CN111662025A - Preparation method and application of carbon nanotube grafted carbon fiber multi-scale reinforcement - Google Patents

Preparation method and application of carbon nanotube grafted carbon fiber multi-scale reinforcement Download PDF

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CN111662025A
CN111662025A CN202010499256.7A CN202010499256A CN111662025A CN 111662025 A CN111662025 A CN 111662025A CN 202010499256 A CN202010499256 A CN 202010499256A CN 111662025 A CN111662025 A CN 111662025A
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carbon fiber
carbon
putting
cement
test
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刘小艳
余瑾瑶
李田雨
江波
刘力
刘彦琦
揭汉铎
李世杰
姜可伟
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Hohai University HHU
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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
    • C04B18/00—Use of agglomerated or waste materials or refuse as fillers for mortars, concrete or artificial stone; Treatment of agglomerated or waste materials or refuse, specially adapted to enhance their filling properties in mortars, concrete or artificial stone
    • C04B18/02—Agglomerated materials, e.g. artificial aggregates
    • 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
    • C04B20/02—Treatment
    • C04B20/023—Chemical treatment
    • 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
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
    • 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
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N3/20—Investigating strength properties of solid materials by application of mechanical stress by applying steady bending forces
    • 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
    • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
    • C04B2111/00991—Uses not provided for elsewhere in C04B2111/00 for testing
    • 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
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
    • D06M2101/00—Chemical constitution of the fibres, threads, yarns, fabrics or fibrous goods made from such materials, to be treated
    • D06M2101/40—Fibres of carbon

Abstract

The invention discloses a preparation method and application of a carbon nanotube grafted carbon fiber multi-scale reinforcement, wherein firstly, a multi-wall carbon nanotube is put into strong acid to realize carboxyl functional treatment; putting the carbon fiber into strong acid to realize acid oxidation; drying the treated multi-walled carbon nano-tube, then placing the multi-walled carbon nano-tube into a reaction kettle, adding ethylenediamine and N, N-dimethylformamide, carrying out ultrasonic treatment, then placing the acid-oxidized carbon fiber, and grafting the multi-walled carbon nano-tube to the multi-scale composite reinforcement on the surface of the carbon fiber through chemical connection between the multi-walled carbon nano-tube and the carbon fiber; and finally, fully drying the carbon fibers grafted with the carbon nanotubes, putting the carbon fibers into a cement-based material, and performing bending and compression tests to finally obtain the high-strength cement test block. The method and the application can effectively improve the grafting density, enhance the bonding strength between the cement and the cement base, improve the bending strength and the compressive strength of the cement test block and prolong the service life of the test block.

Description

Preparation method and application of carbon nanotube grafted carbon fiber multi-scale reinforcement
Technical Field
The invention belongs to the technical field of constructional engineering, and particularly relates to a preparation method and application of a carbon nanotube grafted carbon fiber multi-scale reinforcement.
Background
The carbon nano tube is taken as an ideal filler of the reinforcement due to the excellent performance, and the filling effect and the bridging effect of the carbon nano tube can effectively improve the interface gap in the cement and improve the compactness of the interface. However, since the carbon nanotubes often undergo "agglomeration" due to strong van der waals forces between the molecules, a certain amount of dispersant is added to disperse the carbon nanotubes in the solution.
In experiments, the carbon fibers have excellent mechanical properties, so that the flexural strength and the compressive strength of the test block can be enhanced by manufacturing the cement-based material containing the carbon fibers.
The carbon nano tube and the carbon fiber can simultaneously meet the characteristic of enhancing the mechanical property of the cement-based material, and the multi-scale reinforcement composite material has important application in engineering in recent years. The physical or chemical combination of two materials with excellent properties has become a hot spot of research in recent years.
Although cement-based test blocks used in the engineering field have good mechanical properties, the defect of high brittleness is gradually exposed along with the increase of service life and the influence of external environments such as temperature, humidity and the like, and the durability of the structure is influenced because the compression resistance reaches the peak value for a long time to generate cracks.
Disclosure of Invention
The invention aims to solve the problem that the folding strength and the compressive strength of a cement-based material in the engineering field are damaged due to long-term use, so that the durability of the structure is adversely affected, and provides a preparation method and application of a carbon nanotube grafted carbon fiber (CNTs/CF) multi-scale reinforcement.
