U.S. patent application number 10/320567 was filed with the patent office on 2003-08-07 for catalyst system for producing carbon fibrils.
Invention is credited to Levinson, Lionel Monty, Singh, Navjot, Sun, Xiao-Dong.
Application Number | 20030149163 10/320567 |
Document ID | / |
Family ID | 26825281 |
Filed Date | 2003-08-07 |
United States Patent
Application |
20030149163 |
Kind Code |
A1 |
Sun, Xiao-Dong ; et
al. |
August 7, 2003 |
Catalyst system for producing carbon fibrils
Abstract
A catalyst system and method for making carbon fibrils is
provided which comprises a catalytic amount of an inorganic
catalyst comprising nickel and one of the following substances
selected from the group consisting of chromium; chromium and iron;
chromium and molybdenum; chromium, molybdenum, and iron; aluminum;
yttrium and iron; yttrium, iron and aluminum; zinc; copper;
yttrium; yttrium and chromium; and yttrium, chromium and zinc. In a
further aspect of the invention, a catalyst system and method is
provided for making carbon fibrils which comprises a catalytic
amount of an inorganic catalyst comprising cobalt and one of the
following substances selected from the group consisting of
chromium; aluminum; zinc; copper; copper and zinc; copper, zinc,
and chromium; copper and iron; copper, iron, and aluminum; copper
and nickel; and yttrium, nickel and copper.
Inventors: |
Sun, Xiao-Dong;
(Schenectady, NY) ; Singh, Navjot; (Clifton Park,
NY) ; Levinson, Lionel Monty; (Schenectady,
NY) |
Correspondence
Address: |
General Electric Company
CRD Patent Docket Rm 4A59
M.N. Salamone
P.O. Box 8, Bldg. K1
Schenectady
NY
12301
US
|
Family ID: |
26825281 |
Appl. No.: |
10/320567 |
Filed: |
December 16, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10320567 |
Dec 16, 2002 |
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09535811 |
Mar 28, 2000 |
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6518218 |
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60127038 |
Mar 31, 1999 |
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Current U.S.
Class: |
524/496 ;
423/447.3; 502/302; 502/315; 502/325; 502/331 |
Current CPC
Class: |
B01J 2219/00612
20130101; Y10S 977/881 20130101; B01J 2219/00747 20130101; B01J
2219/00707 20130101; C40B 30/08 20130101; Y10S 977/774 20130101;
C40B 40/18 20130101; Y10S 977/896 20130101; B01J 2219/00605
20130101; B01J 2219/00659 20130101; B01J 2219/0043 20130101; C08K
7/06 20130101; C40B 60/14 20130101; G01N 31/10 20130101; Y10S
977/775 20130101; B01J 23/866 20130101; B01J 2219/00585 20130101;
B01J 2219/00745 20130101; B01J 23/72 20130101; D01F 9/127 20130101;
B01J 23/864 20130101; B01J 23/8878 20130101; B01J 23/83 20130101;
B01J 19/0046 20130101; B01J 37/347 20130101; B01J 2219/00376
20130101; B01J 23/80 20130101; B01J 2219/00369 20130101; Y10S
977/742 20130101; B82Y 30/00 20130101; B01J 2219/00635 20130101;
Y10S 977/89 20130101; B01J 2219/00695 20130101 |
Class at
Publication: |
524/496 ;
502/302; 502/315; 502/325; 502/331; 423/447.3 |
International
Class: |
B01J 023/26; D01F
009/12; C08K 003/04 |
Claims
What is claimed is:
1. A catalyst system for making carbon fibrils, the system
comprising a catalytic amount of an inorganic catalyst comprising
nickel and one of the following substances selected from the group
consisting of chromium; chromium and iron; chromium and molybdenum;
chromium, molybdenum, and iron; aluminum; yttrium and iron;
yttrium, iron and aluminum; zinc; copper; yttrium; yttrium and
chromium; and yttrium, chromium and zinc.
2. The system of claim 1, wherein the inorganic catalyst comprises
nickel and chromium.
3. The system of claim 2, wherein the inorganic catalyst further
comprises iron.
4. The system of claim 2, wherein the inorganic catalyst further
comprises molybdenum.
5. The system of claim 4, wherein the inorganic catalyst further
comprises iron.
6. The system of claim 2, wherein the inorganic catalyst further
comprises yttrium.
7. The system of claim 6, wherein the inorganic catalyst further
comprises zinc.
8. The system of claim 1, wherein the inorganic catalyst comprises
nickel and aluminum.
9. The system of claim 1, wherein the inorganic catalyst comprises
nickel and yttrium.
10. The system of claim 9, wherein the inorganic catalyst further
comprises iron.
11. The system of claim 10, wherein the inorganic catalyst further
comprises aluminum.
12. The system of claim 1, wherein the inorganic catalyst comprises
nickel and zinc.
13. The system of claim 1, wherein the inorganic catalyst comprises
nickel and copper.
14. The system of claim 1, wherein the inorganic catalyst is
substantially free of iron.
15. A catalyst system for making carbon fibrils, the system
comprising a catalytic amount of an inorganic catalyst comprising
cobalt and one of the following substances selected from the group
consisting of chromium; aluminum; zinc; copper; copper and zinc;
copper, zinc, and chromium; copper and iron; copper, iron, and
aluminum; copper and nickel; and yttrium, nickel and copper.
16. The system of claim 15, wherein the inorganic catalyst
comprises cobalt and chromium.
17. The system of claim 15, wherein the inorganic catalyst
comprises cobalt and aluminum.
18. The system of claim 15, wherein the inorganic catalyst
comprises cobalt and copper.
19. The system of claim 18, wherein the inorganic catalyst further
comprises zinc.
20. The system of claim 19, wherein the inorganic catalyst further
comprises chromium.
21. The system of claim 18, wherein the inorganic catalyst further
comprises iron.
