CN120776589A - Sizing agent raw material composition, sizing agent, preparation method and application thereof - Google Patents
Sizing agent raw material composition, sizing agent, preparation method and application thereofInfo
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- CN120776589A CN120776589A CN202410421751.4A CN202410421751A CN120776589A CN 120776589 A CN120776589 A CN 120776589A CN 202410421751 A CN202410421751 A CN 202410421751A CN 120776589 A CN120776589 A CN 120776589A
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- carbon nanotubes
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Abstract
The invention relates to the technical field of sizing agents, in particular to a sizing agent composition and a preparation method of the sizing agent; the invention provides a sizing agent composition, which comprises epoxy resin, modified multi-wall carbon nano tubes and a solvent, wherein the multi-wall carbon nano tubes contain high molecular groups and oxygen-containing functional groups, the composition is used for preparing sizing agents, has the advantages of excellent dispersibility, stability and the like, can better improve the interlayer shearing force of carbon fibers after sizing the carbon fibers, and is simple in preparation method, mild in condition, low in cost and suitable for large-scale production.
Description
Technical Field
The invention relates to the technical field of sizing agents, in particular to a sizing agent raw material composition, a sizing agent, a preparation method and application thereof.
Background
The carbon fiber reinforced polymer matrix composite material is a lightweight material, has the characteristics of high strength, high rigidity, low thermal expansion coefficient, corrosion resistance, wear resistance and the like, and plays an increasingly important role in the aspects of weapon equipment, aerospace, automobile manufacturing and the like. However, the carbon fiber has smooth surface, large chemical inertia and low surface energy, so that the stress load between the carbon fiber and the polymer matrix cannot be effectively transmitted, and an effective interface bonding effect is difficult to form with the polymer, thereby directly affecting the performance of the composite material. Therefore, the interfacial properties between the carbon fibers and the matrix are critical to the properties of the composite.
At present, the carbon fiber modification method comprises surface coating (such as polymers, metal particles, inorganic nonmetal, a compound thereof and the like) treatment, oxidation treatment (such as adding oxygen-containing functional groups on the surface to form carboxyl groups, hydroxyl groups and the like), a surface grafting method, an energy beam treatment method and the like, so that the specific surface area, the surface roughness and the surface free energy of the carbon fiber are optimized, the wettability, the chemical bonding effect and the mechanical meshing effect between the carbon fiber and a polymer matrix are improved, and the performance of the composite material is further enhanced. The carbon nano material is put into the emulsion sizing agent, carbon fibers are modified in the sizing process, the wettability of the surfaces of the carbon fibers can be improved, and meanwhile, the interfacial strength of the carbon fibers and a polymer matrix is improved through a mechanical locking effect, so that the method is an effective method for enhancing the interfacial performance of the composite material. There is an urgent need to develop stable, high-performance carbon nanomaterial-modified composite sizing agents.
The carbon nano tube has the advantages of large surface area, excellent electric conduction and mechanical properties and the like, and can be used for reinforcing a matrix material. The carbon nano tube is introduced into the carbon fiber reinforced matrix composite material through the carbon nano tube composite sizing agent, so that the transfer capability of stress load can be greatly improved, the interaction between the carbon fiber and the polymer matrix is enhanced, and the structure of the carbon fiber is not damaged.
Disclosure of Invention
In order to solve the defects of poor dispersibility and poor stability of sizing agents for preparing carbon fiber reinforced matrix materials of carbon nanotubes in the prior art, the invention provides a sizing agent raw material composition, a sizing agent and a preparation method thereof, and the sizing agent prepared by adopting the sizing agent composition and the preparation method has the advantages of excellent dispersibility, stability and the like; the sizing agent can better improve the interlaminar shear force of the carbon fiber after sizing the carbon fiber.
In order to achieve the above object, a first aspect of the present invention provides a sizing agent raw material composition comprising an epoxy resin, a modified multi-walled carbon nanotube and a solvent, the modified multi-walled carbon nanotube being a multi-walled carbon nanotube having a polymer group and an oxygen-containing functional group;
The high polymer group is selected from one or more of polyethylene glycol group, polyvinylpyrrolidone and polyvinyl alcohol;
the oxygen-containing functional group is selected from one or more of carboxyl, hydroxyl and ester groups.
In a second aspect, the invention provides a method for preparing a sizing agent comprising mixing the materials of the composition of the invention as described above.
The third aspect of the invention provides the sizing agent prepared by the preparation method.
In a fourth aspect, the present invention provides the use of a sizing agent as described above for surface modification of fibers.
Through the technical scheme, the invention has the following beneficial effects:
In the sizing agent raw material composition, the modified multi-wall carbon nano tube contains a high molecular group and an oxygen-containing functional group, and the modified multi-wall carbon nano tube has the advantages of excellent dispersibility, stability and the like when being used for preparing sizing agents. The sizing agent can better improve the interlaminar shear force of the carbon fibers after sizing the carbon fibers.
