Disclosure of Invention
The invention provides a preparation method and application of a carbon nanofiber multistage non-woven fabric which has a three-dimensional cavity structure, has a high specific surface area and can efficiently load a catalyst, and aims to make up for the market blank of the current industrialized carbon nanofiber multistage non-woven fabric and meet the requirements of modern chemical enterprises on carbon fiber non-woven fabrics with high specific surface areas. The carbon nanofiber multistage non-woven fabric has a high specific surface area, a large number of three-dimensional cavity structures are formed in the non-woven fabric through the structural design of the carbon nanofibers, anisotropy is shown among the fibers at each stage, and the gas permeability is kept while the mechanical performance is ensured. Meanwhile, the carbon nanofiber multistage non-woven fabric has the advantages of high temperature stability, chemical corrosion resistance, small mass density and the like due to the fact that the main chemical structure of the carbon nanofiber multistage non-woven fabric is carbon-carbon.
In order to achieve the technical purpose, the technical scheme adopted by the invention is as follows:
a preparation method of asphalt-based carbon nanofiber multistage non-woven fabric with a three-dimensional cavity structure comprises the following steps:
(1) Uniformly mixing the functional nano material and a dispersing agent according to the mass ratio of 100 to 1-20, and adding the mixture into a ball mill for grinding to obtain a functional additive suitable for asphalt melt-blown spinning;
(2) Uniformly mixing a functional additive suitable for asphalt melt-blown spinning with an asphalt material according to the mass ratio of 1-100, and then blending and granulating through a screw extruder to prepare asphalt melt-blown masterbatch;
(3) Adding the asphalt melt-blown masterbatch into a melt-blown spinning machine to form a melt, extruding the melt through a spinneret orifice, and cooling and solidifying the melt by air to form a nascent asphalt fiber web;
(4) And (3) carrying out alkali washing and water washing treatment on the nascent asphalt fiber web, and then carrying out preoxidation, drafting carbonization and graphitization heat treatment to finally prepare the asphalt-based carbon nanofiber multistage non-woven fabric with a three-dimensional cavity structure. The alkali washing and the water washing of the nascent asphalt fiber web are specifically carried out by washing with 5-10% NaOH aqueous solution and then washing to be neutral.
Preferably, the nano material in step (1) is a nano metal oxide or a nano non-metal oxide. The main function of the nano material is to make the melt-blown fiber anisotropic so as to build up a multi-stage nano fiber net structure.
More preferably, the nanomaterial in step (1) is graphene or carbon nanotubes.
Preferably, the dispersant in the step (1) is one or more of stearic acid, polyoxyethylene octyl phenol ether and fatty alcohol-polyoxyethylene ether.
Preferably, the asphalt material in the step (2) is one or more of coal-based asphalt, petroleum-based asphalt and rubber asphalt.
Preferably, the screw extruder in the step (2) is a twin-screw extruder or a single-screw extruder.
Preferably, the melt in the step (3) is extruded through a spinneret orifice and can be supplemented with high-pressure gas of about 0.3Mpa to form anisotropic melt trickle, so that spinning is facilitated.
Preferably, the specific method of the pre-oxidation, the drawing carbonization and the graphitization heat treatment in the step (4) is as follows:
A. pre-oxidation: treating with oxidizing concentrated acid under ultrasonic assistance for 0.5-10 hr, taking out non-woven fabric from the acid bath, rapidly heating to 200-500 deg.C in air, and maintaining for 0.5-1.5 hr;
B. drawing and carbonizing: rapidly heating the pre-oxidized non-woven fabric to over 1200 ℃ under the protection of high-pressure inert gas with the pressure of over 85Kpa, and keeping for 0.5-10h;
C. graphitization: after drafting and carbonization, further heating to more than 2000 ℃ and keeping for 0.5-10h to improve the graphitization degree of the product, finally carrying out ultrasonic water washing to remove impurities, and drying to obtain the final product.
Preferably, the temperature rise rate in step A and step B is more than 10 ℃/min.
Preferably, in step a, the concentrated acid is one or more of 98% concentrated sulfuric acid, 85% concentrated phosphoric acid and 68% concentrated nitric acid.
The non-woven fabric prepared by the invention can be used as a catalyst carrier to prepare a high-performance catalyst in a vapor deposition mode, or can be used as a base material to improve the functionality in other loading modes, and can be used for preparing an air filtering material, a catalytic material and an adsorbing material with multiple functions.
Advantageous effects
The method is suitable for preparing the asphalt-based carbon nanofiber multistage non-woven fabric, improves the additional value and the application field of asphalt, is convenient for large-scale processing and production, and has simple process, convenient operation and convenient implementation. The prepared asphalt-based carbon nanofiber multistage non-woven fabric with the three-dimensional cavity has excellent index performance and large specific surface area, and has a good catalytic function after being loaded with a catalyst.
