阅读说明：本技术 一种高强度的碳纳米管修饰酚醛树脂阻燃材料及其制法 (High-strength carbon nanotube modified phenolic resin flame-retardant material and preparation method thereof ) 是由 王京慧 于 2020-12-16 设计创作，主要内容包括：本发明涉及酚醛树脂技术领域,且公开了一种高强度的碳纳米管修饰酚醛树脂阻燃材料,含炔基酚醛树脂的炔基与叠氮功能化碳纳米管的叠氮基团通过快速的点击化反应,从而将碳纳米管通过化学共价键修饰到酚醛树脂的侧链中,提高了碳纳米管与酚醛树脂的界面相容性,在共价键的修饰作用下,避免了纳米粒子之间相互聚集和团聚,以碳纳米管的叠氮基团作为交联位点,增加了酚醛树脂的交联度,降低了酚醛树脂材料的脆性,提高了材料的韧性和拉伸强度,碳纳米管在高温燃烧下有利于促进材料表面炭化,形成致密而连续的碳层,提高材料的成炭率和抑烟率,使高强度的碳纳米管修饰酚醛树脂表现出优异的阻燃性能。(The invention relates to the technical field of phenolic resin and discloses a high-strength carbon nano tube modified phenolic resin flame-retardant material, wherein alkynyl of alkynyl-containing phenolic resin and azide groups of azide-functionalized carbon nano tubes are subjected to rapid click reaction, thereby modifying the carbon nano tube into the side chain of the phenolic resin through a chemical covalent bond, improving the interface compatibility of the carbon nano tube and the phenolic resin, under the modification action of covalent bonds, mutual aggregation and agglomeration of nano particles are avoided, the azide group of the carbon nano tube is taken as a crosslinking site, the crosslinking degree of the phenolic resin is increased, the brittleness of the phenolic resin material is reduced, the toughness and tensile strength of the material are improved, the carbon nano tube is favorable for promoting the surface carbonization of the material under high-temperature combustion to form a compact and continuous carbon layer, the char formation rate and smoke suppression rate of the material are improved, and the high-strength carbon nano tube modified phenolic resin shows excellent flame retardant property.)

1. A high-strength carbon nanotube modified phenolic resin flame-retardant material is characterized in that: the preparation method of the high-strength carbon nanotube modified phenolic resin flame-retardant material comprises the following steps:

(1) adding carbon nano tubes into a mixed solution of concentrated sulfuric acid and concentrated nitric acid with the volume ratio of 1:2.5-3.5, placing the mixture in an ultrasonic device, carrying out ultrasonic dispersion uniformly, heating to the temperature of 130-150 ℃, carrying out reflux reaction for 3-5h, carrying out centrifugal separation, washing and drying to prepare hydroxylated carbon nano tubes;

(2) adding a hydroxylated carbon nanotube into a toluene solvent, adding 3-chloropropyltriethoxysilane after uniformly dispersing by ultrasonic, reacting for 12-24h at 80-110 ℃, centrifugally separating, washing and drying to prepare a chloropropylated carbon nanotube;

(3) adding chloropropyl carbon nano-tubes into a toluene solvent, after uniform ultrasonic dispersion, adding sodium azide, a catalyst and an accelerant into a nitrogen atmosphere, heating to 80-110 ℃, reacting for 24-48h, centrifugally separating, washing and drying to prepare the carbon nano-tubes;

(4) adding m-ethynylaniline into 10-18% hydrochloric acid solution by mass fraction, uniformly reacting for 30-60min at 55-65 ℃, reducing the temperature to-5 to 0 ℃, dropwise adding sodium nitrite aqueous solution, and reacting for 2-3h to prepare m-ethynylbenzene diazonium salt;

(5) adding ethanol solvent into sodium hydroxide aqueous solution, adding phenolic resin, adding m-ethynylbenzene diazonium salt at the temperature of between-5 and 0 ℃, reacting for 6 to 12 hours, precipitating, filtering, washing and drying to prepare phenolic resin containing alkynyl;

(6) adding alkynyl-containing phenolic resin and carbon nano azide tubes into a toluene solvent, performing ultrasonic dispersion uniformly in a nitrogen atmosphere, adding a catalyst and a cocatalyst, reacting for 12-24h, performing reduced pressure distillation, washing and drying to prepare the high-strength carbon nano tube modified phenolic resin flame retardant material.