The preparation method of the modified multiwall carbon nanotube is simple, mild in condition and low in cost, and is suitable for large-scale production.
Drawings
FIG. 1 is a transmission electron microscope image of a raw material carbon nanotube and a modified multi-walled carbon nanotube in preparation example 1, (a-c) multi-walled carbon nanotube, (d-f) PEG-modified multi-walled carbon nanotube;
FIG. 2 is an infrared spectrum of the multiwall carbon nanotubes, the carboxyl-modified multiwall carbon nanotubes and the PEG-modified multiwall carbon nanotubes of preparation example 1;
FIG. 3 is an optical image of the sizing agent prepared in example 1 and comparative example 1 after 0 and 30 days of standing.
Detailed Description
The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.
The first aspect of the present invention provides a sizing agent raw material composition, which comprises an epoxy resin, a modified multi-walled carbon nanotube and a solvent, wherein the modified multi-walled carbon nanotube is a multi-walled carbon nanotube containing a macromolecule group and an oxygen-containing functional group;
The high polymer group is selected from one or more of polyethylene glycol group, polyvinylpyrrolidone and polyvinyl alcohol;
The oxygen-containing functional group is selected from one or more of carboxyl, hydroxyl and ester groups. The modified multiwall carbon nanotube provided by the invention contains a macromolecule group and an oxygen-containing functional group, has the advantages of excellent dispersibility, stability and the like when being used for preparing a sizing agent, and can better improve the interlaminar shear force of carbon fibers after sizing the carbon fibers.
According to a preferred embodiment of the present invention, the polymer group accounts for 10 to 99.9wt%, preferably 85 to 99.75wt%, more preferably 90 to 99.75wt% of the mass of the modified multi-walled carbon nanotube.
According to a preferred embodiment of the present invention, the oxygen-containing functional group-containing multi-walled carbon nanotubes account for 0.1 to 90wt%, preferably 0.25 to 15wt%, more preferably 0.25 to 10wt% of the mass of the modified multi-walled carbon nanotubes.
According to a preferred embodiment of the invention, the polyvinylpyrrolidone has a relative molecular mass of 2000-50000g/mol.
According to a preferred embodiment of the invention, the relative molecular mass of the polyvinyl alcohol is in the range from 2000 to 50000g/mol.
According to a preferred embodiment of the invention, the polyethylene glycol has a relative molecular mass of 2000-50000g/mol.
According to a preferred embodiment of the present invention, the composition comprises 30-40 parts of epoxy resin, 0.01-2 parts of modified multi-walled carbon nanotubes, and 40-80 parts of solvent.
According to a preferred embodiment of the present invention, the composition comprises 0.5 to 2 parts of modified multi-walled carbon nanotubes.
According to a preferred embodiment of the invention, the epoxy resin is selected from the group consisting of E51 type epoxy resins and/or bisphenol A type epoxy resins E44.
According to a preferred embodiment of the invention, the composition further comprises an emulsifier for forming an epoxy emulsion of the epoxy resin with the solvent.
According to a preferred embodiment of the invention, the emulsifier is present in an amount of 1-20wt% of the epoxy resin. The kind of the emulsifier is not particularly limited in the present invention, and may be an emulsifier which is conventional in the art, preferably, the emulsifier is selected from one or more kinds of alkyl sulfonate, and for example, sodium dodecyl sulfonate may be used.
According to a preferred embodiment of the invention, the solvent is water.
According to a preferred embodiment of the present invention, the method for preparing the modified multiwall carbon nanotubes comprises:
In the presence of a first catalyst, a second catalyst and an organic solvent, contacting the multi-wall carbon nano tube containing carboxyl with a high polymer material, carrying out solid-liquid separation, washing and drying;
The high polymer material is selected from one or more of polyethylene glycol, polyvinylpyrrolidone and polyvinyl alcohol;
The first catalyst is selected from 2-dimethylaminopyridine and/or N-hydroxysuccinimide, preferably 2-dimethylaminopyridine;
The second catalyst is selected from N, N dicyclohexylcarbodiimide and/or 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride, preferably N, N dicyclohexylcarbodiimide.
In the present invention, the contacting comprises esterification and/or electrostatic interaction, and the conditions for the contacting are selected from a wide range, and according to a preferred embodiment of the present invention, the contacting conditions comprise a temperature of 20-35 ℃ and a contacting time of 2-48h.
According to a preferred embodiment of the present invention, the mass ratio of the carboxyl group-containing multiwall carbon nanotubes to the polymer material is 1:5-500, preferably 9-450.
According to a preferred embodiment of the present invention, the mass ratio of the carboxyl group-containing multiwall carbon nanotubes to the first catalyst is 1:3-10.
According to a preferred embodiment of the present invention, the mass ratio of the carboxyl group-containing multiwall carbon nanotubes to the second catalyst is 1:10-50.
