US3876444A - Method of treating high strength carbon fibers - Google Patents
Method of treating high strength carbon fibers Download PDFInfo
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- US3876444A US3876444A US296625A US29662572A US3876444A US 3876444 A US3876444 A US 3876444A US 296625 A US296625 A US 296625A US 29662572 A US29662572 A US 29662572A US 3876444 A US3876444 A US 3876444A
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- carbon fibers
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- 229920000049 Carbon (fiber) Polymers 0.000 title claims abstract description 21
- 239000004917 carbon fiber Substances 0.000 title claims abstract description 21
- 238000000034 method Methods 0.000 title claims abstract description 20
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 12
- GNTDGMZSJNCJKK-UHFFFAOYSA-N divanadium pentaoxide Chemical class O=[V](=O)O[V](=O)=O GNTDGMZSJNCJKK-UHFFFAOYSA-N 0.000 claims abstract description 12
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 12
- 239000001301 oxygen Substances 0.000 claims abstract description 12
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical class [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 claims abstract description 6
- 229910017052 cobalt Inorganic materials 0.000 claims abstract description 6
- 239000010941 cobalt Chemical class 0.000 claims abstract description 6
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical class [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims abstract description 6
- 239000011133 lead Chemical class 0.000 claims abstract description 6
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 claims abstract description 3
- BDAGIHXWWSANSR-UHFFFAOYSA-M Formate Chemical compound [O-]C=O BDAGIHXWWSANSR-UHFFFAOYSA-M 0.000 claims abstract description 3
- 150000002823 nitrates Chemical class 0.000 claims abstract description 3
- 150000003839 salts Chemical class 0.000 claims description 12
- OPQARKPSCNTWTJ-UHFFFAOYSA-L copper(ii) acetate Chemical group [Cu+2].CC([O-])=O.CC([O-])=O OPQARKPSCNTWTJ-UHFFFAOYSA-L 0.000 claims description 11
- 239000011159 matrix material Substances 0.000 claims description 8
- 239000011248 coating agent Substances 0.000 claims description 7
- 238000000576 coating method Methods 0.000 claims description 7
- 238000010438 heat treatment Methods 0.000 claims description 7
- 229940076286 cupric acetate Drugs 0.000 claims description 5
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 5
- 229940046892 lead acetate Drugs 0.000 claims description 4
- 229910052793 cadmium Inorganic materials 0.000 claims description 3
- 239000011260 aqueous acid Substances 0.000 claims description 2
- 230000000694 effects Effects 0.000 claims description 2
- 239000000835 fiber Substances 0.000 abstract description 45
- 239000002131 composite material Substances 0.000 abstract description 12
- 229920000642 polymer Polymers 0.000 abstract description 7
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical class [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 abstract description 5
- 229910052802 copper Inorganic materials 0.000 abstract description 5
- 239000010949 copper Substances 0.000 abstract description 5
- CXKCTMHTOKXKQT-UHFFFAOYSA-N cadmium oxide Chemical class [Cd]=O CXKCTMHTOKXKQT-UHFFFAOYSA-N 0.000 abstract description 3
- 239000007864 aqueous solution Substances 0.000 abstract description 2
- 230000001590 oxidative effect Effects 0.000 abstract description 2
- 239000000243 solution Substances 0.000 description 10
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 9
- -1 inorganic acid salts Chemical class 0.000 description 5
- 230000003647 oxidation Effects 0.000 description 5
- 238000007254 oxidation reaction Methods 0.000 description 5
- 239000004593 Epoxy Substances 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 239000003822 epoxy resin Substances 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 229920000647 polyepoxide Polymers 0.000 description 3
- 238000005406 washing Methods 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 239000012153 distilled water Substances 0.000 description 2
- 229910002804 graphite Inorganic materials 0.000 description 2