2. The high-strength carbon nanotube modified phenolic resin flame retardant material of claim 1, wherein: the ultrasonic device in the step (1) comprises a water bath, ultrasonic transmitters are fixedly connected to two sides inside the water bath, an objective table is fixedly connected to the lower portion inside the water bath, a reaction bottle is arranged above the objective table, a guide rail is fixedly connected to the upper portion of the water bath, a guide wheel is movably connected to the guide rail, and a cover plate is movably connected to the guide wheel.

3. The high-strength carbon nanotube modified phenolic resin flame retardant material of claim 1, wherein: the mass ratio of the hydroxylated carbon nanotube to the 3-chloropropyltriethoxysilane in the step (2) is 10: 15-30.

4. The high-strength carbon nanotube modified phenolic resin flame retardant material of claim 1, wherein: the catalyst in the step (3) is potassium iodide, the accelerator is tetrabutyl ammonium bromide, and the mass ratio of the chloropropyl carbon nano tube to the sodium azide to the potassium iodide to the tetrabutyl ammonium bromide is 100:30-60:8-15: 15-30.

5. The high-strength carbon nanotube modified phenolic resin flame retardant material of claim 1, wherein: the molecular formula of the m-ethynylbenzene diazonium salt in the step (4) is C₈H₅N₂Cl₂Structural formula is

6. The high-strength carbon nanotube modified phenolic resin flame retardant material of claim 1, wherein: the mass ratio of the phenolic resin to the m-ethynylbenzene diazonium salt in the step (5) is 100: 2-8.

7. The high-strength carbon nanotube modified phenolic resin flame retardant material of claim 1, wherein: the catalyst in the step (6) is sodium ascorbate, the cocatalyst is copper sulfate, and the mass ratio of the alkynyl phenolic resin, the carbon azide nanotube, the sodium ascorbate and the copper sulfate is 100:0.5-2:0.1-0.4: 0.08-0.32.

Technical Field

The invention relates to the technical field of phenolic resin, in particular to a high-strength carbon nano tube modified phenolic resin flame-retardant material and a preparation method thereof.

Background

The phenolic resin has the characteristics of low price, electric insulation, low toxicity, low smoke, good adhesion performance and the like, and is widely applied to the fields of chemical engineering, building materials, vehicle engineering, aerospace and aviation, but the traditional phenolic resin has high brittleness, low toughness and tensile strength, low heat resistance and heat stability, poor flame retardance, low carbon residue rate and smoke suppression rate of high-temperature thermal decomposition and easy generation of a large amount of toxic gases, so that the mechanical properties of the phenolic resin material such as toughness, tensile strength and the like, and the thermal stability and flame retardance of the material need to be improved.

The flame retardant is a functional auxiliary agent for endowing a high polymer material with flame retardancy, the traditional flame retardant mainly comprises a brominated flame retardant, a nitrogen-phosphorus flame retardant and the like, the carbon nano tube has a tubular one-dimensional nano structure, and has high mechanical strength, high temperature resistance, high heat conduction performance and high flame retardant performance, the carbon nano tube is used as a filler to be combined with the high polymer material, such as acrylic resin, phenolic resin and the like, so that the high temperature resistance and the flame retardant performance of the material can be obviously improved, but the compatibility of the carbon nano tube and the phenolic resin is poor, the specific surface area of the carbon nano tube is large, strong van der Waals force exists among nano particles, the carbon nano tube is not uniformly dispersed in a phenolic resin matrix and is easy to be mutually wound or agglomerated into a bundle, and the.

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides a high-strength carbon nanotube modified phenolic resin flame-retardant material and a preparation method thereof, which solve the problems of high brittleness, poor mechanical properties such as toughness and tensile strength and the like of phenolic resin and solve the problems of low heat resistance and flame retardance of phenolic resin.