The invention is realized by the following technical scheme:
a preparation method of a carbon nanotube grafted carbon fiber multi-scale reinforcement comprises the following steps:
step 1) processing of multi-walled carbon nanotubes: putting the multi-walled carbon nanotubes into a beaker, adding mixed acid into the beaker, putting the beaker into an ultrasonic instrument with 600W continuous pulse for ultrasonic dispersion for 15-25 min, putting the beaker into a 100 ℃ constant-temperature water bath kettle for acid oxidation treatment for 8-10 h after ultrasonic treatment, putting the treated carbon nanotubes into a microporous filter membrane for vacuum reduced pressure filtration, repeatedly washing the carbon nanotubes with deionized water until the filtrate is neutral, and putting the multi-walled carbon nanotubes into a 100-180 ℃ vacuum drying oven for drying for 24h and storing for later use;
step 2) carbon fiber treatment: putting carbon fibers into a beaker, adding mixed acid into the beaker, reacting for 8-10 h at the temperature of (20 +/-3) DEG C, repeatedly cleaning the carbon fibers by deionized water after the reaction is finished until the cleaned deionized water is neutral, and drying the treated carbon fibers in a vacuum drying oven at the temperature of 100-180 ℃ for 24h for later use;
step 3) weighing the multi-walled carbon nanotubes treated in the step 1), putting the multi-walled carbon nanotubes into a hydrothermal reaction kettle, adding an ethylenediamine solution and an N, N-dimethylformamide solution into the hydrothermal reaction kettle, ultrasonically dispersing the multi-walled carbon nanotubes in a 600W continuous pulse ultrasonic instrument for 45-60 min, then adding the carbon fibers treated in the step 2) into the reaction kettle, ultrasonically dispersing the carbon fibers for 10-15 min, and putting the reaction kettle into a vacuum drying box at 180 ℃ for drying for 48h and storing for later use;
and 4) taking the carbon fiber dried in the step 3) out of the reaction kettle, ultrasonically dispersing the carbon fiber in an ethanol solution for 15-25 min, repeatedly cleaning the carbon fiber by using the ethanol solution to fully remove redundant carbon nanotubes, ethylenediamine and N, N-dimethylformamide on the surface of the carbon fiber, and drying the carbon fiber in a vacuum drying oven at the temperature of 80-100 ℃ for 8-10 h to obtain the carbon nanotube grafted carbon fiber multi-scale reinforcement.
Preferably, the water bath kettle in the step 1) is a DF-101S heat collection type constant temperature magnetic stirrer.
Preferably, the mixed acid is prepared by mixing 65% concentrated nitric acid and 95% concentrated sulfuric acid according to the volume ratio of 3: 1.
The application of the carbon nanotube grafted carbon fiber multi-scale reinforcement prepared by the preparation method in testing the fracture resistance and the compression resistance of the cement-based material is as follows: adopting an instrument to stir cement mortar, putting the carbon nanotube grafted carbon fiber multi-scale reinforcement into the cement mortar to prepare a standard test block of 40mm multiplied by 160mm, demoulding after 24h, putting the test block into a standard curing box with the temperature of 20 +/-5 ℃ and the relative humidity of 60%, respectively putting the test blocks of 3d and 28d into a bending resistance testing machine and a pressure testing machine, testing the bending resistance and the compression resistance relative to a blank standard test block, and obtaining a conclusion.
Preferably, the instrument is a JJ-5 type cement mortar stirrer, the anti-bending tester is a DKZ-5000 electric anti-bending tester, and the compression testing machine is a NYL-300D compression testing machine.
Preferably, in the cement mortar, the mass ratio of cement to Chinese ISO standard sand is 1:3, and the water cement ratio is 0.5.
Preferably, the flexural strength value is measured in a manner such asThe following: putting the prism test piece into a clamp, enabling the side surface of the test piece to be in contact with the cylinder of the clamp when the test piece is formed, and adjusting the clamp to enable the lever to be as close to a balance position as possible when the lever is broken in time; loading at the speed of (50 +/-10) N/s until the test piece is broken, and recording the breaking load P1And calculating the flexural strength fFolding deviceThe specific formula is shown in formula 1 below:
Figure BDA0002524070060000031
in formula 1: f. ofFolding deviceThe flexural strength is expressed in MPa; p1For destructive loads, unit N; l is the central distance of the supporting cylinder, and the value is 100 mm; b. h is the width and the height of the section of the test piece respectively, and the numerical values are all 40 mm;
the arithmetic mean of the flexural strength measurements obtained on 3 of the prism test pieces was used as the measurement result.
