionality may be incorporated in the dispersant,
such as reactive groups present in the tail or extender portion of
the dispersant that react with the matrix material. The anchoring
or binding group of the dispersant may interact with the
nanoparticle through ionic bonding, acid/base interactions,
hydrogen bonding, polarization interaction, and/or van der Waals
interactions. There may be one anchoring group per dispersant
molecule or many anchoring groups, as is the case for so-called
"comb polymers." The tail portion of the dispersant is of
sufficient length to provide a steric barrier to prevent the
nanoparticle from reaggregating.
[0101] Suitable dispersants include for example and without
limitation, a copolymer comprising acidic groups, for instance BYK
W9010. Another suitable dispersant is BYK 2152, which is a
hyperbranched high molecular weight polyester with aminic groups.
Each of the BYK dispersants is commercially available from BYK USA,
Inc. (Wallingford, Conn.). A further suitable dispersant is a
nonionic polymeric polyester copolymer, for instance ZEPHRYM PD
2246, which is commercially available from Croda, Inc. (Edison,
N.J.). Another suitable dispersant is a slightly anionic polymeric
polyester having part acid functionality, for instance ZEPHRYM PD
1000, which is commercially available from Croda, Inc. (Edison,
N.J.). An additional suitable dispersant is an acrylic polymer
salt, for example SOLPLUS D570, which is commercially available
from Lubrizol Additives (Wickliffe, Ohio). Another suitable
dispersant is a Jeffamine sulfonate, the sulfonic acid ligand
containing JEFFAMINE M-6000 (commercially available from Huntsman
Corporation, (The Woodlands, Tex.)) reacted with propane sulfone,
as described in International Patent Publication No. WO 2010/080459
(Schultz et al.). Other suitable dispersants include polymeric
dispersants commercially available under the trade designations
SOLPLUS D510 (available from Lubrizol Additives (Wickliffe, Ohio).
In many embodiments, the polymeric dispersants are added to the
nanocomposite at the same time as the aggregated layered
nanoparticles and curable resin. The polymeric dispersants are
often added to the nanocomposite at the same time as the aggregated
layered nanoparticles and curing agent. Typical high molecular
weight dispersants are polymeric and have weight average molecular
weights (Mw) of greater than 1000 gm/mole, or even greater than
2000 gm/mole. In certain embodiments, the dispersant is
crosslinkable.
[0102] In certain embodiments, the nanocomposite or article
comprises from about 0.5% to 20% by weight, inclusive, of the
dispersant, or from about 0.5 to about 10% by weight, or from about
0.5 to about 5.0% by weight, or from about 0.5 to about 3.0% by
weight, or from about 0.5 to about 2.0% by weight percent, or from
about 0.5 to about 1.0% by weight dispersant,
[0103] Nanocomposites comprising layered nanoparticles and a
dispersant dispersed in a curable resin comprise a wide viscosity
range, such as of 50 to 200 Pascalssecond (Pas), inclusive, as
measured according to ASTM D2196 at 30 degrees Celsius, or up to
about 6,000 Pas, as measured according to ASTM 2196 at 50 degrees
Celsius. Advantageously, in embodiments comprising hydrotalcite
layered nanoparticles and a dispersant dispersed in a curable
resin, a viscosity comparable to the viscosity of nanocomposites
instead containing spherical colloidal silica nanoparticles is
attained. For instance, a nanocomposite comprising 20 wt. %
nanoparticles, hydrotalcite layered and a dispersant, dispersed in
a curable resin typically comprises a viscosity of less than 100
Pas, or less than 80 Pas (as measured according to ASTM D2196 at 30
degrees Celsius).
[0104] In an embodiment, the layered nanoparticles include at least
one intercalating agent for preventing aggregation and/or
agglomeration of layered nanoparticles (or clusters of layered
nanoparticles. Suitable intercalating agents include for example
and without limitation the intercalating agents disclosed
above.
[0105] In an embodiment, the nanocomposite or article includes one
or more catalysts for reacting silanol groups on the surface of the
layered nanoparticles with the curable resin system. Suitable
catalysts include for instance stannous chloride (SnCl.sub.2) and
methylethylketone peroxide.
[0106] In an embodiment, the nanocomposite or article includes one
or more defoamers for acting as a defoamer and/or as an entrapped
air release agent. Suitable defoamers include for instance BYK-1790
and BYK-A535, silicone-free polymeric defoamers, and BYK-A500 air
release additives, commercially available from BYK USA, Inc.
(Wallingford, Conn.).
[0107] Generally, "surface modified nanoparticles" comprise surface
treatment agents attached to the surface of a nanoparticle.
Advantageously, according to methods of the present disclosure, it
is not necessary to modify the surface of layered nanoparticles in
a separate step, prior to incorporating the nanoparticles into the
nanocomposite. Surface treatment agents, if desired, can simply be
added to the nanocomposite and mixed in with the curable resin and
layered nanoparticles, treating the surfaces of the layered
nanoparticles during the dispersion of the layered nanoparticles in
the curable resin.
[0108] In many embodiments, a surface treatment agent is an organic
species having a first functional group capable of chemically
attaching (e.g., covalently or ionically bonding) or physically
attaching (e.g., strong physisorptively attaching) to the surface
of a nanoparticle, wherein the attached surface treatment agent
alters one or more properties of the nanoparticle. In some
embodiments, covalently-bonded surface treatment agents may be
preferred. In some embodiments, surface treatment agents have no
more than three functional groups for attaching to the core. In
some embodiments, the surface treatment agents have a low molecular
weight, e.g. a weight average molecular weight less than 1000 grams
per mole. In some embodiments, the surface treatment agent is an
organosilane (e.g., alkyl chlorosilanes, trialkoxy arylsilanes, or
trialkoxy alkylsilanes) or a compound having oxirane groups.
Exemplary surface treatment agents include
methacryloxypropyltrimethoxysilane, phenyl trimethoxysilane,
3-(trimethoxysilyl)propyl methacrylate)
polyethyleneglycol(trimethoxy)silane benzooxasilepin dimethyl
ester, phenethyltrimethoxysilane, N-phenylaminopropyl
trimethoxysilane, diglycidylether of bisphenol-A,
glycidylmethacrylate, allylglycidylether, or combinations
thereof.
[0109] In some embodiments, the surface treatment agent further
includes one or more additional functional groups providing one or
more additional desired properties. For example, in some
embodiments, an additional functional group may be selected to
provide a desired degree of compatibility between the surface
modified nanoparticles and one or more of the additional
constituents of the resin system, e.g., one or more of the curable
resins and/or diluents. In some embodiments, an additional
functional group may be selected to modify the rheology of the
resin system, e.g., to increase or decrease the viscosity, or to
provide non-Newtonian rheological behavior, e.g., thixotropy
(shear-thinning) In an embodiment, the layered nanoparticles
comprise treated surfaces, for example layered nanoparticle
surfaces treated with an organosilane, a monohydric alcohol, or a
polyol.
[0110] In some embodiments, the surface-modified nanoparticles are
reactive; that is, at least one of the surface treatment agents
used to surface modify the nanoparticles of the present disclosure
may include a second functional group capable of reacting with one
or more of the curable resin(s) and/or one or more reactive
diluent(s) present in the nanocomposite.
[0111] In an embodiment, the nanocomposite or article includes at
least one diluent, including at least one reactive diluent.