(II) technical scheme

In order to achieve the purpose, the invention provides the following technical scheme: a high-strength carbon nanotube modified phenolic resin flame-retardant material is prepared by the following steps:

(1) adding a mixed solution of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 1:2.5-3.5 into a reaction bottle, adding a carbon nano tube, placing the mixture into an ultrasonic device, heating the mixture to 130-class temperature after uniform ultrasonic dispersion, stirring at a constant speed, refluxing for reaction for 3-5h, centrifugally separating to remove the solvent, washing the mixture to be neutral by using distilled water, and drying to prepare the hydroxylated carbon nano tube.

(2) Adding a toluene solvent and the hydroxylated carbon nano tube into a reaction bottle, uniformly dispersing by ultrasonic, adding 3-chloropropyltriethoxysilane, reacting for 12-24h at 80-110 ℃, centrifugally separating to remove the solvent, washing with distilled water and ethanol, and drying to prepare the chloropropylated carbon nano tube.

(3) Adding a toluene solvent and a chloropropylated carbon nanotube into a reaction bottle, uniformly dispersing by ultrasonic wave, adding sodium azide, a catalyst and an accelerant into a nitrogen atmosphere, heating to 80-110 ℃, uniformly stirring for reaction for 24-48h, centrifugally separating to remove the solvent, washing with distilled water and ethanol, and drying to prepare the carbon azide nanotube.

(4) Adding 10-18% by mass of hydrochloric acid solution into a reaction bottle, adding m-ethynylaniline, uniformly stirring and reacting at 55-65 ℃ for 30-60min, cooling to-5 to 0 ℃, slowly dropwise adding sodium nitrite aqueous solution, and reacting for 2-3h to obtain the m-ethynylbenzene diazonium salt.

(5) Adding a sodium hydroxide aqueous solution and an ethanol solvent into a reaction bottle, adding phenolic resin, stirring uniformly, adding m-ethynylbenzene diazonium salt at the temperature of-5 to 0 ℃, stirring at a constant speed for reaction for 6 to 12 hours, slowly dropwise adding dilute hydrochloric acid to adjust the pH of the solution to be neutral until precipitation is generated, filtering the solvent, washing with distilled water and drying to prepare the alkynyl-containing phenolic resin.

(6) Adding a toluene solvent, alkynyl-containing phenolic resin and carbon nano-tubes azide into a reaction bottle, performing ultrasonic dispersion uniformly in a nitrogen atmosphere, adding a catalyst and a cocatalyst, reacting for 12-24h, performing reduced pressure distillation to remove the solvent, washing with distilled water and drying to prepare the high-strength carbon nano-tube modified phenolic resin flame-retardant material.

Preferably, the ultrasonic device in the step (1) comprises a water bath, ultrasonic emitters are fixedly connected to two sides inside the water bath, an objective table is fixedly connected to the lower portion inside the water bath, a reaction bottle is arranged above the objective table, a guide rail is fixedly connected to the upper portion of the water bath, a guide wheel is movably connected to the guide rail, and a cover plate is movably connected to the guide wheel.

Preferably, the mass ratio of the hydroxylated carbon nanotube to the 3-chloropropyltriethoxysilane in the step (2) is 10: 15-30.

Preferably, the catalyst in the step (3) is potassium iodide, the accelerator is tetrabutyl ammonium bromide, and the mass ratio of the chloropropyl carbon nanotube, the sodium azide, the potassium iodide to the tetrabutyl ammonium bromide is 100:30-60:8-15: 15-30.

Preferably, the m-ethynylbenzene in the step (4) is heavyThe molecular formula of the nitrogen salt is C₈H₅N₂Cl₂Structural formula is

Preferably, the mass ratio of the phenolic resin to the m-ethynylbenzene diazonium salt in the step (5) is 100: 2-8.

Preferably, the catalyst in the step (6) is sodium ascorbate, the cocatalyst is copper sulfate, and the mass ratio of the alkynyl phenolic resin, the carbon azide nanotube, the sodium ascorbate and the copper sulfate is 100:0.5-2:0.1-0.4: 0.08-0.32.

(III) advantageous technical effects

Compared with the prior art, the invention has the following beneficial technical effects:

according to the high-strength carbon nanotube modified phenolic resin flame retardant material, rich hydroxyl groups of the hydroxylated carbon nanotube can react with 3-chloropropyltriethoxysilane to obtain a chloropropylated carbon nanotube, and chlorine atoms react with sodium azide under the catalytic action of potassium iodide and tetrabutylammonium bromide to obtain an azide functionalized carbon nanotube.