According to a preferred embodiment of the present invention, the organic solvent is used in an amount of 10 to 800ml relative to 15mg of the carboxyl group-containing multi-walled carbon nanotubes.
According to a preferred embodiment of the present invention, the organic solvent is selected from at least one of dichloromethane, dichlorobenzene, trichloroethylene and ethanol, preferably dichloromethane.
In the invention, the solid-liquid separation mode is suction filtration, and the solvent selected for washing comprises CH 2Cl2, absolute ethyl alcohol and deionized water for washing, so that the specific operation of the step has no special requirement, and the washing can be performed by referring to the prior art.
In the present invention, the carboxyl group-containing multiwall carbon nanotubes may be conventional carboxyl group-containing multiwall carbon nanotubes in the art, and according to a preferred embodiment of the present invention, the method for preparing the carboxyl group-containing multiwall carbon nanotubes comprises reacting the multiwall carbon nanotubes with an acidic solution, separating, and drying.
The acidic solution is selected from at least one of concentrated nitric acid and/or concentrated sulfuric acid, preferably, the concentration of the concentrated nitric acid is 60-68wt% and the concentration of the concentrated sulfuric acid is 60-80wt%.
According to a preferred embodiment of the invention, the multiwall carbon nanotubes have a diameter of less than 50nm, for example 45nm, 40nm, 30nm, 20nm, 15nm, 10nm, preferably 10-20nm.
In the present invention, the ratio of the amount of the carbon nanotubes to the amount of the acidic solution is not particularly limited, and may be determined according to actual requirements.
According to a preferred embodiment of the invention, the acidic solution is a mixed solution of 60-68wt% of concentrated nitric acid and concentrated sulfuric acid, and the volume ratio of the concentrated nitric acid to the concentrated sulfuric acid in the mixed solution is preferably 1:3-5.
In the preparation step of the multi-wall carbon nanotube solution, after the carbon nanotubes are respectively mixed with the acidic solution and the polymer group-containing solution, the steps of solution suction filtration and deionized water cleaning are also needed before drying, and the steps have no special requirements and can be carried out according to the prior art.
In a second aspect, the invention provides a method for preparing a sizing agent, which comprises mixing the raw materials in the composition of the invention.
According to a preferred embodiment of the present invention, the method for preparing the sizing agent comprises (1) mixing the modified multi-walled carbon nanotubes with a solvent;
(2) Mixing the product obtained in the step (1) with epoxy resin;
preferably, in the step (1), the mixing mode is ultrasonic mixing, and the ultrasonic conditions comprise the temperature of 20-35 ℃ and the ultrasonic time of 4-8 hours.
According to a preferred embodiment of the present invention, in step (2), the product obtained in step (1) is mixed with an epoxy resin emulsion. In the present invention, the epoxy resin emulsion refers to an emulsion in which an epoxy resin and an emulsifier are dispersed in a solvent.
The third aspect of the invention provides the sizing agent prepared by the preparation method.
In a fourth aspect, the present invention provides the use of a sizing agent as described above for surface modification of fibers.
According to a preferred embodiment of the present invention, the fibers comprise carbon fibers and/or graphite fibers, preferably carbon fibers, preferably the carbon fibers comprise, but are not limited to, one or more of SCF-35S-12K carbon fibers.
According to a preferred embodiment of the invention, the amount of said fibres is between 10 and 5000g relative to 100mL of said sizing agent.
The present invention will be described in further detail with reference to the following examples in order to make the objects, technical solutions and advantages of the present invention more apparent. The specific embodiments described herein are for purposes of illustration only and are not to be construed as limiting the invention in any way. In addition, in the following description, descriptions of well-known structures and techniques are omitted so as not to unnecessarily obscure the concepts of the present disclosure. Such structures and techniques are also described in a number of publications.
The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.
The present invention will be described in detail by examples.
In the following examples, the mass of the polymer group and the mass of the oxygen-containing functional group of the multi-walled carbon nanotube in the modified multi-walled carbon nanotube were tested by TGA thermogravimetric analysis.
In the following examples, the concentrated nitric acid concentration was 68wt% and the concentrated sulfuric acid concentration was 70wt%.
Preparation example 1
(1) 50Mg of multi-wall carbon nano tube (10-20 nm) is added into 240mL of mixed acid (the volume ratio of 68wt% concentrated nitric acid to 70wt% concentrated sulfuric acid is 1:3), the mixed acid is evenly dispersed by ultrasonic treatment for 8 hours, and the obtained mixed solution is subjected to suction filtration, deionized water cleaning and freeze drying to obtain the carbon nano tube containing a large amount of carboxyl groups.
