CN113320234A - Carbon fiber preform and preparation method thereof - Google Patents

Carbon fiber preform and preparation method thereof Download PDF

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Publication number
CN113320234A
CN113320234A CN202110395425.7A CN202110395425A CN113320234A CN 113320234 A CN113320234 A CN 113320234A CN 202110395425 A CN202110395425 A CN 202110395425A CN 113320234 A CN113320234 A CN 113320234A
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carbon fiber
carbon
catalyst
reaction
carboxyl
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李爱军
茅思佳
贾林涛
王梦千
郭小凤
张丹
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Shaoxing Institute Of Shanghai University
University of Shanghai for Science and Technology
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Shaoxing Institute Of Shanghai University
University of Shanghai for Science and Technology
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
    • B32B5/02—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by structural features of a fibrous or filamentary layer
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B37/00—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding
    • B32B37/02—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by a sequence of laminating steps, e.g. by adding new layers at consecutive laminating stations
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
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    • B32B5/028—Net structure, e.g. spaced apart filaments bonded at the crossing points
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
    • B32B5/02—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by structural features of a fibrous or filamentary layer
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
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    • B32B5/24—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer
    • B32B5/26—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer another layer next to it also being fibrous or filamentary
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    • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
    • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
    • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
    • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
    • D04H1/42—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties characterised by the use of certain kinds of fibres insofar as this use has no preponderant influence on the consolidation of the fleece
    • D04H1/4209—Inorganic fibres
    • D04H1/4242—Carbon fibres
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    • D06M11/00—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising
    • D06M11/51—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising with sulfur, selenium, tellurium, polonium or compounds thereof
    • D06M11/55—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising with sulfur, selenium, tellurium, polonium or compounds thereof with sulfur trioxide; with sulfuric acid or thiosulfuric acid or their salts
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    • D06M11/58—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising with nitrogen or compounds thereof, e.g. with nitrides
    • D06M11/64—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising with nitrogen or compounds thereof, e.g. with nitrides with nitrogen oxides; with oxyacids of nitrogen or their salts
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    • D06M11/00—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising
    • D06M11/73—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising with carbon or compounds thereof
    • D06M11/74—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with inorganic substances or complexes thereof; Such treatment combined with mechanical treatment, e.g. mercerising with carbon or compounds thereof with carbon or graphite; with carbides; with graphitic acids or their salts
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    • D06M13/00—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment
    • D06M13/322—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment with compounds containing nitrogen
    • D06M13/325—Amines
    • D06M13/332—Di- or polyamines
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    • D06M13/322—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment with compounds containing nitrogen
    • D06M13/35—Heterocyclic compounds
    • D06M13/355—Heterocyclic compounds having six-membered heterocyclic rings
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    • D06M13/00—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment
    • D06M13/322—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment with compounds containing nitrogen
    • D06M13/402—Amides imides, sulfamic acids
    • D06M13/432—Urea, thiourea or derivatives thereof, e.g. biurets; Urea-inclusion compounds; Dicyanamides; Carbodiimides; Guanidines, e.g. dicyandiamides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2262/00—Composition or structural features of fibres which form a fibrous or filamentary layer or are present as additives
    • B32B2262/10—Inorganic fibres
    • B32B2262/106—Carbon fibres, e.g. graphite fibres
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    • D06M2101/40—Fibres of carbon

Abstract

The invention belongs to the technical field of preparation of preforms, and particularly relates to a carbon fiber preform and a preparation method thereof. According to the invention, inorganic acid is adopted to carry out oxidation treatment on the pretreated carbon fiber, so that a large amount of carboxyl functional groups can be endowed to the carbon fiber; the acidified carbon fiber and one amino group in the bridging agent molecule are subjected to condensation reaction under the action of the first condensing agent, other amino groups in the bridging agent molecule are subjected to condensation reaction with carboxyl groups in the carboxyl carbon nano tube in the chemical grafting reaction, and the carboxyl carbon fiber is grafted to the carbon fiber, so that the specific surface area of the carbon fiber is increased. The carbon fiber preform obtained by the invention contains a large amount of active groups, and has more deposition surface areas and surface active sites when the CVI pair is used for densification, so that the densification speed of the carbon fiber preform is improved.

Description

Carbon fiber preform and preparation method thereof
Technical Field
The invention relates to the technical field of preparation of preforms, in particular to a carbon fiber preform and a preparation method thereof.