Detailed Description
The technical solution of the present invention is further described below with reference to specific embodiments, but is not limited thereto.
Example 1
A preparation method of asphalt-based carbon nanofiber multi-stage non-woven fabric with a three-dimensional cavity structure comprises the following steps:
(1) Uniformly mixing the functional nano material and a dispersing agent according to the mass ratio of 100;
(2) Uniformly mixing a functional additive suitable for asphalt melt-blown spinning with an asphalt material according to a mass ratio of 1;
(3) Adding the asphalt melt-blown masterbatch into a melt-blown spinning machine to form a melt, extruding the melt through a spinneret orifice, and cooling and solidifying the melt by air to form a nascent asphalt fiber web;
(4) And (3) carrying out alkali washing and water washing treatment on the nascent asphalt fiber web, and then carrying out preoxidation, drafting carbonization and graphitization heat treatment to finally prepare the asphalt-based carbon nanofiber multistage non-woven fabric with a three-dimensional cavity structure. The primary asphalt fiber net is washed by alkali and water, specifically, 10% NaOH aqueous solution is used for washing, and then the water is washed to be neutral.
The main function of the nano material is to make the melt-blown fiber anisotropic so as to build up a multi-stage nano fiber net structure.
The nano material in the step (1) is graphene.
The dispersing agent in the step (1) is a mixture of stearic acid, polyoxyethylene octyl phenol ether, fatty alcohol-polyoxyethylene ether and the like in mass.
And (3) the asphalt material in the step (2) is rubber asphalt.
And (3) the screw extruder in the step (2) is a single screw extruder.
And (3) extruding the melt in the step (3) through a spinneret orifice, and assisting high-pressure gas to form anisotropic melt trickle, so that spinning is facilitated. The specific method for the pre-oxidation, the drawing carbonization and the graphitization heat treatment in the step (4) comprises the following steps:
A. pre-oxidation: treating with oxidizing concentrated acid under ultrasonic assistance for 10h, taking out the non-woven fabric from the acid bath, rapidly heating to 500 deg.C in air, and maintaining for 1.5h;
B. drawing and carbonizing: quickly heating the pre-oxidized non-woven fabric to 1500 ℃ under the protection of high-pressure inert gas with the pressure of more than 85Kpa, and keeping the temperature for 10 hours;
C. graphitization: after drafting and carbonization, further heating to 2500 ℃ and keeping for 10 hours to improve the graphitization degree of the product, finally carrying out ultrasonic water washing to remove impurities, and drying to obtain the final product.
The temperature rise rate in the step A and the step B is 50 ℃/min.
In the step A, the concentrated acid is 98% concentrated sulfuric acid.
Example 2
A preparation method of asphalt-based carbon nanofiber multistage non-woven fabric with a three-dimensional cavity structure comprises the following steps:
(1) Uniformly mixing the functional nano material and a dispersing agent according to the mass ratio of 100;
(2) Uniformly mixing a functional additive suitable for asphalt melt-blown spinning with an asphalt material according to a mass ratio of 1;
(3) Adding the asphalt melt-blown masterbatch into a melt-blown spinning machine to form a melt, extruding the melt through a spinneret orifice, and cooling and solidifying the melt by air to form a nascent asphalt fiber web;
(4) And (3) carrying out alkali washing and water washing treatment on the nascent asphalt fiber web, and then carrying out preoxidation, drafting carbonization and graphitization heat treatment to finally prepare the asphalt-based carbon nanofiber multistage non-woven fabric with a three-dimensional cavity structure. The primary asphalt fiber net is washed by alkali and water, specifically, 10% NaOH aqueous solution is used for washing, and then the water is washed to be neutral.
The nano material in the step (1) is graphene; the main function of the nano material is to make the melt-blown fiber anisotropic so as to build up a multi-stage nano fiber net structure.
The dispersant in the step (1) is stearic acid.
And (3) the asphalt material in the step (2) is coal-based asphalt.
The screw extruder in the step (2) is a double-screw extruder.
And (3) extruding the melt in the step (3) through a spinneret orifice, and assisting high-pressure gas to form anisotropic melt trickle, so that spinning is facilitated.
The specific method for the pre-oxidation, the drawing carbonization and the graphitization heat treatment in the step (4) comprises the following steps:
A. pre-oxidation: treating with oxidizing concentrated acid under ultrasonic assistance for 5h, taking out the non-woven fabric from the acid bath, rapidly heating to 300 deg.C in air, and maintaining for 0.5h;
B. drawing and carbonizing: rapidly heating the pre-oxidized non-woven fabric to 1300 ℃ under the protection of high-pressure inert gas with the pressure of more than 85Kpa, and keeping the temperature for 2 hours;
C. graphitization: after drafting and carbonization, further heating to 2000 ℃ and keeping for 0.5h to improve the graphitization degree of the product, finally carrying out ultrasonic water washing to remove impurities, and drying to obtain the final product.