22. The system of claim 18, wherein the inorganic catalyst further
comprises nickel.
23. The system of claim 21, wherein the inorganic catalyst further
comprises aluminum.
24. The system of claim 22, wherein the inorganic catalyst further
comprises yttrium.
25. The system of claim 15, wherein the inorganic catalyst
comprises cobalt and zinc.
26. A method for making carbon fibrils wherein the method comprises
reacting a carbon source and a catalyst system comprising an
inorganic catalyst comprising nickel and one of the following
substances selected from the group consisting of chromium; chromium
and iron; chromium and molybdenum; chromium, molybdenum, and iron;
aluminum; yttrium and iron; yttrium, iron and aluminum; zinc;
copper; yttrium; yttrium and chromium; and yttrium, chromium and
zinc.
27. The method of claim 26, wherein the inorganic catalyst
comprises nickel and chromium.
28. The method of claim 27, wherein the inorganic catalyst further
comprises iron.
29. The method of claim 28, wherein the inorganic catalyst further
comprises molybdenum.
30. The method of claim 29, wherein the inorganic catalyst further
comprises iron.
31. The method of claim 27, wherein the inorganic catalyst further
comprises yttrium.
32. The method of claim 31, wherein the inorganic catalyst further
comprises zinc.
33. The method of claim 26, wherein the inorganic catalyst
comprises nickel and aluminum.
34. The method of claim 26, wherein the inorganic catalyst
comprises nickel and yttrium.
35. The method of claim 34, wherein the inorganic catalyst further
comprises iron.
36. The method of claim 35, wherein the inorganic catalyst further
comprises aluminum.
37. The method of claim 26, wherein the inorganic catalyst
comprises nickel and zinc.
38. The method of claim 26, wherein the inorganic catalyst
comprises nickel and copper.
39. The method of claim 26, wherein the inorganic catalyst is
substantially free of iron.
40. The method of claim 26, wherein the carbon source comprises
acetylene, ethylene, methane, benzene, carbon monoxide or mixtures
thereof.
41. A method for making carbon fibrils wherein the method comprises
reacting an carbon source and a catalyst system comprising an
inorganic catalyst comprising cobalt and one of the following
substances selected from the group consisting of chromium;
aluminum; zinc; copper; copper and zinc; copper, zinc, and
chromium; copper and iron; copper, iron, and aluminum; copper and
nickel; and yttrium, nickel and copper.
42. The method of claim 41, wherein the inorganic catalyst
comprises cobalt and chromium.
43. The method of claim 41, wherein the inorganic catalyst
comprises cobalt and aluminum.
44. The method of claim 41, wherein the inorganic catalyst
comprises cobalt and copper.
45. The method of claim 44, wherein the inorganic catalyst further
comprises zinc.
46. The method of claim 45, wherein the inorganic catalyst further
comprises chromium.
47. The method of claim 44, wherein the inorganic catalyst further
comprises iron.
48. The method of claim 44, wherein the inorganic catalyst further
comprises nickel.
49. The method of claim 47, wherein the inorganic catalyst further
comprises aluminum.
50. The method of claim 48, wherein the inorganic catalyst further
comprises yttrium.
51. The method of claim 41, wherein the inorganic catalyst
comprises cobalt and zinc.
52. The method of claim 41, wherein the carbon source comprises
acetylene, ethylene, methane, benzene, carbon monoxide or mixtures
thereof.
53. A carbon fibril made from the catalyst system of claim 1.
54. A carbon fibril made from. the catalyst system of claim 15.
55. A carbon fibril made by the method of claim 26.
56. A carbon fibril made by the method of claim 41.
57. An organic resin which comprises carbon fibrils made from the
catalyst system of claim 1.
58. The organic resin of claim 57 wherein the carbon fibrils are
present in a range between about 0.01% by weight and about 20% by
weight of the organic resin.
59. The organic resin of claim 58 wherein the carbon fibrils are
present in a range between about 0.1% by weight and about 7% by
weight of the organic resin.
60. The organic resin of claim 57 wherein the organic resin
comprises polyphenylene ether or polycarbonate.
61. An organic resin which comprises carbon fibrils made from the
catalyst system of claim 15.
62. The organic resin of claim 61 wherein the carbon fibrils are
present in a range between about 0.01% by weight and about 20% by
weight of the organic resin.
63. The organic resin of claim 62 wherein the carbon fibrils are
present in a range between about 0.1% by weight and about 7% by
weight of the organic resin.
64. The organic resin of claim 61 wherein the organic resin
comprises polyphenylene ether or polycarbonate.
65. A organic resin which comprises carbon fibrils made by the
method of claim 26.
66. The organic resin of claim 65 wherein the carbon fibrils are
present in a range between about 0.01% by weight and about 20% by
weight of the organic resin.
67. The organic resin of claim 66 wherein the carbon fibrils are
present in a range between about 0.1% by weight and about 7% by
weight of the organic resin.
68. The organic resin of claim 65 wherein the organic resin
comprises polyphenylene ether or polycarbonate.
69. A organic resin which comprises carbon fibrils made by the
method of claim 41.
70. The organic resin of claim 69 wherein the carbon fibrils are
present in a range between about 0.01% by weight and about 20% by
weight of the organic resin.
71. The organic resin of claim 70 wherein the carbon fibrils are
present in a range between about 0.1% by weight and about 7% by
weight of the organic resin.
72. The organic resin of claim 69 wherein the organic resin
comprises polyphenylene ether or polycarbonate.
73. A organic resin comprising carbon fibrils in a range between
about 0.01% by weight and about 20% by weight of the organic
resin.
74. The organic resin in accordance with claim 73, wherein the
carbon fibrils are present in a range between about 0.1% by weight
and about 7% by weight of the organic resin.
75. A polyphenylene ether comprising carbon fibrils in a range
between about 0.1% by weight and about 7% by weight of the
polyphenylene ether.