Background
C/C composite materials are increasingly used in the aerospace field due to their excellent properties. The C/C composite material is mainly characterized in that a carbon fiber preform is placed in a constant temperature area in an isothermal chemical vapor deposition furnace through a Chemical Vapor Infiltration (CVI) process, and then carrier gas is used for carrying in a gaseous precursor; the gases enter the interior of the C fiber preform through diffusion, and are pyrolyzed and polymerized at high temperature to generate hydrocarbon products with different carbon-hydrogen ratios; meanwhile, the gas-phase reaction products are deposited on the surface of the fiber through physical adsorption or chemical adsorption and undergo dehydrogenation reaction to generate pyrolytic C which is wrapped around the fiber; the thickness of the pyrolytic carbon gradually increases along with the increase of the deposition time, and finally, the pyrolytic carbon fills the pores and is connected with each other to form a continuous carbon matrix, thereby completing the densification process.
The existing CVI process for densifying the carbon fiber preform generally needs more than 120h of deposition time, has low densification rate and poor densification and is extremely unfavorable for industrial production.
Disclosure of Invention
In view of the above, the present invention is directed to a carbon fiber preform and a method for preparing the same. When the carbon fiber preform obtained by the preparation method provided by the invention is densified by adopting CVI, the speed is high; and the compact effect is good.
In order to achieve the above object, the present invention provides the following technical solutions:
the invention provides a preparation method of a carbon fiber preform, which comprises the following steps:
pretreating carbon fibers to obtain pretreated carbon fibers;
mixing the pretreated carbon fiber and inorganic acid, and carrying out an acidification reaction to obtain acidified carbon fiber;
mixing the acidified carbon fibers, a first condensing agent, a bridging agent, a first catalyst and a first organic solvent, and carrying out modification reaction to obtain modified carbon fibers;
mixing the modified carbon fibers, the carboxyl carbon nanotubes, a second condensing agent, a second catalyst and a second organic solvent, and performing a chemical grafting reaction to obtain carbon nanotube-grafted carbon fibers;
weaving the carbon nanotube grafted carbon fibers to obtain unidirectional carbon fiber cloth;
weaving the carbon nanotube grafted carbon fiber to obtain a net tire;
carrying out needle punching molding on the unidirectional carbon fiber cloth and the net tire to obtain the carbon fiber prefabricated body;
the number of amino groups in a single bridging agent molecule is more than or equal to 2.
Preferably, the inorganic acid is a mixed acid of nitric acid and sulfuric acid; the volume ratio of nitric acid to sulfuric acid in the mixed acid is 4: 1; the mass concentration of the nitric acid is 2-3 mol/L; the concentration of the sulfuric acid is 15-20 mol/L.
Preferably, the temperature of the acidification reaction is 80-100 ℃, and the time is 2-3 h.
Preferably, the first and second condensing agents are independently organic amine condensing agents including one or more of dicyclohexylcarbodiimide, diisopropylcarbodiimide, and 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide; the first catalyst and the second catalyst are 4-dimethylaminopyridine; the first organic solvent and the second organic solvent are dimethylformamide; the bridging agent comprises hexamethylenediamine and/or 1, 3-propanediamine.
Preferably, the mass ratio of the acidified carbon fibers, the first condensing agent, the bridging agent and the first catalyst is 20: (1-1.5): (1-1.5): (1-1.5).
Preferably, the temperature of the modification reaction is room temperature, and the time is 12-24 h.
Preferably, the mass ratio of the modified carbon fibers, the carboxyl carbon nanotubes, the second condensing agent and the second catalyst is 20: (3-6): (0.5-1): (0.5 to 1).
Preferably, the temperature of the chemical grafting reaction is room temperature, and the time is 12-24 h.
Preferably, the pre-treatment comprises: water washing and acetone washing are sequentially carried out.
The invention also provides the carbon fiber preform obtained by the preparation method in the technical scheme.