Suitable diluents include, a polyfunctional glycidyl ether,
styrene, mono- and multi-functional (meth)acrylates, or
combinations thereof. Some exemplary suitable diluents include for
example and without limitation dicyclopentenyloxyethyl
methacrylate, alpha-methylstyrene, vinyl toluene, divinylbenzene,
triallyl cyanurate, methyl methacrylate, diallyl phthalate,
ethylene glycol dimethacrylate, hydroxyethyl methacrylate,
hydroxyethyl acrylate. Other suitable reactive diluents for epoxy
resins include for example mono- and multi-functional, aliphatic
and aromatic, glycidyl ethers including, e.g., some of those
available under the trade name HELOXY from Hexion Specialty
Chemicals, Columbus, Ohio. Exemplary reactive diluents include,
e.g., polypropylene glycol diglycidyl ether, allyl glycidyl ether,
trimethylol propane trigylcidyl ether, 1,4-butane diol diglycidyl
ether, neopentyl glycol diglycidyl ether, n-butyl glycidyl ether,
2-ethylhexyl glycidyl ether, p-tertiary butyl phenyl glycidyl
ether, phenyl glycidyl ether, and cyclohexane dimethanol diglycidyl
ether.
[0112] In certain embodiments, the nanocomposite or article
includes a curing agent. The term "curative" as used herein also
refers to a curing agent. Typically, the curing agent comprises an
amine curing agent, an anhydride curing agent, a dicyandiamide
curing agent, or a combination thereof. More particularly, in an
aspect, the curing agent comprises an amine curing agent. In an
aspect, the curing agent comprises an anhydride curing agent. In an
aspect, the curing agent comprises a dicyandiamide curing agent. In
an aspect, the curing agent comprises a mixed curing agent. A
suitable amine curing agent includes for instance EPIKURE 3230
(commercially available from Momentive Performance Materials Inc.
(Albany, N.Y.)) and a suitable anhydride curing agent includes for
example LINDRIDE 36V (commercially available from Lindau Chemicals
Inc. (Columbia S.C.)).
[0113] Epoxy resins can be cured by a variety of curing agents,
some of which are described (along with a method for calculating
the amounts to be used) by Lee and Neville in Handbook of Epoxy
Resins, McGraw-Hill, pages 36-140, New York (1967). Useful epoxy
resin curing agents include polyamines such as ethylenediamine,
diethylenetriamine, aminoethylethanolamine, and the like,
diaminodiphenylsulfone, 9,9-bis(4-aminophenyl)fluorene,
9,9-bis(3-chloro-4-(aminophenyl)fluorene, amides such as
dicyandiamide, polycarboxylic acids such as adipic acid, acid
anhydrides such as phthalic anhydride and chlorendic anhydride, and
polyphenols such as bisphenol A, and the like. Generally, the epoxy
resin and curing agent are used in stoichiometric amounts, but the
curing agent can be used in amounts ranging from about 0.1 to 1.7
times the stoichiometric amount of epoxy resin.
[0114] Thermally-activated catalytic agents, e.g., Lewis acids and
bases, tertiary amines, imidazoles, complexed Lewis acids, and
organometallic compounds and salts, can also be utilized in curing
epoxy resins. Thermally-activated catalysts can generally be used
in amounts ranging from about 0.05 to about 5 percent by weight,
based on the amount of epoxy resin present in the curable resin
nanocomposite.
[0115] N,N'-bismaleimide resins can be cured using diamine curing
agents, such as those described in U.S. Pat. No. 3,562,223 (Bargain
et al.), the description of which is incorporated herein by
reference. Generally, from about 0.2 to about 0.8 moles of diamine
can be used per mole of N,N'-bismaleimide. N,N'-bismaleimides can
also cure by other mechanisms, e.g., co-cure with aromatic olefins
(such as bis-allylphenyl ether,
4,4'-bis(o-propenylphenoxy)benzophenone, or o,o'-diallylbisphenol
A) or thermal cure via a self-polymerization mechanism.
[0116] Polycyanate resins can be cyclotrimerized by application of
heat and/or by using catalysts such as zinc octoate, tin octoate,
zinc stearate, tin stearate, copper acetylacetonate, and chelates
of iron, cobalt, zinc, copper, manganese, and titanium with
bidentate ligands such as catechol. Such catalysts can generally be
used in amounts of from about 0.001 to about 10 parts by weight per
100 parts of polycyanate ester resin.
[0117] In certain embodiments, the nanocomposite or article further
comprises reinforcing fibers, and optionally the reinforcing fibers
are continuous. Suitable reinforcing fibers include for example and
without limitation, carbon, glass, ceramic, boron, silicon carbide,
polyimide, polyamide, polyethylene, or a combination thereof. In an
embodiment, the reinforcing fibers comprise a unidirectional array
of individual continuous fibers, woven fabric, knitted fabric,
yarn, roving, braided constructions, or non-woven mat.
[0118] Advantageously, the nanocomposite is suitable for use in a
prepreg, which includes any reinforcing or molding material that
can be impregnated with the nanocomposite. In an embodiment, a
prepreg includes the nanocomposite of any of the aspects or
embodiments disclosed above. The curable nanocomposites of the
invention can be used to make composite articles by a variety of
conventional processes, e.g., resin transfer molding, filament
winding, tow placement, resin infusion processes, compression sheet
molding, or traditional prepreg processes. Prepregs can be prepared
by impregnating an array of fibers (or a fabric) with the
nanocomposite and then layering the impregnated tape or fabric. The
resulting prepreg can then be cured by application of heat, along
with the application of pressure or vacuum (or both) to remove any
trapped air.
[0119] The nanocomposites can also be used to make composite parts
by a resin transfer molding process, which is widely used to
prepare composite parts for the aerospace and automotive
industries. In this process, fibers are first shaped into a preform
which is then compressed to final part shape in a metal mold. The
nanocomposite can then be deposited into the mold and
heat-cured.
[0120] Composites can also be prepared from the nanocomposites by a
filament winding process, which is typically used to prepare
cylinders or other composites having a circular or oval
cross-sectional shape. In this process, a fiber tow or an array of
tows is impregnated with the nanocomposite by running it through a
resin bath (preferably, containing a low viscosity resin) and
immediately winding the impregnated tow onto a mandrel. The
resulting composite can then be heat-cured.
[0121] A pultrusion process (a continuous process used to prepare
constant cross-section parts) can also be used to make composites
from the curable resin sols. In such a process, a large array of
continuous fibers is first wetted out in a resin bath (preferably,
containing a low viscosity resin). The resulting wet array is then
pulled through a heated die, where trapped air is squeezed out and
the resin is cured.
[0122] In a further exemplary embodiment, a method is provided of
preparing a nanoparticle-containing curable resin system. The
method comprises mixing from 1 to 70 weight percent of aggregated
layered nanoparticles with a curable resin, a first dispersant, and
optionally a catalyst, a surface treatment agent, and/or a diluent,
to form a first mixture, wherein the mixture includes less than 2%
by weight solvent; milling the first mixture in a first immersion
mill including milling media to form a milled resin system
comprising layered nanoparticles and the dispersant dispersed in
the curable resin.
[0123] Advantageously, methods according to the present application
eliminate the need to employ a solvent, or a layered nanoparticle
sol to effectively disperse the layered nanoparticles in a curable
resin. The layered nanoparticles, moreover, need not be
functionalized with a surface treatment agent prior to mixing with
a curable resin. Hence, it is a benefit of certain embodiments of
the method that high loadings (e.g., greater than 10 weight
percent) of aggregated layered nanoparticles are dispersed in a
curable resin with a dispersant, while optionally including in the
nanocomposite one or more of a catalyst, a diluent, a surface
treatment agent, or a curing agent. Such optional components,
however, are able to be mixed into the nanocomposite simultaneously
with the aggregated layered nanoparticles, curable resin, and
dispersant.
[0124] Methods of the present disclosure are typically performed
using an immersion mill apparatus, which combines milling and
mixing to disperse a solid component into a liquid component,
particularly for high viscosity systems. One suitable immersion
mill apparatus is described in U.S. Pat. No. 7,175,118 (Hockmeyer).