Preferably, the compression strength value is measured by placing the smooth side surface of a half prism on a test machine, using a compression clamp for the compression test to ensure that the compression area of the test piece is 40mm × 40mm, the bottom surface of the test piece abuts against a positioning pin on the clamp, the part of the broken block exposed out of the upper pressure plate is not less than 10mm, positioning the clamp at the center of a pressure bearing plate of a press machine in the whole loading process, uniformly loading at the speed of (2400 +/-200) N/s until the broken block is damaged, and recording the damage load P2And calculating the compressive strength f of each test piecePress and pressThe specific formula is shown in formula 2 below:
Figure BDA0002524070060000032
in formula 2: f. ofPress and pressCompressive strength in MPa; p2A is the pressed area with the value of 40mm × 40 mm;
the arithmetic mean of the values of the compressive strength measurements obtained for 6 of said half prisms was taken as the measurement result.
The invention has the following beneficial effects:
the treated carbon nanotubes are connected into the modified carbon fibers through chemical bonds, so that the CNTs/CF multi-scale reinforcement is realized. The CNTs/CF multi-scale reinforcement is added into the cement-based material, and the excellent bonding property of the carbon nano tubes and the strong tensile and compression resistance of the carbon fibers can correspondingly improve the defects of the cement-based material and prolong the service life of the structure. And the preparation process is simple, has small harm to the environment, has good stability and has wide application prospect.
Detailed Description
The present invention will be described in further detail with reference to specific examples.
Example 1
A preparation method of a CNTs/CF multi-scale reinforcement body comprises the following specific steps:
(1) putting 1g of multi-walled carbon nanotubes into a 250mL round-bottom beaker, adding 100 mL of concentrated nitric acid (with the mass percent concentration of 65 percent, the same below) and 35mL of concentrated sulfuric acid (with the mass percent concentration of 95 percent, the same below), putting the beaker into an ultrasonic instrument with 600W continuous pulses for ultrasonic dispersion for 10min, putting the beaker into a 100 ℃ constant-temperature water bath (DF-101S heat collection type constant-temperature magnetic stirrer, the same below) for acid oxidation treatment for 8h after ultrasonic treatment, putting the treated carbon nanotubes into a microporous filter membrane for vacuum reduced-pressure filtration, repeatedly washing the carbon nanotubes with deionized water until the filtrate is neutral, and putting the multi-walled carbon nanotubes into a 100 ℃ vacuum drying box for drying for 24h and storing for later use.
(2) Putting 1g of carbon fiber into a 250mL round bottom beaker, adding 120mL of concentrated nitric acid and 40mL of concentrated nitric acid into the beaker, reacting for 8 hours at the temperature of 20 +/-3 ℃, repeatedly washing the carbon fiber by deionized water after the reaction is finished until the washed deionized water is neutral, and drying the treated carbon fiber in a vacuum drying oven at 100 ℃ for 24 hours for later use.
(3) Weighing 0.06g of the carbon nano tube dried in the step (1), putting the carbon nano tube into a hydrothermal reaction kettle, adding 10mL of ethylenediamine solution and 60mL of N, N-dimethylformamide solution, ultrasonically dispersing the mixture in a 600W continuous pulse ultrasonic instrument for 50min, then adding 0.7g of the carbon fiber dried in the step (2) into the reaction kettle, ultrasonically dispersing the mixture for 5min, and putting the reaction kettle into a vacuum drying box at 180 ℃ for drying for 48h and storing the mixture for later use.
(4) And (4) taking the carbon fiber dried in the step (3) out of the reaction kettle, ultrasonically dispersing the carbon fiber in an ethanol solution for 15min, repeatedly cleaning the carbon fiber by using the ethanol solution to fully take out redundant carbon nanotubes, ethylenediamine and N, N-dimethylformamide solution on the surface of the carbon fiber, and then putting the carbon fiber into a vacuum drying oven at 80 ℃ to dry for 8 h. The obtained product is the CNTs/CF multi-scale reinforcement.