- 239000010439 graphite Substances 0.000 description 2
- 150000007524 organic acids Chemical class 0.000 description 2
- 239000002952 polymeric resin Substances 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 229920003002 synthetic resin Polymers 0.000 description 2
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
- 241001522296 Erithacus rubecula Species 0.000 description 1
- PEEHTFAAVSWFBL-UHFFFAOYSA-N Maleimide Chemical compound O=C1NC(=O)C=C1 PEEHTFAAVSWFBL-UHFFFAOYSA-N 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 239000000020 Nitrocellulose Substances 0.000 description 1
- 239000004642 Polyimide Substances 0.000 description 1
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- FJWGYAHXMCUOOM-QHOUIDNNSA-N [(2s,3r,4s,5r,6r)-2-[(2r,3r,4s,5r,6s)-4,5-dinitrooxy-2-(nitrooxymethyl)-6-[(2r,3r,4s,5r,6s)-4,5,6-trinitrooxy-2-(nitrooxymethyl)oxan-3-yl]oxyoxan-3-yl]oxy-3,5-dinitrooxy-6-(nitrooxymethyl)oxan-4-yl] nitrate Chemical compound O([C@@H]1O[C@@H]([C@H]([C@H](O[N+]([O-])=O)[C@H]1O[N+]([O-])=O)O[C@H]1[C@@H]([C@@H](O[N+]([O-])=O)[C@H](O[N+]([O-])=O)[C@@H](CO[N+]([O-])=O)O1)O[N+]([O-])=O)CO[N+](=O)[O-])[C@@H]1[C@@H](CO[N+]([O-])=O)O[C@@H](O[N+]([O-])=O)[C@H](O[N+]([O-])=O)[C@H]1O[N+]([O-])=O FJWGYAHXMCUOOM-QHOUIDNNSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 238000010306 acid treatment Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- LHQLJMJLROMYRN-UHFFFAOYSA-L cadmium acetate Chemical compound [Cd+2].CC([O-])=O.CC([O-])=O LHQLJMJLROMYRN-UHFFFAOYSA-L 0.000 description 1
- XIEPJMXMMWZAAV-UHFFFAOYSA-N cadmium nitrate Inorganic materials [Cd+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O XIEPJMXMMWZAAV-UHFFFAOYSA-N 0.000 description 1
- BAAYWLNVHTVAJJ-UHFFFAOYSA-L cadmium(2+);diformate Chemical compound [Cd+2].[O-]C=O.[O-]C=O BAAYWLNVHTVAJJ-UHFFFAOYSA-L 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 229920002301 cellulose acetate Polymers 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 229940011182 cobalt acetate Drugs 0.000 description 1
- QAHREYKOYSIQPH-UHFFFAOYSA-L cobalt(II) acetate Chemical compound [Co+2].CC([O-])=O.CC([O-])=O QAHREYKOYSIQPH-UHFFFAOYSA-L 0.000 description 1
- PFQLIVQUKOIJJD-UHFFFAOYSA-L cobalt(ii) formate Chemical compound [Co+2].[O-]C=O.[O-]C=O PFQLIVQUKOIJJD-UHFFFAOYSA-L 0.000 description 1
- XTVVROIMIGLXTD-UHFFFAOYSA-N copper(II) nitrate Chemical compound [Cu+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O XTVVROIMIGLXTD-UHFFFAOYSA-N 0.000 description 1
- HFDWIMBEIXDNQS-UHFFFAOYSA-L copper;diformate Chemical compound [Cu+2].[O-]C=O.[O-]C=O HFDWIMBEIXDNQS-UHFFFAOYSA-L 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- RLJMLMKIBZAXJO-UHFFFAOYSA-N lead nitrate Chemical compound [O-][N+](=O)O[Pb]O[N+]([O-])=O RLJMLMKIBZAXJO-UHFFFAOYSA-N 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 229920001220 nitrocellulos Polymers 0.000 description 1
- 239000007800 oxidant agent Substances 0.000 description 1
- NMHMNPHRMNGLLB-UHFFFAOYSA-N phloretic acid Chemical compound OC(=O)CCC1=CC=C(O)C=C1 NMHMNPHRMNGLLB-UHFFFAOYSA-N 0.000 description 1
- 229920002239 polyacrylonitrile Polymers 0.000 description 1
- 229920001225 polyester resin Polymers 0.000 description 1
- 239000004645 polyester resin Substances 0.000 description 1
- 229920001721 polyimide Polymers 0.000 description 1
- 229920005596 polymer binder Polymers 0.000 description 1
- 239000002491 polymer binding agent Substances 0.000 description 1
- 229920000915 polyvinyl chloride Polymers 0.000 description 1
- 239000004800 polyvinyl chloride Substances 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 229910000077 silane Inorganic materials 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
Classifications
-
- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
- D01F11/00—Chemical after-treatment of artificial filaments or the like during manufacture
- D01F11/10—Chemical after-treatment of artificial filaments or the like during manufacture of carbon
- D01F11/14—Chemical after-treatment of artificial filaments or the like during manufacture of carbon with organic compounds, e.g. macromolecular compounds
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K9/00—Use of pretreated ingredients
-
- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
- D01F11/00—Chemical after-treatment of artificial filaments or the like during manufacture
- D01F11/10—Chemical after-treatment of artificial filaments or the like during manufacture of carbon
- D01F11/12—Chemical after-treatment of artificial filaments or the like during manufacture of carbon with inorganic substances ; Intercalation
-
- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
- D01F11/00—Chemical after-treatment of artificial filaments or the like during manufacture
- D01F11/10—Chemical after-treatment of artificial filaments or the like during manufacture of carbon
- D01F11/12—Chemical after-treatment of artificial filaments or the like during manufacture of carbon with inorganic substances ; Intercalation
- D01F11/122—Oxygen, oxygen-generating compounds
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
- Y10T428/2913—Rod, strand, filament or fiber
- Y10T428/2918—Rod, strand, filament or fiber including free carbon or carbide or therewith [not as steel]
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
- Y10T428/2913—Rod, strand, filament or fiber
- Y10T428/2933—Coated or with bond, impregnation or core
Definitions
- This invention relates to a method of treating high strength carbon fibers and more particularly to such a method wherein the surface is roughened in a uniform manner.
- high strength carbon fibers which include both carbon fibers and graphite fibers signifies carbon fiber having a tensile strength of at least 200,000 psi and a modulus of at least 20 X l psi.
- Composites can be prepared generally by mixing together 50-70 weight percent of carbon fibers with 5'0-30 weight percent conventional polymer binder such as epoxy resin as the matrix material. These structures are then prepared in a conventional manner by a heat. vacuum. pressure cycle resulting in composites which are lightweight but exhibit excellent flexural strength.
- the present invention is based on the discovery that improved interlaminar spear can be achieved between carbon fiber and polymer matrix by contacting the carbon fiber with an aqueous solution or dispersion of organic or inorganic acid salts of copper, lead, cobalt, and cadmium and certain metal oxides such as vanadium pentoxide. after which the fibers are heated in an oxygen containing atmosphere.
- My improved method results in the fibers having a uniformly roughened surface as opposed to a surface with deep etch pitting and resultant structural weakness.
- a method for treating high modulus graphite fiber to improve the bonding characteristics of said fiber to a resin matrix which comprises 1. Coating the fiber with about 0.01 to about percent by weight of a coating compound selected from the class consisting of organic acid salts of copper, lead, cobalt, and cadmium, inorganic salts of copper, lead, cobalt and cadmium and vanadium pentoxide.
- a coating compound selected from the class consisting of organic acid salts of copper, lead, cobalt, and cadmium, inorganic salts of copper, lead, cobalt and cadmium and vanadium pentoxide.
- Suitable salts include cupric acetate, copper formate, copper nitrate, lead acetate, lead nitrate, cobalt acetate, c'obalt nitrate, cobalt formate, cadmium acetate, cadmium nitrate, cadmium formate, etc.
- the oxidant can be oxygen or air.
- the period of time for such oxidation can be varied over a wide range but it is preferred to employ a time period from about 5 to 30 minutes. Experience has shown that the use of oxygen reduces the time period.
- Such fibers can then be made into a composite in a conventional manner by mixing together 50-70 weight percent of carbon fibers with 50-30 weight percent of a generally employed polymer resin such as an epoxy. polyimide, maleimide, etc., and subjecting the mixture to a heat, vacuum and pressure cycle.
- a generally employed polymer resin such as an epoxy. polyimide, maleimide, etc.
- carbon fibers treated in accordance with my method are carbon fibers derived from carbonized polyacrylonitrile. cellulose acetate, cellulose nitrate, etc. such as Morganite Type l and Il, Thornel 25. 40, 50 etc.. fiber made from molten polyvinyl chloride pitch. etc.