The invention provides a preparation method of a carbon fiber preform, which comprises the following steps: pretreating carbon fibers to obtain pretreated carbon fibers; mixing the pretreated carbon fiber and inorganic acid, and carrying out an acidification reaction to obtain acidified carbon fiber; mixing the acidified carbon fibers, a first condensing agent, a bridging agent, a first catalyst and a first organic solvent, and carrying out modification reaction to obtain modified carbon fibers; mixing the modified carbon fibers, the carboxyl carbon nanotubes, a second condensing agent, a second catalyst and a second organic solvent, and performing a chemical grafting reaction to obtain carbon nanotube-grafted carbon fibers; weaving the carbon nanotube grafted carbon fibers to obtain unidirectional carbon fiber cloth; weaving the carbon nanotube grafted carbon fiber to obtain a net tire; carrying out needle punching molding on the unidirectional carbon fiber cloth and the net tire to obtain the carbon fiber prefabricated body; the number of amino groups in a single bridging agent molecule is more than or equal to 2.
According to the invention, inorganic acid is adopted to carry out acidification treatment on the pretreated carbon fiber, so that a large amount of carboxyl functional groups can be endowed to the pretreated carbon fiber; the acidified carbon fiber and one amino group in the bridging agent molecule are subjected to condensation reaction under the action of the first condensing agent, other amino groups in the bridging agent molecule are subjected to condensation reaction with carboxyl groups in the carboxyl carbon nano tube in the chemical grafting reaction, and the carboxyl carbon fiber is grafted to the carbon fiber, so that the specific surface area of the carbon fiber is increased. The carbon fiber preform obtained by the preparation method provided by the invention contains a large number of active groups, and when CVI is adopted to densify the carbon fiber preform, more deposition surface areas and surface active sites can be provided, the densification speed of the carbon fiber preform is improved, and the densification effect is good.
Drawings
FIG. 1 is a schematic diagram of the modification reaction and chemical grafting reaction of the acidified carbon fiber according to the present invention.
Detailed Description
The invention provides a preparation method of a carbon fiber preform, which comprises the following steps:
pretreating carbon fibers to obtain pretreated carbon fibers;
mixing the pretreated carbon fiber and inorganic acid, and carrying out an acidification reaction to obtain acidified carbon fiber;
mixing the acidified carbon fibers, a first condensing agent, a bridging agent, a first catalyst and a first organic solvent, and carrying out modification reaction to obtain modified carbon fibers;
mixing the modified carbon fibers, the carboxyl carbon nanotubes, a second condensing agent, a second catalyst and a second organic solvent, and performing a chemical grafting reaction to obtain carbon nanotube-grafted carbon fibers;
weaving the carbon nanotube grafted carbon fibers to obtain unidirectional carbon fiber cloth;
weaving the carbon nanotube grafted carbon fiber to obtain a net tire;
and carrying out needle punching molding on the unidirectional carbon fiber cloth and the net tire to obtain the carbon fiber preform.
In the present invention, the starting materials used in the present invention are preferably commercially available products unless otherwise specified.
The invention carries out pretreatment on carbon fibers to obtain the pretreated carbon fibers.
In the present invention, the carbon fiber is preferably a 3K carbon fiber, a 6K carbon fiber, a 12K carbon fiber, or an 18K carbon fiber, and more preferably a 12K carbon fiber.
In the present invention, the pretreatment preferably includes: water washing and acetone washing are sequentially carried out. In the invention, the soaking is preferably performed in the water washing mode, and the water washing time is preferably 1-2 h, and more preferably 1.5 h. In the invention, the acetone washing mode is preferably soaking, and the time for acetone washing is preferably 2-3 h, and more preferably 2.5 h.
In the invention, the pretreatment can remove the glue layer on the surface of the carbon fiber.
After the pretreated carbon fiber is obtained, the pretreated carbon fiber and inorganic acid are mixed for acidification reaction to obtain the acidified carbon fiber.
In the present invention, the inorganic acid is preferably a mixed acid of nitric acid and sulfuric acid; the volume ratio of nitric acid to sulfuric acid in the mixed acid is preferably 4: 1; the concentration of the nitric acid is preferably 2-3 mol/L, and particularly preferably 2mol/L, 2.5mol/L or 3 mol/L; the concentration of the sulfuric acid is preferably 15-20 mol/L, and particularly preferably 15mol/L, 18.5mol/L or 20 mol/L.
In the present invention, the acidification reaction is preferably performed in the following manner: and (3) soaking the pretreated carbon fiber in inorganic acid for acidification reaction. In the present invention, the amount ratio of the pretreated carbon fiber to the inorganic acid is preferably 20 g: (100-500) mL, more preferably 20 g: (300-450) mL.