According to the high-strength carbon nanotube modified phenolic resin flame retardant material, a diazo group of m-ethynylbenzene diazonium salt reacts with a phenolic resin hydroxyl para-position carbon atom to obtain alkynyl phenolic resin with a side chain containing an ethynyl-diazo group, the alkynyl reacts with an azide group of an azide-functionalized carbon nanotube through rapid click reaction in a catalytic system of sodium ascorbate and copper sulfate to realize efficient 1, 3-dipole ring addition reaction to generate a triazole group, so that the carbon nanotube is modified into the side chain of the phenolic resin through a chemical covalent bond, the interface compatibility of the carbon nanotube and the phenolic resin is greatly improved, and the nanoparticles are prevented from being mutually aggregated and agglomerated due to van der Waals force under the modification effect of the covalent bond of the carbon nanotube, and are uniformly dispersed in a phenolic resin matrix.

The high-strength carbon nanotube modified phenolic resin flame-retardant material takes the azide group of the carbon nanotube as a crosslinking site, increases the crosslinking degree of the phenolic resin, and simultaneously the carbon nanotube has excellent mechanical properties, thereby reducing the brittleness of the phenolic resin material, improving the mechanical properties of the material, such as toughness, tensile strength, elastic modulus and the like, obviously improving the thermal stability and high temperature resistance of the material because the carbon nano tubes are highly dispersed in the phenolic resin, and under high-temperature combustion, the method is favorable for promoting the surface carbonization of the material, forming a compact and continuous carbon layer, improving the char forming rate and smoke suppression rate of the material, and the diazo matrix and the triazole group contained in the side chain contain rich nitrogen elements, the high-strength carbon nano tube modified phenolic resin can be decomposed into nitrogen-containing non-combustible gas under high-temperature combustion, so that the concentration of oxygen around the high-temperature carbon nano tube modified phenolic resin is reduced, the combustion process is further inhibited, and the high-strength carbon nano tube modified phenolic resin has excellent flame retardant property.

Drawings

FIG. 1 is a schematic front view of an ultrasound device;

FIG. 2 is a chemical structural formula of m-ethynylbenzene diazonium salt;

FIG. 3 is a reaction equation of m-ethynylaniline.

1-an ultrasonic device; 2-water bath; 3-an ultrasonic transmitter; 4-an object stage; 5-reaction flask; 6-a guide rail; 7-a guide wheel; 8-cover plate.

Detailed Description

To achieve the above object, the present invention provides the following embodiments and examples: a high-strength carbon nanotube modified phenolic resin flame-retardant material is prepared by the following steps:

(1) adding a mixed solution of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 1:2.5-3.5 into a reaction bottle, adding a carbon nano tube, placing the carbon nano tube into an ultrasonic device, wherein the ultrasonic device comprises a water bath, two sides in the water bath are fixedly connected with ultrasonic emitters, the lower part in the water bath is fixedly connected with an objective table, a reaction bottle is arranged above the objective table, a guide rail is fixedly connected above the water bath and is movably connected with a guide wheel, the guide wheel is movably connected with a cover plate, after the ultrasonic dispersion is uniform, heating is carried out to 130-phase and 150 ℃, carrying out uniform stirring reflux reaction for 3-5h, carrying out centrifugal separation to remove a solvent, washing the mixture to be neutral by distilled water and drying the mixture, thus.

(2) Adding a toluene solvent and a hydroxylated carbon nano tube into a reaction bottle, uniformly dispersing by ultrasonic, adding 3-chloropropyltriethoxysilane at the mass ratio of 10:15-30, reacting at 80-110 ℃ for 12-24h, centrifugally separating to remove the solvent, washing with distilled water and ethanol, and drying to prepare the chloropropylated carbon nano tube.

(3) Adding a toluene solvent and a chloropropylated carbon nanotube into a reaction bottle, uniformly dispersing by ultrasonic, adding sodium azide, a catalyst potassium iodide and an accelerator tetrabutylammonium bromide in a nitrogen atmosphere at a mass ratio of 100:30-60:8-15:15-30, heating to 80-110 ℃, uniformly stirring for reaction for 24-48h, centrifugally separating to remove the solvent, washing with distilled water and ethanol, and drying to prepare the azidoated carbon nanotube.

