EP0251491B1 - Multi-electrolyte treatment of carbon fibres to modify shear resistance - Google Patents

Multi-electrolyte treatment of carbon fibres to modify shear resistance Download PDF

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Publication number
EP0251491B1
EP0251491B1 EP87304726A EP87304726A EP0251491B1 EP 0251491 B1 EP0251491 B1 EP 0251491B1 EP 87304726 A EP87304726 A EP 87304726A EP 87304726 A EP87304726 A EP 87304726A EP 0251491 B1 EP0251491 B1 EP 0251491B1
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bis
fiber
bath
anode
ammonium
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EP87304726A
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German (de)
English (en)
French (fr)
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EP0251491A1 (en
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Stuart Mitchell
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BP Corp North America Inc
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BP Corp North America Inc
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    • 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
    • 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
    • D01F11/16—Chemical after-treatment of artificial filaments or the like during manufacture of carbon by physicochemical methods

Definitions

  • This invention relates to a process for electrolytically treating the surface of carbon fibers to improve mechanical properties, particularly when the fibers are combined with a resin matrix to form a composite.
  • the invention further relates to the improved carbon fibers per se and to composites comprising the improved fibers in a bis-maleimide matrix resin.
  • Electrolytic treatments of carbon fibers to improve adhesion between the fibers and a matrix resin when forming composite materials are known.
  • Strength properties and their permanence in composite materials, particularly in an adverse environment, depend on the interfacial bonding of the composite, that is on the strength of the bonding between the carbon fiber and the resin matrix.
  • U.S. patent 3,671,411 to Ray et al discloses subjecting a carbon or graphite fiber to an electrolytic reaction in an aqueous electrolyte whereby negative ions are attracted to the surface of the fiber acting as anode, thereby modifying the fiber surface.
  • the patentees state that subsequent bonding to plastics and resins is improved to such an extent that the shear strengths are increased in many cases to more than double the values obtained without this particular pretreatment with little or no loss in tensile strength.
  • U.S. patent 4,401,533 to Saito et al. discloses electrolytically surface treating carbon fibers in an aqueous solution of a sulfuric acid salt while passing a current through the fiber at a specified range of current density, a specified range for the product of current density, voltage, and processing time, and while continuously moving the carbon fiber as an anode in the aqueous electrolytic solution.
  • the patentees state that their method produces carbon fibers having good adhesive properties to resins and high tensile strength and heat-oxidation resistance.
  • U.S. patent 3,832,297 to Paul, Jr. discloses an electrolytic process for surface treating graphite fibers wherein the improvement resides in using organic and inorganic ammonium compounds dissolved in water which compounds will decompose substantially completely to gaseous products on heating at temperatures below about 250°C.
  • Illustrative ammonium compounds are stated to include ammonium hydroxide, ammonium carbonate, ammonium bicarbonate, ammonium carbamate, ammonium benzoate, ammonium dithionate, ammonium hydrosulfide, ammonium sulfite, ammonium thiosulfate, and ammonium tartrate.
  • EDS edge delamination strength
  • This invention provides a method of surface treating carbon fibers to improve the mechanical properties of composites comprising said fibers reinforcing a bis-maleimide matrix resin, comprising the steps of:
