Disclosure of Invention
The invention aims to provide a method for improving the interface performance of a fiber metal laminate, which improves the surface roughness and polarity of carbon fibers by grafting carboxylated carbon nanotubes on the surfaces of the carbon fibers, so that the carbon fibers are better combined with a matrix, and the interface performance of the fiber metal laminate is improved. The preparation process is simple, the carbon fiber modification process is controllable, and the method is a very effective method for improving the interface performance of the fiber metal laminate.
The invention is realized by adopting the following technical scheme,
a method for improving interface performance of a fiber metal laminate specifically comprises the following steps:
placing the carbon fiber cloth subjected to desizing and oxidation treatment in a tetrahydrofuran solution of melamine, adding 2- (7-benzotriazole oxide) -N, N, N ', N' -tetramethylurea Hexafluorophosphate (HATU), performing amide condensation for 4-5 h at 50-60 ℃, washing with tetrahydrofuran and deionized water, and drying;
and step two, arranging the carbon fiber dried in the step one in an N, N-dimethylformamide solution of a carboxylated carbon nanotube, adding 2- (7-benzotriazole oxide) -N, N, N ', N' -tetramethylurea hexafluorophosphate, performing amide condensation for 4-5 h at 85-95 ℃, washing with N, N-dimethylformamide and deionized water, and drying.
Further, in the first step, the desizing treatment comprises the steps of arranging the carbon fibers in a mixed solution of ethanol and acetone in a volume ratio of 1:1, performing ultrasonic treatment at 50 ℃ for 2-4h, washing with deionized water, and drying.
Further, in the first step, the oxidation treatment comprises disposing the carbon fiber after the desizing treatment on concentrated HNO with a volume ratio of 1:13And concentrated H2SO4Soaking the mixture in the mixed solution at 60 deg.C for 10-20min, washing with deionized water, and drying.
Further, in the first step, the concentration of the tetrahydrofuran solution of melamine is 1 x 10-4The ratio of mol/l, 2- (7-benzotriazole oxide) -N, N, N ', N' -tetramethylurea hexafluorophosphate to the tetrahydrofuran solution of melamine is 1 mg: 5 ml.
Further, in the second step, the concentration of the N, N-dimethylformamide solution of the carboxylated carbon nanotubes is 0.1 to 0.3mg/ml, preferably 0.2mg/ml, and the ratio of the 2- (7-benzotriazole oxide) -N, N' -tetramethylurea hexafluorophosphate to the N, N-dimethylformamide solution of the carboxylated carbon nanotubes is 1 mg: 5 ml.
Compared with the prior art, the invention has the advantages that:
(1) the invention improves the fiber roughness and surface polarity by chemically grafting the carboxylated carbon nano tube on the surface of the carbon fiber, and the modified carbon fiber can be better combined with a matrix, thereby effectively improving the interface performance of the fiber metal laminate. (2) When the concentration of the carboxylated carbon nanotube solution is 0.2mg/ml, the carbon nanotubes can be uniformly grafted on the surface of the carbon fiber, and the single lap shear strength of the fiber metal laminate reaches 26.52MPa, which is greatly improved compared with the single lap shear strength of a sample prepared by using carbon fiber cloth without grafting, which is 19.94 MPa.
Detailed Description
The technical solution of the present invention is further illustrated by the following examples and the accompanying drawings, but the present invention is not limited to these examples.
Example 1
Step one, respectively measuring 15ml of absolute ethyl alcohol and 15ml of acetone solution, pouring the absolute ethyl alcohol and the 15ml of acetone solution into a beaker, uniformly mixing, putting a piece of carbon fiber cloth with the size of 6 multiplied by 6cm, covering the carbon fiber cloth with a glass dish, and sealing the carbon fiber cloth with a preservative film. The beaker was placed in an ultrasonic cleaner for 2h, the temperature was adjusted to 50 ℃. And then taking out, washing with deionized water for several times, and then putting into an air-blast drying oven for drying at 70 ℃ for 1h, wherein the mark is desized carbon fiber.
And step two, respectively measuring 10ml of concentrated sulfuric acid and 10ml of concentrated nitric acid, pouring the concentrated sulfuric acid and the concentrated nitric acid into a beaker for mixing, putting the carbon fiber cloth in the step one into the beaker, putting the beaker into a water bath for heating at 60 ℃, keeping the temperature for 15min, taking out the beaker, washing the beaker to be neutral by using deionized water, putting the beaker into an air-blast drying oven for drying at 70 ℃ for 1h, and marking the carbon fiber cloth as oxidized carbon fiber.