(4) Adding 10-18% hydrochloric acid solution into a reaction bottle, adding m-ethynylaniline, uniformly stirring and reacting at 55-65 ℃ for 30-60min, cooling to-5 to 0 ℃, slowly dropwise adding sodium nitrite aqueous solution, and reacting for 2-3h to obtain m-ethynylbenzene diazonium salt with molecular formula of C₈H₅N₂Cl₂Structural formula isThe reaction equation is

(5) Adding a sodium hydroxide aqueous solution and an ethanol solvent into a reaction bottle, adding phenolic resin, stirring uniformly, adding m-ethynylbenzene diazonium salt at the temperature of-5 to 0 ℃, stirring at a constant speed for 6 to 12 hours, slowly dropwise adding dilute hydrochloric acid to adjust the pH of the solution to be neutral until precipitation is generated, filtering the solvent, washing with distilled water and drying to prepare the alkynyl-containing phenolic resin.

(6) Adding a toluene solvent, alkynyl-containing phenolic resin and carbon nano-tubes azide into a reaction bottle, performing ultrasonic dispersion uniformly in a nitrogen atmosphere, adding a catalyst sodium ascorbate and a cocatalyst copper sulfate in a mass ratio of 100:0.5-2:0.1-0.4:0.08-0.32, reacting for 12-24h, performing reduced pressure distillation to remove the solvent, washing with distilled water and drying to prepare the high-strength carbon nano-tube modified phenolic resin flame-retardant material.

Example 1

(1) Adding a mixed solution of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 1:2.5 into a reaction bottle, adding a carbon nano tube, placing the reaction bottle into an ultrasonic device, wherein the ultrasonic device comprises a water bath, two sides inside the water bath are fixedly connected with ultrasonic emitters, an objective table is fixedly connected below the inside of the water bath, the reaction bottle is arranged above the objective table, a guide rail is fixedly connected above the water bath and movably connected with a guide wheel, the guide wheel is movably connected with a cover plate, heating is carried out to 130 ℃ after uniform ultrasonic dispersion, stirring at a constant speed is carried out, reflux reaction is carried out for 3 hours, a solvent is removed by centrifugal separation, washing is carried out to be neutral by distilled water, and drying is.

(2) Adding a toluene solvent and the hydroxylated carbon nanotube into a reaction bottle, uniformly dispersing by ultrasonic, adding 3-chloropropyltriethoxysilane at the mass ratio of 10:15, reacting for 12 hours at 80 ℃, centrifugally separating to remove the solvent, washing with distilled water and ethanol, and drying to prepare the chloropropylated carbon nanotube.

(3) Adding a toluene solvent and a chloropropylated carbon nanotube into a reaction bottle, uniformly dispersing by ultrasonic wave, adding sodium azide, a catalyst potassium iodide and an accelerator tetrabutylammonium bromide into a nitrogen atmosphere, wherein the mass ratio of the sodium azide to the catalyst potassium iodide to the accelerator tetrabutylammonium bromide is 100:30:8:15, heating to 80 ℃, uniformly stirring for reaction for 24 hours, centrifugally separating to remove the solvent, washing with distilled water and ethanol, and drying to prepare the carbon nanotube azide.

(4) Adding 10% hydrochloric acid solution by mass into a reaction bottle, adding m-ethynylaniline, stirring at a constant speed at 55 ℃ for reaction for 30min, cooling to-5 ℃, slowly dropwise adding sodium nitrite aqueous solution, and reacting for 2h to obtain the m-ethynylbenzene diazonium salt.

(5) Adding a sodium hydroxide aqueous solution and an ethanol solvent into a reaction bottle, adding phenolic resin, stirring uniformly, adding m-ethynylbenzene diazonium salt at the temperature of-5 ℃, stirring at a constant speed for 6 hours, slowly dropwise adding dilute hydrochloric acid to adjust the pH of the solution to be neutral until precipitation is separated out, filtering the solvent, washing with distilled water and drying to prepare the alkynyl-containing phenolic resin.