(2) 15Mg of carboxyl carbon nano tube is slowly added into 6.3g of polyethylene glycol (PEG, relative molecular mass is 4000 g/mol), and ultrasonic treatment is carried out for 4 hours, thus obtaining evenly dispersed carboxyl carbon nano tube mixed solution. Subsequently, 0.102g of 4-Dimethylaminopyridine (DMAP) and 0.399 g of N, N' -Dicyclohexylcarbodiimide (DCC) were added to the above mixed solution, and 40mL of methylene chloride (CH 2Cl2) was added thereto, followed by magnetic stirring at room temperature (25 ℃) for 24 hours to disperse them uniformly. Finally, the solution is subjected to suction filtration, CH 2Cl2, absolute ethyl alcohol and deionized water are washed, and the modified multiwall carbon nanotube is obtained through freeze drying.
The polyethylene glycol content in the modified multi-walled carbon nanotubes was 99.75wt% and the content of the oxygen functional group-containing multi-walled carbon nanotubes was 0.25wt% as determined by TGA thermogravimetric analysis.
FIG. 1 shows a transmission electron microscope of a raw material carbon nanotube and a modified multiwall carbon nanotube, wherein (a-c) is a multiwall carbon nanotube, and (d-f) is a PEG modified multiwall carbon nanotube, and as can be seen from FIG. 1, the diameter of the carbon nanotube is about 20nm, and the surface of the nanotube is smooth and the contour is clear. However, the surface of the carbon nano tube modified by the macromolecule PEG becomes rough, which further proves that the carbon nano tube is modified by the PEG.
As can be seen from fig. 2, only-OH groups are present in the infrared spectrum of the carbon nanotubes. The absorption peak of the-OH group in the infrared spectrum of the carboxyl modified carbon nano tube is increased, and simultaneously, the C=O (1640 cm -1) and the C-O (1270 cm -1) stretching vibration peak of the carboxyl and the hydroxyl occur, so that a grafting site is provided for the subsequent esterification reaction. For the infrared spectrogram of the PEG-modified carbon nanotubes, a new absorption peak was generated at 2893cm -1, corresponding to the vibration of the methylene (-CH 2 -) bond in PEG.
Example 1
The sizing agent is prepared by mixing 35 parts of epoxy resin (E51), 5 parts of emulsifier (sodium dodecyl sulfonate) and 50 parts of water at 10000 revolutions for 20 minutes to prepare an epoxy resin emulsion, mixing 2 parts of the modified multi-wall carbon nano tube of preparation example 1 with 10 parts of water, carrying out ultrasonic treatment at 25 ℃ for 6 hours, and stirring and mixing the mixture with the epoxy resin emulsion.
FIG. 3 (a) is an optical image of the sizing agent prepared in example 1 (labeled CNT-g-PEG) after being left for 0 days, and FIG. 3 (b) is an optical image of the sizing agent prepared in example 1 after being left for 30 days, and as can be seen from FIG. 3, the sizing agent has little precipitate after being left for 30 days, and good dispersibility and stability can be maintained.
Preparation example 2
(1) 50Mg of multi-wall carbon nano tube (10-20 nm) is added into 240ml of mixed acid (volume ratio is 1:3) solution of concentrated nitric acid and concentrated sulfuric acid, and the mixed solution is subjected to ultrasonic treatment for 8 hours to be uniformly dispersed, and the obtained mixed solution is subjected to suction filtration, deionized water cleaning and freeze drying to obtain the carbon nano tube containing a large amount of carboxyl groups.
(2) 15Mg of carboxyl carbon nano tube is slowly added into 3.3g of PEG (relative molecular mass is 4000 g/mol), and ultrasonic treatment is carried out for 4 hours, thus obtaining a uniformly dispersed carboxyl carbon nano tube mixed solution. Subsequently, 0.102g of 4-Dimethylaminopyridine (DMAP) and 0.399 g of N, N' -Dicyclohexylcarbodiimide (DCC) were added to the above mixed solution, 40mL of methylene chloride CH 2Cl2 was added thereto, and the mixture was magnetically stirred at room temperature for 24 hours to uniformly disperse the mixture. Finally, the solution is subjected to suction filtration, CH 2Cl2, absolute ethyl alcohol and deionized water are washed, and the modified multiwall carbon nanotube is obtained through freeze drying.
The preparation method described in example 1 increases the proportion of PEG and increases the-CH 2 -functional group on the surface of the multiwall carbon nanotube. The content of polyethylene glycol in the modified multi-walled carbon nanotubes was 99.5wt% and the content of the multi-walled carbon nanotubes containing oxygen functional groups was 0.5wt% as determined by TGA thermogravimetric analysis.
Example 2
40 Parts of epoxy resin (E51), 5 parts of emulsifier (sodium dodecyl sulfonate) and 45 parts of water are stirred at 10000 revolutions for 20 minutes to prepare an epoxy resin emulsion, 2 parts of the modified multi-wall carbon nano tube of preparation example 2 are mixed with 10 parts of water, ultrasonic treatment is carried out at 25 ℃ for 6 hours, and stirring and mixing are carried out with the epoxy resin emulsion to obtain the sizing agent. The optical image of the sizing agent after 30 days is similar to that of fig. 3 (b), and the sizing agent hardly precipitates after 30 days, and can still maintain good dispersibility and stability.
