CN113024141B - Modified carbon fiber, preparation method thereof and modified carbon fiber reinforced cement-based material - Google Patents
Modified carbon fiber, preparation method thereof and modified carbon fiber reinforced cement-based material Download PDFInfo
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- CN113024141B CN113024141B CN202110243494.6A CN202110243494A CN113024141B CN 113024141 B CN113024141 B CN 113024141B CN 202110243494 A CN202110243494 A CN 202110243494A CN 113024141 B CN113024141 B CN 113024141B
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B20/00—Use of materials as fillers for mortars, concrete or artificial stone according to more than one of groups C04B14/00 - C04B18/00 and characterised by shape or grain distribution; Treatment of materials according to more than one of the groups C04B14/00 - C04B18/00 specially adapted to enhance their filling properties in mortars, concrete or artificial stone; Expanding or defibrillating materials
- C04B20/10—Coating or impregnating
- C04B20/12—Multiple coating or impregnating
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
- C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
- C04B28/04—Portland cements
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2201/00—Mortars, concrete or artificial stone characterised by specific physical values
- C04B2201/50—Mortars, concrete or artificial stone characterised by specific physical values for the mechanical strength
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/91—Use of waste materials as fillers for mortars or concrete
Abstract
The invention discloses modified carbon fibers, a preparation method thereof and a modified carbon fiber reinforced cement-based material. The modified carbon fiber is carbon fiber with nano silicon dioxide and carbon nano tubes grown in situ on the surface. The preparation method of the modified carbon fiber comprises the following steps: (1) removing the epoxy coating on the surface of the carbon fiber; (2) surface oxidation of the carbon fibers; (3) growing nano silicon dioxide on the surface of the carbon fiber with oxidized surface in situ; (4) growing the carbon nano tube on the surface of the product obtained in the step (3) in situ. According to the invention, the nano-silica and the carbon nano-tube are simultaneously grown on the surface of the carbon fiber in situ, the modified carbon fiber combines the volcanic ash effect of the nano-silica with the bridging nucleation effect of the nano-carbon tube, and is doped into the cement-based material, so that the interface strength of the carbon fiber and the cement-based material can be obviously improved, and the modified carbon fiber fills the pores of the cement-based material, so that the structure is more compact, and the early shrinkage performance of the cement-based material is effectively improved.
Description
Technical Field
The invention relates to a modified carbon fiber, a preparation method thereof and a modified carbon fiber reinforced cement-based material, belonging to the technical field of carbon fiber modification.
Background
The cement-based material is the most widely used traditional material, and has the advantages of low price, good fire resistance and capability of being poured into various shapes according to templates. However, the conventional cement-based materials are brittle materials, and micro cracks and macro cracks are developed due to factors such as early self shrinkage, temperature drop shrinkage and drying shrinkage. For very long basement structures and roofing structures, cracking due to shrinkage is much more likely. The durability of cement-based materials tends to deteriorate when cracking occurs.
The nano material has the characteristics of small particle size, large surface energy and the like, so that the microstructure of the cement-based material is more compact, and the performance of the cement-based material can be improved. Among them, carbon fiber is used to improve cement-based materials due to its advantages of low density, high specific strength and modulus, and chemical corrosion resistance. Research shows that the carbon fiber can effectively improve the strength, especially the tensile strength, of the cement material, and therefore, the shrinkage performance and the durability of the cement-based material can be improved. However, whether carbon fiber can effectively improve the performance of cement-based materials depends on the interfacial bonding strength between the carbon fiber and the cement matrix. The good interface bonding can effectively transfer load, thereby improving the mechanical property of the cement-based material. However, the untreated carbon fiber has a smooth surface and lower surface energy, has weak interfacial adhesion with a cement matrix and small interfacial slip resistance, and is easy to separate from the matrix under the action of external force, so that the effect of the carbon fiber modified cement-based material is weakened. This drawback severely limits the use of carbon fibers in modified cement-based materials. Therefore, it is necessary to modify the surface of the carbon fibers to improve the interface bonding strength between the carbon fibers and the cement matrix, thereby improving the effect of modifying the cement-based material with the carbon fibers.