Such immersion mill apparatuses typically include a mixing tank for
holding the mixture to be milled, each of 1) a high shear impeller
assembly, 2) a low shear mixer blade assembly, and 3) an immersion
mill, for immersion in the mixing tank, and controllers for
simultaneously operating the assemblies. In operation, the mixture
is directed by the low shear mixer blade assembly to the high shear
impeller assembly to initiate dispersion of the solid components
into the liquid components, and then to the immersion mill for
milling to decrease the aggregate sizes of any aggregated solid
components (e.g., aggregated layered nanoparticles) and to further
disperse the solid component in the liquid component. In certain
embodiments, the milling media in the immersion mill comprises
zirconia particles, preferably yttrium-stabilized zirconia
beads.
[0125] The aggregated layered nanoparticles typically comprise a
particle size of about 5 micrometers (m), or between about 2 .mu.m
and about 20 .mu.m, or between about 5 .mu.m and about 30 .mu.m, or
between about 5 .mu.m and about 10 .mu.m, or between about 10 .mu.m
and about 20 .mu.m.
[0126] In embodiments of the method, the milling of the aggregated
layered nanoparticles and curable resin is performed until the
aggregated layered nanoparticles are dispersed to form layered
nanoparticles comprising an average particle size (of the longest
dimension) in the range from about 1 nanometer to about 1000
nanometers, or from about 1 nanometer to about 500 nanometers, or
from about 1 nanometer to about 100 nanometers, or from about 1
nanometer to about 50 nanometers, or from about 100 nanometers to
about 400 nanometers, or from about 500 nanometers to about 1000
nanometers. The layered nanoparticles typically comprise a bimodal
particle size distribution or a unimodal particle size
distribution.
[0127] In certain embodiments of the method, the
nanoparticle-containing curable resin system comprises from about 1
to about 70 weight percent, or from about 10 to about 30 weight
percent, or from about 10 to about 50 weight percent, or from about
10 to about 70 weight percent, or from about 15 to about 50 weight
percent, or from about 20 to about 50 weight percent, or from about
20 to about 35 weight percent, or from about 25 to about 50 weight
percent, or from about 30 to about 50 weight percent, or from about
15 to about 70 weight percent, or from about 25 to about 70 weight
percent, or from about 35 to about 70 weight percent, or from about
50 to about 70 weight percent of the layered nanoparticles. In an
embodiment, the milled resin system consists essentially of about 1
to about 70 weight percent of layered nanoparticles dispersed in a
curable resin with a dispersant.
[0128] In certain embodiments, the method comprises including at
least one additional component (e.g., additive) with the aggregated
layered nanoparticles and curable resin. Such components include
for example and without limitation, diluents, catalysts, surface
treatment agents, curing agents, cure accelerators, defoamers, air
release agents, crosslinking agents, dyes, flame retardants,
pigments, impact modifiers, and flow control agents. In certain
embodiments, the method further comprises including a catalyst with
the aggregated layered nanoparticles and curable resin for reacting
silanol groups on the surface of the layered nanoparticles with the
curable resin system. In certain embodiments, the method further
comprises including a diluent with the aggregated layered
nanoparticles and curable resin. In certain embodiments, the method
further comprises including a surface treatment agent with the
aggregated layered nanoparticles and curable resin. It is an
advantage of such embodiments that a catalyst, a diluent, and/or a
surface treatment agent are included in a nanocomposite comprising
a curable resin and aggregated layered nanoparticles, rather than
requiring mixture or reaction with the aggregated layered
nanoparticles prior to mixing with the curable resin. Suitable
catalyst(s), diluent(s) and surface treatment agent(s) are as
described in detail above.
[0129] In some embodiments, the method further comprises including
fillers (e.g., reinforcing fibers, hollow glass spheres, etc.) in
the milled resin system. Fillers suitable for including in the
milled resin system are as described in detail above.
Exemplary Embodiments
[0130] 1. A nanocomposite including layered nanoparticles and a
dispersant dispersed in a curable resin, wherein the nanocomposite
contains less than 2% by weight solvent.
[0131] 2. The nanocomposite of embodiment 1 wherein the layered
nanoparticles include a platelet shape, an acicular shape, an
irregular shape, or combinations thereof.
[0132] 3. The nanocomposite of embodiment 2 wherein the irregular
shaped nanoparticles include clusters of primary layered
particles.
[0133] 4. The nanocomposite of embodiment 2 wherein the
nanoparticles are hollow.
[0134] 5. The nanocomposite of embodiment 1 or embodiment 2 wherein
the platelet shaped nanoparticles include talc, halloysite,
hydrotalcite, montmorillonite, kaolin, mica, or combinations
thereof.
[0135] 6. The nanocomposite of embodiment 1, embodiment 2, or
embodiment 5 wherein the nanocomposite includes an intercalating
agent.
[0136] 7. The nanocomposite of any one of embodiments 1 through 6
wherein the dispersant includes an anchoring group and a tail
portion.
[0137] 8. The nanocomposite of any one of embodiments 1 through 7
wherein the dispersant includes a phosphoric acid polyester
dispersant, a Jeffamine sulfonate, a hyperbranched high molecular
weight polyester, or a combination thereof.
[0138] 9. The nanocomposite of any one of embodiments 1 through 8
wherein the dispersant is present in amount from 0.5% to 20% by
weight, inclusive, of the total weight of the nanocomposite.
[0139] 10. The nanocomposite of any one of embodiments 1 through 9
wherein the dispersant is present in amount from 0.5% to 5.0% by
weight, inclusive, of the total weight of the nanocomposite.
[0140] 11. The nanocomposite of any one of embodiments 1 through 10
wherein the dispersant is present in amount from 0.5% to 2.0% by
weight, inclusive, of the total weight of the nanocomposite.
[0141] 12. The nanocomposite of any one of embodiments 1 through 11
further including a catalyst for reacting hydroxyl groups on the
surface of the nanoparticles with the curable resin system.
[0142] 13. The nanocomposite of embodiment 12 wherein the catalyst
includes stannous chloride (SnCl.sub.2) or methylethylketone
peroxide.
[0143] 14. The nanocomposite of any one of embodiments 1 through 13
further including a surface treatment agent including an
organosilane, a monohydric alcohol, a polyol, or a combination
thereof.
[0144] 15. The nanocomposite of embodiment 14 wherein the surface
treatment agent comprises phenyl trimethoxysilane, benzooxasilepin
dimethyl ester, phenethyltrimethoxy silane, N-phenylaminopropyl
trimethoxysilane, or a mixture thereof.
[0145] 16. The nanocomposite of any one of embodiments 1 through 15
further including at least one diluent.
[0146] 17. The nanocomposite of embodiment 16 wherein the at least
one diluent includes a mono- or poly-functional glycidyl ether,
styrene, or a combination thereof.
[0147] 18. The nanocomposite of any one of embodiments 1 through 17
further including at least one additive selected from the group
consisting of curing agents, cure accelerators, defoamers, air
release agents, crosslinking agents, dyes, flame retardants,
pigments, impact modifiers, and flow control agents.
[0148] 19. The nanocomposite of any one of embodiments 1 through 18
wherein the layered nanoparticles include a bimodal particle size
distribution.
[0149] 20. The nanocomposite of any one of embodiments 1 through 18
wherein the layered nanoparticles include a unimodal particle size
distribution.
[0150] 21. The nanocomposite of any one of embodiments 1 through 20
wherein the curable resin includes an epoxy resin, a curable imide
resin, a vinyl ester resin, an acrylic resin, a bisbenzocyclobutane
resin, a polycyanate ester resin, or a mixture thereof.
[0151] 22. The nanocomposite of any one of embodiments 1 through 21
wherein the curable resin includes an epoxy resin, a maleimide
resin, a polycyanate ester resins, or a mixture thereof.
[0152] 23. The nanocomposite of any one of embodiments 1 through 22
wherein the curable resin includes a digycidyl ether of bisphenol
A, a diglycidyl ether of bisphenol F, ethylidene bis-4,1-phenylene
dicyanate, N,N'-4,4'-diphenylmethanebismaleimide,
4,4'-(1-methylethylidene)bis(2-(2-propenyl)phenol), or a mixture
thereof.