76. A polycarbonate comprising carbon fibrils in a range between
about 0.1% by weight and about 7% by weight of the polycarbonate
resin.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority from Provisional
Application Ser. No. 60/127,038 entitled "New Catalysts for
Synthesis of Carbon Fibrils," filed on Mar. 31, 1999 which is
incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] The present invention is related to a catalyst system for
preparing carbon fibrils. More specifically, the invention is
related to carbon fibrils and new catalysts which have been found
useful for the synthesis of carbon fibrils.
[0003] Carbon fibrils, also known as carbon nanotubes, are
microscopic fibers of carbon which are either tubes or dense fibers
(i.e. not hollow) with a typical diameter in a range between about
1 nanometer and about 500 nanometers. In particular, it is often
preferable to synthesize carbon fibrils with a diameter in a range
between about 10 nanometers and about 50 nanometers. The aspect
ratio of length of the carbon fibril to the diameter of the carbon
fibril is typically greater than about 100.
[0004] Production of carbon fibrils is a well known synthetic
process. They are typically synthesized using a catalytic vapor
decomposition process, in which an organic vapor is flushed over
dispersed metal catalysts at temperatures ranging from 400.degree.
C. to 1300.degree. C. to form carbon fibrils. The chemical nature
of the metal catalysts influences the yield and morphology of the
synthesized carbon fibrils.
[0005] Mandeville et al. and Moy et al., U.S. Pat. Nos. 5,500,200
and 5,726,116 respectively, discuss the reaction of a source of
carbon over a catalyst in a reaction system to produce carbon
fibrils. However, Mandeville et al. and Moy et al. are ostensibly
limited to iron catalysts and their binary alloys. In addition,
these patents are not concerned with tertiary or quaternary
combinations of catalysts which may have a synergistic effect
compared to singular or binary combinations.
[0006] Due to the increasing interest in carbon fibrils, alternate
catalysts that will result in the synthesis of carbon fibrils at
high yield and high efficiency are constantly being sought.
BRIEF SUMMARY OF THE INVENTION
[0007] In one embodiment, the present invention provides a catalyst
system for making carbon fibrils, the system comprising a catalytic
amount of an inorganic catalyst comprising nickel and one of the
following substances selected from the group consisting of:
[0008] chromium;
[0009] chromium and iron;
[0010] chromium and molybdenum;
[0011] chromium, molybdenum, and iron;
[0012] aluminum;
[0013] yttrium and iron;
[0014] yttrium, iron and aluminum;
[0015] zinc;
[0016] copper;
[0017] yttrium;
[0018] yttrium and chromium; and
[0019] yttrium, chromium and zinc.
[0020] A further aspect of the invention provides a catalyst system
for making carbon fibrils, the system comprising a catalytic amount
of an inorganic catalyst comprising cobalt and one of the following
substances selected from the group consisting of:
[0021] chromium;
[0022] aluminum;
[0023] zinc;
[0024] copper;
[0025] copper and zinc;
[0026] copper, zinc, and chromium;
[0027] copper and iron;
[0028] copper, iron, and aluminum;
[0029] copper and nickel; and
[0030] yttrium, nickel and copper.
[0031] Yet another aspect of the present invention is a method for
making carbon fibrils wherein the method comprises reacting a
carbon source and a catalyst system. The catalyst system comprises
an inorganic catalyst comprising nickel and one of the following
substances selected from the group consisting of:
[0032] chromium;
[0033] chromium and iron;
[0034] chromium and molybdenum;
[0035] chromium, molybdenum, and iron;
[0036] aluminum;
[0037] yttrium and iron;
[0038] yttrium, iron and aluminum;
[0039] zinc;
[0040] copper;
[0041] yttrium;
[0042] yttrium and chromium; and
[0043] yttrium, chromium and zinc.
[0044] Yet a further aspect of the present invention is a method
for making carbon fibrils wherein the method comprises reacting a
carbon source and a catalyst system. The catalyst system comprises
an inorganic catalyst comprising cobalt and one of the following
substances selected from the group consisting of: chromium;
[0045] aluminum;
[0046] zinc;
[0047] copper;
[0048] copper and zinc;
[0049] copper, zinc, and chromium;
[0050] copper and iron;
[0051] copper, iron, and aluminum;
[0052] copper and nickel; and
[0053] yttrium, nickel and copper.
DETAILED DESCRIPTION OF THE INVENTION
[0054] One aspect of the present invention is directed to new
catalysts which successfully synthesize carbon fibrils have been
discovered. The synthesis of carbon fibrils typically involves the
reaction of a carbon source in the presence of an inorganic
catalyst. In one embodiment of the present invention, the carbon
fibrils are synthesized with a catalytic amount of a catalyst which
includes nickel and at least one other substance. The catalyst may
be substantially free of iron. "Substantially free" of iron as used
herein refers to iron present in an amount less than 1% by weight
of the total catalyst. In a second embodiment of the present
invention, the carbon fibrils are synthesized with a catalytic
amount of a catalyst which includes cobalt and at least one other
substance. A "substance" as used herein refers to at least one
metal, metal alloy, or combinations thereof with cobalt or nickel.
"Catalytic amount" as used herein refers to an amount of catalyst
sufficient to form carbon fibrils.
[0055] When the catalyst system is binary, the ratio of the metals,
metal alloys, or mixtures thereof are typically in a range between
about 10:1 and about 1:1. When the catalyst system is tertiary, the
ratio of the metals, metal alloys, or mixtures thereof are
typically in a range between about 10:10:1 and about 1:1:1. When
the catalyst system is quaternary, the ratio of the metals, metal
alloys or mixtures thereof are typically in a range between about
10:10:10:1 and about :1:11::1.