In the invention, the temperature of the acidification reaction is preferably 80-100 ℃, and further preferably 90 ℃; the time is preferably 2 to 3 hours, and more preferably 2.5 hours. In the present invention, the acidification reaction is preferably performed under magnetic stirring.
After the acidification reaction, the invention preferably further comprises filtering the obtained acidification reaction feed liquid, washing and drying the obtained precipitate to obtain the acidified carbon fiber. In the present invention, the washing agent is preferably water; the number of washing is not particularly limited in the present invention, as long as the excess reaction reagent can be removed. In the present invention, the temperature and time of the drying are not particularly limited as long as the washed reagent can be completely removed.
In the invention, the acidification reaction can introduce carboxyl on the surface of the pretreated carbon fiber.
After the acidified carbon fiber is obtained, the acidified carbon fiber, the first condensing agent, the bridging agent, the first coupling agent and the first organic solvent are mixed for modification reaction to obtain the modified carbon fiber.
In the present invention, the first condensing agent is preferably an organic amine condensing agent, and the organic amine condensing agent preferably includes one or more of dicyclohexylcarbodiimide, diisopropylcarbodiimide, and 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide, and more preferably dicyclohexylcarbodiimide. In the present invention, the first catalyst is preferably 4-dimethylaminopyridine; the first organic solvent is preferably dimethylformamide. In the invention, the number of amino groups in a single bridging agent molecule is more than or equal to 2, and preferably 2; the bridging agent preferably comprises hexamethylenediamine and/or 1, 3-propanediamine, more preferably 1, 3-propanediamine.
In the present invention, the mass ratio of the acidified carbon fibers, the first condensing agent, the bridging agent, and the first catalyst is preferably 20: (1-1.5): (1-1.5): (1 to 1.5), and particularly preferably 20: 1: 1: 1. 20: 1.5: 1.5: 1.5 or 20: 1.2: 1.2: 1.2. in the present invention, the ratio of the amount of the acidified carbon fibers to the first organic solvent is preferably 20 g: (100-300) mL.
In the present invention, the mixing order of the acidified carbon fibers, the first condensing agent, the bridging agent, the first catalyst, and the first organic solvent is preferably: and mixing the acidified carbon fibers with a first organic solvent, and then sequentially adding a first condensing agent, a bridging agent and a first catalyst.
In the present invention, the temperature of the modification reaction is preferably room temperature, i.e., neither additional heating nor additional cooling is required; the time of the modification reaction is preferably 12-24 hours, and more preferably 20 hours. In the present invention, the modification reaction is preferably carried out under magnetic stirring.
After the modification reaction, the modified reaction liquid is preferably filtered, and the obtained precipitate is washed and dried to obtain the modified carbon fiber. In the present invention, the washing reagent is preferably water, and the number of times of washing is not particularly limited as long as unreacted substances can be removed cleanly. In the invention, the drying temperature is preferably 80-120 ℃, and more preferably 90 ℃; the time is preferably 2 to 4 hours, and more preferably 3 hours.
In the invention, carboxyl in the acidified carbon fiber and a bridging agent are subjected to condensation reaction under the action of a condensing agent to introduce amino-NH2And preparing for connecting the carbon nano tube by subsequent chemical grafting reaction.
After the modified carbon fiber is obtained, the modified carbon fiber, the carboxyl carbon nanotube, the second condensing agent, the second catalyst and the second organic solvent are mixed for chemical grafting reaction, so that the carbon nanotube-grafted carbon fiber is obtained.
In the invention, the diameter of the carboxyl carbon nano tube is preferably 5-10 nm, and the length of the carboxyl carbon nano tube is preferably 0.5-3 μm. In the present invention, the carboxyl carbon nanotube is preferably a commercially available product. In the present invention, the types of the second condensing agent, the second catalyst and the second organic solvent are the same as those in the above technical solution, and are not described herein again.
In the present invention, the mass ratio of the modified carbon fibers, the carboxyl carbon nanotubes, the second condensing agent, and the second catalyst is preferably 20: (3-6): (0.5-1): (0.5 to 1), and particularly preferably 20: 3: 0.5: 0.5, 20: 6: 1: 1 or 20: 5: 0.6: 0.6. in the present invention, the amount ratio of the modified carbon fiber to the second organic solvent is preferably 20 g: (100-300) mL.