  • carbon fiber as used herein is intended to be generic to both carbon and graphite fibers and includes fibers prepared by heating fibrous polymeric materials such as polyacrylonitrile, polyvinyl alcohol, pitch, natural and regenerated cellulose and the like to carbonizing or graphitizing temperatures.
  • fibrous polymeric materials such as polyacrylonitrile, polyvinyl alcohol, pitch, natural and regenerated cellulose and the like
  • the fibers which are composed of individual filaments too thin to have any practical mechanical ruggedness, are conveniently treated in multi-filament bundles well known in the art as tows. Other physical arrangements of fibers such as woven or non-woven mats are also possible.
  • the electrolytes which may be used in the first aqueous electrolytic bath include any electrolyte which electrolytically generates oxygen at the surface of the anode, i.e. the carbon fiber being treated, whereby oxygen functionalities are generated on the fiber surface.
  • mineral acids and bases such as aqueous solutions of phosphoric acid, nitric acid, sulfuric acid, and alkali metal hydroxides including sodium and potassium hydroxide, and the like.
  • neutral salts i.e. which, when dissolved in water, yield a pH between about 4 and about 8
  • concentrations of electrolyte generally in the range of 0.05 to 20 weight percent, preferably in the range of 1 to 10 weight percent, are preferred.
  • ammonium bath any ammonium salt which dissolves in water to yield a pH of at least about 8 may be employed.
  • Preferred are ammonium hydroxide and ammonium bicarbonate.
  • the ammonium compound is believed to improve composite properties through modifying the carbon fiber surface with -NH2 functionalities.
  • the concentration of ammonium salt can be any desired concentration sufficient to impart -NH2 functionality to the carbon fiber surface such that mechanical properties in the composite are improved as measured, for example, by edge delamination strength. Generally such concentration will fall in a range of about 0.02 Molar (M) to about 5M, preferably about 0.05M to about 3M.
  • auxiliary electrolyte such as any of the neutral salts or alkali metal hydroxides noted as suitable for use in the oxygen bath may be used to increase conductivity in the ammonium bath.
  • concentration of such auxiliary electrolytes will range between about 0.01M and about 0.5M.
  • the voltage is not narrowly critical and can be adjusted generally to give a current density between about 0.5 and 5 milliamperes per square centimeter (mA/cm2) of fiber surface area. Generally, the voltages employed in each bath will range between about 5 and 80 volts.
  • Bath temperatures are not narrowly critical and will generally be in the range of about 5°C to 50°C, the prevailing ambient (room) temperature or below being most preferably employed.
  • Voltage, current density, and residence time can be advantageously manipulated to expose the fiber to a total charge of from about 4 to 100 coulombs/gm, preferably about 7 to about 20 coulombs/gm.
  • residence times between about 0.05 and about 1 minute are generally sufficient to achieve exposure to a charge within these ranges.
  • line speeds of up to about 40 ft/min. (12.192 m/min) are entirely feasible.
  • thermosetting resin composites beyond that which can be ascribed to either of the baths alone or to their additive contributions. This result is surprising since electrolytically treating carbon fibers in the reverse bath sequence to that stipulated in the claims results in no improvement or, sometimes, even less improvement than that which results from using an oxygen bath alone.
  • Thermosetting bis-maleimide resins suitable for use in this invention are widely known in the art and, generally, are made by reacting a N,N ⁇ -bis-maleimide with a reactive comonomer capable of being copolymerized therewith.