On the other hand, other nano materials can also effectively improve the performance of the cement-based material and are widely applied to the cement-based material. Currently, nano-silica and carbon nanotubes are more widely used. The nano-silica has good particle filling effect and pozzolanic activity, and can be used as a nucleation site for cement hydration to promote cement hydration in the initial stage of cement hydration. The carbon nano tube can obviously improve the mechanical property of the cement-based material due to the excellent mechanical property of the carbon nano tube. However, the nano-silica and the carbon nano-tube are easy to agglomerate and difficult to uniformly disperse due to the high ion concentration of the cement paste. Therefore, it is difficult to sufficiently exert the modifying effect on the cement-based material.
On the other hand, if the advantages of the cement-based reinforced nano material can be exerted, the existing problems can be overcome, the performance of the cement-based material can be effectively improved, and the effect of the modified cement-based material can be fully exerted.
Disclosure of Invention
The purpose of the invention is as follows: aiming at the problems of low interface bonding strength with a cement matrix, poor dispersibility in the cement matrix and the like of the existing cement-based reinforcing material, the invention provides a modified carbon fiber capable of effectively enhancing the interface bonding strength with the cement-based material, and provides a preparation method of the modified carbon fiber; in addition, the invention also provides the modified carbon fiber reinforced cement-based material.
The technical scheme is as follows: the modified carbon fiber is a carbon fiber with the surface in-situ grown with nano silicon dioxide and carbon nano tubes.
The preparation method of the modified carbon fiber comprises the following steps:
(1) removing the epoxy coating on the surface of the carbon fiber;
(2) surface oxidation of the carbon fibers;
(3) growing nano silicon dioxide on the surface of the carbon fiber with oxidized surface in situ;
(4) growing the carbon nano tube on the surface of the product obtained in the step (3) in situ.
In the step (1), the method for removing the epoxy coating on the surface of the carbon fiber may be: and (2) putting the carbon fiber into a container filled with acetone, reacting at the temperature of 75-85 ℃, cooling to room temperature after the reaction is finished, taking out the carbon fiber, and drying at the temperature of 70-90 ℃ to obtain the carbon fiber with the epoxy coating removed on the surface. Preferably, in the step, the reaction time is 20-48 h, and the drying time is 1-3 h.
In the step (2), the surface oxidation method may be: firstly, soaking the carbon fiber obtained in the step (1) into concentrated nitric acid, heating to 70-80 ℃, reacting for 2-3 h, and taking out; and washing and drying to obtain the dried oxidized carbon fiber. Optionally, in the step, the washing step is to soak the fabric in distilled water for 5-10 min, and wash the fabric with ethanol for 3-5 times after taking out; the drying is carried out for 2-4 h at the temperature of 70-80 ℃. Preferably, the amount of concentrated nitric acid used satisfies the following proportional relationship: the volume ratio of the mass of the original carbon fiber to the concentrated nitric acid is 1g: 80-100 ml.
In the step (3), the method for in-situ growth of the nano silicon dioxide on the surface of the carbon fiber with the oxidized surface specifically comprises the following steps:
soaking the carbon fiber with the oxidized surface in a silane coupling agent solution at a constant temperature of 70 ℃ for 2-3 h, taking out, washing and drying;
secondly, putting the carbon fiber obtained in the step one into an ethanol solvent, adding an ionic surfactant CTAB, and uniformly stirring;
thirdly, adding ammonia water serving as a catalyst into the mixture obtained in the second step, and performing ultrasonic treatment for 30-90 min;
dripping ethyl orthosilicate into the mixture obtained in the step (III) under the stirring condition, and stirring and reacting for 10-12 hours at the constant temperature of 40-50 ℃ to obtain carbon fibers with nano silicon dioxide growing on the surfaces in situ;
fifthly, taking the carbon fiber with the surface in-situ grown with the nano silicon dioxide obtained in the step (iv) out of the solution, washing and drying.