[0153] 24. The nanocomposite of any one of embodiments 1 through 23
wherein the curable resin includes an epoxy resin or a mixture of
epoxy resins.
[0154] 25. The nanocomposite of any one of embodiments 1 through 24
wherein the layered nanoparticles include an average particle size
in the range from about 1 nanometer to about 1000 nanometers.
[0155] 26. The nanocomposite of any one of embodiments 1 through 25
wherein the layered nanoparticles include an average particle size
in the range from about 1 nanometer to about 500 nanometers.
[0156] 27. The nanocomposite of any one of embodiments 1 through 26
wherein the layered nanoparticles include an average particle size
in the range from about 1 nanometer to about 100 nanometers.
[0157] 28. The nanocomposite of any one of embodiments 1 through 27
wherein the nanocomposite includes from about 1 to about 70 weight
percent of the layered nanoparticles.
[0158] 29. The nanocomposite of any one of embodiments 1 through 28
wherein the nanocomposite includes from about 15 to about 50 weight
percent of the layered nanoparticles.
[0159] 30. The nanocomposite of any one of embodiments 1 through 28
wherein the nanocomposite includes from about 50 to about 70 weight
percent of the layered nanoparticles.
[0160] 31. The nanocomposite of any one of embodiments 1 through 30
further including a filler including at least one of reinforcing
continuous fibers, reinforcing discontinuous fibers, and hollow
glass bubbles.
[0161] 32. The nanocomposite of embodiment 31 wherein the filler
includes at least one of reinforcing continuous fibers and
reinforcing discontinuous fibers.
[0162] 33. The nanocomposite of embodiment 31 or embodiment 32
wherein the filler includes carbon, glass, ceramic, boron, silicon
carbide, basalt, ceramic, polyimide, polyamide, polyethylene, or a
combination thereof.
[0163] 34. The nanocomposite of any one of embodiments 31 through
33 wherein said reinforcing fibers include a unidirectional array
of individual continuous fibers, woven fabric, knitted fabric,
yarn, roving, braided constructions, or non-woven mat.
[0164] 35. The nanocomposite of any one of embodiments 1 through 34
wherein the nanocomposite includes less than 0.5% by weight
solvent.
[0165] 36. The nanocomposite of any one of embodiments 1 through 35
further including a curing agent including an amine curing agent,
an anhydride curing agent, a dicyandiamide curing agent, a
diaminodiphenyl sulfone curing agent, or a combination thereof.
[0166] 37. The nanocomposite of embodiment 36 wherein the curing
agent includes an amine curing agent.
[0167] 38. The nanocomposite of embodiment 36 wherein the curing
agent includes an anhydride curing agent.
[0168] 39. The nanocomposite of embodiment 36 wherein the curing
agent includes a dicyandiamide curing agent.
[0169] 40. The nanocomposite of embodiment 1 wherein the
nanocomposite consists essentially of the layered nanoparticles and
the dispersant dispersed in the curable resin.
[0170] 41. A prepreg including the nanocomposite of any one of
embodiments 1 through 40.
[0171] 42. A composite including the cured nanocomposite of any one
of embodiments 1 through 30 or 35 through 40 as a matrix resin and
at least one filler embedded in the matrix resin.
[0172] 43. An article including the composite of embodiment 42.
[0173] 44. A composite including from about 1 to 70 weight percent
of layered nanoparticles, and a dispersant, dispersed in a cured
resin; and a filler embedded in the cured resin. The filler
includes at least one of a reinforcing continuous fiber,
reinforcing discontinuous fibers, and hollow glass bubbles.
[0174] 45. The composite of embodiment 44 wherein the layered
nanoparticles include a platelet shape, an acicular shape, an
irregular shape, or combinations thereof.
[0175] 46. The composite of embodiment 45 wherein the irregular
shaped nanoparticles include clusters of primary layered
particles.
[0176] 47. The composite of embodiment 45 wherein the nanoparticles
are hollow.
[0177] 48. The composite of embodiment 44 or embodiment 45 wherein
the platelet shaped nanoparticles include talc, halloysite,
hydrotalcite, montmorillonite, kaolin, mica, or combinations
thereof.
[0178] 49. The composite of embodiment 44, embodiment 45, or
embodiment 48 wherein the nanocomposite includes an intercalating
agent.
[0179] 50. The composite of any one of embodiments 44 through 49
wherein the dispersant includes an anchoring group and a tail
portion.
[0180] 51. The composite of any one of embodiments 44 through 50
wherein the dispersant includes a phosphoric acid polyester
dispersant, a Jeffamine sulfonate, a hyperbranched high molecular
weight polyester, or a combination thereof.
[0181] 52. The composite of any one of embodiments 44 through 51
wherein the dispersant is present in amount from 0.5% to 20% by
weight, inclusive, of the total weight of the nanocomposite.
[0182] 53. The composite of any one of embodiments 44 through 52
wherein the dispersant is present in amount from 0.5% to 5.0% by
weight, inclusive, of the total weight of the nanocomposite.
[0183] 54. The composite of any one of embodiments 44 through 53
wherein the dispersant is present in amount from 0.5% to 2.0% by
weight, inclusive, of the total weight of the nanocomposite.
[0184] 55. The composite of any one of embodiments 44 through 54
further including a catalyst.
[0185] 56. The composite of embodiment 55 wherein the catalyst
includes stannous chloride (SnCl.sub.2) or methylethylketone
peroxide.
[0186] 57. The composite of any one of embodiments 42 through 56
further including a surface treatment agent including an
organosilane, a monohydric alcohol, a polyol, or a combination
thereof.
[0187] 58. The composite of embodiment 57 wherein the surface
treatment agent comprises phenyl trimethoxysilane, benzooxasilepin
dimethyl ester, phenethyltrimethoxy silane, N-phenylaminopropyl
trimethoxysilane, or a mixture thereof.
[0188] 59. The composite of any one of embodiments 44 through 58
further including at least one diluent.
[0189] 60. The composite of embodiment 59 wherein the at least one
diluent includes a mono- or poly-functional glycidyl ether,
styrene, or a combination thereof.
[0190] 61. The composite of any one of embodiments 44 through 60
further including at least one additive selected from the group
consisting of curing agents, cure accelerators, defoamers, air
release agents, crosslinking agents, dyes, flame retardants,
pigments, impact modifiers, and flow control agents.
[0191] 62. The composite of any one of embodiments 44 through 61
wherein the layered nanoparticles include a bimodal particle size
distribution.
[0192] 63. The composite of any one of embodiments 44 through 61
wherein the layered nanoparticles include a unimodal particle size
distribution.
[0193] 64. The composite of any one of embodiments 44 through 63
wherein the cured resin includes an epoxy resin, a cured imide
resin, a vinyl ester resin, an acrylic resin, a bisbenzocyclobutane
resin, a polycyanate ester resin, or a mixture thereof.
[0194] 65. The composite of any one of embodiments 44 through 64
wherein the cured resin includes an epoxy resin, a maleimide resin,
a polycyanate ester resins, or a mixture thereof.
[0195] 66. The composite of any one of embodiments 44 through 65
wherein the cured resin includes a digycidyl ether of bisphenol A,
a diglycidyl ether of bisphenol F, ethylidene bis-4,1-phenylene
dicyanate, N,N'-4,4'-diphenylmethanebismaleimide,
4,4'-(1-methylethylidene)bis(2-(2-propenyl)phenol), or a mixture
thereof.
[0196] 67. The composite of any one of embodiments 44 through 66
wherein the cured resin includes an epoxy resin or a mixture of
epoxy resins.
[0197] 68. The composite of any one of embodiments 44 through 67
wherein the layered nanoparticles include an average particle size
in the range from about 1 nanometer to about 1000 nanometers.