The temperature rise rate in the step A and the step B is 100 ℃/min.
In the step A, the concentrated acid is 98% concentrated sulfuric acid.
Example 3
A preparation method of asphalt-based carbon nanofiber multi-stage non-woven fabric with a three-dimensional cavity structure comprises the following steps:
(1) Uniformly mixing the functional nano material and a dispersing agent according to a mass ratio of 50;
(2) Uniformly mixing a functional additive suitable for asphalt melt-blown spinning with an asphalt material according to a mass ratio of 1;
(3) Adding the asphalt melt-blown master batch into a melt-blown spinning machine to form a melt, extruding the melt through a spinneret orifice, and cooling and solidifying the melt by air to form a nascent asphalt fiber web;
(4) And (3) carrying out alkali washing and water washing treatment on the nascent asphalt fiber web, and then carrying out preoxidation, drafting carbonization and graphitization heat treatment to finally prepare the asphalt-based carbon nanofiber multistage non-woven fabric with a three-dimensional cavity structure. The alkali washing and the water washing of the nascent asphalt fiber web are specifically carried out by washing with a 5% NaOH aqueous solution and then washing to be neutral.
The nano material in the step (1) is a carbon nano tube; the main function of the nano material is to make the melt-blown fiber anisotropic so as to build up a multi-stage nano fiber net structure.
The dispersing agent in the step (1) is fatty alcohol-polyoxyethylene ether.
And (3) the asphalt material in the step (2) is petroleum-based asphalt.
The screw extruder in the step (2) is a double-screw extruder.
And (3) extruding the melt in the step (3) through a spinneret orifice, and assisting high-pressure gas to form anisotropic melt trickle, so that spinning is facilitated.
The specific method for the pre-oxidation, the drawing carbonization and the graphitization heat treatment in the step (4) comprises the following steps:
A. pre-oxidation: treating with oxidizing concentrated acid under ultrasonic assistance for 5h, taking out the non-woven fabric from the acid bath, rapidly heating to 350 deg.C in air, and maintaining for 1h;
B. drawing and carbonizing: rapidly heating the pre-oxidized non-woven fabric to 1200 ℃ under the protection of high-pressure inert gas with the pressure of more than 85Kpa, and keeping the temperature for 1h;
C. graphitizing: after drawing and carbonization, further heating to 2200 ℃ and keeping for 1h to improve the graphitization degree of the product, finally carrying out ultrasonic water washing to remove impurities, and drying to obtain the final product.
The temperature rise rate in the step A and the step B is 200 ℃/min.
In the step A, the concentrated acid is 68% concentrated nitric acid.
Example 4
A preparation method of asphalt-based carbon nanofiber multistage non-woven fabric with a three-dimensional cavity structure comprises the following steps:
(1) Uniformly mixing the functional nano material and a dispersing agent according to the mass ratio of 100;
(2) Uniformly mixing a functional additive suitable for asphalt melt-blown spinning with an asphalt material according to the mass ratio of 1;
(3) Adding the asphalt melt-blown master batch into a melt-blown spinning machine to form a melt, extruding the melt through a spinneret orifice, and cooling and solidifying the melt by air to form a nascent asphalt fiber web;
(4) And (3) carrying out alkali washing and water washing treatment on the nascent asphalt fiber web, and then carrying out preoxidation, drafting carbonization and graphitization heat treatment to finally prepare the asphalt-based carbon nanofiber multistage non-woven fabric with a three-dimensional cavity structure. The alkali washing and the water washing of the nascent asphalt fiber web are specifically carried out by washing with 10% NaOH aqueous solution and then washing to be neutral.
The nano material in the step (1) is nano metal oxide zinc oxide. The main function of the nano material is to make the melt-blown fiber anisotropic so as to build up a multi-stage nano fiber net structure.
The dispersing agent in the step (1) is polyoxyethylene octyl phenol ether.
And (3) the asphalt material in the step (2) is coal-based asphalt.
And (3) the screw extruder in the step (2) is a double-screw extruder.
And (3) extruding the melt in the step (3) through a spinneret orifice, and assisting high-pressure gas to form anisotropic melt trickle, so that spinning is facilitated.