Preparation example 3
50Mg of multi-wall carbon nano tube (10-20 nm) is added into 240ml of mixed acid (volume ratio is 1:5) solution of concentrated nitric acid and concentrated sulfuric acid, and the mixed solution is subjected to ultrasonic treatment for 8 hours to be uniformly dispersed, and the obtained mixed solution is subjected to suction filtration, deionized water cleaning and freeze drying to obtain the carbon nano tube containing a large amount of carboxyl groups.
15Mg of carboxyl carbon nano tube is slowly added into 1.5g of PEG (relative molecular mass is 4000 g/mol), and ultrasonic treatment is carried out for 6 hours, thus obtaining a uniformly dispersed carboxyl carbon nano tube mixed solution. Subsequently, 0.102g of 4-Dimethylaminopyridine (DMAP) and 0.399 g of N, N' -Dicyclohexylcarbodiimide (DCC) were added to the above mixed solution, 40mL of methylene chloride CH 2Cl2 was added thereto, and the mixture was magnetically stirred at room temperature for 24 hours to uniformly disperse the mixture. Finally, the solution is subjected to suction filtration, CH 2Cl2, absolute ethyl alcohol and deionized water, and the multi-wall carbon nano tube containing a large amount of carboxyl and high molecular functional groups is obtained through freeze drying.
The preparation method described in example 1 increases the proportion of concentrated sulfuric acid and PEG, and increases the hydroxyl and-CH 2 -functional groups on the surface of the multi-walled carbon nanotube. The content of polyethylene glycol in the modified multi-wall carbon nano tube is 99wt% and the content of the multi-wall carbon nano tube containing oxygen functional groups is 1wt% as measured by TGA thermogravimetric analysis.
Example 3
30 Parts of epoxy resin (E51), 5 parts of emulsifier (sodium dodecyl sulfonate) and 55 parts of water are stirred at 10000 revolutions for 20 minutes to prepare an epoxy resin emulsion, 1 part of modified multi-wall carbon nano tube of preparation example 3 is mixed with 10 parts of water, ultrasonic treatment is carried out at 25 ℃ for 6 hours, and stirring and mixing are carried out with the epoxy resin emulsion to obtain the sizing agent. The optical image of the sizing agent after 30 days is similar to that of fig. 3 (b), and the sizing agent hardly precipitates after 30 days, and can still maintain good dispersibility and stability.
Preparation example 4
(1) 50Mg of multi-wall carbon nano tube (10-20 nm) is added into 240mL of mixed acid (the volume ratio of 68wt% concentrated nitric acid to 70wt% concentrated sulfuric acid is 1:3), the mixed acid is evenly dispersed by ultrasonic treatment for 8 hours, and the obtained mixed solution is subjected to suction filtration, deionized water cleaning and freeze drying to obtain the carbon nano tube containing a large amount of carboxyl groups.
(2) 15Mg of carboxyl carbon nanotube, 0.78g of polyvinyl alcohol (relative molecular mass: 33000 g/mol), 0.102g of 4-Dimethylaminopyridine (DMAP) and 0.399 g of N, N' -Dicyclohexylcarbodiimide (DCC) were added to 40mL of methylene chloride (CH 2Cl2), and the mixture was magnetically stirred at room temperature for 24 hours to uniformly disperse the mixture. Finally, the solution is subjected to suction filtration, CH 2Cl2, absolute ethyl alcohol and deionized water are washed, and the modified multiwall carbon nanotube is obtained through freeze drying.
The content of polyvinyl alcohol in the modified multi-walled carbon nanotubes was 98wt% and the content of the multi-walled carbon nanotubes having an oxygen-containing functional group was 2wt% as determined by TGA thermogravimetric analysis.
Example 4
The procedure of example 1 was followed, except that the modified multi-walled carbon nanotube prepared in preparation example 4 was used instead of the modified multi-walled carbon nanotube prepared in preparation example 1, with the remaining conditions being the same as in example 1. The optical image of the sizing agent after 30 days is similar to that of fig. 3 (b), and the sizing agent hardly precipitates after 30 days, and can still maintain good dispersibility and stability.
Preparation example 5
(1) 50Mg of multi-wall carbon nano tube (10-20 nm) is added into 240mL of mixed acid (the volume ratio of 68wt% concentrated nitric acid to 70wt% concentrated sulfuric acid is 1:3), the mixed acid is evenly dispersed by ultrasonic treatment for 8 hours, and the obtained mixed solution is subjected to suction filtration, deionized water cleaning and freeze drying to obtain the carbon nano tube containing a large amount of carboxyl groups.