[0198] 69. The composite of any one of embodiments 44 through 68
wherein the layered nanoparticles include an average particle size
in the range from about 1 nanometer to about 500 nanometers.
[0199] 70. The composite of any one of embodiments 44 through 69
wherein the layered nanoparticles include an average particle size
in the range from about 1 nanometer to about 100 nanometers.
[0200] 71. The composite of any one of embodiments 44 through 70
wherein the composite includes from about 10 to about 50 weight
percent of the layered nanoparticles.
[0201] 72. The composite of any one of embodiments 44 through 71
wherein the composite includes from about 15 to about 30 weight
percent of the layered nanoparticles.
[0202] 73. The composite of any one of embodiments 44 through 70
wherein the composite includes from about 50 to about 70 weight
percent of the layered nanoparticles.
[0203] 74. The composite of any one of embodiments 44 through 73
wherein the filler includes at least one of reinforcing continuous
fibers and reinforcing discontinuous fibers.
[0204] 75. The composite of embodiment 74 wherein the filler
includes carbon, glass, ceramic, boron, silicon carbide, basalt,
ceramic, polyimide, polyamide, polyethylene, polypropylene,
polyacrylnitrile, or a combination thereof.
[0205] 76. The composite of embodiment 74 or embodiment 75 wherein
the reinforcing continuous fibers include a unidirectional array of
individual continuous fibers, woven fabric, knitted fabric, yarn,
roving, braided constructions, or non-woven mat.
[0206] 77. The composite of any one of embodiments 44 through 76
further including a curing agent including an amine curing agent,
an anhydride curing agent, a dicyandiamide curing agent, a
diaminodiphenyl sulfone curing agent, or a combination thereof.
[0207] 78. The composite of embodiment 77 wherein the curing agent
includes an amine curing agent.
[0208] 79. The composite of embodiment 77 wherein the curing agent
includes an anhydride curing agent.
[0209] 80. The composite of embodiment 77 wherein the curing agent
includes a dicyandiamide curing agent.
[0210] 81. The composite of embodiment 77 wherein the curing agent
includes a diaminodiphenyl sulfone curing agent.
[0211] 82. The composite of embodiment 44 wherein the composite
consists essentially of the layered nanoparticles and dispersant
dispersed in the cured resin and the filler embedded in the cured
resin.
[0212] 83. An article including from about 1 to about 70 weight
percent of layered nanoparticles, and a dispersant, dispersed in a
cured resin.
[0213] 84. The article of embodiment 83 wherein the layered
nanoparticles include a platelet shape, an acicular shape, an
irregular shape, or combinations thereof.
[0214] 85. The article of embodiment 84 wherein the irregular
shaped nanoparticles include clusters of primary layered
particles.
[0215] 86. The article of embodiment 83 or embodiment 84 wherein
the nanoparticles are hollow.
[0216] 87. The article of embodiment 83 or embodiment 84 wherein
the platelet shaped nanoparticles include talc, halloysite,
hydrotalcite, montmorillonite, kaolin, mica, or combinations
thereof.
[0217] 88. The article of embodiment 83, embodiment 84, or
embodiment 87 wherein the nanocomposite includes an intercalating
agent.
[0218] 89. The article of any one of embodiments 83 through 88
wherein the dispersant includes an anchoring group and a tail
portion.
[0219] 90. The article of any one of embodiments 83 through 89
wherein the dispersant includes a phosphoric acid polyester
dispersant, a Jeffamine sulfonate, a hyperbranched high molecular
weight polyester, or a combination thereof.
[0220] 91. The article of any one of embodiments 83 through 90
wherein the dispersant is present in amount from 0.5% to 20% by
weight, inclusive, of the total weight of the nanocomposite.
[0221] 92. The article of any one of embodiments 1 through 91
wherein the dispersant is present in amount from 0.5% to 5.0% by
weight, inclusive, of the total weight of the nanocomposite.
[0222] 93. The article of any one of embodiments 1 through 92
wherein the dispersant is present in amount from 0.5% to 2.0% by
weight, inclusive, of the total weight of the nanocomposite.
[0223] 94. The article of any one of embodiments 83 through 93
further including a catalyst.
[0224] 95. The article of embodiment 94 wherein the catalyst
includes stannous chloride (SnCl.sub.2) or methylethylketone
peroxide.
[0225] 96. The article of any one of embodiments 83 through 95
further including a surface treatment agent including an
organosilane, a monohydric alcohol, a polyol, or a combination
thereof.
[0226] 97. The article of embodiment 96 wherein the surface
treatment agent comprises phenyl trimethoxysilane, benzooxasilepin
dimethyl ester, phenethyltrimethoxy silane, N-phenylaminopropyl
trimethoxysilane, or a mixture thereof.
[0227] 98. The article of any one of embodiments 83 through 97
further including at least one diluent.
[0228] 99. The article of embodiment 98 wherein the at least one
diluent includes a mono- or poly-functional glycidyl ether,
styrene, or a combination thereof.
[0229] 100. The article of any one of embodiments 83 through 99
further including at least one additive selected from the group
consisting of curing agents, cure accelerators, defoamers, air
release agents, crosslinking agents, dyes, flame retardants,
pigments, impact modifiers, and flow control agents.
[0230] 101. The article of any one of embodiments 83 through 100
wherein the layered nanoparticles include a bimodal particle size
distribution.
[0231] 102. The article of any one of embodiments 83 through 100
wherein the layered nanoparticles include a unimodal particle size
distribution.
[0232] 103. The article of any one of embodiments 83 through 102
wherein the cured resin includes an epoxy resin, a cured imide
resin, a vinyl ester resin, an acrylic resin, a bisbenzocyclobutane
resin, a polycyanate ester resin, or a mixture thereof.
[0233] 104. The article of any one of embodiments 83 through 103
wherein the cured resin includes an epoxy resin, a maleimide resin,
a polycyanate ester resins, or a mixture thereof.
[0234] 105. The article of any one of embodiments 83 through 104
wherein the cured resin includes a digycidyl ether of bisphenol A,
a diglycidyl ether of bisphenol F, ethylidene bis-4,1-phenylene
dicyanate, N,N'-4,4'-diphenylmethanebismaleimide,
4,4'-(1-methylethylidene)bis(2-(2-propenyl)phenol), or a mixture
thereof.
[0235] 106. The article of any one of embodiments 83 through 105
wherein the cured resin includes an epoxy resin or a mixture of
epoxy resins.
[0236] 107. The article of any one of embodiments 83 through 106
wherein the layered nanoparticles include an average particle size
in the range from about 1 nanometer to about 1000 nanometers.
[0237] 108. The article of any one of embodiments 83 through 107
wherein the layered nanoparticles include an average particle size
in the range from about 1 nanometer to about 500 nanometers.
[0238] 109. The article of any one of embodiments 83 through 108
wherein the layered nanoparticles include an average particle size
in the range from about 1 nanometer to about 100 nanometers.
[0239] 110. The article of any one of embodiments 83 through 109
wherein the article includes from about 15 to about 50 weight
percent of the layered nanoparticles.
[0240] 111. The article of any one of embodiments 83 through 109
wherein the article includes from about 1 to about 5 weight percent
of the layered nanoparticles.
[0241] 112. The article of any one of embodiments 83 through 109
wherein the article includes from about 25 to about 70 weight
percent of the layered nanoparticles.
[0242] 113. The article of any one of embodiments 83 through 112
further including a filler embedded in the cured resin, wherein the
filler includes at least one of reinforcing continuous fibers,
reinforcing discontinuous fibers, and hollow glass bubbles.
[0243] 114. The article of embodiment 113 wherein the filler
includes at least one of reinforcing continuous fibers and
reinforcing discontinuous fibers.
[0244] 115. The article of embodiment 113 or embodiment 114 wherein
the filler includes carbon, glass, ceramic, boron, silicon carbide,
basalt, ceramic polyimide, polyamide, polyethylene, polypropylene,
polyacrylnitrile, or a combination thereof.