- EXAMPLE l A 0.1% cupric acetate solution was prepared and heated to a temperature of C. in a beaker. A plurality of commercially available high strength carbon fibers were immersed for l5 minutes in the hot cupric acetate solution. The fibers were then removed from the solution and dried in air for a period of 30 minutes. The fibers were then heated in air at 500C. for 30 minutes. After cooling the fibers were washed with a l07c dilute acetic acid solution. This washing was followed by a washing with distilled water. The fibers were then allowed to dry in air.
- EXAMPLE 2 A solution of 0.1% copper acetate was prepared and heated to a temperature of 80C. in a beaker. A plurality of commercially available high strength carbon fibers were immersed in the solution for a period 0f 15 minutes. The fibers were then removed from the solution and dried in air. These fibers were heated in oxygen in a tube furnace for 60 minutes. The fibers were then washed with a 10% dilute acetic acid after which they were subjected to a second washing with distilled 'water. The fibers were then dried in air.
- EXAMPLE 3 A solution of 0.1% lead acetate was prepared and heated in a beaker to a temperature of 80C. A plurality of commercially available carbon fibers were immersed in the solution for a-period of minutes. The fibers were then removed and dried in air. The fibers were then heated in air at a temperature of 400C. for 30 minutes. After cooling, the fibers were washed in a 10% dilute acetic acid. Subsequently the fibers were washed with distilled water. The fibers were then dried in air.
- Example 4 Ten carbon-epoxy composites were prepared in bar form with dimensions of 1.5 X 0.080 X 0.050 inch. Each composite was prepared from 50 weight percent of fibers and 50 weight percent conventional epoxy resin mixture.
- the epoxy resin mixture was a mixture of Epon epoxy 823 and Epon epoxy 1031 which are manufactured by Shell Chemical Company, New York, New York.
- the first bar which is identified as Example 4 was prepared by using commercially available carbon fibers which had not been treated in accordance with my invention. Examples 5-7 employed fibers from Example l. Examples 8-10 contain fibers from Example 2. Examples ll-l3 contained fibers from Example 3.
- a method for treating high strength carbon fiber having a tensile strength of at least 200,000 psi and a modulus of at least 20 X 10 psi to improve the bonding characteristics of the fiber to resin matrix which comprises:
- heating temperature is about 400C.
Abstract
A method of treating high strength carbon fibers comprises treating such fibers with an aqueous solution of the formate, acetate and nitrate salts of copper, lead, cobalt and cadmium, and vanadium pentoxide, and subsequently mildly oxidizing the fibers in air or oxygen at a temperature in the range of from 200.degree. to 600.degree.C. This method uniformly roughens the fiber surfaces thereby providing a desirable fiber structure for employment in a carbon-polymer composite.
Description
United States Patent 91 McKee 51 Apr. 8, 1975 METHOD OF TREATING HIGH STRENGTH CARBON FIBERS [75] lnventor: Douglas W. McKee, Schenectady,
[73] Assignee: General Electric Company,
Schenectady, N.Y.
[22] Filed: Oct. 11, 1972 [21] Appl. No.: 296,625
[52] US. Cl. 117/8; 8/1 15.5; 8/115.6; 8/116; 117/118; 117/47 R; 117/169 R;
[51] Int. Cl COlb 31/07 [58] Field of Search ..8/115.5,116,115.6; 423/447, 448; 117/137, 8,169 R, 47 R, DIG.
[56] References Cited UNITED STATES PATENTS 3,242,000 3/1966 Lynch 8/116 X 3,385,915
5/1968 Hamling 23/2091 F UX 3,403,008 9/1968 Hamling 23/2091 F UX 3,416,874 12/1968 Robin 8/52 3,476,703 11/1969 Wadsworth et a1. 23/2091 F X 3,484,183 12/1969 Dickson et a1 8/116 3,556,729 1/1971 Holsten et a1. 23/2091 F Primary Examiner-Wi1liam D. Martin Assistant Examiner-lanyce A. Bell Attorney, Agent, or FirmWilliam A. Teoli; Joseph T. Cohen; Jerome C. Squillaro 1 1 ABSTRACT employment in a carbon-polymer composite.
3 Claims, No Drawings METHOD OF TREATING HIGH STRENGTH CARBON FIBERS This is a continuation-in-part of my copending application, Serial No. 31,743, filed Apr. 24. 1970 and now abandoned.
This invention relates to a method of treating high strength carbon fibers and more particularly to such a method wherein the surface is roughened in a uniform manner.