In the present invention, the modified carbon fiber, the carboxyl carbon nanotube, the second condensing agent, the second catalyst, and the second organic solvent are preferably mixed in the order of: the modified carbon fiber is mixed with a carboxyl carbon fiber tube, a second condensing agent and a second catalyst in sequence. In the present invention, the means of mixing is preferably ultrasound; the time of the ultrasonic treatment is preferably 20-30 min.
In the present invention, the temperature of the chemical grafting reaction is preferably room temperature, i.e. neither additional heating nor additional cooling is required; the time of the chemical grafting reaction is preferably 12-24 h. In the present invention, the chemical grafting reaction is preferably performed under magnetic stirring.
After the chemical grafting reaction, the present invention preferably further comprises: and filtering the obtained chemical grafting reaction liquid, washing and drying the obtained precipitate to obtain the carbon nanotube grafted carbon fiber. In the present invention, the washing reagent is preferably water, and the number of times of washing is not particularly limited as long as unreacted substances can be removed cleanly. In the invention, the drying temperature is preferably 80-120 ℃, and more preferably 100 ℃; the time is preferably 2-4 h.
According to the invention, the chemical grafting reaction can graft the carboxyl carbon nanotube on the surface of the carbon fiber, so that the specific surface area of the carbon fiber is improved, and the carboxyl group on the carbon nanotube further improves the content of an active group of the carbon fiber, so that a large amount of specific surface area and active sites are provided for the densification of a prefabricated body formed by the carbon nanotube, and the densification rate of the final prefabricated body of the carbon fiber is improved.
In the present invention, the schematic diagram of the modification reaction and the chemical grafting reaction of the acidified carbon fiber is shown in fig. 1, and it can be seen from fig. 1 that: the acidified carbon fiber is subjected to modification reaction, amino groups are introduced on the carbon fiber, and then the carbon nanotube is grafted on the carbon fiber through amide groups through chemical grafting reaction.
After the carbon nanotube grafted carbon fiber is obtained, the carbon nanotube grafted carbon fiber is woven to obtain the unidirectional carbon fiber cloth.
The weaving parameters are not particularly limited in the present invention, and weaving parameters known to those skilled in the art may be used.
After the carbon nanotube grafted carbon fiber is obtained, the carbon nanotube grafted carbon fiber is woven to obtain the net tire.
In the invention, the surface density of the net tire is preferably 80-100 g/cm2。
In the present invention, the weaving preferably comprises the steps of: and chopping, humidifying, opening, carding and lapping the carbon nanotube grafted carbon fiber in sequence. The parameters of chopping, humidifying, opening, carding and lapping are not particularly limited in the invention, and technical means well known to those skilled in the art can be adopted.
After the unidirectional carbon fiber cloth and the net tire are obtained, the unidirectional carbon fiber cloth and the net tire are subjected to needle punching forming to obtain the carbon fiber preform.
In the present invention, the unidirectional carbon fiber cloth and the mesh tire are preferably stacked before needle punching. In the present invention, the lamination arrangement preferably comprises the steps of:
the method comprises the following steps of sequentially stacking a layer of net tire, a layer of 0-degree unidirectional carbon fiber cloth, a layer of net tire, a layer of 90-degree unidirectional carbon fiber cloth, a layer of net tire, a layer of 0-degree unidirectional carbon fiber cloth, a layer of net tire and a layer of 90-degree unidirectional carbon fiber cloth. In the invention, the 0-degree unidirectional carbon fiber cloth and the 90-degree unidirectional carbon fiber cloth represent that the carbon fibers in the two layers of unidirectional carbon fiber cloth are placed at 90 degrees. The number of layers of the net tire or the unidirectional carbon fiber cloth is not particularly limited, and the net tire or the unidirectional carbon fiber cloth can be set by a person skilled in the art according to actual requirements.
The parameters of the needle-punching molding are not particularly limited in the present invention, and the technical means known to those skilled in the art can be adopted.
The invention also provides the carbon fiber preform obtained by the preparation method in the technical scheme. In the invention, the carbon fiber preform improves the specific surface area of the final carbon fiber preform due to the grafting of the carbon nano tube; meanwhile, acid treatment, modification treatment and grafting of the carboxyl carbon nano tube endow a large number of active groups to the fiber, and the deposition active sites of the final carbon fiber preform are improved; when the carbon fiber preform is deposited, the densification speed is high, and the effect is good.