In the step (i), preferably, the amount of the silane coupling agent solution satisfies the following proportional relationship: the volume ratio of the mass of the original carbon fiber to the silane coupling agent solution is 1g: 200-300 ml, wherein the silane coupling agent can be KH550 and the like; preferably, the washing is washing with ethanol for 2-3 times, and the drying is drying for 2-4 hours at 70-80 ℃. In the second step, the dosage of the ethanol satisfies the following relationship: the volume ratio of the mass of the original carbon fiber to the ethanol is preferably 1g: 400-600 ml; preferably, the mass fraction of CTAB in ethanol is 1-3%. In the step III, the volume ratio of the ammonia water to the ethanol is preferably 1: 20-25, so as to provide a reaction alkaline environment. In the step IV, the volume ratio of the ethyl orthosilicate to the ethanol is preferably 1: 12-20. In the fifth step, preferably, methanol is adopted for washing for 3-5 times, and then the drying is carried out for 2-3 hours under the condition of 70-80 ℃.
In the step (4), the method for further growing the carbon nanotube on the surface in situ comprises the following steps: and (2) uniformly mixing the carbon fiber with the surface in-situ grown with the nano-silica with the ferrocene, pouring the obtained mixture into a container, placing the container in a microwave oven, performing microwave radiation for 10-30 s, and then cooling to room temperature to obtain the carbon fiber with the surface in-situ grown with the nano-silica and the carbon nano tube. Ferrocene absorbs heat to generate the carbon nano tube, the output of the carbon nano tube is controlled by controlling the length of the microwave radiation time, the longer the microwave radiation time is, the more heat required by the growth of the carbon nano tube can be continuously provided, and the length and the number of the carbon nano tube can be improved; when the microwave radiation time is less than 10s, the growth amount of the carbon nano tube is too small, and when the microwave radiation time is more than 30s, the growth amount of the carbon nano tube is too large, the nano silicon dioxide is coated possibly, and the performance of the modified carbon fiber is deteriorated. The mass ratio of the carbon fiber with the surface in-situ grown nano-silica to the ferrocene is preferably 1: 1-3.
The modified carbon fiber reinforced cement-based material comprises a cement cementing material and the modified carbon fibers, wherein the mixing amount of the modified carbon fibers is 0.3-1.2% of the mass of the cement cementing material.
The invention principle is as follows: according to the invention, the in-situ growth of nano silicon dioxide and carbon nano tube modified carbon fiber is utilized, and firstly, acetone is utilized to remove a hydrophobic coating-an epoxy coating on the surface of the original carbon fiber, so that the carbon fiber has hydrophilicity and is convenient for subsequent reaction; then, surface oxidation is carried out on the carbon fiber by using concentrated nitric acid, on one hand, the surface of the carbon fiber is rough, heterogeneous nucleation of nano silicon dioxide and carbon nano tubes is facilitated, on the other hand, the surface of the carbon fiber is activated, the adsorption capacity of the carbon fiber on ions is improved, and in-situ growth of the nano silicon dioxide and the carbon nano tubes is promoted; in addition, because the nano silicon dioxide and the carbon nano tubes grow on the surface of the carbon fiber in situ, the nano silicon dioxide and the carbon nano tubes are combined with the carbon fiber through chemical bonds, the bonding force is strong, and the carbon fiber is difficult to fall off. Based on this, the modified carbon fiber of the present invention was obtained.