[0056] The catalyst, catalyst precursors or mixtures thereof are
placed on a substrate. "Substrate" as used herein refers to any
material which supports a collection of solid state materials (i.e.
catalysts, catalyst precursors, or mixtures thereof). There is
typically minimum interaction between the supported solid state
materials and substrate material during chemical reaction or
synthesis. However, certain substrates which have been found to be
catalytic substances may have a synergistic effect on the
production of carbon fibrils. Typical substrates include ceramics,
for example, alumina; glass; metals, for example, aluminum,
stainless steel, copper, silver, gold, platinum, and brass; and
single crystals, for example, quartz, magnesium oxide, silicon,
sapphire, and lanthanum aluminate.
[0057] The amount of catalysts placed on the substrate is typically
in a range between nanograms and a few tens of milligrams. Typical
total catalyst loading on the substrate is in a range between
micrograms and a few grams, although with larger reactor size, the
amount of catalysts loaded in a reactor may commonly be as much as
a few pounds.
[0058] The catalysts may be deposited on the substrate sequentially
or preferably, simultaneously. Catalysts may be deposited on a
substrate using a gun sputtering deposition system. A gun
sputtering deposition system contains elemental metal sources,
metal alloy sources, or mixtures thereof placed in the gun cavity.
An electrical discharge can be created at each source by applying
radio frequency (RF) or direct current (DC) power in a range
between about 10 Watts and about 1,000 Watts through the sputter
gun, which heats the metal, metal alloy, or mixture thereof to form
a metal plasma vapor. The metal vapor from the sputter gun is
deposited onto a counter-facing substrate. The thickness of the
material deposited is dependent upon several factors, including
fixed power input. The amount of material deposited can be altered
by changing the amount of time the sputter gun is pulsed.
[0059] Once the metal vapors have been deposited on the substrate,
the catalysts are typically thermally annealed. The catalysts are
heated to a temperature in a range between about 200.degree. C. and
about 1100.degree. C., and preferably, to a temperature in a range
between about 600.degree. C. and about 800.degree. C. During
annealing, the catalysts are also typically in an environment to
prevent the oxidation of the elemental metals or metal alloys.
Examples of typical gases include argon, helium, nitrogen, hydrogen
and mixtures thereof. Although the invention is not dependent upon
theory, the temperature and atmospheric conditions may promote the
interdiffusion and mixing of the combined metals to form
catalysts.
[0060] An alternative manner for depositing a catalyst on a
substrate is through the use of a liquid dispensing system. Each
liquid dispenser is individually controlled and programmed to
dispense a liquid material. The liquid dispensers are each filled
with a soluble metal precursor such as a nitrate, acetate, and
other aqueous soluble metal salt compound. The elemental metal,
metal mixture, or mixtures thereof are carried in the soluble
precursor. Once the soluble precursor comprising elemental metal,
metal mixture, or mixtures thereof is deposited on the substrate as
a liquid, the precursor is typically dried, calcined, and annealed
(for example, in nitrogen, argon, helium, or mixtures thereof) to
form an oxide-containing powder catalyst. To synthesize metal or
alloy catalysts from such oxide-containing powders, reducing (for
example, using hydrogen, charcoal, or carbon monoxide) in a time
range between about 0.5 hours and about 12 hours at a temperature
in a range between about 300.degree. C. and about 800.degree. C. is
typically sufficient. By use of a soluble precursor, any oxidation
of the inorganic metal or metal alloy is not a problem.
[0061] Once the above-mentioned catalysts are created, the
catalysts may be used to synthesize carbon fibrils. The method
commonly used to synthesize carbon fibrils may be a solid state
reaction. The catalysts on the substrate are typically placed in a
reaction chamber, such as a quartz tube reactor, at a temperature
in a range between about 300.degree. C. and about 100.degree. C.,
and preferably in a range between about 400.degree. C. and about
700.degree. C. The elevated temperature in the reactor facilitates
the synthesis of the carbon fibrils.
[0062] The reactor can be operated under a pressure in a range
between about 1 torr and about 100 atmospheres. The synthesis is
typically run at a pressure in a range between about 100 torr and
about 10 atmospheres.
[0063] In preferred embodiments, the reactor is filled with a gas
in order to create a non-reactive atmosphere in the reaction
chamber. In particular, the reactor is filled with a gas in order
to create a non-oxidative environment such that the metal catalysts
will not be oxidized. Commonly, there is a constant flow of gas.
Examples of suitable gases include argon, helium, nitrogen,
hydrogen, and mixtures thereof. Typically, argon and hydrogen are
used and are present in a volume ratio in a range between about
5.5:1 and about 1:1. A mixture of argon and hydrogen is most
commonly used at a volume ratio of 5:1 of argon to hydrogen. Due to
the varying volume capacity of different reaction chambers, the
flow rate can vary. Typically, the flow rate of the gas is such
that it takes approximately 8 minutes to refresh the gas in the
tube.
[0064] The reaction chamber is then filled with a steady flow of a
carbon source, for example organic vapor, at the elevated reaction
temperature. Typical organic vapors which can be used in the
present invention include acetylene, ethylene, methane, benzene,
carbon monoxide and mixtures thereof. Commonly, the organic vapor
is mixed with one of the gases mentioned above. Typically, a
combination of ethylene gas with hydrogen gas is used at a volume
ratio of 5:1. When the organic vapor comes in contact with the
catalyst, the organic vapor and catalyst react and carbon fibrils
are synthesized. Carbon fibrils may also be synthesized from a
reactant product of the gas and the organic vapor under the process
conditions.
[0065] Depending on the reactivity of the catalysts, among other
factors, the reaction time to synthesize carbon fibrils can be in a
range between seconds and hours. With the reactor used in the
present invention, the reaction time is typically in a range
between about 10 minutes and about 8 hours.
[0066] The yields and morphology of the carbon fibrils are
typically examined by standard techniques. These techniques include
optical microscopy, scanning electron microscopy (SEM),
transmission electron microscopy, X-ray diffraction, Raman
scattering and laser profilometry. In addition, the electrical
conductivity of the carbon fibrils formed is typically measured
using a standard conductivity measurement, for example, a direct
four point contact measurement.