(6) Adding a toluene solvent, alkynyl-containing phenolic resin and carbon nano-tubes azide into a reaction bottle, performing ultrasonic dispersion uniformly in a nitrogen atmosphere, adding a catalyst sodium ascorbate and a cocatalyst copper sulfate in a mass ratio of 100:0.5:0.1:0.08, reacting for 12 hours, performing reduced pressure distillation to remove the solvent, washing with distilled water and drying to prepare the high-strength carbon nano-tube modified phenolic resin flame-retardant material 1.

Example 2

(1) Adding a mixed solution of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 1:2.8 into a reaction bottle, adding a carbon nano tube, placing the reaction bottle into an ultrasonic device, wherein the ultrasonic device comprises a water bath, two sides inside the water bath are fixedly connected with ultrasonic emitters, an objective table is fixedly connected below the inside of the water bath, the reaction bottle is arranged above the objective table, a guide rail is fixedly connected above the water bath and movably connected with a guide wheel, the guide wheel is movably connected with a cover plate, heating is carried out to 140 ℃ after uniform ultrasonic dispersion, stirring at a constant speed is carried out for reflux reaction for 4 hours, centrifugally separating to remove a solvent, washing with distilled water to be neutral, and drying to prepare the hydroxylated carbon nano tube.

(2) Adding a toluene solvent and a hydroxylated carbon nanotube into a reaction bottle, uniformly dispersing by ultrasonic, adding 3-chloropropyltriethoxysilane at the mass ratio of 10:20, reacting for 18h at 100 ℃, centrifugally separating to remove the solvent, washing with distilled water and ethanol, and drying to obtain the chloropropylated carbon nanotube.

(3) Adding a toluene solvent and a chloropropylated carbon nanotube into a reaction bottle, uniformly dispersing by ultrasonic wave, adding sodium azide, a catalyst potassium iodide and an accelerator tetrabutylammonium bromide into a nitrogen atmosphere, wherein the mass ratio of the sodium azide to the catalyst potassium iodide to the accelerator tetrabutylammonium bromide is 100:40:10:20, heating to 110 ℃, uniformly stirring for reaction for 48 hours, centrifugally separating to remove the solvent, washing with distilled water and ethanol, and drying to prepare the carbon nanotube azide.

(4) Adding a hydrochloric acid solution with the mass fraction of 15% into a reaction bottle, adding m-ethynylaniline, stirring at a constant speed at 65 ℃ for reacting for 40min, cooling the temperature to 0 ℃, slowly dropwise adding an aqueous solution of sodium nitrite, and reacting for 2.5h to prepare the m-ethynylbenzene diazonium salt.

(5) Adding a sodium hydroxide aqueous solution and an ethanol solvent into a reaction bottle, adding phenolic resin, stirring uniformly, adding m-ethynylbenzene diazonium salt at the temperature of-5 ℃, stirring at a constant speed for 10 hours, slowly dropwise adding dilute hydrochloric acid to adjust the pH of the solution to be neutral until precipitation is separated out, filtering the solvent, washing with distilled water and drying to prepare the alkynyl-containing phenolic resin.

(6) Adding a toluene solvent, alkynyl-containing phenolic resin and carbon nano-tubes azide into a reaction bottle, performing ultrasonic dispersion uniformly in a nitrogen atmosphere, adding a catalyst sodium ascorbate and a cocatalyst copper sulfate in a mass ratio of 100:1:0.2:0.016, reacting for 24 hours, performing reduced pressure distillation to remove the solvent, washing with distilled water and drying to prepare the high-strength carbon nano-tube modified phenolic resin flame-retardant material 2.

Example 3

(1) Adding a mixed solution of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 1:3.2 into a reaction bottle, adding a carbon nano tube, placing the reaction bottle into an ultrasonic device, wherein the ultrasonic device comprises a water bath, two sides inside the water bath are fixedly connected with ultrasonic emitters, an objective table is fixedly connected below the inside of the water bath, the reaction bottle is arranged above the objective table, a guide rail is fixedly connected above the water bath and movably connected with a guide wheel, the guide wheel is movably connected with a cover plate, heating is carried out to 140 ℃ after uniform ultrasonic dispersion, stirring at a constant speed is carried out for reflux reaction for 4 hours, centrifugally separating to remove a solvent, washing with distilled water to be neutral, and drying to obtain the hydroxylated carbon nano tube.