The obtained modified carbon fiber is applied to the cement-based material, and the nano silicon dioxide and the carbon nano tubes growing on the surface of the carbon fiber in situ obviously improve the roughness of the surface of the carbon fiber, so that the bonding strength of the carbon fiber and a cement matrix can be enhanced. Moreover, the nano silicon dioxide can provide nucleation sites for cement hydration, so that cement hydration products grow around the nano silicon dioxide, and the bonding of the carbon fibers and a cement matrix can be strengthened; meanwhile, the nano-silica has pozzolan activity and can react with calcium hydroxide generated by cement hydration to generate hydrated calcium silicate, which is also a process for improving the bonding strength of the carbon fiber and a cement matrix. In addition, the carbon nano tube has excellent mechanical property and bridging nucleation effect, can strengthen the cement-based material, and can effectively improve the strength of the interface transition zone of the carbon fiber and the cement matrix when the carbon nano tube grows on the surface of the carbon fiber in situ. Therefore, the nano-silica and the carbon nanotubes which grow on the surface of the carbon fiber in situ, and the carbon fiber are cooperated, so that the bonding strength of the carbon fiber and the cement matrix is efficiently improved.
In addition, the nano silicon dioxide and the carbon nano tube take the carbon fiber as a matrix, grow on the surface of the carbon fiber in situ, and can hinder the agglomeration of the nano silicon dioxide and the carbon nano tube in the preparation process by means of the steric hindrance effect of the carbon fiber, so that the dispersibility of the nano silicon dioxide and the carbon nano tube in the preparation process is improved. In addition, in the cement matrix, the nano silicon dioxide and the carbon nano tubes grown in situ can be dispersed in the cement matrix along with the matrix carbon fibers, so that the agglomeration can be reduced, and the modification effect of the nano silicon dioxide and the carbon nano tubes on the cement matrix can be fully realized.
Has the advantages that: compared with the prior art, the invention has the advantages that: (1) according to the modified carbon fiber, the nano-silica and the carbon nano-tube are simultaneously grown on the surface of the carbon fiber in situ, so that the crystal nucleus effect and the volcanic ash effect of the nano-silica are combined with the bridging nucleation effect of the carbon nano-tube, the bonding strength of the carbon fiber and a cement matrix can be obviously improved, and an interface transition region is improved; (2) according to the modified carbon fiber, the nano silicon dioxide and the carbon nano tube grow on the surface of the carbon fiber in situ, so that the dispersibility of the carbon fiber in the preparation and use processes can be improved, the effects of the nano silicon dioxide, the carbon nano tube and the carbon fiber are fully exerted, and the density of a cement-based material is improved more efficiently by the cooperation of the nano silicon dioxide, the carbon nano tube and the carbon fiber, and the early shrinkage performance and mechanical properties of the cement-based material are effectively improved.
Drawings
FIG. 1 is an SEM image (a) and an EDS image (b) of CF @ NS prepared in example 1;
FIG. 2 is an XRD pattern (a) of the starting CF and an XRD pattern (b) of the prepared CF @ NS @ CNT in example 1;
FIG. 3 is an SEM image of CF @ NS @ CNT prepared in example 1;
FIG. 4 is a TEM image of CF @ NS @ CNT prepared in example 1;
FIG. 5 is an SEM image of CF @ NS @ CNT prepared in example 2;
FIG. 6 is a scanning picture of undisturbed carbon fiber in cement paste, wherein (b) is an enlarged view of the middle square area in (a);
fig. 7 is a scanning picture of modified carbon fibers in cement paste, wherein (b) is an enlarged view of the middle square area in (a).
Note: CF @ NS @ CNT is a carbon fiber with nano-silica and carbon nanotubes grown in situ on the surface.
Detailed Description
The technical solution of the present invention is further explained with reference to the drawings and the embodiments.
The modified carbon fiber is the carbon fiber with the surface in-situ grown with the nano-silica and the carbon nano-tube, combines the volcanic ash effect of the nano-silica and the bridging nucleation effect of the nano-carbon tube, and can improve the interface bonding strength of the carbon fiber and the cement-based material and the early shrinkage performance of the cement-based material.
Example 1
The preparation process of the modified carbon fiber in the embodiment is as follows:
(1) removal of epoxy coating on carbon fiber surface
And (2) putting 1g of carbon fiber into a Soxhlet extractor filled with acetone, cleaning with acetone at 75 ℃ to remove impurities on the surface of the carbon fiber for 24 hours, cooling to room temperature after the reaction is finished, taking out the carbon fiber, and drying at 70 ℃ for 2 hours to obtain the carbon fiber with the epoxy coating removed on the surface.