[0067] The morphology of the carbon fibrils, after examination
through scanning electron microscopy, are typically found to be
either coiled or straight. In addition, the diameters of some of
the carbon fibrils produced are typically found to be in a range of
between about 1 nanometer and about 500 nanometers.
[0068] Carbon fibrils can be used for a variety of applications.
Most typically, carbon fibrils are used as an additive in organic
resins such as thermoplastic resin compositions or thermoset
polymer compositions to impart particular physical properties. For
example, carbon fibrils are used to make conductive composites with
thermoplastic resins that can be used for electrostatic painting
and electrostatic dissipation applications. The major constituent
of the thermoplastic resin compositions is at least one
thermoplastic polymer. Both addition and condensation polymers are
included. Illustrative, non-limiting examples of thermoplastic
polymers are olefin-derived polymers such as polyethylene,
polypropylene, and their copolymers; polymethylpentane;
diene-derived polymers such as polybutadiene, polyisoprene, and
their copolymers; polymers of ethylenically unsaturated carboxylic
acids and their functional derivatives, including acrylic polymers
such as poly(alkyl acrylates), poly(alkyl methacrylates),
polyacrylamides, polyacrylonitrile and polyacrylic acid;
alkenylaromatic polymers such as polystyrene,
poly-alpha-methylstyrene, polyvinyltoluene, and rubber-modified
polystyrenes; polyamides such as nylon-6, nylon-66, nylon-11, and
nylon-12; polyesters; polycarbonates; polyestercarbonates;
polyethers such as polyarylene ethers, polyethersulfones,
polyetherketones, polyetheretherketones, and polyetherimides;
polyarylene sulfides, polysulfones, and polysulfidesulfones; and
liquid crystalline polymers.
[0069] Both thermoplastic polyesters and thermoplastic elastomeric
polyesters are suitable for use in the present invention.
Illustrative, non-limiting examples of thermoplastic polyesters
include poly(ethylene terephthalate), poly(1,4-butylene
terephthalate), poly(1,3-propylene terephthalate),
poly(cyclohexanedimethanol terephthalate),
poly(cyclohexanedimethanol-co-ethylene terephthalate),
poly(ethylene naphthalate), poly(butylene naphthalate), and
polyarylates. Illustrative, non-limiting examples of thermoplastic
elastomeric polyesters (commonly known as TPE) include
polyetheresters such as poly(alkylene terephthalate)s (particularly
poly[ethylene terephthalate] and poly[butylene terephthalate])
containing soft-block segments of poly(alkylene oxide),
particularly segments of poly(ethylene oxide) and poly(butylene
oxide); and polyesteramides such as those synthesized by the
condensation of an aromatic diisocyanate with dicarboxylic acids
and a carboxylic acid-terminated polyester or polyether
prepolymer.
[0070] Suitable polyarylates include, but are not limited to, the
polyphthalate esters of 2,2-bis(4-hydroxyphenyl)propane (commonly
known as bisphenol A), and polyesters consisting of structural
units of the formula II: 1
[0071] wherein R.sup.4 is hydrogen or C.sub.1-4 alkyl, optionally
in combination with structural units of the formula III: 2
[0072] wherein R.sup.5 is a divalent C4.sub.4-12 aliphatic,
alicyclic or mixed aliphatic-alicyclic radical. The latter
polyesters may be prepared by the reaction of a
1,3-dihydroxybenzene moiety with at least one aromatic dicarboxylic
acid chloride under alkaline conditions. Structural units of
formula II contain a 1,3-dihydroxybenzene moiety which may be
substituted with halogen, usually chlorine or bromine, or
preferably with C.sub.1-4 alkyl; e.g., methyl, ethyl, isopropyl,
propyl, butyl. Said alkyl groups are preferably primary or
secondary groups, with methyl being more preferred, and are most
often located in the ortho position to both oxygen atoms although
other positions are also contemplated. The most preferred moieties
are resorcinol moieties, in which R.sup.4 is hydrogen. Said
1,3-dihydroxybenzene moieties are linked to aromatic dicarboxylic
acid moieties which may be monocyclic moieties, e.g., isophthalate
or terephthalate, or polycyclic moieties, e.g.,
naphthalenedicarboxylate. Preferably, the aromatic dicarboxylic
acid moieties are isophthalate and/or terephthalate: either or both
of said moieties may be present. For the most part, both are
present in a molar ratio of isophthalate to terephthalate in a
range between about 0.25 and about 4.0:1, preferably in a range
between about 0.8 and about 2.5:1.
[0073] In the optional soft block units of formula II, resorcinol
or alkylresorcinol moieties are again present in ester-forming
combination with R.sup.5 which is a divalent C.sub.4-12 aliphatic,
alicyclic or mixed aliphatic-alicyclic radical. It is preferably
aliphatic and especially C.sub.8-12 straight chain aliphatic. A
particularly preferred arylate polymer containing soft block units
is one consisting of resorcinol isophthalate and resorcinol
sebacate units in a molar ratio in a range between about 8.5:1.5
and about 9.5:0.5.
[0074] Polycarbonates useful in the compositions of the invention
include those comprising structural units of the formula IV: 3
[0075] wherein at least about 60 percent of the total number of
R.sup.6 groups are aromatic organic radicals and the balance
thereof are aliphatic, alicyclic, or aromatic radicals. Suitable
R.sup.6 radicals include m-phenylene, p-phenylene,
4,4'-biphenylene, 4,4'-bi(3,5-dimethyl)-phenylene,
2,2-bis(4-phenylene)propane, 6,6'-(3,3,3', 3'-tetramethyl-
1,1'-spirobi[1H-indan]),
1,1'-bis(4-phenylene)-3,3,5-trimethylcyclohexane, and similar
radicals such as those which correspond to the
dihydroxy-substituted aromatic hydrocarbons disclosed by name or
formula (generic or specific) in U.S. Pat. No. 4,217,438.