(2) Slowly adding 15mg of carboxyl carbon nano tube into 160mg of polyethylene glycol (PEG, relative molecular mass is 4000 g/mol), and performing ultrasonic treatment for 4 hours to obtain a uniformly dispersed carboxyl carbon nano tube mixed solution. Subsequently, 0.102g of 4-Dimethylaminopyridine (DMAP) and 0.399 g of N, N' -Dicyclohexylcarbodiimide (DCC) were added to the above mixed solution, 40mL of methylene chloride (CH 2Cl2) was added thereto, and the mixture was magnetically stirred at room temperature for 24 hours to uniformly disperse the mixture. Finally, the solution is subjected to suction filtration, CH 2Cl2, absolute ethyl alcohol and deionized water are washed, and the modified multiwall carbon nanotube is obtained through freeze drying.
The content of polyethylene glycol in the modified multi-wall carbon nanotube was 90wt% and the content of the multi-wall carbon nanotube containing an oxygen functional group was 10wt% as measured by TGA thermogravimetric analysis.
Example 5
The procedure of example 1 was followed, except that the modified multi-walled carbon nanotube prepared in preparation example 5 was used instead of the modified multi-walled carbon nanotube prepared in preparation example 1, with the remaining conditions being the same as in example 1. The optical image of the sizing agent after 30 days is similar to that of fig. 3 (b), and the sizing agent hardly precipitates after 30 days, and can still maintain good dispersibility and stability.
Preparation example 6
(1) 50Mg of multi-wall carbon nano tube (10-20 nm) is added into 240mL of mixed acid (the volume ratio of 68wt% concentrated nitric acid to 70wt% concentrated sulfuric acid is 1:3), the mixed acid is evenly dispersed by ultrasonic treatment for 8 hours, and the obtained mixed solution is subjected to suction filtration, deionized water cleaning and freeze drying to obtain the carbon nano tube containing a large amount of carboxyl groups.
(2) Slowly adding 15mg of carboxyl carbon nano tube into 100mg of polyethylene glycol (PEG, relative molecular mass is 4000 g/mol), and performing ultrasonic treatment for 4 hours to obtain a uniformly dispersed carboxyl carbon nano tube mixed solution. Subsequently, 0.102g of 4-Dimethylaminopyridine (DMAP) and 0.399 g of N, N' -Dicyclohexylcarbodiimide (DCC) were added to the above mixed solution, 40mL of methylene chloride (CH 2Cl2) was added thereto, and the mixture was magnetically stirred at room temperature for 24 hours to uniformly disperse the mixture. Finally, the solution is subjected to suction filtration, CH 2Cl2, absolute ethyl alcohol and deionized water are washed, and the modified multiwall carbon nanotube is obtained through freeze drying.
The modified multi-walled carbon nanotubes were 85wt% polyethylene glycol and 15wt% oxygen functional group containing multi-walled carbon nanotubes as determined by TGA thermogravimetric analysis.
Example 6
The procedure of example 1 was followed, except that the modified multi-walled carbon nanotube prepared in preparation example 6 was used instead of the modified multi-walled carbon nanotube prepared in preparation example 1, with the remaining conditions being the same as in example 1. The optical image of the sizing agent after 30 days is similar to that of fig. 3 (b), and the sizing agent hardly precipitates after 30 days, and can still maintain good dispersibility and stability.
Preparation example 7
50Mg of multi-wall carbon nano tube (10-20 nm) is added into 240ml of mixed acid (volume ratio is 1:5) solution of concentrated nitric acid and concentrated sulfuric acid, and the mixed solution is subjected to ultrasonic treatment for 8 hours to be uniformly dispersed, and the obtained mixed solution is subjected to suction filtration, deionized water cleaning and freeze drying to obtain the carbon nano tube containing a large amount of carboxyl groups.
15Mg of carboxyl carbon nano tube is slowly added into 1.5g of polyvinylpyrrolidone (the relative molecular mass is 10000 g/mol), and ultrasonic treatment is carried out for 6 hours, thus obtaining evenly dispersed carboxyl carbon nano tube mixed solution. Subsequently, 0.102g of 4-Dimethylaminopyridine (DMAP) and 0.399 g of N, N' -Dicyclohexylcarbodiimide (DCC) were added to the above mixed solution, 40mL of methylene chloride CH 2Cl2 was added thereto, and the mixture was magnetically stirred at room temperature for 24 hours to uniformly disperse the mixture. Finally, the solution is subjected to suction filtration, CH 2Cl2, absolute ethyl alcohol and deionized water, and the multi-wall carbon nano tube containing a large amount of carboxyl and high molecular functional groups is obtained through freeze drying.
The modified multi-walled carbon nanotubes were 99wt% polyvinylpyrrolidone and 1wt% in the oxygen functional group-containing multi-walled carbon nanotubes as determined by TGA thermogravimetric analysis.
Example 7
The procedure of example 1 was followed, except that the modified multi-walled carbon nanotube prepared in preparation example 7 was used instead of the modified multi-walled carbon nanotube prepared in preparation example 1, with the remaining conditions being the same as in example 1. The optical image of the sizing agent after 30 days is similar to that of fig. 3 (b), and the sizing agent hardly precipitates after 30 days, and can still maintain good dispersibility and stability.