The carbon fiber preform and the method for producing the same according to the present invention will be described in detail with reference to examples, but they should not be construed as limiting the scope of the present invention.
Example 1
(1) The 12K carbon fiber is soaked in deionized water for washing for 1h, and then soaked in acetone for washing for 2h, so that the pretreated carbon fiber is obtained.
(2) 20g of the above pretreated carbon fiber was immersed in 300mL of mixed acid (HNO)3And H2SO4Is 4: 1, HNO3Has a concentration of 2mol/L, H2SO415mol/L), magnetically stirring at 80 ℃ for 2 hours, filtering the obtained acidification reaction liquid, washing the obtained precipitate with water, and drying to obtain the acidification carbon fiber.
(3) Immersing the acidified carbon fiber into 100mL of dimethylformamide, sequentially adding 1g of dicyclohexylcarbodiimide, 1g of 1, 3-propanediamine and 1g of 4-dimethylaminopyridine, magnetically stirring at room temperature for 12h, filtering the obtained modified reaction liquid, washing the obtained precipitate with water, and drying at 80 ℃ for 2h in a vacuum drying oven to obtain the modified carbon fiber.
(4) Immersing the modified carbon fiber into 100mL of dimethylformamide, then adding 3g of carboxyl carbon nano tube (the diameter is 5nm, the microscopic length is 0.5 mu m), adding 0.5g of dicyclohexylcarbodiimide and 0.5g of 4-dimethylaminopyridine, and carrying out ultrasonic treatment for 20 min; magnetically stirring at room temperature for 12h, filtering the obtained chemical grafting reaction liquid, washing the obtained precipitate with water, and vacuum drying at 80 ℃ for 2h to obtain the carbon nanotube grafted carbon fiber.
(5) And weaving the carbon nanotube grafted carbon fiber to obtain the unidirectional carbon fiber cloth.
(6) Chopping, humidifying, opening, carding and lapping the carbon nanotube grafted carbon fiber to obtain a net body, wherein the surface density of the net body is 80g/cm2。
(7) Superposing a layer of net tire, a layer of 0-degree unidirectional carbon fiber cloth, a layer of net tire and a layer of 90-degree unidirectional carbon fiber cloth together to form a structural unit, superposing 20 structural units together along the thickness direction, and then carrying out needle punching forming to obtain a carbon fiber preform; the 90-degree unidirectional carbon fiber cloth and the 0-degree unidirectional carbon fiber cloth are placed in a way that carbon fibers in the 0-degree unidirectional carbon fiber cloth and carbon fibers in the 90-degree unidirectional carbon fiber cloth are 90 degrees.
The prepared carbon fiber preform was subjected to densification test: ar gas as protective gas, CH4For C source gas, the flow rate of Ar gas is 300mL/min, CH4The flow rate was 200mL/min and the deposition temperature was 1000 ℃. After 40h of deposition densification, the density reaches 1.78g/cm3And the deposition is completed.
Example 2
(1) And (3) soaking the 12K carbon fiber in deionized water for washing for 2h, and then soaking in acetone for washing for 3h to obtain the pretreated carbon fiber.
(2) 20g of the above pretreated carbon fiber was immersed in 500mL of mixed acid (HNO)3And H2SO4Is 4: 1, HNO3Has a concentration of 2.5mol/L, H2SO418.5mol/L), magnetically stirring for 3h at 100 ℃, filtering the obtained reaction solution, washing the obtained precipitate with water, and drying to obtain the acidified carbon fiber.
(3) Immersing the acidified carbon fiber into 300mL of dimethylformamide, sequentially adding 1.5g of dicyclohexylcarbodiimide, 1.5g of 1, 3-propanediamine and 1.5g of 4-dimethylaminopyridine, magnetically stirring for 24h at room temperature, filtering the obtained modified reaction liquid, washing the obtained precipitate with water, and drying for 4h at 120 ℃ in a vacuum drying oven to obtain the modified carbon fiber.
(4) Immersing the modified carbon fiber into 300mL of dimethylformamide, then adding 6g of carboxyl carbon nano tube (the diameter is 6nm, the length is 1 mu m), adding 1g of dicyclohexylcarbodiimide and 1g of 4-dimethylaminopyridine, and carrying out ultrasonic treatment for 20 min; and magnetically stirring for 24 hours at room temperature, filtering the obtained chemical grafting reaction liquid, washing the obtained precipitate with water, and then drying in vacuum at 120 ℃ for 4 hours to obtain the carbon nanotube grafted carbon fiber.