(2) Oxidation of carbon fibers
Step 21, soaking the carbon fiber obtained in the step 1 in concentrated nitric acid, wherein the volume ratio of the mass of the carbon fiber to the concentrated nitric acid is 1g:100ml, heating to 80 ℃, reacting for 3 hours, and then taking out the carbon fiber in the concentrated nitric acid;
and step 22, soaking the carbon fiber obtained in the step 21 in distilled water for 5min, taking out, washing with ethanol for 3 times, and drying at the temperature of 70 ℃ for 3h to obtain the dried oxidized carbon fiber.
(3) In-situ growth of nano silicon dioxide on carbon fiber surface
Step 31, soaking the carbon fiber obtained in the step 22 in a KH550 solution (the mass fraction is 3%, and the volume ratio of the mass of the carbon fiber to the KH550 solution is 1g:200ml), and soaking for 3 hours at a constant temperature of 70 ℃; then taking out the carbon fiber, washing the carbon fiber for 3 times by using ethanol, and drying the carbon fiber for 2 hours at the temperature of 70 ℃;
step 32, putting the carbon fiber obtained in the step 31 into an analytically pure ethanol solvent (the volume ratio of the mass of the carbon fiber to the ethanol is 1g:500ml), and then adding the ionic surfactant CTAB with the mass fraction of 1% (mass fraction of CTAB in an ethanol solution) into the mixture and uniformly stirring;
step 33, adding ammonia water (ammonia water: ethanol volume ratio is 1:25) as a catalyst to the mixture obtained in step 32 to provide an alkaline reaction environment and performing ultrasonic treatment for 30 min;
step 34, dropwise adding tetraethoxysilane (the volume ratio of tetraethoxysilane to ethanol is 1:12.5) into the mixture obtained in the step 33 under the action of a magnetic stirrer, and slowly stirring for 10 hours at the constant temperature of 45 ℃;
step 35, taking the carbon fiber with the surface in-situ grown nano-silica obtained in the step 34 out of the solution, washing the carbon fiber with the surface in-situ grown nano-silica for 3 times by using methanol, and drying the carbon fiber for 3 hours at the temperature of 70 ℃ to obtain dry carbon fiber (CF @ NS) with the surface in-situ grown nano-silica;
the SEM image and EDS image of CF @ NS obtained after the above steps are shown in FIG. 1. From the SEM image, a layer of substance is grown in situ on the surface of the carbon fiber, and from the EDS, silicon dioxide is grown in situ on the surface of the carbon fiber.
(4) In-situ growth of carbon nanotube on carbon fiber surface
Step 41, uniformly mixing the carbon fiber with the surface in-situ grown nano-silica obtained in the step 35 and ferrocene according to the mass ratio of 1: 1;
and 42, pouring the mixture obtained in the step 41 into a crucible, placing the crucible in a microwave oven, radiating the crucible by microwave for 30s, and cooling the crucible to room temperature to obtain the carbon fiber (CF @ NS @ CNT) with the surface on which the nano silicon dioxide and the carbon nano tube grow in situ.
Fig. 2 (a) and (b) are XRD patterns of untreated carbon fibers CF and CF @ NS @ CNT, respectively. As can be seen from fig. 2, CF has a diffraction peak of graphite at 26 °, amorphous carbon at 20 to 25 ° and 40 to 45 °, CF @ NS @ CNT is obtained by a sol-gel method and a microwave radiation method, and has a diffraction peak of iron at 45 °, amorphous carbon and amorphous silica at 20 to 25 °, amorphous carbon at 40 to 45 °, and a diffraction peak of crystalline silica in addition to a diffraction peak of graphite at 26 °, so that silica coated on the surface of carbon fiber after microwave radiation is obtained without crystallization.