Example 2
A preparation method of a CNTs/CF multi-scale reinforcement body comprises the following specific steps:
(1) putting 1g of multi-walled carbon nano-tube into a 250mL round bottom beaker, adding 100 mL of concentrated nitric acid and 35mL of concentrated sulfuric acid into the beaker, putting the beaker into an ultrasonic instrument with 600W continuous pulse for ultrasonic dispersion for 15min, putting the beaker into a 100 ℃ constant-temperature water bath kettle for acid oxidation treatment for 9h after ultrasonic treatment, putting the treated carbon nano-tube into a microporous filter membrane for vacuum reduced pressure filtration, repeatedly washing the carbon nano-tube with deionized water until the filtrate is neutral, and putting the multi-walled carbon nano-tube into a 140 ℃ vacuum drying oven for drying for 24h for later use.
(2) Putting 1g of carbon fiber into a 250mL round bottom beaker, adding 120mL of concentrated nitric acid and 40mL of concentrated nitric acid into the beaker, reacting at the temperature of 20 +/-3) ℃ for 9 hours, repeatedly washing the carbon fiber with deionized water after the reaction is finished until the washed deionized water is neutral, and drying the treated carbon fiber in a vacuum drying oven at the temperature of 140 ℃ for 24 hours for later use.
(3) Weighing 0.06g of the carbon nano tube dried in the step (1), putting the carbon nano tube into a hydrothermal reaction kettle, adding 10mL of ethylenediamine solution and 60mL of N, N-dimethylformamide solution, ultrasonically dispersing the mixture in a 600W continuous pulse ultrasonic instrument for 55min, then adding 0.7g of the carbon fiber dried in the step (2) into the reaction kettle, ultrasonically dispersing the mixture for 10min, and putting the reaction kettle into a vacuum drying box at 180 ℃ for drying for 48h and storing the mixture for later use.
(4) And (4) taking the carbon fiber dried in the step (3) out of the reaction kettle, ultrasonically dispersing the carbon fiber in an ethanol solution for 20min, repeatedly cleaning the carbon fiber by using the ethanol solution to fully take out redundant carbon nanotubes, ethylenediamine and N, N-dimethylformamide solution on the surface of the carbon fiber, and then putting the carbon fiber into a vacuum drying oven at the temperature of 90 ℃ to dry for 9 h. The obtained product is the CNTs/CF multi-scale reinforcement.
Example 3
A preparation method of a CNTs/CF multi-scale reinforcement body comprises the following specific steps:
(1) putting 1g of multi-walled carbon nano-tube into a 250mL round bottom beaker, adding 100 mL of concentrated nitric acid and 35mL of concentrated sulfuric acid into the beaker, putting the beaker into an ultrasonic instrument with 600W continuous pulse for ultrasonic dispersion for 20min, putting the beaker into a 100 ℃ constant-temperature water bath kettle for acid oxidation treatment for 10h after ultrasonic treatment, putting the treated carbon nano-tube into a microporous filter membrane for vacuum reduced pressure filtration, repeatedly washing the carbon nano-tube with deionized water until the filtrate is neutral, and putting the multi-walled carbon nano-tube into a 180 ℃ vacuum drying oven for drying for 24h for later use.
(2) Putting 1g of carbon fiber into a 250mL round bottom beaker, adding 120mL of concentrated nitric acid and 40mL of concentrated nitric acid into the beaker, reacting at the temperature of 20 +/-3) ℃ for 10 hours, repeatedly washing the carbon fiber with deionized water after the reaction is finished until the washed deionized water is neutral, and drying the treated carbon fiber in a vacuum drying oven at the temperature of 180 ℃ for 24 hours for later use.
(3) Weighing 0.06g of the carbon nano tube dried in the step (1), putting the carbon nano tube into a hydrothermal reaction kettle, adding 10mL of ethylenediamine solution and 60mL of N, N-dimethylformamide solution, ultrasonically dispersing the mixture in a 600W continuous pulse ultrasonic instrument for 60min, then adding 0.7g of the carbon fiber dried in the step (2) into the reaction kettle, ultrasonically dispersing the mixture for 15min, and putting the reaction kettle into a vacuum drying box at 180 ℃ for drying for 48h and storing the mixture for later use.
(4) And (4) taking the carbon fiber dried in the step (3) out of the reaction kettle, ultrasonically dispersing the carbon fiber in an ethanol solution for 25min, repeatedly cleaning the carbon fiber by using the ethanol solution to fully take out redundant carbon nanotubes, ethylenediamine and N, N-dimethylformamide solution on the surface of the carbon fiber, and then putting the carbon fiber into a vacuum drying oven at 100 ℃ to dry for 10 h. The obtained product is the CNTs/CF multi-scale reinforcement.