[0245] 116. The article of embodiment 113 through 115 wherein the
reinforcing continuous fibers include a unidirectional array of
individual continuous fibers, woven fabric, knitted fabric, yarn,
roving, braided constructions, or non-woven mat.
[0246] 117. The article of any one of embodiments 83 through 116
further including a curing agent including an amine curing agent,
an anhydride curing agent, a dicyandiamide curing agent, a
diaminodiphenyl sulfone, or a combination thereof.
[0247] 118. The article of embodiment 117 wherein the curing agent
includes an amine curing agent.
[0248] 119. The article of embodiment 117 wherein the curing agent
includes an anhydride curing agent.
[0249] 120. The article of embodiment 117 wherein the curing agent
includes a dicyandiamide curing agent.
[0250] 121. The article of embodiment 117 wherein the curing agent
includes a diaminodiphenyl sulfone curing agent.
[0251] 122. The article of any one of embodiments 83 through 121
wherein the article includes a turbine blade, a pressure vessel, an
aerospace part, a cable, or sporting goods equipment.
[0252] 123. The article of embodiment 122 wherein the article
includes a golf club, a baseball bat, a fishing rod, a racquet, or
a bicycle frame.
[0253] 124. The article of embodiment 122, wherein the article
includes a pressure vessel.
[0254] 125. The article of embodiment 83 wherein the article
consists essentially of about 1 to about 70 weight percent of
layered nanoparticles, and dispersant, dispersed in a cured
resin.
[0255] 126. A method of preparing a nanoparticle-containing curable
resin system including mixing from 1 to 70 weight percent of
aggregated layered nanoparticles with a curable resin, a
dispersant, and optionally a catalyst, a surface treatment agent,
and/or a diluent, to form a mixture, wherein the mixture includes
less than 2% by weight solvent; and milling the mixture in a first
immersion mill including milling media to form a milled resin
system comprising layered nanoparticles and dispersant dispersed in
the curable resin.
[0256] 127. The method of embodiment 126 wherein the aggregated
nanoparticles include an average size in the range from about 2
micrometers (.mu.m) to about 20 .mu.m.
[0257] 128. The method of embodiment 126 or embodiment 127 wherein
the layered nanoparticles include a platelet shape, an acicular
shape, an irregular shape, or combinations thereof.
[0258] 129. The method of embodiment 126 wherein the irregular
shaped nanoparticles include clusters of primary layered
particles.
[0259] 130. The method of embodiment 128 wherein the nanoparticles
are hollow.
[0260] 131. The method of any one of embodiments 126 through 128
wherein the platelet shaped nanoparticles include talc, halloysite,
hydrotalcite, montmorillonite, kaolin, mica, or combinations
thereof.
[0261] 132. The method of any one of embodiments 126 through 127 or
embodiment 130 wherein the nanocomposite includes an intercalating
agent.
[0262] 133. The method of any one of embodiments 126 through 132
wherein the dispersant includes an anchoring group and a tail
portion.
[0263] 134. The method of any one of embodiments 126 through 133
wherein the dispersant includes a phosphoric acid polyester
dispersant, a Jeffamine sulfonate, a hyperbranched high molecular
weight polyester, or a combination thereof.
[0264] 135. The method of any one of embodiments 126 through 134
wherein the dispersant is present in amount from 0.5% to 20% by
weight, inclusive, of the total weight of the nanocomposite.
[0265] 136. The method of any one of embodiments 126 through 135
wherein the dispersant is present in amount from 0.5% to 5.0% by
weight, inclusive, of the total weight of the nanocomposite.
[0266] 137. The method of any one of embodiments 126 through 136
wherein the dispersant is present in amount from 0.5% to 2.0% by
weight, inclusive, of the total weight of the nanocomposite.
[0267] 138. The method of any one of embodiments 126 through 137
wherein the milling media includes zirconia particles.
[0268] 139. The method of any one of embodiments 126 through 138
wherein the milling media includes yttrium-stabilized zirconia
beads.
[0269] 140. The method of any one of embodiments 126 through 139
wherein the milling is performed until the aggregated nanoparticles
are dispersed to form layered nanoparticles including an average
particle size in the range from about 1 nanometer to about 1000
nanometers.
[0270] 141. The method of any one of embodiments 126 through 140
wherein the layered nanoparticles include an average particle size
in the range from about 1 nanometer to about 500 nanometers.
[0271] 142. The method of any one of embodiments 126 through 141
wherein the layered nanoparticles include an average particle size
in the range from about 1 nanometer to about 100 nanometers.
[0272] 143. The method of any one of embodiments 126 through 142
further comprising including a catalyst in the mixture for reacting
hydroxyl groups on the surface of the nanoparticles with the
curable resin system.
[0273] 144. The method of embodiment 143 wherein the catalyst
includes stannous chloride (SnCl.sub.2) or methylethylketone
peroxide.
[0274] 145. The method of any one of embodiments 126 through 144
further including a surface treatment agent including an
organosilane, a monohydric alcohol, a polyol, or a combination
thereof.
[0275] 146. The method of embodiment 145 wherein the surface
treatment agent includes surfaces treated with phenyl
trimethoxysilane, benzooxasilepin dimethyl ester,
phenethyltrimethoxy silane, N-phenylaminopropyl trimethoxysilane,
or a mixture thereof.
[0276] 147. The method of any one of embodiments 126 through 146
further comprising including at least one diluent in the
mixture.
[0277] 148. The method of embodiment 147 wherein the at least one
diluent includes a mono- or poly-functional glycidyl ether,
styrene, or a combination thereof.
[0278] 149. The method of any one of embodiments 126 through 148
further including at least one additive selected from the group
consisting of curing agents, cure accelerators, defoamers, air
release agents, catalysts, crosslinking agents, dyes, flame
retardants, pigments, impact modifiers, and flow control
agents.
[0279] 150. The method of any one of embodiments 126 through 149
wherein the layered nanoparticles include a bimodal particle size
distribution.
[0280] 151. The method of any one of embodiments 126 through 149
wherein the layered nanoparticles include a unimodal particle size
distribution.
[0281] 152. The method of any one of embodiments 126 through 151
wherein the curable resin includes an epoxy resin, a curable imide
resin, a vinyl ester resin, an acrylic resin, a bisbenzocyclobutane
resin, a polycyanate ester resin, or a mixture thereof.
[0282] 153. The method of any one of embodiments 126 through 152
wherein the curable resin includes an epoxy resin, a maleimide
resin, a polycyanate ester resins, or a mixture thereof.
[0283] 154. The method of any one of embodiments 126 through 153
wherein the curable resin includes a digycidyl ether of bisphenol
A, a diglycidyl ether of bisphenol F, ethylidene bis-4,1-phenylene
dicyanate, N,N'-4,4'-diphenylmethanebismaleimide,
4,4'-(1-methylethylidene)bis(2-(2-propenyl)phenol), or a mixture
thereof.
[0284] 155. The method of any one of embodiments 126 through 154
wherein the curable resin includes an epoxy resin or a mixture of
epoxy resins.
[0285] 156. The method of any one of embodiments 126 through 155
wherein the milled resin system includes from about 15 to about 50
weight percent of the layered nanoparticles.
[0286] 157. The method of any one of embodiments 126 through 155
wherein the milled resin system includes from about 10 to about 30
weight percent of the layered nanoparticles.
[0287] 158. The method of any one of embodiments 126 through 155
wherein the milled resin system includes from about 20 to about 70
weight percent of the layered nanoparticles.
[0288] 159. The method of any one of embodiments 126 through 158
further comprising including a filler in the milled resin system
including at least one of reinforcing continuous fibers,
reinforcing discontinuous fibers, and hollow glass bubbles.
[0289] 160. The method of embodiment 159 wherein the filler
includes at least one of reinforcing continuous fibers and
reinforcing discontinuous fibers.