[0076] More preferably, R.sup.6 is an aromatic organic radical and
still more preferably a radical of the formula V: 4
[0077] wherein each A.sup.1 and A.sup.2 is a monocyclic divalent
aryl radical and Y.sup.1 is a bridging radical in which one or two
atoms separate A.sup.1 and A.sup.1. For example, A.sup.1 and
A.sup.2 typically represent unsubstituted phenylene or substituted
derivatives thereof. The bridging radical Y.sup.2 is most often a
hydrocarbon group and particularly a saturated group such as
methylene; cyclohexylidene, 3,3,5-trimethylcyclohexylidene; or
isopropylidene. The most preferred polycarbonates are bisphenol A
polycarbonates, in which each of A.sup.1 and A.sup.2 is p-phenylene
and Y.sup.1 is isopropylidene. Preferably, the weight average
molecular weight of the initial polycarbonate is in a range between
about 5,000 and about 100,000; more preferably in a range between
about 10,000 and about 65,000, still more preferably in a range
between about 16,000 and about 40,000, and most preferably in a
range between about 20,000 and about 36,000. Suitable
polycarbonates may be made using any process known in the art,
including interfacial, solution, solid state, or melt
processes.
[0078] In one embodiment the present invention comprises a
composition containing at least one polycarbonate. In another
embodiment the invention comprises compositions containing two
different polycarbonates. Both homopolycarbonates derived from a
single dihydroxy compound monomer and copolycarbonates derived from
more than one dihydroxy compound monomer are encompassed.
[0079] Polyarylene ethers used in the present invention are most
often polyphenylene ethers having structural units of the formula:
5
[0080] wherein each Q.sup.2 is independently halogen, primary or
secondary lower alkyl, phenyl, haloalkyl, aminoalkyl,
hydrocarbonoxy, or halohydrocarbonoxy wherein at least two carbon
atoms separate the halogen and oxygen atoms, and each Q.sup.3 is
independently hydrogen, halogen, primary or secondary lower alkyl,
phenyl, haloalkyl, hydrocarbonoxy or halohydrocarbonoxy as defined
for Q.sup.2.
[0081] Both homopolymer and copolymer polyphenylene ethers are
included. The preferred homopolymers are those containing
2,6-dimethyl-1,4-phenylen- e ether units. Suitable copolymers
include random copolymers containing such units in combination
with, for example, 2,3,6-trimethyl-1,4-phenylen- e ether units.
Also included are polyphenylene ethers containing moieties prepared
by grafting onto the polyphenylene ether in known manner such
materials as vinyl monomers or polymers such as polystyrenes and
elastomers, as well as coupled polyphenylene ethers in which
coupling agents such as low molecular weight polycarbonates,
quinones, heterocycles and formals undergo reaction in known manner
with the hydroxy groups of two polyphenylene ether chains to
produce a higher molecular weight polymer.
[0082] The polyphenylene ethers generally have an intrinsic
viscosity greater than about 0.1, most often in a range between
about 0.2 deciliters per gram and about 0.6 deciliters per gram and
especially about 0.35 deciliters per grams and about 0.6 deciliters
per gram (dl./g.), as measured in chloroform at 25.degree. C.
[0083] The polyphenylene ethers are typically prepared by the
oxidative coupling of at least one monohydroxyaromatic compound
such as 2,6-xylenol or 2,3,6-trimethylphenol. Catalyst systems are
generally employed for such coupling; they typically contain at
least one heavy metal compound such as a copper, manganese or
cobalt compound, usually in combination with various other
materials.
[0084] Particularly useful polyphenylene ethers are those which
comprise molecules having at least one aminoalkyl-containing end
group. The aminoalkyl radical is covalently bound to a carbon atom
located in an ortho position to a hydroxy group. Products
containing such end groups may be obtained by incorporating an
appropriate primary or secondary monoamine such as di-n-butylamine
or dimethylamine as one of the constituents of the oxidative
coupling reaction mixture. Also frequently present are
4-hydroxybiphenyl end groups and/or biphenyl structural units,
typically obtained from reaction mixtures in which a by-product
diphenoquinone is present, especially in a copper-halide-secondary
or tertiary amine system. A substantial proportion of the polymer
molecules, typically constituting as much as about 90% by weight of
the polymer, may contain at least one of said aminoalkyl-containing
and 4-hydroxy-biphenyl end groups. It will be apparent to those
skilled in the art from the foregoing that the polyphenylene ethers
contemplated for use in the invention include all those presently
known, irrespective of variations in structural units or ancillary
chemical features.
[0085] Both homopolymer and copolymer thermoplastic polymers are
included in the compositions of the present invention. Copolymers
may include random, block or graft type. Thus, for example,
suitable polystyrenes include homopolymers, such as amorphous
polystyrene and syndiotactic polystyrene, and copolymers containing
these species. The latter embraces high impact polystyrene (HIPS),
a genus of rubber-modified polystyrenes comprising blends and
grafts wherein the rubber is a polybutadiene or a rubbery copolymer
of styrene in a range between about 70% by weight and about 98% by
weight and diene monomer in a range between about 2% by weight and
about 30% by weight. Also included are ABS copolymers, which are
typically grafts of styrene and acrylonitrile on a previously
formed diene polymer backbone (e.g., polybutadiene or
polyisoprene). Suitable ABS copolymers may be produced by any
methods known in the art. Especially preferred ABS copolymers are
typically produced by mass polymerization (often referred to as
bulk ABS) or emulsion polymerization (often referred to as high
rubber graft ABS).
[0086] The preferred thermoplastic polymers for many purposes are
polyesters, polycarbonates, polyphenylene ethers, polystyrene
resin, high impact polystyrene resin (HIPS), and
styrene-acrylonitrile copolymers (SAN), including ABS copolymers.