  • the general formula for suitable bis-maleimides includes those compounds of the formula wherein Y represents a divalent radical of at least 2 carbon atoms, preferably 2 to 6 carbon atoms, containing a carbon-carbon double bond.
  • Y may, for example, be of the formula
  • the preferred structure for Y is Y may, for example, be derived from acids or anhydrides such as maleic, citraconic, tetrahydrophthalic, and the like.
  • Z is a divalent radical which can be the residuum of a diamine containing at least 2 carbon atoms and generally not more than about 20 carbon atoms.
  • "Residuum" refers to that portion of a diamine exclusive of the two amino groups.
  • Z can, for example, be alkylene of 2 to 20 carbons atoms; cycloalkylene of 5 or 6 carbon atoms; heterocyclic of 4 or 5 carbon atoms and at least one nitrogen, sulfur, or oxygen atom in the heterocyclic ring; or at least two mono-or dicarbocyclic aromatic or cycloalkylene groups which are linked to each other by a direct carbon-to-carbon bond or through a divalent linking group such as ⁇ O ⁇ , ⁇ S ⁇ , alkylene of 1 to 3 carbon atoms, or a group of the formula ⁇ P(O)R1 ⁇ : in which R1, which is alkyl of l to 5 carbon atoms, need not be the same within those groups containing more than one R1.
  • Suitable N,N, ⁇ -bis-maleimides include 1,2-bismaleimido ethane, 1,6-bismaleimido hexane, 1,12-bismaleimido dodecane, 1,6-bismaleimido -(2,2,4-trimethyl) hexane, 1,3-bismaleimido benzene, 1,4-bismaleimido benzene, 4,4 ⁇ -bismaleimido diphenyl methane, 2,4-bismaleimido toluene, 2,6-bismaleimido toluene, 3,3 ⁇ -bismaleimido diphenyl sulfone, 4,4 ⁇ -bismaleimido diphenyl sulfone, 4,4 ⁇ -bismaleimido diphenyl ether, 4,4 ⁇ -bismaleimido dicyclohexyl methane, 4,4 ⁇ -bismaleimido diphenyl cyclohexane, 4,4 ⁇ -bismaleimido diphen
  • ether bis-maleimides having the formula wherein R2, R3, R4 and R5 are independently hydrogen, lower alkyl having 1 to 6 carbon atoms, lower alkoxy having 1 to 6 carbon atoms. chlorine or bromine; R6 and R7 are independently hydrogen. methyl, ethyl, trifluoromethyl, or trichloromethyl; and D is an ethylenically unsaturated divalent group containing 2 to 24 carbon atoms.
  • Particularly preferred is the following ether bis-maleimide which can be made by reacting 2,2-bis [4-(4-aminophenoxy)phenyl] propane with maleic anhydride in acetone.
  • Preferred bis-maleimides include
  • liquid coreactants suitable for use in this invention for reacting with bis-maleimides to make bis-maleimide resins include 0,0,-diallybisphenol A which has the structure N-vinyl-2-pyrrolidinone, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, triallyl isocyanurate, diallyl phthalate, triallyl trimellitate, divinyl benzene, dicyclopentadienyl dienyl acrylate, dicyclopentadienyl oxyethyl acrylate, vinyl cyclohexene monoepoxide, 1,4-butanediol divinyl ether, 1,4-dihydroxy-2-butene, styrene, alpha methyl
  • Preferred liquid coreactants include 0,0 ⁇ -diallylbisphenol A, N-vinyl-2-pyrrolidone, triallyl isocyanurate, divinyl benzene, and ethylene glycol dimethacrylate.
  • liquid coreactants include epoxy resins containing one or more epoxy groups having the following formula:
  • the epoxy groups can be terminal epoxy groups or internal epoxy groups.
  • the epoxides are of two general types: polyglycidyl compounds or products derived from epoxidation of dienes or polyenes.
  • Polyglycidyl compounds contain a plurality of 1,2-epoxide groups derived from the reaction of a polyfunctional active hydrogen containing compound with an excess of an epihalohydrin under basic conditions.
  • the active hydrogen compound is a polyhydric alcohol or phenol
  • the resulting epoxide resin contains glycidyl ether groups.
  • a preferred group of polyglycidyl compounds are made via condensation reactions with 2,2-bis(4-hydroxyphenyl)propane, also known as bisphenol A, and have structures such as I: where n has a value from about 0 to about 15.