Comparative example 1
Mixing 35 parts of epoxy resin (E51), 5 parts of emulsifier (sodium dodecyl sulfonate) and 50 parts of water at 10000 revolutions for 20 minutes to prepare epoxy resin emulsion, mixing 2 parts of multi-wall carbon nano tubes (10-20 nm) with 10 parts of water, carrying out ultrasonic treatment at 25 ℃ for 6 hours, and stirring and mixing with the epoxy resin emulsion to obtain sizing agent.
Fig. 3 (a) is a sizing agent (labeled CNT) prepared in comparative example 1, which is placed for 0 days, fig. 3 (b) is a sizing agent prepared in comparative example 1, which is placed for 30 days, and fig. 3 shows that carbon nanotubes are almost precipitated at the bottom in the sizing agent after being placed for 30 days.
Comparative example 2
(1) 50Mg of multi-wall carbon nano tube (10-20 nm) is added into 240mL of mixed acid (the volume ratio of 68wt% concentrated nitric acid to 70wt% concentrated sulfuric acid is 1:3), the mixed acid is evenly dispersed by ultrasonic treatment for 8 hours, and the obtained mixed solution is subjected to suction filtration, deionized water cleaning and freeze drying to obtain the carbon nano tube containing carboxyl.
(2) Mixing 35 parts of epoxy resin (E51), 5 parts of emulsifier (sodium dodecyl sulfonate) and 50 parts of water at 10000 revolutions for 20 minutes to prepare epoxy resin emulsion, mixing 2 parts of carbon nano tube containing carboxyl with 10 parts of water, performing ultrasonic treatment at 25 ℃ for 6 hours, and stirring and mixing with the epoxy resin emulsion to obtain sizing agent. In the sizing agent after 30 days, the carbon nanotubes were almost precipitated at the bottom.
Comparative example 3
(1) 50Mg of multi-wall carbon nano tube (10-20 nm) is added into 240mL of mixed acid (the volume ratio of 68wt% concentrated nitric acid to 70wt% concentrated sulfuric acid is 1:3), the mixed acid is evenly dispersed by ultrasonic treatment for 8 hours, and the obtained mixed solution is subjected to suction filtration, deionized water cleaning and freeze drying to obtain the carbon nano tube containing carboxyl.
(2) Mixing 35 parts of epoxy resin (E51), 5 parts of emulsifier (sodium dodecyl sulfonate) and 50 parts of water at 10000 revolutions for 20 minutes to prepare epoxy resin emulsion, mixing 0.2 part of carbon nano tube containing carboxyl, 1.8 parts of polyethylene glycol and 10 parts of water, carrying out ultrasonic treatment at 25 ℃ for 6 hours, and stirring and mixing with the epoxy resin emulsion to obtain sizing agent. In the sizing agent after 30 days, the carbon nanotubes were almost precipitated at the bottom.
Test case
Preparing sizing carbon fiber:
The sizing agents of the examples and the comparative examples are respectively put into a sizing tank, unglued carbon fibers are immersed in the sizing agent and pass through the sizing tank at 0.5m/min, the sizing time is 1min, the redundant sizing agent of the carbon fibers out of the tank is extruded, and then the sized carbon fibers are dried at a gradient temperature of 100 ℃,130 ℃ and 160 ℃.
Preparing a sizing carbon fiber/epoxy unidirectional composite spline and testing the interlayer shear strength of the spline, comprising the following steps:
(1) Uniformly mixing epoxy resin (model E51) and a curing agent (triethylene tetramine) according to a mass ratio of 10:1 to prepare an epoxy resin matrix;
(2) Uniformly coating resin on unidirectional sizing carbon fiber tows, flatly laying the unidirectional sizing carbon fiber tows in a die, wherein the size is 200 x 10 x 2mm, layering 28 layers, and firmly fixing the unidirectional sizing carbon fiber tows by using a clamp, so that the resin fully infiltrates the carbon fibers, and eliminating bubbles in the die;
(3) Placing the sample strip in an oven, and curing at 80 ℃ for 2 hours;
(4) Cooling to room temperature, and demolding to obtain a composite material spline;
(5) The interlayer shear strength of the composite bars was measured on a wire-bonding tester (5566A) using the standard ISO 14130:1991 short beam method. The test results are shown in Table 1.
TABLE 1
| Numbering device | Interlaminar shear strength (MPa) |
| Example 1 | 89 |
| Example 2 | 90 |
| Example 3 | 88 |
| Example 4 | 89 |
| Example 5 | 88 |
| Example 6 | 82 |
| Example 7 | 85 |
| Comparative example 1 | 72 |
| Comparative example 2 | 75 |
| Comparative example 3 | 77 |
The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, a number of simple variants of the technical solution of the invention are possible, including combinations of the individual technical features in any other suitable way, which simple variants and combinations should likewise be regarded as being disclosed by the invention, all falling within the scope of protection of the invention.