And step three, weighing 0.0089g of melamine, dissolving the melamine in 50ml of tetrahydrofuran solution, putting the carbon fiber cloth in the step two into the beaker, sealing the opening of the beaker by using a preservative film, placing the beaker into a water bath for heating at 55 ℃ for reaction for 4 hours, washing the beaker with tetrahydrofuran and deionized water for several times after the reaction is finished, then placing the beaker into an air-blowing drying oven for drying at 70 ℃ for 1 hour, and marking the beaker as modified carbon fiber.
Weighing 0.0102g of carboxylated carbon nanotubes, dissolving in 50ml of N, N-dimethylformamide solution, putting the carbon fiber cloth in the step three into the solution, sealing the beaker with a preservative film, placing the beaker in a water bath for heating at 90 ℃ for reacting for 4 hours, and after the reaction is finished, using N, N-dimethyl formamideWashing with amide and deionized water for several times, drying in air-blast drying oven at 70 deg.C for 1 hr, and labeling as carbon fiber cloth CF-CNT0.2。
Step five, testing the carbon fiber cloth CF-CNT0.2The adhesion performance of the alloy is that two titanium alloy plates (100 multiplied by 25 multiplied by 1.5mm) are cleaned by absolute ethyl alcohol; weighing 3.0024g of epoxy resin A glue (commercially available) and 1.0005g of epoxy resin B glue (commercially available), mixing uniformly, and mixing the carbon fiber cloth CF-CNT in the fourth step0.2Cutting into 25 × 12.5mm, placing at the joint of titanium alloy plate, dropping 2-3 drops of epoxy resin, clamping with dovetail clamp, placing in vacuum drying oven, maintaining at 50 deg.C for 1 hr, and heating to 70 deg.C for 3 hr. The dovetail clips were removed every other day to yield single lap tensile test sample 1.
Example 2
Step one, respectively measuring 15ml of absolute ethyl alcohol and 15ml of acetone solution, pouring the absolute ethyl alcohol and the 15ml of acetone solution into a beaker, uniformly mixing, putting a piece of carbon fiber cloth with the size of 6 multiplied by 6cm, covering the carbon fiber cloth with a glass dish, and sealing the carbon fiber cloth with a preservative film. The beaker was placed in an ultrasonic cleaner for 2h, the temperature was adjusted to 50 ℃. And then taking out, washing with deionized water for several times, and then putting into an air-blast drying oven for drying at 70 ℃ for 1h, wherein the mark is desized carbon fiber.
And step two, respectively measuring 10ml of concentrated sulfuric acid and 10ml of concentrated nitric acid, pouring the concentrated sulfuric acid and the concentrated nitric acid into a beaker for mixing, putting the carbon fiber cloth in the step one into the beaker, putting the beaker into a water bath for heating at 60 ℃, keeping the temperature for 15min, taking out the beaker, washing the beaker to be neutral by using deionized water, putting the beaker into an air-blast drying oven for drying at 70 ℃ for 1h, and marking the carbon fiber cloth as oxidized carbon fiber.
And step three, weighing 0.0085g of melamine, dissolving the melamine in 50mL of tetrahydrofuran solution, putting the carbon fiber cloth in the step two into the beaker, sealing the opening of the beaker by using a preservative film, placing the beaker into a water bath for heating at 55 ℃ for reaction for 4 hours, washing the beaker with tetrahydrofuran and deionized water for several times after the reaction is finished, then placing the beaker into an air-blowing drying oven for drying at 70 ℃ for 1 hour, and marking the beaker as modified carbon fiber.
Step four, weighing 0.0051g of carboxylated carbon nanotube, dissolving in 50ml of N, N-dimethylformamide solution, putting the carbon fiber cloth in the step three into the solution, sealing the beaker with a preservative film, placing the beaker in a water bath, heating the beaker in the water bath at 90 ℃ for reacting for 4 hours, and using N, N-dimethylformamide after the reaction is finishedWashing with deionized water for several times, drying in air-blast drying oven at 70 deg.C for 1 hr, and labeling as carbon fiber cloth CF-CNT0.1。
Step five, cleaning two titanium alloy plates (100 multiplied by 25 multiplied by 1.5mm) by absolute ethyl alcohol; weighing 3.0022g of epoxy resin A glue and 1.0003g of epoxy resin B glue, uniformly mixing, and mixing the carbon fiber cloth CF-CNT in the fourth step0.1Cutting into 25 × 12.5mm, placing at the joint of titanium alloy plate, dropping 2-3 drops of epoxy resin, clamping with dovetail clamp, placing in vacuum drying oven, maintaining at 50 deg.C for 1 hr, and heating to 70 deg.C for 3 hr. The dovetail clips were removed every other day to yield single lap tensile test sample 2.