These may be employed individually or as blends. Especially
preferred blends include those of polyphenylene ether with at least
one of HIPS, amorphous polystyrene, syndiotactic polystyrene,
polyester, and polyamide; and polycarbonate blends with at least
one of ABS, SAN, and polyester.
[0087] Ilustrative, non-limiting examples of thermoset polymers
include polymers derived from silicones, polyphenelene ethers,
epoxys, cyanate esters, unsaturated polyesters, multifunctional
allylic compounds such as diallylphthalate, acrylics, alkyds,
phenol-formaldehyde, novolacs, resoles, bismaleimides, PMR resins,
melamine-formaldehyde, urea-formaldehyde, benzocyclobutanes,
hydroxymethylfurans, and isocyanates. In one embodiment of the
present invention, the thermoset polymer further comprises at least
one thermoplastic polymer, such as, but not limited to,
polyphenylene ether, polyphenylene sulfide, polysulfone,
polyetherimide, or polyester. The thermoplastic polymer is
typically combined with a thermoset monomer mixture before curing
of said thermoset.
[0088] Carbon fibrils are most often used as an additive with
polyphenylene ether compositions and polycarbonate compositions.
Carbon fibrils may be present in a range between about 0.01% by
weight and about 20% by weight of the thermoplastic resin or
mixture of resins and more commonly, in a range between about 0.1%
by weight and about 7% by weight of the thermoplastic resin or
mixtures of resins.
[0089] In order that those skilled in the art will be better able
to practice the invention, the following examples are given by way
of illustration and not by way of limitation.
EXAMPLE 1
[0090] Catalysts were fabricated with four metals: iron, nickel,
molybdenum, and chromium on a quartz substrate using a gun
sputtering deposition system using argon as sputtering gas. The
catalysts were annealed at 200.degree. C. for 24 hours in a vacuum
oven at a pressure of N.sub.2 around 10 torr. The catalysts were
then loaded into a chemical vapor deposition reactor which was free
of any volatile materials, pumped to high vacuum (less than about 1
torr) and the reactor was flushed with a mixture of high purity
(greater than 99.9%) hydrogen and high purity argon wherein the
argon and hydrogen were in a volume ratio of about 5:1. The flow
rate was such that it took about 8 minutes to refresh the gas in
the tube. The temperature was slowly ramnped up from room
temperature to 500.degree. C. The catalysts were annealed for about
13 hours before ramping up to the temperature of 600.degree. C. at
2.degree. C. per minute under the same gas flow. The argon was
switched off and replaced with a flow of ethylene. The volume ratio
of ethylene to hydrogen was about 5:1. The catalysts were reacted
for a half an hour before the ethylene source was shut off and
replaced with argon. Under a constant flow of argon and hydrogen,
the furnace was then turned off and allowed to cool to room
temperature before the catalysts was taken out for analysis.
[0091] The catalysts were observed under a reflective optical
microscope for the primary screen of catalyst candidates.
Subsequently, scanning electron microscopy was used for secondary
screening focusing on sample sites with adequate amount of carbon
product. The following catalysts were shown to produce carbon
fibrils by primary and secondary screening of the catalysts
candidates: nickel and molybdenum; nickel and chromium; nickel,
molybdenum and chromium; iron, nickel, and chromium; iron, nickel
and molybdenum; and iron, nickel, molybdenum, and chromium.
EXAMPLE2
[0092] Catalysts were fabricated with six metals: iron, cobalt,
aluminum, zinc, chromium, and yttrium on a quartz substrate.
Solutions of high purity metal nitrates were used as metal
precursors (the concentration of all nitrate solutions used herein
was 1 molar). Once the precursors were deposited on the substrate,
the precursors were annealed at 200.degree. C. for greater than 24
hours in a vacuum oven (pressure about 10 torr) to form catalysts.
The catalysts were then loaded into a chemical vapor deposition
reactor which was free of any volatile materials, pumped to high
vacuum (less than 1 torr), and the reactor was flushed with a
mixture of high purity (greater than 99.9%) hydrogen and high
purity (greater than 99.9%) argon into the tube wherein the argon
to hydrogen volume ratio was about 5:1. The flow rate was such that
it took about 8 minutes to refresh the gas in the tube. The
temperature was slowly ramped up from room temperature to
500.degree. C. The catalysts were annealed for about 13 hours
before ramping up the temperature to 600.degree. C. at 2.degree. C.
per minute, under the same gas flow. Thereafter, the argon was
switched off and replaced with a flow of ethylene. The volume ratio
of ethylene to hydrogen was about 5:1. The catalysts reacted for
about 30 minutes before the ethylene source was shut off and
replaced with argon. Under a constant flow of argon and hydrogen,
the furnace was then turned off and allowed to cool to room
temperature before the catalysts were taken out for evaluation.
[0093] The catalysts were observed under a reflective optical
microscope for the primary screen of catalyst candidates. A
secondary screen was made using scanning electron microscopy (SEM)
focusing on sample sites with adequate amount of carbon product.
The following catalysts were determined as catalysts which produced
carbon fibrils: nickel and iron; cobalt and iron; chromium and
cobalt; zinc and cobalt; nickel and cobalt; nickel and chromium;
nickel and zinc; nickel and copper; cobalt and copper; and nickel
and aluminum.
EXAMPLE 3
[0094] Using the method of Example 2, catalysts were fabricated
with eight metals: copper, iron, zinc, nickel, aluminum, cobalt,
yttrium, and chromium on a quartz substrate. The following
catalysts were shown to produce carbon fibrils: copper and iron;
and aluminum and cobalt.
EXAMPLE 4
[0095] Using the method of Example 2, catalysts were fabricated
with eight metals: copper, iron, zinc, nickel, aluminum, cobalt,
yttrium, and chromium on a quartz substrate. The following
catalysts produced carbon fibrils: cobalt, iron and copper; nickel,
iron and yttrium; copper, iron, cobalt, and aluminum; cobalt and
copper; zinc, cobalt, chromium, and copper; yttrium, cobalt,
nickel, and copper; cobalt, nickel and copper; nickel, chromium,
and yttrium; cobalt, zinc and copper; zinc, yttrium, chromium, and
nickel; aluminum, iron, and nickel; nickel, iron, yttrium, and
aluminum; chromium and zinc; nickel and yttrium; and chromium,
aluminum, and iron.