[0290] 161. The method of embodiment 159 or embodiment 160 wherein
the filler includes carbon, glass, ceramic, boron, silicon carbide,
basalt, ceramic, polyimide, polyamide, polyethylene, polypropylene,
polyacrylnitrile, or a combination thereof.
[0291] 162. The method of embodiment 159 or embodiment 160 wherein
the reinforcing continuous fibers include a unidirectional array of
individual continuous fibers, woven fabric, knitted fabric, yarn,
roving, braided constructions, or non-woven mat.
[0292] 163. The method of any one of embodiments 126 through 162
further comprising including a curing agent in the mixture, the
curing agent including an amine curing agent, an anhydride curing
agent, a dicyandiamide curing agent, a diaminodiphenyl sulfone
curing agent, or a combination thereof.
[0293] 164. The method of embodiment 163 wherein the curing agent
includes an amine curing agent.
[0294] 165. The method of embodiment 163 wherein the curing agent
includes an anhydride curing agent.
[0295] 166. The method of embodiment 163 wherein the curing agent
includes a dicyandiamide curing agent.
[0296] 167. The method of embodiment 163 wherein the curing agent
includes a diaminodiphenyl sulfone curing agent.
[0297] 168. The method of embodiment 126 wherein the milled resin
system consists essentially of about 1 to about 70 weight percent
of layered nanoparticles, and a dispersant dispersed in a curable
resin.
EXAMPLES
[0298] These Examples are merely for illustrative purposes and are
not meant to be overly limiting on the scope of the appended
claims. Notwithstanding that the numerical ranges and parameters
setting forth the broad scope of the present disclosure are
approximations, the numerical values set forth in the specific
examples are reported as precisely as possible. Any numerical
value, however, inherently contains certain errors necessarily
resulting from the standard deviation found in their respective
testing measurements. At the very least, and not as an attempt to
limit the application of the doctrine of equivalents to the scope
of the claims, each numerical parameter should at least be
construed in light of the number of reported significant digits and
by applying ordinary rounding techniques.
Summary of Materials
[0299] Unless otherwise noted, all parts, percentages, ratios, etc.
in the Examples and the rest of the specification are by weight.
Table 1 provides a description or role, and a source, for materials
used in the Examples below:
TABLE-US-00001 TABLE 1 Material Description or Role Source JETFINE
3cc Magnesium silicate nanoparticles Emerys Talc America, San
(platelet shaped layered silicate) Jose, CA DRAGONITE XR Halloysite
nanoparticles (needle Applied Materials, Inc., New shaped layered
silicate) York, NY PURAL MG 63 HT Hydrotalcite nanoparticles
(needle Sasol Germany GmbH, shaped layered double hydroxide)
Hamburg Germany NALCO 2329 Silica nanoparticles (spherical Nalco
Chemical Company, shaped) Oak Brook, IL NALCO 2327 Silica
nanoparticles (spherical Nalco Chemical Company shaped) EPON 826
Liquid epoxy resin Momentive Performance Materials Inc., Albany, NY
DER 332 Liquid epoxy resin Dow Chemical Company, Midland, MI BYK
W9010 Dispersant - copolymer with acidic BYK USA, Inc., groups
Wallingford, CT SOLPLUS D510 Dispersant - polymeric Lubrizol
Additives, Wickliffe, OH Phenyl Surface treatment Momentive
Performance trimethoxysilane Materials Inc. EPIKURE 3230 Amine
curing agent Momentive Performance Materials Inc. 1-methoxy-2-
Solvent Univar USA Inc., Kirkland, propanol WA Methylethylketone
Solvent Avantor Performance Materials, Inc., Center Valley, PA
Deionized water Solvent --
Particle Size Test Method
[0300] Particle size of the layered particles was measured by laser
diffraction using a Horiba LA-950 (Horiba, Kyoto, Japan). The
optical model used a refractive index of 1.46 for the layered
particles and 1.38 for methylethylketone (MEK). The second
differential method was used for smoothing based on 150 iterations.
The dispersion was diluted to approximately 1 weight percent solids
with MEK. The diluted sample was then added to the measurement cell
which was filled with MEK until the transmittance was between the
recommended levels of 85-95%. The particle size was reported as a
mean (i.e., average diameter) and as a D90. D90 is defined as the
diameter at which 90% of the particles have a diameter below the
value.
Viscosity Test Method
[0301] Viscosity was measured according to ASTM D 2196.
Measurements were performed using an AR2000 viscometer (TA
Instruments, New Castle, Del.).
Glass Transition Temperature Test Method
[0302] Glass transition temperature (T.sub.g) was measured
according to ASTM D 7028, using a Q800 dynamic mechanical analyzer
(DMA) (TA Instruments, New Castle, Del.).
Tensile Properties Test Method
[0303] Storage modulus (E') was measured according to ASTM D 638,
using a Q800 dynamic mechanical analyzer (DMA) (TA Instruments, New
Castle, Del.).
Immersion Mill Method
[0304] Example layered nanocomposites were prepared using the
following solvent-free milling method. A premix was prepared with
the components of the layered nanocomposite. Epoxy (EPON 826 or DER
332) was preheated to 90.degree. C. to decrease its viscosity for
ease of handling. The preheated epoxy resin was transferred to a
stainless steel jacketed kettle. To the kettle may be added a
dispersant (W9010). 1:3 ethylene glycol:water mixture was
circulated through the jacket of the kettle to control composition
temperature during preparation of the premix as well as during
milling. The temperature of the glycol:water mixture, and in turn,
the composition was regulated by a circulator (PHOENIX II, Thermo
Fisher Scientific, Newington, N.H.). The kettle containing the
liquid components was secured to the frame of a disperser equipped
with a 90 millimeter f-blade (DISPERMAT, CN-10, BYK-Gardner,
Columbia, Md.). After activation of the f-blade and mixing of the
liquid components, the dry particles were gradually added to the
kettle as described in the examples.
[0305] Milling was performed using a Micro Mill immersion mill
(Hockmeyer Equipment Corporation, Elizabeth City, N.C.). The
immersion mill was operated with a 0.1 millimeter wire wedge screen
filled with approximately 40 milliliters (65 grams) 0.5-0.7 mm
yttrium-stabilized zirconia milling media (Zirmil, Saint-Gobain, Le
Pontet Cedex, France). Enclosed in the media field were 8 pegs to
agitate the media. A turbo prop at the bottom exterior of the
screen provided the driving force for material to circulate through
the media field. No auger was used when milling. The kettle
containing the premix was then transferred from the disperser
station to the milling station and milling initiated. The mill was
operated at 4,000 revolutions per minute (rpm).
[0306] Milling resulted in size reduction of the layered particles
from a few micrometers to submicron size, as well as simultaneous
surface modification of the particle surface, and compounding of
the layered nanoparticles into the epoxy. Milling was continued
until no further significant reduction in particle size was
measured.
Comparative Example 1
Resin without Nanoparticles
[0307] The resin of Comparative Example 1 was pure epoxy (EPON
826).
Comparative Example 2
Nanocomposite with Spherical Nanoparticles
[0308] The silica nanocomposite of Comparative Example 2 was
prepared using a mixture of surface treated colloidal silicas
(NALCO 2329 and NALCO 2327). The surface treatment process of
Comparative Example 2 was similar to the methods described in
Examples 1 and 9-13 of International Patent Application Publication
No. WO 2009/120846 (Tiefenbruck et al.). Phenyl trimethoxysilane
(TMPS) was used as the surface treatment agent. Upon completion of
the surface treatment process, epoxy (EPON 826) was compounded into
the dispersion. The dispersion was then fed through a wiped film
evaporator to remove the water and solvent from the dispersion,
according to methods described in International Patent Application
Publication No. WO 2011/159521 (Thunhorst et al.). The completion
of the stripping process yielded a nanocomposite of silane
covalently bonded to the silica in epoxy. The silica nanocomposite
was diluted with epoxy (EPON 826) using a speedmixer (Model ARV-3
Vacuum Mixer, Thinky USA, Inc., Laguna Hills, Calif.) to achieve
the final composition of Table 2.