(5) And weaving the carbon nanotube grafted carbon fiber to obtain the unidirectional carbon fiber cloth.
(6) Chopping, humidifying, opening, carding and lapping the carbon nanotube grafted carbon fiber to obtain a net body, wherein the surface density of the net body is 90g/cm2。
(7) Superposing a layer of net tire, a layer of 0-degree unidirectional carbon fiber cloth, a layer of net tire and a layer of 90-degree unidirectional carbon fiber cloth together to form a structural unit, superposing 20 structural units together along the thickness direction, and then carrying out needle punching forming to obtain a carbon fiber preform; wherein the 90-degree unidirectional carbon fiber cloth and the 0-degree unidirectional carbon fiber cloth are placed in a way that the carbon fibers in the 0-degree unidirectional carbon fiber cloth and the carbon fibers in the 90-degree unidirectional carbon fiber cloth are 90 degrees.
The prepared carbon fiber preform was subjected to densification test: ar gas as protective gas, CH4For C source gas, the flow rate of Ar gas is 300mL/min, CH4The flow rate is 200mL/min, the deposition temperature is 1000 ℃, and the density reaches 1.79g/cm after 42h of deposition densification3And the deposition is completed.
Example 3
(1) And (3) soaking the 12K carbon fiber in deionized water for washing for 1.5h, and then soaking in acetone for washing for 2.5h to obtain the pretreated carbon fiber.
(2) 20g of pretreated carbon fibers were immersed in 450mL of mixed acid (HNO)3And H2SO4Is 4: 1, HNO3Has a concentration of 3mol/L, H2SO420mol/L), magnetically stirring at 90 ℃ for 2 hours, filtering the obtained reaction solution, washing the obtained precipitate with water, and drying to obtain the acidified carbon fiber.
(3) Immersing the acidified carbon fiber into 300mL of dimethylformamide, sequentially adding 1.2g of dicyclohexylcarbodiimide, 1.2g of 1, 3-propanediamine and 1.2g of 4-dimethylaminopyridine, magnetically stirring at room temperature for 20h, filtering the obtained modified reaction liquid, washing the obtained precipitate with water, and drying at 90 ℃ for 3h in a vacuum drying oven to obtain the modified carbon fiber.
(4) The modified carbon fiber is immersed in 300mL of dimethylformamide, then 5g of carboxyl carbon nano tube (the length is 10nm, the diameter is 3 mu m) is added, 0.6g of dicyclohexylcarbodiimide and 0.6g of 4-dimethylaminopyridine are added, ultrasonic treatment is carried out for 30min, magnetic stirring is carried out at room temperature for 24h, the obtained chemical grafting reaction liquid is filtered, the obtained precipitate is washed clean with water, and then vacuum drying is carried out at 100 ℃ for 4h, so as to obtain the carbon nano tube grafted carbon fiber.
(5) And weaving the carbon nanotube grafted carbon fiber to obtain the unidirectional carbon fiber cloth.
(6) Chopping, humidifying, opening, carding and lapping the carbon nanotube grafted carbon fiber to obtain a net body, wherein the surface density of the net body is 85g/cm2。
(7) Superposing a layer of net tire, a layer of 0-degree unidirectional carbon fiber cloth, a layer of net tire and a layer of 90-degree unidirectional carbon fiber cloth together to form a structural unit, superposing 20 structural units together along the thickness direction, and then carrying out needle punching forming to obtain a carbon fiber preform; wherein, 90 one-way carbon fiber cloth and 0 one-way carbon fiber cloth are that carbon fiber in 0 one-way carbon fiber cloth and carbon fiber in 90 one-way carbon fiber cloth are placed 90 degrees.
The prepared carbon fiber preform was subjected to densification test: ar gas as protective gas, CH4For C source gas, the flow rate of Ar gas is 300mL/min, CH4The flow rate was 200mL/min and the deposition temperature was 1000 ℃. After 40h of deposition densification, the density reaches 1.77g/cm3And the deposition is completed.