Example 3
Step one, respectively measuring 15ml of absolute ethyl alcohol and 15ml of acetone solution, pouring the absolute ethyl alcohol and the 15ml of acetone solution into a beaker, uniformly mixing, putting a piece of carbon fiber cloth with the size of 6 multiplied by 6cm, covering the carbon fiber cloth with a glass dish, and sealing the carbon fiber cloth with a preservative film. The beaker was placed in an ultrasonic cleaner for 2h, the temperature was adjusted to 50 ℃. And then taking out, washing with deionized water for several times, and then putting into an air-blast drying oven for drying at 70 ℃ for 1h, wherein the mark is desized carbon fiber.
And step two, respectively measuring 10ml of concentrated sulfuric acid and 10ml of concentrated nitric acid, pouring the concentrated sulfuric acid and the concentrated nitric acid into a beaker for mixing, putting the carbon fiber cloth in the step one into the beaker, putting the beaker into a water bath for heating at 60 ℃, keeping the temperature for 15min, taking out the beaker, washing the beaker to be neutral by using deionized water, putting the beaker into an air-blast drying oven for drying at 70 ℃ for 1h, and marking the carbon fiber cloth as oxidized carbon fiber.
And step three, weighing 0.0088g of melamine, dissolving the melamine in 50ml of tetrahydrofuran solution, putting the carbon fiber cloth in the step two into the beaker, sealing the opening of the beaker by using a preservative film, placing the beaker into a water bath for heating at 55 ℃ for reaction for 4 hours, washing the beaker with tetrahydrofuran and deionized water for several times after the reaction is finished, then placing the beaker into an air-blowing drying oven for drying at 70 ℃ for 1 hour, and marking the beaker as modified carbon fiber.
Step four, weighing 0.0154g of carboxylated carbon nanotube, dissolving the carboxylated carbon nanotube in 50ml of N, N-dimethylformamide solution, putting the carbon fiber cloth in the step three into the solution, sealing the mouth of a beaker by a preservative film, placing the beaker in a water bath, heating the beaker in the water bath for 4 hours, washing the beaker with N, N-dimethylformamide and deionized water for several times after the reaction is finished, placing the beaker in an air-blast drying oven, drying the beaker at 70 ℃ for 1 hour, and marking the beaker as the carbon fiberWeibu CF-CNT0.3。
Step five, cleaning two titanium alloy plates (100 multiplied by 25 multiplied by 1.5mm) by absolute ethyl alcohol; weighing 3.0025g of epoxy resin A glue and 1.0007g of epoxy resin B glue, uniformly mixing, and mixing the carbon fiber cloth CF-CNT in the fourth step0.3Cutting into 25 × 12.5mm, placing at the joint of titanium alloy plate, dropping 2-3 drops of epoxy resin, clamping with dovetail clamp, placing in vacuum drying oven, maintaining at 50 deg.C for 1 hr, and heating to 70 deg.C for 3 hr. The dovetail clips were removed every other day to yield single lap tensile test sample 3.
Comparative example 1
Step one, respectively measuring 15ml of absolute ethyl alcohol and 15ml of acetone solution, pouring the absolute ethyl alcohol and the 15ml of acetone solution into a beaker, uniformly mixing, putting a piece of carbon fiber cloth with the size of 6 multiplied by 6cm, covering the carbon fiber cloth with a glass dish, and sealing the carbon fiber cloth with a preservative film. The beaker was placed in an ultrasonic cleaner for 2h, the temperature was adjusted to 50 ℃. And then taking out, washing with deionized water for several times, and then putting into an air-blast drying oven for drying at 70 ℃ for 1h, wherein the mark is desized carbon fiber.
Step two, cleaning two titanium alloy plates (100 multiplied by 25 multiplied by 1.5mm) by absolute ethyl alcohol; weighing 3.0020g of epoxy resin A glue and 1.0002g of epoxy resin B glue, uniformly mixing, cutting the carbon fiber cloth in the step one into a size of 25 multiplied by 12.5mm, placing the carbon fiber cloth at a joint of a titanium alloy plate, dripping 2-3 drops of epoxy resin, clamping the epoxy resin by a dovetail clamp, placing the carbon fiber cloth in a vacuum drying oven, preserving heat at 50 ℃ for 1h, and then heating to 70 ℃ for 3 h. The dovetail clips were removed every other day to yield single lap tensile test sample 4.