The specific method for the pre-oxidation, drawing carbonization and graphitization heat treatment in the step (4) comprises the following steps:
A. pre-oxidation: treating with oxidizing concentrated acid under the assistance of ultrasound for 0.5-10h, taking out non-woven fabric from acid bath, rapidly heating to 300 deg.C in air, and maintaining for 1.5h;
B. drawing and carbonizing: rapidly heating the pre-oxidized non-woven fabric to 1200 ℃ under the protection of high-pressure inert gas with the pressure of more than 85Kpa, and keeping the temperature for 1h;
C. graphitization: after drafting and carbonization, further heating to 2300 ℃ and keeping for 1.5h to improve the graphitization degree of the product, finally carrying out ultrasonic water washing to remove impurities, and drying to obtain the final product.
In the step A and the step B, the temperature rise speed is 100 ℃/min.
In the step A, the concentrated acid is 85 percent concentrated phosphoric acid.
Example 5
A preparation method of asphalt-based carbon nanofiber multi-stage non-woven fabric with a three-dimensional cavity structure comprises the following steps:
(1) Uniformly mixing the functional nano material and a dispersing agent according to a mass ratio of 20;
(2) Uniformly mixing a functional additive suitable for asphalt melt-blown spinning with an asphalt material according to a mass ratio of 1;
(3) Adding the asphalt melt-blown masterbatch into a melt-blown spinning machine to form a melt, extruding the melt through a spinneret orifice, and cooling and solidifying the melt by air to form a nascent asphalt fiber web;
(4) And (3) carrying out alkali washing and water washing treatment on the nascent asphalt fiber web, and then carrying out preoxidation, drafting carbonization and graphitization heat treatment to finally prepare the asphalt-based carbon nanofiber multistage non-woven fabric with a three-dimensional cavity structure. The alkali washing and the water washing of the nascent asphalt fiber web are specifically carried out by washing with a 5% NaOH aqueous solution and then washing to be neutral.
The main function of the nano material is to make the melt-blown fiber anisotropic so as to build up a multi-stage nano fiber net structure.
The nano material in the step (1) is a carbon nano tube.
The dispersant in the step (1) is stearic acid.
And (3) mixing the asphalt material in the step (2) with coal-based asphalt, petroleum-based asphalt and rubber asphalt according to a mass ratio of 1.
And (3) the screw extruder in the step (2) is a double-screw extruder.
And (3) extruding the melt in the step (3) through a spinneret orifice, and assisting high-pressure gas to form anisotropic melt trickle, so that spinning is facilitated.
Preferably, the specific method of the pre-oxidation, the drawing carbonization and the graphitization heat treatment in the step (4) is as follows:
A. pre-oxidation: treating for 5h with oxidative concentrated acid under the assistance of ultrasound, taking out the non-woven fabric from an acid bath, rapidly heating to 250 ℃ in the air, and keeping for 1h;
B. drawing and carbonizing: quickly heating the pre-oxidized non-woven fabric to 1500 ℃ under the protection of high-pressure inert gas with the pressure of more than 85Kpa, and keeping the temperature for 5 hours;
C. graphitization: after drafting and carbonization, further heating to more than 2000 ℃ and keeping for 5 hours to improve the graphitization degree of the product, finally carrying out ultrasonic water washing to remove impurities, and drying to obtain the final product.
The temperature rise rate in the step A and the step B is 30 ℃/min.
In the step A, the concentrated acid is 98% concentrated sulfuric acid.
Performance test
(1) Fiber fineness: analysis by scanning Electron microscopy
(2) Mass per unit volume: measuring the volume with a vernier caliper, and then weighing the mass with an analytical balance
(3) Strength: GB/T24218.6-2010 textile non-woven fabric test method determination of breaking strength and breaking elongation (strip sample method)
(4) Young's modulus of single fiber: the single fiber in the non-woven fabric is separated and then measured by a single fiber strength tester
(5) Specific surface area: nitrogen adsorption process
The test results are shown in Table 1
Table 1 results of performance testing
As can be seen from the experimental data in Table 1, the asphalt-based carbon nanofiber multi-stage non-woven fabric obtained by the invention has the advantages of higher mechanical strength, larger specific surface area and smaller fiber fineness. Meanwhile, electron microscope analysis is carried out on the non-woven fabric obtained in the embodiment 1 of the invention, and as can be seen from the attached drawings 1-3, the nascent pitch fibers are anisotropic, a large number of three-dimensional cavity structures are formed in the non-woven fabric after subsequent treatment, and anisotropy is shown among all levels of fibers, so that the mechanical property is guaranteed, and the gas permeability can be kept.
It should be noted that the above-mentioned embodiments are only some of the preferred modes for implementing the invention, and not all of them. Obviously, all other embodiments obtained by persons skilled in the art based on the above embodiments of the present invention without making creative efforts shall fall within the protection scope of the present invention.