  • epoxides are bisphenol-A epoxy resins. They are available commercially under the trade names such as "Epon 828,” “Epon 1001", and “Epon 1009” from Shell Chemical Co., and as "DER 331", and "DER 334" from Dow Chemical Co.
  • the most preferred bisphenol A epoxy resins have an "n" value between 0 and 10.
  • Polyepoxides which are polyglycidyl ethers of 4,4 ⁇ -dihydroxydiphenyl methane, 4,4 ⁇ -dihydroxydiphenyl sulfone, 4,4 ⁇ -biphenol, 4,4 ⁇ -dihydroxydiphenyl sulfide, phenolphthalein, resorcinol, 4,2 ⁇ -biphenol, or tris(4-hydroxyphenyl) methane and the like, are useful in this invention.
  • EPON 1031 a tetraglycidyl derivative of 1,1,2,2-tetrakis(hydroxyphenyl)ethane from Shell Chemical Company
  • Apogen 101 a methylolated bisphenol A resin from Schaefer Chemical Co.
  • Halogenated polyglycidyl compounds such as D.E.R. 542 (a brominated bisphenol A epoxy resin from Dow Chemical Company) are also useful.
  • suitable epoxy resins include polyepoxides prepared from polyols such as pentaerythritol, glycerol, butanediol or trimethylolpropane and an epihalohydrin.
  • the former are commercially available as D.E.N 431, D.E.N. 438, and D.E.N. 485 from Dow Chemical Company.
  • the latter are available as, for example, ECN 1235, ECN 1273, and ECN 1299 (obtained from Ciba Geigy Corporation, Ardsley, NY).
  • Other epoxidized novolaks such as SU-8 (obtained from Celanese Polymer Specialties Company, Louisville, KY) are also suitable.
  • polyfunctional active hydrogen compounds besides phenols and alcohols may be used to prepare the polyglycidyl adducts useful as reactive comonomers in this invention. They include amines, aminoalcohols and polycarboxylic acids.
  • Adducts derived from amines include N,N-diglycidyl aniline, N,N-diglycidyl toluidine, N,N,N ⁇ ,N ⁇ -tetraglycidylxylylene diamine, (i.e., IV) N,N,N ⁇ ,N ⁇ tetraglycidyl-bis (methylamino) cyclohexane (i.e. V) , N,N,N ⁇ ,N ⁇ tetraglycidyl-4,4 ⁇ -diaminodiphenyl methane, (i.e.
  • N,N,N ⁇ ,N ⁇ -tetraglycidyl 3,3 ⁇ -diaminodiphenyl sulfone, and N,N ⁇ -dimethyl-N,N ⁇ -diglycidyl-4,4 ⁇ -diaminodiphenyl methane Commercially available resins of this type include Glyamine 135 and Glyamine 125 (obtained from F.I.C. Corporation, San Francisco, CA.), Araldite MY-720 (obtained from Ciba Geigy Corporation) and PGA-X and PGA-C (obtained from The Sherwin-Williams Co., Chicago, Illinois).
  • Suitable polyglycidyl adducts derived from amino alcohols include O,N,N-triglycidyl-4-aminophenol, available as Araldite 0500 or Araldite 0510 (obtained from Ciba Geigy Corporation) and O,N,N-triglycidyl-3-aminophenol (available as Glyamine 115 from F.I.C. Corporation).
  • glycidyl esters of carboxylic acids include, for example, diglycidyl phthalate, diglycidyl terephthalate, diglycidyl isophthalate, and diglycidyl adipate.
  • polyepoxides such as triglycidyl cyanurates and isocyanurates, N,N-diglycidyl oxamides, N,N ⁇ -diglycidyl derivatives of hydantoins such as "XB 2793" (obtained from Ciba Geigy Corporation), diglycidyl esters of cycloaliphatic dicarboxylic acids, and polyglycidyl thioethers of polythiols.
  • polyepoxides such as triglycidyl cyanurates and isocyanurates, N,N-diglycidyl oxamides, N,N ⁇ -diglycidyl derivatives of hydantoins such as "XB 2793" (obtained from Ciba Geigy Corporation), diglycidyl esters of cycloaliphatic dicarboxylic acids, and polyglycidyl thioethers of polythiols.
  • Other reactive epoxy-containing materials are copolymers of acrylic acid esters of glycidol such as glycidyl acrylate and glycidyl methacrylate with one or more copolymerizable vinyl compounds.
  • Examples of such copolymers are l:l styrene-glycidyl methacrylate, 1:1 methyl methacrylate-glycidyl acrylate and 62.5:24:13.5 methyl methacrylate:ethyl acrylate:glycidyl methacrylate.
  • Silicone resins containing epoxy functionality e.g., 2,4,6,8,10-pentakis [3-(2,3-epoxypropoxy)propyl]-2,4,6,8,10-pentamethylcyclopentasiloxane and the diglycidyl ether of 1,3-bis-(3-hydroxypropyl)tetramethyldisiloxane) are also usable.