Test example 1
The CNTs/CF multi-scale reinforcement prepared in the embodiment 1-3 is used for testing the fracture resistance and the compression resistance of a cement-based material, and specifically comprises the following steps:
(a) stirring cement mortar by adopting a JJ-5 type cement mortar stirrer, wherein the mixing ratio of the cement mortar is as follows: the mass ratio of the cement to the Chinese ISO standard sand is 1:3, and the water cement ratio is 0.5. Specifically, it can be expressed as: cement: (450. + -. 2) g, China ISO standard sand: (1350. + -.5) g, mix water: (225. + -. 5) mL.
(b) And (2) putting the CNTs/CF multi-scale reinforcement into the cement mortar obtained in the step (a) to prepare a standard test block of 40mm multiplied by 160mm, demoulding after 24h, putting the test block into a standard curing box of (20 +/-5) DEG C and 60% of relative humidity, putting the test blocks of 3D and 28D into a DKZ-5000 electric bending resistance tester and an NYL-300D pressure tester respectively, measuring the bending resistance and the compression resistance relative to a blank standard test block, and obtaining a conclusion.
① the bending strength test method comprises placing a prism test piece in a fixture, contacting the side surface of the test piece with the column of the fixture, adjusting the fixture to make the lever as close to the balance position as possible when the lever is broken, loading at a speed of (50 + -10) N/s until the test piece is broken, recording the breaking load P1(N) and calculating the flexural strength fFolding device(to the nearest 0.1MPa), the specific formula is shown in the following formula 1:
Figure BDA0002524070060000061
in formula 1: f. ofFolding deviceThe flexural strength is expressed in MPa; p1For destructive loads, unit N; l is the central distance of the supporting cylinder, and the value is 100 mm; b. h is the width and the height of the section of the test piece respectively, and the numerical values are all 40 mm.
The results of measurement were obtained as the arithmetic mean of the flexural strength measurements obtained from 3 prismatic test pieces, as shown in Table 1 below.
TABLE 1 flexural strength of blank specimens and Cement specimens incorporating CNTs/CF multiscale reinforcements prepared in examples 1-3
Figure BDA0002524070060000062
Figure BDA0002524070060000071
② the compression strength test is carried out by placing the side surface (smooth surface) of a half prism on a test machine, using a compression clamp for compression test to make the compression area (A) of the test piece 40mm × mm, abutting the bottom surface of the test piece against a positioning pin on the clamp, exposing the broken block out of the upper press plate to a depth of 10mm or more, locating the clamp at the center of the press plate during the whole loading process, loading uniformly at a rate of (2400 +/-200) N/s until the broken block is destroyed, recording the destruction load P2(kN) and calculating the compressive strength f of each test piecePress and press(to the nearest 0.1MPa), the specific formula is shown in the following formula 2:
Figure BDA0002524070060000072
in formula 2: f. ofPress and pressCompressive strength in MPa; p2The breaking load is expressed in kN, and A is the pressed area, and the value is 40mm × 40 mm.
The results of measurement were obtained as the arithmetic mean of 6 measurements of the compressive strength obtained from 3 prisms (i.e., 6 half prisms) as shown in Table 2 below.
TABLE 1 compression Strength of blank test pieces and Cement test pieces incorporating CNTs/CF multiscale reinforcements prepared in examples 1-3
Figure BDA0002524070060000073
From the experimental data in tables 1 and 2, it can be seen that, compared with the blank test piece, the carbon nanotubes are grafted to the carbon fibers, and the carbon nanotubes are used as a reinforcement and put into the cement-based material, so that the compression strength and the flexural strength of the test piece can be effectively enhanced. And when the carbon nano tube is subjected to ultrasonic dispersion for 20min in a strong acid environment, the acid oxidation time is 10h, the drying temperature is 180 ℃, and the acid oxidation treatment of the carbon nano tube is the most sufficient. When the reaction time of the carbon fiber is 10 hours at room temperature and the carbon fiber after acid oxidation is put into a drying oven at 180 ℃ to be dried for 24 hours, the treatment (example 3) is the most sufficient. And (2) putting the treated carbon fiber into a solution containing acid-oxidized carbon nano tubes, ethylenediamine and medium N, N-dimethylformamide for ultrasonic dispersion for 15min, so that the carbon nano tubes and the carbon fiber are fully fused and uniformly dispersed in the solution, finally putting the grafted carbon fiber into ethanol for ultrasonic dispersion for 15min, fully taking out the excess carbon nano tubes without successfully grafting on the surface of the carbon fiber, and drying the carbon nano tubes in a drying box at 100 ℃ for 10h to fully dry the reinforcement and remove surface impurities. The reinforcement (example 3) at this time is the best in effect, and the bending strength and the compressive strength of the test piece can be greatly improved to a certain extent, and the bending strength of the test piece is improved to the greatest extent at 3d in the early stage, and the compressive lifting rate is the highest at 28 d.