As used hereinafter, the term high strength carbon fibers", which include both carbon fibers and graphite fibers signifies carbon fiber having a tensile strength of at least 200,000 psi and a modulus of at least 20 X l psi. Composites can be prepared generally by mixing together 50-70 weight percent of carbon fibers with 5'0-30 weight percent conventional polymer binder such as epoxy resin as the matrix material. These structures are then prepared in a conventional manner by a heat. vacuum. pressure cycle resulting in composites which are lightweight but exhibit excellent flexural strength. However. a major problem exists in the use of such carbon-polymer composites in that these composites exhibit low interlaminar shear strength caused by poor bonding between fibers and polymer matrix.
One approach. which has been made to improve the bonding characteristics of carbon fibers to a polymer resin matrix. has been to subject initially the fibers to oxidation in air. However, such oxidation has resulted in etch pitting of fiber surfaces. Another approach has been to etch mildly the fiber surfaces by subjecting the fibers to a prolonged treatment in nitric acid. While the resultant fibers are suitable. the process is time consuming and the results are non-uniform unless the process is controlled carefully. The above methods are discussed, for example, in an article entitled Silane Coupling in Fibre-Reinforced Polyester Resin" by Harris et al. in the Journal of Materials Science" 4 (1969) at pages 432-438.
The present invention is based on the discovery that improved interlaminar spear can be achieved between carbon fiber and polymer matrix by contacting the carbon fiber with an aqueous solution or dispersion of organic or inorganic acid salts of copper, lead, cobalt, and cadmium and certain metal oxides such as vanadium pentoxide. after which the fibers are heated in an oxygen containing atmosphere. My improved method results in the fibers having a uniformly roughened surface as opposed to a surface with deep etch pitting and resultant structural weakness.
1 found also that organic acid salts of other metals such as silver. titanium and boron do not give the desirable features of my invention but promote etch pit formation. As mentioned above the etch pitting tends to weaken the fiber structure and thus is unsuitable for use in carbon-polymer composites since it leads to a decline in the interlaminar shear strength.
There is provided by the present invention a method for treating high modulus graphite fiber to improve the bonding characteristics of said fiber to a resin matrix which comprises 1. Coating the fiber with about 0.01 to about percent by weight of a coating compound selected from the class consisting of organic acid salts of copper, lead, cobalt, and cadmium, inorganic salts of copper, lead, cobalt and cadmium and vanadium pentoxide.
2. Heating the fiber at a temperature in the range of from 200 to 600C. in an oxygen containing atmosphere, and
3. Effecting the removal of the coating compound from the surface of the fiber. Various organic and inorganic acid salts of the above types are useable in my process. For example, suitable salts include cupric acetate, copper formate, copper nitrate, lead acetate, lead nitrate, cobalt acetate, c'obalt nitrate, cobalt formate, cadmium acetate, cadmium nitrate, cadmium formate, etc.
For the mild oxidation following the treatment with one of the above salts or with vanadium pentoxide, the oxidant can be oxygen or air. The period of time for such oxidation can be varied over a wide range but it is preferred to employ a time period from about 5 to 30 minutes. Experience has shown that the use of oxygen reduces the time period.
After the oxidation of the fiber, it is desirable to use a dilute acid which is compatible with the previously used salt to remove any remaining salt. The retention of salt on the fiber can lead to degradation of the polymer employed as the matrix in the composite. After the acid treatment the fiber is dried.
Such fibers can then be made into a composite in a conventional manner by mixing together 50-70 weight percent of carbon fibers with 50-30 weight percent of a generally employed polymer resin such as an epoxy. polyimide, maleimide, etc., and subjecting the mixture to a heat, vacuum and pressure cycle.
Examples of carbon fibers treated in accordance with my method are carbon fibers derived from carbonized polyacrylonitrile. cellulose acetate, cellulose nitrate, etc. such as Morganite Type l and Il, Thornel 25. 40, 50 etc.. fiber made from molten polyvinyl chloride pitch. etc.
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. All parts are by weight.
EXAMPLE l A 0.1% cupric acetate solution was prepared and heated to a temperature of C. in a beaker. A plurality of commercially available high strength carbon fibers were immersed for l5 minutes in the hot cupric acetate solution. The fibers were then removed from the solution and dried in air for a period of 30 minutes. The fibers were then heated in air at 500C. for 30 minutes. After cooling the fibers were washed with a l07c dilute acetic acid solution. This washing was followed by a washing with distilled water. The fibers were then allowed to dry in air.