  • epoxy functionality e.g., 2,4,6,8,10-pentakis [3-(2,3-epoxypropoxy)propyl]-2,4,6,8,10-pentamethylcyclopentasiloxane and the diglycidyl ether of 1,3-bis-(3-hydroxypropyl)tetramethyldisiloxane
  • the second group of epoxy resins is prepared by epoxidation of dienes or polyenes.
  • Resins of this type include bis(2,3-epoxycyclopentyl) ether, VII, reaction products of VII with ethylene glycol which are described in U.S. Patent 3,398,102, 5(6)-glycidyl-2-(1,2-epoxyethyl)bicyclo[2.2.1] heptane, VIII, and dicyclopentadiene diepoxide.
  • epoxides include vinylcyclohexene dioxide, e.g., "ERL-4206” (obtained from Union Carbide Corp.), 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexane carboxylate, e.g., "ERL-4221” (obtained from Union Carbide Corp.), 3,4-epoxy-6-methylcyclohexylmethyl 3,4-epoxy-6-methylcyclohexane carboxylate, e.g., "ERL-4201” (obtained from Union Carbide Corp.), bis(3,4-epoxy-6-methylcyclohexylmethyl) adipate, e.g., "ERL-4289” (obtained from Union Carbide Corp.), dipentene dioxide, e.g., "ERL-4269” (obtained from Union Carbide Corp.) 2-(3,4-epoxycyclohexyl-5,5-
  • Suitable epoxides include: where n is 1 to 4, m is (5-n), and R9 is H, halogen or C1 to C4 alkyl.
  • the preferred epoxy resins are bis(2,3-epoxycyclopentyl)ether, N,N,N ⁇ ,N ⁇ -tetraglycidyl xylylenediamine, N,N,N ⁇ ,N ⁇ - tetraglycidyl methylene dianiline, O,N,N-triglycidyl-4-aminophenol, and O,N,N-triglycidyl-3-aminophenol.
  • epoxy resins are used, it may be desireable to add an aromatic diamine to the formulation.
  • the diamine should have a low level of reactivity with the epoxy resin and the bis-maleimide at room temperature.
  • Suitable polyamine hardeners for use in epoxy resin systems include 4,4 ⁇ -diaminodiphenyl sulfone, 3,3 ⁇ -diaminodiphenyl sulfone, 3,4 ⁇ -diaminobenzophenone, m-phenylene diamine, 4,4 ⁇ -methylene dianiline, diethylene triamine, and the like.
  • a stoichimetry of 0.3 to 2.0, preferably 0.5 to 1.5 equivalents of -NH per equivalent of 1,2-epoxide group can be used.
  • the epoxy resin system may additionally contain an accelerator to increase the rate of cure of the epoxy plus amine reation.
  • Accelerators which may be used herein include Lewis acid; amine complexes such as BF3.monoethylamine, BF3.piperdine, BF3.2-methylimidazole; amines, such as imidazole and its derivatives such as 4-ethyl-2-methylimidazole, 1-methylimidazole, 2-methylimidazole; N,N-dimethylbenzylamine; acid salts of tertiary amines, such as the p-toluene sulfonic acid:imidazole complex, salts of trifluoro methane sulfonic acid, such as FC-520 (obtained from 3M Company), organophosphonium halides and dicyandiamide.
  • the accelerator may be from 1 to 6 percent by weight of the epoxy component.
  • thermosetting resins may also contain compounds with one or more cyanate ester groups.
  • cyanate ester is meant a compound having at least one cyanate group in its molecule.
  • the cyanate ester is represented by the formula R10-(O-C ⁇ N) g wherein R10 is a residue derived from an aromatic hydrocarbon selected from the group consisting of benzene, biphenyl and naphthalene, or a residue derived from a compound in which at least two benzene rings are bonded to each other by a bridging member selected from the group consisting of wherein R11 and R12 are the same or different and each represents a hydrogen atom or an alkyl group containing 1 to 4 carbon atoms, said aromatic residue R10 may be optionally substituted by a substituent selected from the group consisting of alkyl groups containing 1 to 4 carbon atoms, alkoxy groups containing 1 to 4 carbon atoms, chlorine and bromine; g is an integer of 1 to 5, and the cyanate group is always directly bonded to the aromatic nucleus.