As shown in fig. 3, the SEM picture of CF @ NS @ CNT prepared in this example shows that nano-silica and carbon nanotubes grow on the surface of CF @ NS, and the growth of carbon nanotubes is more; TEM image of the obtained CF @ NS @ CNT is shown in FIG. 4, and hollow tubular carbon nanotubes can be seen.
Example 2
The preparation process of the modified carbon fiber in the embodiment is as follows:
(1) removal of epoxy coating on carbon fiber surface
And (2) putting 1g of carbon fiber into a Soxhlet extractor filled with acetone, cleaning with acetone at 75 ℃ to remove impurities on the surface of the carbon fiber for 24 hours, cooling to room temperature after the reaction is finished, taking out the carbon fiber, and drying at 70 ℃ for 2 hours to obtain the carbon fiber with the epoxy coating removed on the surface.
(2) Oxidation of carbon fibers
Step 21, soaking the carbon fiber obtained in the step (1) into concentrated nitric acid, heating to 80 ℃, reacting for 3 hours, and taking out the carbon fiber from the concentrated nitric acid, wherein the volume ratio of the mass of the carbon fiber to the concentrated nitric acid is 1g:100 ml;
and step 22, soaking the carbon fiber obtained in the step 21 in distilled water for 5min, taking out, washing with ethanol for 3 times, and drying at the temperature of 70 ℃ for 3h to obtain the dried oxidized carbon fiber.
(3) In-situ growth of nano silicon dioxide on carbon fiber surface
Step 31, soaking the carbon fiber obtained in the step 22 in a KH550 solution (the mass fraction is 3%, and the volume ratio of the mass of the carbon fiber to the KH550 solution is 1g:200ml), and soaking for 3 hours at a constant temperature of 70 ℃; then taking out the carbon fiber, washing the carbon fiber for 3 times by using ethanol, and drying the carbon fiber for 2 hours at the temperature of 70 ℃;
step 32, putting the carbon fiber obtained in the step 31 into an analytically pure ethanol solvent, wherein the volume ratio of the mass of the carbon fiber to the ethanol is 1g:500ml, and then adding the ionic surfactant CTAB with the mass fraction of 1% (the mass fraction of CTAB in the ethanol solution) into the mixture and uniformly stirring;
step 33, adding ammonia water (ammonia water: ethanol volume ratio is 1:25) as a catalyst to the mixture obtained in step 32 to provide an alkaline reaction environment and performing ultrasonic treatment for 90 min;
step 34, dropwise adding tetraethoxysilane (the volume ratio of tetraethoxysilane to ethanol is 1:12.5) into the mixture obtained in the step 33 under the action of a magnetic stirrer, and slowly stirring for 10 hours at the constant temperature of 45 ℃;
and step 35, taking the carbon fiber with the nano-silica growing on the surface in situ obtained in the step 34 out of the solution, washing the carbon fiber with methanol for 3 times, and drying the carbon fiber for 3 hours at the temperature of 70 ℃ to obtain the dried carbon fiber (CF @ NS) with the nano-silica growing on the surface in situ.
(4) In-situ growth of carbon nanotube on carbon fiber surface
Step 41, uniformly mixing the carbon fiber with the surface in-situ grown nano-silica obtained in the step 35 and ferrocene according to a mass ratio of 1: 1;
and 42, pouring the mixture obtained in the step 41 into a crucible, placing the crucible in a microwave oven, radiating the crucible by microwave for 10s, and cooling the crucible to room temperature to obtain the carbon fiber (CF @ NS @ CNT) with the surface on which the nano silicon dioxide and the carbon nano tube grow in situ.
The SEM picture of the modified carbon fiber obtained through the above steps is shown in fig. 5. The figure shows that the surface of the carbon fiber is uniformly coated with the nano silicon dioxide and the carbon nano tubes.