Claims (10)
1. The sizing agent raw material composition is characterized by comprising epoxy resin, modified multi-wall carbon nano tubes and a solvent, wherein the modified multi-wall carbon nano tubes are multi-wall carbon nano tubes containing macromolecule groups and oxygen-containing functional groups;
the polymer group is selected from one or more of polyethylene glycol, polyvinylpyrrolidone and polyvinyl alcohol;
the oxygen-containing functional group is selected from one or more of carboxyl, hydroxyl and ester groups.
2. The composition of claim 1, wherein,
The composition comprises 30-40 parts of epoxy resin, 0.01-2 parts of modified multi-wall carbon nano tube and 40-80 parts of solvent.
3. The composition according to claim 1 or 2, wherein,
The polymer group accounts for 10 to 99.9wt%, preferably 85 to 99.75wt%, more preferably 90 to 99.75wt%, and/or the modified multi-walled carbon nanotube
The oxygen-containing functional group-containing multi-wall carbon nanotubes comprise 0.1 to 90wt%, preferably 0.25 to 15wt%, more preferably 0.25 to 10wt%, and/or the mass of the modified multi-wall carbon nanotubes
Polyvinylpyrrolidone having a relative molecular weight of 2000-50000g/mol, and/or
The relative molecular mass of the polyvinyl alcohol is 2000-50000g/mol, and/or
The relative molecular weight of polyethylene glycol is 2000-50000g/mol.
4. The composition of any of claims 1-3, wherein the method of preparing the modified multiwall carbon nanotubes comprises:
In the presence of a first catalyst, a second catalyst and an organic solvent, contacting the multi-wall carbon nano tube containing carboxyl with a high polymer material, carrying out solid-liquid separation, washing and drying;
the high polymer material is selected from one or more of polyethylene glycol group, polyvinylpyrrolidone and polyvinyl alcohol;
The first catalyst is selected from 2-dimethylaminopyridine and/or N-hydroxysuccinimide, preferably 2-dimethylaminopyridine;
The second catalyst is selected from N, N dicyclohexylcarbodiimide and/or 1-ethyl- (3-dimethylaminopropyl) carbodiimide hydrochloride, preferably N, N dicyclohexylcarbodiimide.
5. The composition of claim 4, wherein,
The contacting conditions include a temperature of 20-35 ℃ and a contacting time of 2-48 hours, and/or
The mass ratio of the carboxyl group-containing multiwall carbon nanotubes to the polymer material is 1:5-500, preferably 1:9-450, and/or
The mass ratio of the carboxyl group-containing multiwall carbon nanotubes to the first catalyst is 1:3-10, and/or
The mass ratio of the carboxyl group-containing multiwall carbon nanotubes to the second catalyst is 1:10-50, and/or
The dosage of the organic solvent is 10-800ml relative to 15mg of the multi-wall carbon nano tube containing carboxyl;
and/or
The organic solvent is selected from at least one of dichloromethane, dichlorobenzene, trichloroethylene and ethanol, preferably dichloromethane.
6. The composition according to claim 4 or 5, wherein the method for preparing the carboxyl group-containing multi-walled carbon nanotubes comprises reacting multi-walled carbon nanotubes with an acidic solution, separating, and drying;
The acidic solution is at least one of concentrated nitric acid and/or concentrated sulfuric acid, preferably a mixed solution of 60-68wt% of concentrated nitric acid and 60-80wt% of concentrated sulfuric acid, wherein the volume ratio of the concentrated nitric acid to the concentrated sulfuric acid in the mixed solution is 1:3-5;
Preferably, the diameter of the multi-walled carbon nanotubes is less than 50nm, preferably 10-20nm.
7. The composition according to any one of claim 1 to 6, wherein,
The epoxy resin is selected from E51 type epoxy resin and/or bisphenol A type epoxy resin E44, and/or
The solvent is water, and/or
The composition further comprises an emulsifier, wherein the content of the emulsifier is 1-20wt% of the epoxy resin;
More preferably the emulsifier is selected from one or more of the alkyl sulphonates.
8. A process for preparing a sizing agent, which comprises mixing the raw materials of the composition according to any one of claims 1 to 7;
preferably, the preparation method of the sizing agent comprises the following steps:
(1) Mixing the modified multiwall carbon nanotubes with a solvent;
(2) Mixing the product obtained in the step (1) with an epoxy resin emulsion;
preferably, in the step (1), the mixing mode is ultrasonic mixing, and the ultrasonic conditions comprise the temperature of 20-35 ℃ and the ultrasonic time of 4-8 hours.
9. The sizing agent prepared by the preparation method of claim 8.
10. Use of the sizing agent of claim 9 for surface modification of fibers.
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| Publication Number | Publication Date |
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| CN120776589A true CN120776589A (en) | 2025-10-14 |
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