EXAMPLE 2 A solution of 0.1% copper acetate was prepared and heated to a temperature of 80C. in a beaker. A plurality of commercially available high strength carbon fibers were immersed in the solution for a period 0f 15 minutes. The fibers were then removed from the solution and dried in air. These fibers were heated in oxygen in a tube furnace for 60 minutes. The fibers were then washed with a 10% dilute acetic acid after which they were subjected to a second washing with distilled 'water. The fibers were then dried in air.
EXAMPLE 3 A solution of 0.1% lead acetate was prepared and heated in a beaker to a temperature of 80C. A plurality of commercially available carbon fibers were immersed in the solution for a-period of minutes. The fibers were then removed and dried in air. The fibers were then heated in air at a temperature of 400C. for 30 minutes. After cooling, the fibers were washed in a 10% dilute acetic acid. Subsequently the fibers were washed with distilled water. The fibers were then dried in air.
EXAMPLES 4-13 Ten carbon-epoxy composites were prepared in bar form with dimensions of 1.5 X 0.080 X 0.050 inch. Each composite was prepared from 50 weight percent of fibers and 50 weight percent conventional epoxy resin mixture. The epoxy resin mixture was a mixture of Epon epoxy 823 and Epon epoxy 1031 which are manufactured by Shell Chemical Company, New York, New York. The first bar which is identified as Example 4 was prepared by using commercially available carbon fibers which had not been treated in accordance with my invention. Examples 5-7 employed fibers from Example l. Examples 8-10 contain fibers from Example 2. Examples ll-l3 contained fibers from Example 3.
These composites were tested and the mechanical properties are listed below in Table 1.
7 89 28.0 6.46 8 I18 30.0 4.38 9 I I4 30.0 4.94 I0 104 27.1 5.00 l l 118 28.7 4.27 l2 121 30.4 4.75 I3 l 16 28.0 4.09
While other modifications of the invention and variations thereof which may be employed within the scope of the invention have not been described, the invention is intended to include such as may be embraced within the following claims.
What I claim as new and desire to secure by Letters Patent of the United States is:
1. A method for treating high strength carbon fiber having a tensile strength of at least 200,000 psi and a modulus of at least 20 X 10 psi to improve the bonding characteristics of the fiber to resin matrix which comprises:
l. coating the fiber with about 0.01 to about 10 percent by weight of the formate, acetate and nitrate salts of a metal selected from the class consisting of copper, lead, cobalt and cadmium, and vanadium pentoxide 2. heating the fiber at a temperature in the range of from 200 to 600C in an oxygen containing atmosphere, and
3. treating the surface of the fiber with an aqueous acid solution to effect the removal of the coating of metal salt.
2. A method as in claim 1 wherein the salt is cupric acetate, the oxygen containing atmosphere is air, the heating temperature is about 500C.
3. A method as in claim 1, wherein the salt is lead acetate, the oxygen containing atmosphere is air, the
heating temperature is about 400C.
=l l l l
Claims (6)
1. A METHOD FOR TREATING HIGH STRENGHT CARBON FIBER HAVING A TENSILE STRENGTH OF AT LEAST 200,000 PSI AND A MODULUS OF AT LEAST 20 X 10**6 PSI TO IMPROVE THE BONDING CHARACTERISTICS OF THE FIBER TO RESIN MATRIX WHICH COMPRISES:
1. COATING THE FIBER WITH ABOUT 0.01 TO ABOUT 10 PERCENT BY WEIGHT OF THE FORMATE, ACETATE AND NITRATE SALTS OF A METAL SELECTED FROM THE CLASS CONSISTING OF COPPER, LEAD, COBALT AND CADMIUM, AND VANADIUM PENTOXIDE
2. HEATING THE FIBER AT A TEMPERATURE IN THE RANGE OF FROM 200* TO 600*C IN AN OXYGEN CONTAINING ATMOSPHERE, AND
2. A method as in claim 1 wherein the salt is cupric acetate, the oxygen containing atmosphere is air, the heating temperature is about 500.degree.C.