The CF @ NS @ CNTs prepared in examples 1 and 2 were blended into cement cements to prepare modified carbon fiber cement mortar test pieces with the blending amounts set to 0.3%, 0.6%, 0.9%, 1.2%. In the test piece, the material mixing ratio of cement mortar is sand: cement: water is 4:2:1, sand is river sand, cement is PO42.5 cement, and water is tap water. And (3) carrying out standard maintenance on the molded test piece for 24h, then demoulding, measuring the initial length after demoulding, sequentially sealing by using a polyethylene plastic film and paraffin, and then measuring once every other day until the 7 th day is measured. The mortar test pieces were molded and tested for flexural strength according to the Cement mortar Strength test method GBT 17671-1999. The test results are given in table 1 below.
Comparative example 1
Carbon fiber cement mortar test pieces were prepared by incorporating carbon fibers as they were without any treatment into a cement binder in accordance with the method in examples. And the test pieces were tested for self-contraction properties and flexural strength properties by the methods of examples. The test results are given in table 1 below.
Comparative example 2
The cement mortar test piece is formed by the cement mortar material mixing ratio and the preparation method in the reference embodiment, and carbon fibers are not doped. And the test pieces were tested for self-contraction properties and flexural strength properties by the methods of examples. The test results are given in table 1 below.
TABLE 1 test results of self-shrinkage and flexural strength of the test pieces
As can be seen from Table 1, the modified carbon fiber of the present invention can significantly improve the shrinkage reducing effect and the flexural strength of the mortar, compared to comparative example 1, and it can be seen from the examples that the effect is the best when the fiber is added in an amount of 0.6%. Comparing fig. 6 and fig. 7, it can be seen that the surface of the undisturbed carbon fiber is smooth and is not tightly bonded to the cement-based interface; the surface of the modified carbon fiber is rough, the interface of the carbon fiber and the cement-based material can not be seen almost, the nano silicon dioxide on the surface of the modified carbon fiber reacts with calcium hydroxide generated by hydration of cement to generate hydrated calcium silicate, and the carbon nano tube plays a bridging role and is tightly wound with a hydration product, so that the interface strength of the modified carbon fiber and the cement-based material is improved, the self-shrinkage of mortar is reduced, and the breaking strength of the mortar is improved.
Claims (8)
1. The modified carbon fiber is characterized in that the surface of the modified carbon fiber is grown with nano silicon dioxide and carbon nano tubes in situ, wherein the method for growing the carbon nano tubes on the surface of the carbon fiber in situ comprises the following steps: and (2) uniformly mixing the carbon fiber with the surface in-situ grown nano-silica with ferrocene, pouring the obtained mixture into a container, placing the container in a microwave oven, performing microwave radiation for 10-30 s, and then cooling to room temperature to obtain the carbon fiber with the surface in-situ grown nano-silica and the carbon nano-tube.
2. The modified carbon fiber according to claim 1, wherein the mass ratio of the carbon fiber with the surface in-situ grown nano-silica to the ferrocene is 1: 1-3.
3. A method for producing a modified carbon fiber according to claim 1, comprising the steps of:
(1) removing the epoxy coating on the surface of the carbon fiber;
(2) surface oxidation of the carbon fibers;
(3) growing nano silicon dioxide on the surface of the carbon fiber with oxidized surface in situ;
(4) growing the carbon nano tube on the surface of the product obtained in the step (3) in situ.
4. The preparation method of the modified carbon fiber according to claim 3, wherein in the step (1), the carbon fiber is put into a container filled with acetone, the reaction is carried out at a temperature of 75-85 ℃, the reaction product is cooled to room temperature after the reaction is finished, the carbon fiber is taken out, and the drying is carried out at a temperature of 70-90 ℃ to obtain the carbon fiber with the epoxy coating removed on the surface.
5. The method for producing modified carbon fiber according to claim 3, wherein in the step (2), the surface oxidation is performed by: immersing the carbon fiber with the epoxy coating removed from the surface obtained in the step (1) into concentrated nitric acid, heating to 70-80 ℃, reacting for 2-3 h, and taking out; and washing and drying to obtain the dried carbon fiber with oxidized surface.