(2) Adding a toluene solvent and the hydroxylated carbon nanotube into a reaction bottle, uniformly dispersing by ultrasonic, adding 3-chloropropyltriethoxysilane at the mass ratio of 10:25, reacting for 18h at 100 ℃, centrifugally separating to remove the solvent, washing with distilled water and ethanol, and drying to obtain the chloropropylated carbon nanotube.

(3) Adding a toluene solvent and a chloropropylated carbon nanotube into a reaction bottle, uniformly dispersing by ultrasonic wave, adding sodium azide, a catalyst potassium iodide and an accelerator tetrabutylammonium bromide in a nitrogen atmosphere at a mass ratio of 100:50:12:25, heating to 100 ℃, uniformly stirring for reacting for 36 hours, centrifugally separating to remove the solvent, washing with distilled water and ethanol, and drying to prepare the carbon nanotube azide.

(4) Adding a hydrochloric acid solution with the mass fraction of 15% into a reaction bottle, adding m-ethynylaniline, stirring at a constant speed at 60 ℃ for reacting for 45min, cooling to-2 ℃, slowly dropwise adding an aqueous solution of sodium nitrite, and reacting for 2.5h to prepare the m-ethynylbenzene diazonium salt.

(5) Adding a sodium hydroxide aqueous solution and an ethanol solvent into a reaction bottle, adding phenolic resin, stirring uniformly, adding m-ethynylbenzene diazonium salt at the temperature of-2 ℃, stirring at a constant speed for 10 hours, slowly dropwise adding dilute hydrochloric acid to adjust the pH of the solution to be neutral until precipitation is separated out, filtering the solvent, washing with distilled water and drying to prepare the alkynyl-containing phenolic resin.

(6) Adding a toluene solvent, alkynyl-containing phenolic resin and carbon nano-tubes azide into a reaction bottle, performing ultrasonic dispersion uniformly in a nitrogen atmosphere, adding a catalyst sodium ascorbate and a cocatalyst copper sulfate in a mass ratio of 100:1.5:0.3:0.024, reacting for 18 hours, performing reduced pressure distillation to remove the solvent, washing with distilled water, and drying to prepare the high-strength carbon nano-tube modified phenolic resin flame-retardant material 3.

Example 4

(1) Adding a mixed solution of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 1:3.5 into a reaction bottle, adding a carbon nano tube, placing the reaction bottle into an ultrasonic device, wherein the ultrasonic device comprises a water bath, two sides inside the water bath are fixedly connected with ultrasonic emitters, an objective table is fixedly connected below the inside of the water bath, the reaction bottle is arranged above the objective table, a guide rail is fixedly connected above the water bath and movably connected with a guide wheel, the guide wheel is movably connected with a cover plate, heating is carried out to 150 ℃ after uniform ultrasonic dispersion, stirring at a constant speed is carried out for reflux reaction for 5 hours, centrifugally separating to remove a solvent, washing with distilled water to be neutral, and drying to obtain the hydroxylated carbon nano tube.

(2) Adding a toluene solvent and the hydroxylated carbon nanotube into a reaction bottle, uniformly dispersing by ultrasonic, adding 3-chloropropyltriethoxysilane at the mass ratio of 10:30, reacting for 24 hours at 110 ℃, centrifugally separating to remove the solvent, washing with distilled water and ethanol, and drying to prepare the chloropropylated carbon nanotube.

(3) Adding a toluene solvent and a chloropropylated carbon nanotube into a reaction bottle, uniformly dispersing by ultrasonic wave, adding sodium azide, a catalyst potassium iodide and an accelerator tetrabutylammonium bromide into a nitrogen atmosphere, wherein the mass ratio of the sodium azide to the catalyst potassium iodide to the accelerator tetrabutylammonium bromide is 100:60:15:30, heating to 110 ℃, uniformly stirring for reaction for 48 hours, centrifugally separating to remove the solvent, washing with distilled water and ethanol, and drying to prepare the carbon nanotube azide.