  • cyanate ester examples include cyanatobenzene, dicyanatobenzene; 1,3,5-tricyanatobenzene; 1,3-, 1,4-, 1,6-, 1,8-, 2,6- or 2,7-dicyanatonaphthalene; 1,3,6-tricyanatonaphthalene; 4,4 ⁇ -dicyanatobiphenyl; bis(4-cyanatophenyl)methane; 2,2-bis(4-cyanatophenyl)propane; 2,2-bis(3,5-dichloro-4-cyanatophenyl)propane; 2,2-bis(3,5-dibromo-4-dicyanatophenyl)propane; bis(4-cyanatophenyl)ether; bis(4-cyanatophenyl)thioether; bis(4-cyanatophenyl)sulfone; bis(4-cyanatophenyl)phosphite; bis(4-cyanatophenyl)phosphate; bis(3-chlor
  • Mixtures of bis-maleimides, epoxy resin systems, and compounds with one or more cyanate ester groups may be employed in this invention.
  • Preferred mixtures are (i) bis-maleimide resin/epoxy resin system mixtures (ii) epoxy resins/cyanate ester compounds. and (iii) bis-maleimide resins/cyanate ester compounds.
  • the composites of this invention may optionally contain a small amount of a thermoplastic polymer. These materials have beneficial effects on the viscosity and film strength characteristics of the bismaleimide/reactive comonomer mixture.
  • thermoplastic polymers used in this invention include polyarylethers of formula IX which are described in U.S. Patents 4,108,837 and 4,175,175, wherein R13 is a residuum of a dihydric phenol such as bisphenol A, hydroquinone, resorcinol, 4,4-biphenol, 4,4 ⁇ -dihydroxydiphenyl sulfone, 4,4-dihydroxy-3,3 5,5 ⁇ -tetramethyldiphenyl sulfide, 4,4 ⁇ -dihydroxy-3 ⁇ ,3 ⁇ ,5,5 ⁇ -tetramethyldiphenyl sulfone and the like.
  • a dihydric phenol such as bisphenol A, hydroquinone, resorcinol, 4,4-biphenol, 4,4 ⁇ -dihydroxydiphenyl sulfone, 4,4-dihydroxy-3,3 5,5 ⁇ -tetramethyldiphenyl sulfide, 4,4 ⁇ -dihydroxy-3 ⁇ ,3 ⁇ ,
  • R14 is a residuum of a benzenoid compound susceptible to nucleophilic aromatic substitution reactions such as 4,4 ⁇ -dichlorodiphenyl sulfone, 4,4 ⁇ -difluorobenzophenone, and the like.
  • the average value of n is from about 8 to about 120.
  • polycarbonates such as those based on bisphenol A, tetramethyl bisphenol A, 4,4 ⁇ -dihydroxydiphenyl sulfone, 4,4 ⁇ -d
  • thermoplastics include poly ( ⁇ -caprolactone); polybutadiene; polybutadiene/acrylonitrile copolymers, including those optionally containing amine, carboxyl, hydroxy, or -SH groups; polyesters, such as poly(butylene terephthalate); poly(ethylene terephthalate); polyetherimides such as the Ultem resins (obtained from the General Electric Company); acrylonitrile/ butadiene/styrene copolymers, polyamides such as nylon 6, nylon 6,6, nylon 6,12, and Trogamid T (obtained from Dynamit Nobel Corporation); poly(amide imides) such as Torlon poly(amide imide) (obtained from Amoco Chemical Corporation, Napierville, IL); polyolefins, polyethylene oxide; poly(butyl methacrylate); impact-modified polystyrene; sulfonated polyethylene; polyarylates such as those derived from bisphenol A and isophthalic and terephthalic
  • Poly(vinyl acetate) and copolymers of vinyl acetate with other vinyl and acrylic monomers can also be used.
  • Thermoplastics such as low profile additives, for example, LP-40A, may also be used.
  • the bismaleimide thermosetting resin composition should contain between about 1 and about 99 weight percent, preferably 20-98 percent of bismaleimide; 1 to about 60 weight percent, preferably 3 to 40 percent of the liquid coreactant or mixture of coreactants comprising molecules with one or more amino, epoxy, or cyanate groups and the like, as described above; 1 to about 40 percent, preferably 2 to 30 percent of other additives such as thermoplastic polymers.
  • the amount of carbon fiber in the composite is between about 10 and about 90 percent by weight, preferably between about 20 and about 85 percent by weight.
  • Additional components in the composition can include initators for vinyl polymerization such as di-t-butyl peroxide, dicumyl peroxide, 1,1-bis t-butyl peroxy cyclohexane, azo bis isobutyronitrile and the like.
  • the initiator comprises from 0 to 3 percent by weight of the total composition.
  • Inhibitors for vinyl polymerizations can also be used. They include, hydroquinone, t-butyl hydroquinone, bentoquinone, f-methoxyphenol, and 4-nitro-m-cresol. Inhibitors are present in amounts of from 0 to 2 percent by weight of the total composition.