6. The method for preparing modified carbon fiber according to claim 3, wherein in the step (3), the method for growing nano silica on the surface in situ is as follows:
soaking the carbon fiber with the oxidized surface in a silane coupling agent solution at a constant temperature of 70 ℃ for 2-3 h, taking out, washing and drying;
secondly, putting the carbon fiber obtained in the step one into an ethanol solvent, adding an ionic surfactant CTAB, and uniformly stirring;
thirdly, adding ammonia water into the mixture obtained in the second step to serve as a catalyst, and carrying out ultrasonic treatment for 30-90 min;
dripping ethyl orthosilicate into the mixture obtained in the step (III) under the stirring condition, and stirring and reacting for 10-12 hours at the constant temperature of 40-50 ℃ to obtain carbon fibers with nano silicon dioxide growing on the surfaces in situ;
fifthly, taking the carbon fiber with the nano-silica growing on the surface in situ obtained in the step IV out of the solution, washing and drying.
7. The method for preparing the modified carbon fiber according to claim 6, wherein the volume ratio of CTAB to ethanol is 1: 10-20; the volume ratio of the ammonia water to the ethanol is 1: 20-25; the volume ratio of the ethyl orthosilicate to the ethanol is 1: 12-20.
8. The modified carbon fiber reinforced cement-based material is characterized by comprising a cement cementing material and the modified carbon fiber of claim 1, wherein the mixing amount of the modified carbon fiber is 0.3-1.2% of the mass of the cement cementing material.
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| CN202110243494.6A CN113024141B (en) | 2021-03-05 | 2021-03-05 | Modified carbon fiber, preparation method thereof and modified carbon fiber reinforced cement-based material |
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| CN202110243494.6A CN113024141B (en) | 2021-03-05 | 2021-03-05 | Modified carbon fiber, preparation method thereof and modified carbon fiber reinforced cement-based material |
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| CN113024141B true CN113024141B (en) | 2022-08-30 |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105780452A (en) * | 2014-12-26 | 2016-07-20 | 北京化工大学常州先进材料研究院 | Preparation method for growing carbon nano-tubes on continuous carbon fiber surfaces through one-step method |
| CN105908491A (en) * | 2016-05-31 | 2016-08-31 | 哈尔滨工业大学 | Device and method for preparation of continuous carbon fiber with carbon nanotubes growing on surface |
| CN106977126A (en) * | 2017-04-10 | 2017-07-25 | 哈尔滨工业大学 | A kind of preparation method having with the modified fibre of the high interface binding intensity of cement-based material |
| CN110886089A (en) * | 2019-11-19 | 2020-03-17 | 杭州超探新材料有限公司 | Preparation method of graphene and carbon nanotube in-situ growth co-modified toughened carbon fiber |
| CN111876997A (en) * | 2020-08-28 | 2020-11-03 | 山东大学 | Carbon nanotube/carbon fiber reinforcement and preparation method and application thereof |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105780452A (en) * | 2014-12-26 | 2016-07-20 | 北京化工大学常州先进材料研究院 | Preparation method for growing carbon nano-tubes on continuous carbon fiber surfaces through one-step method |
| CN105908491A (en) * | 2016-05-31 | 2016-08-31 | 哈尔滨工业大学 | Device and method for preparation of continuous carbon fiber with carbon nanotubes growing on surface |
| CN106977126A (en) * | 2017-04-10 | 2017-07-25 | 哈尔滨工业大学 | A kind of preparation method having with the modified fibre of the high interface binding intensity of cement-based material |
| CN110886089A (en) * | 2019-11-19 | 2020-03-17 | 杭州超探新材料有限公司 | Preparation method of graphene and carbon nanotube in-situ growth co-modified toughened carbon fiber |
| CN111876997A (en) * | 2020-08-28 | 2020-11-03 | 山东大学 | Carbon nanotube/carbon fiber reinforcement and preparation method and application thereof |
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