Comparative example 2
Step one, respectively measuring 15ml of absolute ethyl alcohol and 15ml of acetone solution, pouring the absolute ethyl alcohol and the 15ml of acetone solution into a beaker, uniformly mixing, putting a piece of carbon fiber cloth with the size of 6 multiplied by 6cm, covering the carbon fiber cloth with a glass dish, and sealing the carbon fiber cloth with a preservative film. The beaker was placed in an ultrasonic cleaner for 2h, the temperature was adjusted to 50 ℃. And then taking out, washing with deionized water for several times, and then putting into an air-blast drying oven for drying at 70 ℃ for 1h, wherein the mark is desized carbon fiber.
And step two, respectively measuring 10ml of concentrated sulfuric acid and 10ml of concentrated nitric acid, pouring the concentrated sulfuric acid and the concentrated nitric acid into a beaker for mixing, putting the carbon fiber cloth in the step one into the beaker, putting the beaker into a water bath for heating at 60 ℃, keeping the temperature for 15min, taking out the beaker, washing the beaker to be neutral by using deionized water, putting the beaker into an air-blast drying oven for drying at 70 ℃ for 1h, and marking the carbon fiber cloth as oxidized carbon fiber.
Step three, cleaning two titanium alloy plates (100 multiplied by 25 multiplied by 1.5mm) by absolute ethyl alcohol; weighing 3.0026g of epoxy resin A glue and 1.0004g of epoxy resin B glue, uniformly mixing, cutting the carbon fiber cloth in the fourth step to be 25 multiplied by 12.5mm in size, placing the carbon fiber cloth at the joint of the titanium alloy layer plate, dripping 2-3 drops of epoxy resin, clamping the epoxy resin by a dovetail clamp, placing the carbon fiber cloth in a vacuum drying oven, preserving heat for 1h at 50 ℃, and then heating to 70 ℃ and preserving heat for 3 h. The dovetail clips were removed every other day to yield single lap tensile test sample 5.
Fig. 1 is a scanning electron microscope image of carbon fiber cloth grafted with different carbon nanotube solutions and carbon fiber cloth that has not been treated in the examples 1, 2, and 3 of the present invention, and it can be seen from the image that the untreated carbon fiber cloth has a smooth surface, and when the amount of carbon nanotubes added is 0.0102g, the carbon nanotubes can be uniformly distributed on the surface of the carbon fiber, when the amount of carbon nanotubes used is too small, the carbon nanotubes cannot be completely distributed on the surface of the carbon fiber, and when the amount of carbon nanotubes used is too large, the carbon nanotubes can be agglomerated on the surface of the carbon fiber, which indicates that the grafting effect on the surface of the carbon fiber can be affected by the amount of carbon nanotubes used.
Fig. 2 is an XPS spectrum of a carbon fiber surface of example 1 of the present invention, which shows that the relative content of C element on the surface of an untreated carbon fiber is 85.39, the relative content of O element is 14.61, the relative content of O element on the surface of the carbon fiber is increased to 26.63 after oxidation treatment, and then the occurrence of N element indicates that melamine successfully modified the carbon fiber, and when carbon nanotubes are grafted, the relative content of C element is increased to 83.84, the relative content of O element is decreased to 12.86, and the relative content of N element is 3.30, which indicates that the carbon nanotubes are successfully grafted on the surface of the carbon fiber.
FIG. 3 is a graph of single lap tensile shear strength of examples 1, 2, 3 and comparative examples 1, 2 of the present invention, i.e. different samples, comparing examples 1, 2, 3 and comparative example 1 in the process, it can be found that a better single lap tensile shear strength can be obtained with an appropriate amount of carbon nanotubes; from comparative examples 1 and 2, it can be seen that the short time acidification treatment process does not have a great influence on the properties of the fibers themselves.
In summary, the method for improving the interface performance of the fiber metal laminate mainly utilizes the fact that the grafted carbon fibers can be better combined with the matrix, so that the interface performance of the fiber metal laminate is enhanced. The method has the advantages of simple experimental operation, short time, economical and practical price of the adopted coupling agent, controllable operation process and capability of better improving the interface bonding performance of the fiber metal laminate.