  • a matrix resin having the physical characteristics necessary for use in a conventional process for producing prepreg can be obtained and combined with carbon fibers surface-treated according to the invention to make a preimpregnated reinforcement.
  • Preimpregnated reinforcement can be prepared by several techniques known in the art, such as wet winding or hot melt.
  • the fiber is passed into a bath of the resin mixture.
  • a non-reactive, volatile solvent such as methyl ethyl ketone may be optionally included in the resin bath to reduce viscosity.
  • the reinforcement is passed through a die to remove excess resin, sandwiched between plies of release paper, passed through a set of heated rollers, cooled, and taken up on a spool. It can be used within a few days or may be stored for months at 0°F.(-17.78°C)
  • Composites may be prepared by curing preimpregnated reinforcement using heat and, optionally, pressure. Vacuum bag/autoclave cures work well with these compositions. Laminates may also be prepared via wet layup followed by compression molding, resin transfer molding, or by resin injection, as described in European Patent Application 0019149 published November 26, 1980. Typical cure temperatures are 100°F (37.78°C) to 500°F (260°C) preferably 180°F (82.22°C) to 450°F (232.22°C).
  • the composites of this invention may be used as aircraft parts such as wing skins, wing-to-body fairings, floor panels, flaps, radomes; as automotive parts such as driveshafts, bumpers, and springs; and as pressure vessels, tanks and pipes. They are also suitable for protective armor on military vehicles and sporting goods applications such as golf shafts, tennis rackets, and fishing rods.
  • the composition may also contain particulate fillers such as talc, mica, calcium carbonate, aluminum trihydrate, glass microballoons, phenolic thermospheres, and carbon black. Up to half of the weight structural fiber in the composition may be replaced by filler. Thixotropic agents such as fumed silica may also be used.
  • Unsized and unshear treated carbon fiber samples commercially available in tows having about l2000 fibers/tow from Union Carbide Corporation under the trade designation T-300 were electrolytically treated in a nitric acid bath (conc. 0.5M) and/or an ammonium hydroxide bath (conc. 2.65M) except for control fiber which was not treated in a bath.
  • the degree of shear treatment was evaluated by ESCA of the unsized fiber and by composite EDS testing using a bis-maleimide matrix resin consisting of a mixture of 54 parts by weight of methylene dianiline bismaleimide and 46 Parts by weight of 0,0-diallylbisphenol A. The polarity in each bath was the same.
  • the composites were made by laying up ten plies of prepreg made by a hot melt process.
  • the four centermost plies contained T-300 carbon fiber having a fiber area weight of about l45 gm/m2.
  • the other six outer plies (three on each side of the four center plies) were made with T-40 carbon fiber (available from Union Carbide Corporation ) having a fiber area weight of about 136 gm/m2. All composites were autoclave cured and the resin was bled to give a nominal cured composite fiber volume loading of 60%.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Reinforced Plastic Materials (AREA)
  • Inorganic Fibers (AREA)
  • Moulding By Coating Moulds (AREA)
  • Chemical Or Physical Treatment Of Fibers (AREA)
EP87304726A 1986-05-30 1987-05-28 Multi-electrolyte treatment of carbon fibres to modify shear resistance Expired - Lifetime EP0251491B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT87304726T ATE77854T1 (de) 1986-05-30 1987-05-28 Mehrfache elektrolytische behandlung von kohlenstoffasern zur verbesserung des abscherwiderstandes.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US86873786A 1986-05-30 1986-05-30
US868737 1986-05-30