The embodiment shows that the carboxyl carbon nano tube is grafted to the carbon fiber by utilizing the acidification reaction, the modification reaction and the chemical grafting reaction, so that the specific surface area of the carbon fiber is improved; meanwhile, a large number of active groups are introduced on the surface of the carbon fiber; when the obtained carbon fiber preform is subjected to CVI densification, the deposition surface area and the deposition active sites are high, and the densification rate is improved.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims (10)

1. A method for preparing a carbon fiber preform, comprising the steps of:
pretreating carbon fibers to obtain pretreated carbon fibers;
mixing the pretreated carbon fiber and inorganic acid, and carrying out an acidification reaction to obtain acidified carbon fiber;
mixing the acidified carbon fibers, a first condensing agent, a bridging agent, a first catalyst and a first organic solvent, and carrying out modification reaction to obtain modified carbon fibers;
mixing the modified carbon fibers, the carboxyl carbon nanotubes, a second condensing agent, a second catalyst and a second organic solvent, and performing a chemical grafting reaction to obtain carbon nanotube-grafted carbon fibers;
weaving the carbon nanotube grafted carbon fibers to obtain unidirectional carbon fiber cloth;
weaving the carbon nanotube grafted carbon fiber to obtain a net tire;
carrying out needle punching molding on the unidirectional carbon fiber cloth and the net tire to obtain the carbon fiber prefabricated body;
the number of amino groups in a single bridging agent molecule is more than or equal to 2.
2. The production method according to claim 1, wherein the inorganic acid is a mixed acid of nitric acid and sulfuric acid; the volume ratio of nitric acid to sulfuric acid in the mixed acid is 4: 1; the mass concentration of the nitric acid is 2-3 mol/L; the concentration of the sulfuric acid is 15-20 mol/L.
3. The preparation method according to claim 1 or 2, wherein the temperature of the acidification reaction is 80-100 ℃ and the time is 2-3 h.
4. The method according to claim 1, wherein the first and second condensing agents are independently an organic amine condensing agent including one or more of dicyclohexylcarbodiimide, diisopropylcarbodiimide, and 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide; the first catalyst and the second catalyst are 4-dimethylaminopyridine; the first organic solvent and the second organic solvent are dimethylformamide; the bridging agent comprises hexamethylenediamine and/or 1, 3-propanediamine.
5. The production method according to claim 1 or 4, wherein the mass ratio of the acidified carbon fibers, the first condensing agent, the bridging agent, and the first catalyst is 20: (1-1.5): (1-1.5): (1-1.5).
6. The preparation method according to claim 5, wherein the temperature of the modification reaction is room temperature, and the time is 12-24 h.
7. The production method according to claim 1 or 4, wherein the mass ratio of the modified carbon fiber, the carboxyl carbon nanotube, the second condensing agent and the second catalyst is 20: (3-6): (0.5-1): (0.5 to 1).
8. The preparation method according to claim 7, wherein the temperature of the chemical grafting reaction is room temperature, and the time is 12-24 h.
9. The method of claim 1, wherein the pre-treating comprises: water washing and acetone washing are sequentially carried out.
10. A carbon fiber preform obtained by the production method according to any one of claims 1 to 9.
CN202110395425.7A 2021-04-13 2021-04-13 Carbon fiber preform and preparation method thereof Pending CN113320234A (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050069701A1 (en) * 2003-09-26 2005-03-31 Fuji Xerox Co., Ltd Carbon nanotube composite structure and method of manufacturing the same
CN102108634A (en) * 2011-01-04 2011-06-29 同济大学 Method for preparing functional carbon fibers
CN102120866A (en) * 2011-01-12 2011-07-13 同济大学 Method for preparing graphite and functional carbon fiber modified epoxy resin composite material
CN107459771A (en) * 2016-06-03 2017-12-12 南京中赢纳米新材料有限公司 The preparation method of Nano diamond and functionalized carbon fiber reinforced epoxy composite

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050069701A1 (en) * 2003-09-26 2005-03-31 Fuji Xerox Co., Ltd Carbon nanotube composite structure and method of manufacturing the same
CN102108634A (en) * 2011-01-04 2011-06-29 同济大学 Method for preparing functional carbon fibers
CN102120866A (en) * 2011-01-12 2011-07-13 同济大学 Method for preparing graphite and functional carbon fiber modified epoxy resin composite material
CN107459771A (en) * 2016-06-03 2017-12-12 南京中赢纳米新材料有限公司 The preparation method of Nano diamond and functionalized carbon fiber reinforced epoxy composite

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Application publication date: 20210831