3. A method as in claim 1, wherein the salt is lead acetate, the oxygen containing atmosphere is air, the heating temperature is about 400.degree.C.
3. TREATING THE SURFACE OF THE FIBER WITH AN AQUEOUS ACID SOLUTION TO EFFECT THE REMOVAL OF THE COATING OF METAL SALT.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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US296625A US3876444A (en) | 1970-04-24 | 1972-10-11 | Method of treating high strength carbon fibers |
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US3174370A | 1970-04-24 | 1970-04-24 | |
US296625A US3876444A (en) | 1970-04-24 | 1972-10-11 | Method of treating high strength carbon fibers |
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US296625A Expired - Lifetime US3876444A (en) | 1970-04-24 | 1972-10-11 | Method of treating high strength carbon fibers |
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US4311630A (en) * | 1979-04-17 | 1982-01-19 | California Institute Of Technology | Gasifiable carbon-graphite fibers |
US4584252A (en) * | 1983-05-19 | 1986-04-22 | Le Carbone Lorraine, S.A. | Insertion compounds of graphite with improved performances and electrochemical applications of those compounds |
US5260369A (en) * | 1992-03-25 | 1993-11-09 | General Electric Company | Synthetic resin mass having a low content of short carbon fibres |
US20070202033A1 (en) * | 1999-01-12 | 2007-08-30 | Hyperion Catalysis International, Inc. | Method of Using Carbide and/or Oxycarbide Containing Compositions |
US20150216857A1 (en) * | 2005-05-17 | 2015-08-06 | Sarcode Bioscience Inc. | Compositions and methods for treatment |
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US3242000A (en) * | 1963-08-30 | 1966-03-22 | Deering Milliken Res Corp | Impregnated carbonized acrylic textile product and method for producing same |
US3385915A (en) * | 1966-09-02 | 1968-05-28 | Union Carbide Corp | Process for producing metal oxide fibers, textiles and shapes |
US3403008A (en) * | 1966-12-19 | 1968-09-24 | Union Carbide Corp | Process for producing metal carbide fibers, textiles and shapes |
US3416874A (en) * | 1964-02-21 | 1968-12-17 | Crylor | Production of polyacrylonitrile-based articles |
US3476703A (en) * | 1967-02-21 | 1969-11-04 | Nat Res Dev | Treatment of carbon fibres and composite materials including such fibres |
US3484183A (en) * | 1965-06-04 | 1969-12-16 | Minnesota Mining & Mfg | Heat-resistant black fibers and fabrics derived from rayon |
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Publication number | Priority date | Publication date | Assignee | Title |
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US3242000A (en) * | 1963-08-30 | 1966-03-22 | Deering Milliken Res Corp | Impregnated carbonized acrylic textile product and method for producing same |
US3416874A (en) * | 1964-02-21 | 1968-12-17 | Crylor | Production of polyacrylonitrile-based articles |
US3484183A (en) * | 1965-06-04 | 1969-12-16 | Minnesota Mining & Mfg | Heat-resistant black fibers and fabrics derived from rayon |
US3385915A (en) * | 1966-09-02 | 1968-05-28 | Union Carbide Corp | Process for producing metal oxide fibers, textiles and shapes |
US3403008A (en) * | 1966-12-19 | 1968-09-24 | Union Carbide Corp | Process for producing metal carbide fibers, textiles and shapes |
US3476703A (en) * | 1967-02-21 | 1969-11-04 | Nat Res Dev | Treatment of carbon fibres and composite materials including such fibres |
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Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
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US4311630A (en) * | 1979-04-17 | 1982-01-19 | California Institute Of Technology | Gasifiable carbon-graphite fibers |
US4584252A (en) * | 1983-05-19 | 1986-04-22 | Le Carbone Lorraine, S.A. | Insertion compounds of graphite with improved performances and electrochemical applications of those compounds |
US5260369A (en) * | 1992-03-25 | 1993-11-09 | General Electric Company | Synthetic resin mass having a low content of short carbon fibres |
US20070202033A1 (en) * | 1999-01-12 | 2007-08-30 | Hyperion Catalysis International, Inc. | Method of Using Carbide and/or Oxycarbide Containing Compositions |
US20150216857A1 (en) * | 2005-05-17 | 2015-08-06 | Sarcode Bioscience Inc. | Compositions and methods for treatment |
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