At present, the research on independently placing carbon nano tubes or carbon fibers into a cement-based material in China is more, but the research on placing the carbon nano tubes or the carbon fibers into the cement-based material in a reinforcement mode by utilizing chemical construction and combination is less, the problem of interface bonding between the carbon fibers and a matrix and the problem of orientation of the carbon nano tubes in the matrix material can be effectively solved by placing the reinforcement into the cement-based material, the mechanical property of a test block can be greatly enhanced by doping two materials in a trace manner, the preparation process is simple, and the preparation method has wide application prospect for later industrial application.

Claims (8)

1. A preparation method of a carbon nanotube grafted carbon fiber multi-scale reinforcement is characterized by comprising the following steps:
step 1) processing of multi-walled carbon nanotubes: putting the multi-walled carbon nanotubes into a beaker, adding mixed acid into the beaker, putting the beaker into an ultrasonic instrument with 600W continuous pulse for ultrasonic dispersion for 15-25 min, putting the beaker into a 100 ℃ constant-temperature water bath kettle for acid oxidation treatment for 8-10 h after ultrasonic treatment, putting the treated carbon nanotubes into a microporous filter membrane for vacuum reduced pressure filtration, repeatedly washing the carbon nanotubes with deionized water until the filtrate is neutral, and putting the multi-walled carbon nanotubes into a 100-180 ℃ vacuum drying oven for drying for 24h and storing for later use;
step 2) carbon fiber treatment: putting carbon fibers into a beaker, adding mixed acid into the beaker, reacting for 8-10 h at the temperature of (20 +/-3) DEG C, repeatedly cleaning the carbon fibers by deionized water after the reaction is finished until the cleaned deionized water is neutral, and drying the treated carbon fibers in a vacuum drying oven at the temperature of 100-180 ℃ for 24h for later use;
step 3) weighing the multi-walled carbon nanotubes treated in the step 1), putting the multi-walled carbon nanotubes into a hydrothermal reaction kettle, adding an ethylenediamine solution and an N, N-dimethylformamide solution into the hydrothermal reaction kettle, ultrasonically dispersing the multi-walled carbon nanotubes in a 600W continuous pulse ultrasonic instrument for 45-60 min, then adding the carbon fibers treated in the step 2) into the reaction kettle, ultrasonically dispersing the carbon fibers for 10-15 min, and putting the reaction kettle into a vacuum drying box at 180 ℃ for drying for 48h and storing for later use;
and 4) taking the carbon fiber dried in the step 3) out of the reaction kettle, ultrasonically dispersing the carbon fiber in an ethanol solution for 15-25 min, repeatedly cleaning the carbon fiber by using the ethanol solution to fully remove redundant carbon nanotubes, ethylenediamine and N, N-dimethylformamide on the surface of the carbon fiber, and drying the carbon fiber in a vacuum drying oven at the temperature of 80-100 ℃ for 8-10 h to obtain the carbon nanotube grafted carbon fiber multi-scale reinforcement.
2. The method for preparing the carbon nanotube grafted carbon fiber multi-scale reinforcement according to claim 1, wherein the water bath kettle in the step 1) is a DF-101S heat collection type constant temperature magnetic stirrer.
3. The method for preparing the carbon nanotube grafted carbon fiber multi-scale reinforcement according to claim 1, wherein the mixed acid is prepared by mixing 65% by mass of concentrated nitric acid and 95% by mass of concentrated sulfuric acid in a volume ratio of 3: 1.