[0096] It is evident that with the vast array of elemental metals
and metal alloys, there is a multitude of possible catalyst
combinations. However, it was unexpectedly found that some iron
combinations were ineffective catalysts for the production of
carbon fibrils.
EXAMPLE 5
[0097] To form a catalyst, nickel (1 mole) and chromium (1 mole)
were placed on an alumina substrate and were annealed at
200.degree. C. for greater than 24 hours in a vacuum oven at a
pressure around 10 torr in air. The catalyst was then loaded into a
chemical vapor deposition reactor which was free of any volatile
materials, pumped to high vacuum (less than about 1 torr) and the
reactor was flushed with a mixture of high purity (greater than
99.9%) hydrogen and high purity (greater than 99.9%) argon wherein
the argon to hydrogen were in a volume ratio of about 5:1. The gas
flow was 6 cubic centimeters per second. The temperature was slowly
ramped up from room temperature to 700.degree. C. The argon was
switched off and replaced with a flow of ethylene. The volume ratio
of ethylene to hydrogen was about 5:1. The catalyst was reacted for
125 minutes before the ethylene source was shut off and replaced
with argon. Under a constant flow of argon and hydrogen, the
furnace was then turned off and allowed to cool to room temperature
before the catalyst was taken out for analysis via scanning
electron microscopy to verify carbon fibril growth. In addition,
the net yield of carbon fibrils (the ratio of weight of carbon
fibrils versus weight of metal catalyst) synthesized was 63.
EXAMPLE 6
[0098] The general procedure of Example 5 was followed where cobalt
and chromium comprised the catalyst. In this example the mole ratio
of cobalt to chromium was 2:1. The volume ratio of argon to
hydrogen was initially 5:3 as was the volume ratio of ethylene to
hydrogen. The gas flow was 8 cubic centimeters per second. The
temperature of the reaction chamber was ramped up to 700.degree. C.
The reaction chamber was kept at 700.degree. C. for 40 minutes.
Scanning electron microscopy was used to verify carbon fibril
growth. In addition, the net yield of carbon fibrils synthesized
was 167.
EXAMPLE 7
[0099] The general procedure of Example 5 was followed where
cobalt, zinc, and copper comprised the catalyst. The mole ratio of
cobalt:zinc:copper was 2:0.4:1. The volume ratio of argon to
hydrogen was initially 5:3 as was the volume ratio of ethylene to
hydrogen. The gas flow was 8 cubic centimeters per second. The
temperature of the reaction chamber was ramped up to 700.degree. C.
The reaction chamber was kept at 700.degree. C. for 30 minutes.
Scanning electron microscopy was used to verify carbon fibril
growth. In addition, the net yield of carbon fibrils synthesized
was 113.
EXAMPLE 8
[0100] The general procedure of Example 5 was followed where cobalt
and copper comprised the catalyst. In this example, the mole ratio
of cobalt to copper was 2:1. The volume ratio of argon to hydrogen
was initially 5:3 as was the ratio of ethylene to hydrogen. The gas
flow was 8 cubic centimeters per second. The temperature of the
reaction chamber was ramped up to 700.degree. C. The reaction
chamber was kept at 700.degree. C. for 30 minutes. Scanning
electron microscopy was used to verify carbon fibril growth. In
addition, the net yield of carbon fibrils synthesized was 133.
EXAMPLE 9
[0101] The general procedure of Example 5 was followed where
cobalt, zinc, chromium, and copper comprised the catalyst. The mole
ratio of cobalt:zinc:chromium:copper was 2:0.4:1:1. The volume
ratio of argon to hydrogen was initially 5:3 as was the volume
ratio of ethylene to hydrogen. The gas flow was 8 cubic centimeters
per second. The temperature of the reaction chamber was ramped up
to 700.degree. C. The reaction chamber was kept at 700.degree. C.
for 30 minutes. Scanning electron microscopy was used to verify
carbon fibril growth. In addition, the net yield of carbon fibrils
synthesized was 33.
EXAMPLE 10
[0102] The general procedure of Example 5 was followed where
cobalt, nickel and copper comprised the catalyst. In this example
the mole ratio of cobalt:nickel:copper was 1:1:2. The volume ratio
of argon to hydrogen was initially 5:3 as was the volume ratio of
ethylene to hydrogen. The gas flow was 8 cubic centimeters per
second. The temperature of the reaction chamber was ramped up to
700.degree. C. The reaction chamber was kept at 700.degree. C. for
30 minutes. Scanning electron microscopy was used to verify carbon
fibril growth. In addition, the net yield of carbon fibrils
synthesized was 96.
EXAMPLE 11
[0103] The general procedure of Example 5 was followed where
nickel, iron and yttrium comprised the catalyst. In this example,
the mole ratio of nickel:iron:yttrium was 1:1:1. The volume ratio
of argon to hydrogen was initially 5:3 as was the ratio of ethylene
to hydrogen. The gas flow was 8 cubic centimeters per second. The
temperature of the reaction chamber was ramped up to 700.degree. C.
The reaction chamber was kept at 700.degree. C. for 30 minutes.
Scanning electron microscopy was used to verify carbon fibril
growth. In addition, the net yield of carbon fibrils synthesized
was 20.
[0104] While typical embodiments have been set forth for the
purpose of illustration, the foregoing descriptions should not be
deemed to be a limitation on the scope of the invention.
Accordingly, various modifications, adaptations, and alternatives
may occur to one skilled in the art without departing from the
spirit and scope of the present invention as defined by the
following claims.
* * * * *