Example 1
Nanocomposite with Layered Nanoparticles
[0309] The nanocomposite of Example 1 was prepared using layered
double hydroxide nanoparticles (PURAL MG 63 HT) and epoxy resin
(EPON 826). A dispersant (BYK W9010) was used to treat the particle
surface. The dispersant was chosen to serve two purposes: 1) to
reduce the tendency for the particle to reaggregate once milled to
smaller sizes; and 2) to chemically modify the particle surface to
make it more compatible with the matrix material (e.g. epoxy
resin). The Immersion Mill Method was used to prepare the Examples.
The composition, milling conditions, and viscosity are given in
Table 2 below.
Example 2
Nanocomposite with Layered Nanoparticles
[0310] The nanocomposite of Example 2 was prepared as Example 1
except that layered silicate nanoparticles (DRAGONITE XR) were
used. The layered silicate nanoparticles are needle-like and
hollow. The composition, milling conditions, and viscosity are
given in Table 2 below.
Example 3
Nanocomposite with Layered Nanoparticles
[0311] The nanocomposite of Example 3 was prepared as Example 1
except the layered silicate talc (JETFINE 3 cc) was used, which is
a platelet nanoparticle. SOLPLUS D510 was used as the dispersant.
The composition, milling conditions, and viscosity are given in
Table 2 below.
Example 4
Nanocomposite with High Loading of Layered Nanoparticles
[0312] The nanocomposite of Example 4 was prepared as Example 1
except that a higher loading of the layered double hydroxide
nanoparticle (PURAL MG 63HT) was used as well as a different epoxy
(DER 332). The composition, milling conditions, and viscosity are
given in Table 2 below.
TABLE-US-00002 TABLE 2 Composition, milling conditions, and
characterization of control and nanocomposites Control
Solvent-based Solvent-free Example CE 1 CE 2 EX 1 EX 2 EX 3 EX 4
Particle .sup. n/a.sup.1 NALCO PURAL DRAGONITE JETFINE PURAL
Particle Shape n/a spherical platelet hollow needle platelet
platelet Surface Agent n/a TMPS W9010 W9010 D510 W9010 Nanoparticle
-- 20.0 20.0 20.0 20.0 48.3 (wt %) Epoxy (wt %) 100.0 79.3 78.0
78.0 78.0 43.4 Surface Agent -- 0.7 2.0 2.0 2.0 8.3 (wt %) Mill
Time (h:min) n/a n/a 5:00 5:00 15:00 6:00 Mill Temperature n/a n/a
95 92 112 96 (.degree. C.) Mean Particle n/a .sup. NM.sup.2 175 396
238 241 Size (nm) D90 Particle Size n/a NM 251 1,398 516 280 (nm)
Peak 1 n/a NM 97.0 84.0 85.2 97.0 Distribution (%) Viscosity @ 30
90 69 187 5,924 153 30.degree. C. (Pa-s) (50.degree. C.) .sup.1n/a:
not applicable. .sup.2NM: not measured
Comparative Example 1a
Urea Resin without Nanoparticles
[0313] Comparative Example 1a was prepared by mixing Comparative
Example 1 with an amine curative (EPIKURE 3230) according to Table
3 using a speedmixer (Model ARV-3 Vacuum Mixer, Thinky USA, Inc.,
Laguna Hills, Calif.). The mixture was transferred to a mold and
then placed in an oven. The example was cured for 2 hours at
80.degree. C. followed by a post cure for 2 hours at 125.degree.
C.
Comparative Example 2a
Cured Silica Nanocomposite with Spherical Nanoparticles
[0314] Comparative Example 2a was prepared as Comparative Example
1a except the nanocomposite of Comparative Example 2 was used as
the uncured resin.
Examples 1a-3a
Cured Nanocomposites with Layered Nanoparticles
[0315] Examples 1a-3a were prepared as Comparative Example 1a
except the layered nanocomposites of Examples 1-3 were used as the
uncured resin.
TABLE-US-00003 TABLE 3 Composition and characterization of cured
control and nanocomposites Control Solvent-based Solvent-free
Example CE 1a CE 2a EX 1a EX 2a EX 3a Particle n/a.sup.1 NALCO
PURAL DRAGONITE JETFINE Particle Shape spherical platelet hollow
needle platelet Surface Agent n/an/a TMPS W9010 W9010 D510 Epoxy
Nanocomposite (wt %) -- 79.4 79.1 79.1 79.1 (CE 2) (EX 1) (EX 2)
(EX 3) Epoxy (EPON 826) (wt %) 56.4 -- -- -- -- Curative (EPIKURE
3230) 24.8 20.6 20.9 20.9 20.9 (wt %) E'.sub.glass (Mpa) 1,256
1,447 1,521 1,381 1,691 Tg (.degree. C.) 92.9 93.5 102.7 95.1 88.5
E'.sub.rubber (Mpa) 14.64 18.73 24.44 24.84 31.18 .sup.1n/a: not
applicable
[0316] FIG. 1 shows two of the three nanocomposites with layered
nanoparticles exhibit higher viscosity than the nanocomposite with
spherical nanoparticles. FIG. 2 shows the nanocomposites prepared
with the layered nanoparticles exhibit higher glassy and rubber
modulus relative to the unfilled resin. In FIG. 2, each of the
white bars corresponds to the glassy modulus, whereas each of the
patterned bars corresponds to the rubber modulus. Relative to the
nanocomposite with spherical nanoparticles, the nanocomposites with
the layered nanoparticles exhibit similar glassy modulus and higher
rubber modulus.
[0317] FIGS. 3A and 3B provide scanning electron microscope (SEM)
images of Example 1a at two different magnifications. The images
show that hydrotalcite (layered double hydroxide) nanoparticles
(PURAL MG 63 HT) have nonspherical shape with a broad particle size
distribution, and good dispersion quality in the nanocomposite is
shown. FIGS. 4A and 4B provide SEM images of Example 2a, show that
the halloysite (layered silicate) nanoparticles (DRAGONITE XR) have
needle shapes with a broad particle size distribution, and good
dispersion quality in the nanocomposite is shown. FIGS. 5A and 5B
provide SEM images of Example 3a, show that the talc (layered
silicate) nanoparticles (JETFINE 3 cc) have nonspherical shape with
a very broad particle size distribution, and good dispersion
quality in the nanocomposite is shown. The images of 3B, 4B, and 5B
each show dispersions containing a combination of agglomerated
layered nanoparticles, intercalated layered nanoparticles, and
exfoliated layered nanoparticles.
Example 5 (Prophetic Example)
Pressure Vessel Containing Solvent-Free Nanocomposite with Layered
Nanoparticles
[0318] Example 5 is prepared by forming a nanocomposite with
layered nanoparticles according to the formulation and method of
Example 1. A pressure vessel is prepared by winding carbon fiber
(e.g., TORAY T700SC-12000-50C, Lot #A2106M2, Toray Carbon Fibers
America, Inc., Decatur, Ala.) saturated in the nanocomposite,
according to the coating process described in U.S. application Ser.
No. 13/154,615 (Thunhorst et al.). The wound vessel is then cured
according to the conditions described in U.S. application Ser. No.
13/154,615 (Thunhorst et al.) to form the pressure vessel.
[0319] While the specification has described in detail certain
exemplary embodiments, it will be appreciated that those skilled in
the art, upon attaining an understanding of the foregoing, may
readily conceive of alterations to, variations of, and equivalents
to these embodiments. Furthermore, all publications and patents
referenced herein are incorporated by reference in their entirety
to the same extent as if each individual publication or patent was
specifically and individually indicated to be incorporated by
reference. Various exemplary embodiments have been described. These
and other embodiments are within the scope of the following
claims.
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