4. The application of the carbon nanotube grafted carbon fiber multi-scale reinforcement prepared by the preparation method of claim 1 in testing the flexural strength and compressive strength of a cement-based material is characterized in that cement mortar is stirred by an instrument, the carbon nanotube grafted carbon fiber multi-scale reinforcement is placed into the cement mortar to be made into a standard test block of 40mm multiplied by 160mm, the test block is demoulded after 24h, the test block is placed into a standard curing box with the relative humidity of 60 percent at the temperature of 20 +/-5 ℃, the test blocks of 3d and 28d are respectively placed into a flexural strength tester and a compressive strength tester, the flexural strength and compressive strength of the test block relative to a blank standard test block are measured, and the conclusion is drawn.
5. The use of claim 4, wherein the apparatus is a JJ-5 cement mortar mixer, the bending tester is a DKZ-5000 electric bending tester, and the compression tester is a NYL-300D compression tester.
6. The application of claim 4, wherein in the cement mortar, the mass ratio of cement to Chinese ISO standard sand is 1:3, and the water cement ratio is 0.5.
7. Use according to claim 4, wherein the flexural strength value is measured as follows: putting the prism test piece into a clamp, enabling the side surface of the test piece to be in contact with the cylinder of the clamp when the test piece is formed, and adjusting the clamp to enable the lever to be as close to a balance position as possible when the lever is broken in time; loading at the speed of (50 +/-10) N/s until the test piece is broken, and recording the breaking load P1And calculating the flexural strength fFolding deviceThe specific formula is shown in formula 1 below:
Figure FDA0002524070050000021
in formula 1: f. ofFolding deviceThe flexural strength is expressed in MPa; p1For destructive loads, unit N; l is the central distance of the supporting cylinder, and the value is 100 mm; b. h is the width and the height of the section of the test piece respectively, and the numerical values are all 40 mm; the arithmetic mean of the flexural strength measurements obtained on 3 of the prism test pieces was used as the measurement result.
8. The method of claim 4The method is characterized in that the compression strength value is measured by placing the smooth side surface of a half prism on a test machine table, using a compression clamp for the compression test to ensure that the compression area of a test piece is 40mm × 40mm, the bottom surface of the test piece is abutted against a positioning pin on the clamp, the part of a broken block exposed out of an upper pressure plate is not less than 10mm, in the whole loading process, the clamp is positioned at the center of a pressure plate of a press, uniformly loading is carried out at the speed of (2400 +/-200) N/s until the broken block is damaged, and the damage load P is recorded2And calculating the compressive strength f of each test piecePress and pressThe specific formula is shown in formula 2 below:
Figure FDA0002524070050000022
in formula 2: f. ofPress and pressCompressive strength in MPa; p2A is the pressed area with the value of 40mm × 40 mm;
the arithmetic mean of the values of the compressive strength measurements obtained for 6 of said half prisms was taken as the measurement result.
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113045254A (en) * 2021-04-01 2021-06-29 中国人民解放军空军工程大学 Carbon-series micro-nano graded trans-scale fiber reinforced cement mortar and preparation method thereof
CN114456412A (en) * 2021-12-27 2022-05-10 西安航空学院 Preparation method of MWCNT (Metal wrap through carbon) multi-scale reinforced material grafted on surface of carbon fiber

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101274831A (en) * 2008-05-16 2008-10-01 哈尔滨工业大学 Carbon nano-tube fiber cement-based material and preparation thereof
CN102108634A (en) * 2011-01-04 2011-06-29 同济大学 Method for preparing functional carbon fibers
JP2011127071A (en) * 2009-12-21 2011-06-30 Nikkiso Co Ltd Polymer graft carbon nanotube and manufacturing method thereof

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101274831A (en) * 2008-05-16 2008-10-01 哈尔滨工业大学 Carbon nano-tube fiber cement-based material and preparation thereof
JP2011127071A (en) * 2009-12-21 2011-06-30 Nikkiso Co Ltd Polymer graft carbon nanotube and manufacturing method thereof
CN102108634A (en) * 2011-01-04 2011-06-29 同济大学 Method for preparing functional carbon fibers

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
严咸通: "碳纳米管及碳纤维改性水泥基材料力学性能研究", 《中国优秀硕士学位论文全文数据库 工程科技Ⅰ辑》 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113045254A (en) * 2021-04-01 2021-06-29 中国人民解放军空军工程大学 Carbon-series micro-nano graded trans-scale fiber reinforced cement mortar and preparation method thereof
CN114456412A (en) * 2021-12-27 2022-05-10 西安航空学院 Preparation method of MWCNT (Metal wrap through carbon) multi-scale reinforced material grafted on surface of carbon fiber

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