Publications (2)

Publication Number Publication Date
EP0251491A1 EP0251491A1 (en) 1988-01-07
EP0251491B1 true EP0251491B1 (en) 1992-07-01

Family

ID=25352239

Family Applications (1)

Application Number Title Priority Date Filing Date
EP87304726A Expired - Lifetime EP0251491B1 (en) 1986-05-30 1987-05-28 Multi-electrolyte treatment of carbon fibres to modify shear resistance

Country Status (5)

Country Link
EP (1) EP0251491B1 (enrdf_load_stackoverflow)
JP (1) JPS636162A (enrdf_load_stackoverflow)
AT (1) ATE77854T1 (enrdf_load_stackoverflow)
CA (1) CA1314514C (enrdf_load_stackoverflow)
DE (1) DE3780092T2 (enrdf_load_stackoverflow)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11225754B2 (en) 2017-05-26 2022-01-18 Dow Global Technologies Llc Electrochemical grafting of carbon fibers with aliphatic amines for improved composite strength

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6385167A (ja) * 1986-09-22 1988-04-15 東レ株式会社 表面改質炭素繊維とその製造方法
US4839006A (en) * 1987-06-01 1989-06-13 Mitsubishi Rayon Co., Ltd. Surface treatment process for carbon fibers
JPH0284527A (ja) * 1988-02-29 1990-03-26 Toray Ind Inc 炭素繊維の処理方法
CN112746299A (zh) * 2020-12-18 2021-05-04 连云港鹰游工程技术研究院有限公司 一种用于碳纤维碳丝表面处理方法

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1297946A (enrdf_load_stackoverflow) * 1969-03-19 1972-11-29
GB1309252A (en) * 1969-03-25 1973-03-07 Int Research & Dev Co Ltd Electroplating of fibres
US3671411A (en) * 1970-03-03 1972-06-20 Us Air Force Treatment of carbon or graphite fibers and yarns for use in fiber reinforced composites
US4050997A (en) * 1972-12-18 1977-09-27 Maschinenfabrik Augsburg-Nurnberg Aktiengesellschaft Method of manufacturing a fiber reinforced composite material
US3832297A (en) * 1973-03-09 1974-08-27 Hercules Inc Process for electrolytic treatment of graphite fibers
JPS56128362A (en) * 1980-03-05 1981-10-07 Toho Beslon Co Production of carbon fiber
DE3106506A1 (de) * 1981-02-21 1982-10-07 Bayer Ag, 5090 Leverkusen Metallisierte kohlenstoffasern und verbundwerkstoffe, die diese fasern enthalten
EP0149763A3 (en) * 1983-11-29 1985-08-21 Toho Beslon Co., Ltd. Electroplating method for carbon fibers and apparatus therefor
JPH076131B2 (ja) * 1985-12-18 1995-01-30 東レ株式会社 超高強度炭素繊維の製造方法

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11225754B2 (en) 2017-05-26 2022-01-18 Dow Global Technologies Llc Electrochemical grafting of carbon fibers with aliphatic amines for improved composite strength

Also Published As

Publication number Publication date
ATE77854T1 (de) 1992-07-15
DE3780092D1 (de) 1992-08-06
EP0251491A1 (en) 1988-01-07
DE3780092T2 (de) 1993-02-18
CA1314514C (en) 1993-03-16
JPH0242939B2 (enrdf_load_stackoverflow) 1990-09-26
JPS636162A (ja) 1988-01-12

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