(4) Adding a hydrochloric acid solution with the mass fraction of 18% into a reaction bottle, adding m-ethynylaniline, stirring at a constant speed at 65 ℃ for reaction for 60min, cooling the temperature to 0 ℃, slowly dropwise adding an aqueous solution of sodium nitrite, and reacting for 3h to obtain the m-ethynylbenzene diazonium salt.

(5) Adding a sodium hydroxide aqueous solution and an ethanol solvent into a reaction bottle, adding phenolic resin, stirring uniformly, adding m-ethynylbenzene diazonium salt at 0 ℃, wherein the mass ratio of the m-ethynylbenzene diazonium salt to the m-ethynylbenzene diazonium salt is 100:8, stirring at a constant speed for 2 hours, slowly dropwise adding dilute hydrochloric acid to adjust the pH of the solution to be neutral until precipitation is generated, filtering the solvent, washing with distilled water and drying to prepare the alkynyl-containing phenolic resin.

(6) Adding a toluene solvent, alkynyl-containing phenolic resin and carbon nano-tubes azide into a reaction bottle, performing ultrasonic dispersion uniformly in a nitrogen atmosphere, adding a catalyst sodium ascorbate and a cocatalyst copper sulfate in a mass ratio of 100:2:0.4:0.32, reacting for 24 hours, performing reduced pressure distillation to remove the solvent, washing with distilled water, and drying to prepare the high-strength carbon nano-tube modified phenolic resin flame-retardant material 4.

Comparative example 1

(1) Adding a mixed solution of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 1:2 into a reaction bottle, adding a carbon nano tube, placing the reaction bottle into an ultrasonic device, wherein the ultrasonic device comprises a water bath, two sides inside the water bath are fixedly connected with ultrasonic emitters, an objective table is fixedly connected below the inside of the water bath, the reaction bottle is arranged above the objective table, a guide rail is fixedly connected above the water bath, the guide rail is movably connected with a guide wheel, the guide wheel is movably connected with a cover plate, heating is carried out to 150 ℃ after uniform ultrasonic dispersion, stirring and refluxing reaction is carried out at a constant speed for 3h, a solvent is removed by centrifugal separation, washing is carried out to be neutral by distilled water, and drying.

(2) Adding a toluene solvent and a hydroxylated carbon nanotube into a reaction bottle, uniformly dispersing by ultrasonic, adding 3-chloropropyltriethoxysilane at the mass ratio of 1:1, reacting for 24 hours at 110 ℃, centrifugally separating to remove the solvent, washing with distilled water and ethanol, and drying to prepare the chloropropylated carbon nanotube.

(3) Adding a toluene solvent and a chloropropylated carbon nanotube into a reaction bottle, uniformly dispersing by ultrasonic wave, adding sodium azide, a catalyst potassium iodide and an accelerator tetrabutylammonium bromide into a nitrogen atmosphere, wherein the mass ratio of the sodium azide to the catalyst potassium iodide to the accelerator tetrabutylammonium bromide is 100:20:6:10, heating to 110 ℃, uniformly stirring for reaction for 48 hours, centrifugally separating to remove the solvent, washing with distilled water and ethanol, and drying to prepare the carbon nanotube azide.

(4) Adding a hydrochloric acid solution with the mass fraction of 15% into a reaction bottle, adding m-ethynylaniline, stirring at a constant speed at 65 ℃ for reaction for 60min, cooling to-5 ℃, slowly dropwise adding an aqueous solution of sodium nitrite, and reacting for 3h to obtain the m-ethynylbenzene diazonium salt.

(5) Adding a sodium hydroxide aqueous solution and an ethanol solvent into a reaction bottle, adding phenolic resin, stirring uniformly, adding m-ethynylbenzene diazonium salt at 0 ℃, stirring at a constant speed for 12 hours, slowly dropwise adding dilute hydrochloric acid to adjust the pH of the solution to be neutral until precipitation is generated, filtering the solvent, washing with distilled water and drying to prepare the alkynyl-containing phenolic resin.

(6) Adding a toluene solvent, alkynyl-containing phenolic resin and carbon nano-tubes azide into a reaction bottle, performing ultrasonic dispersion uniformly in a nitrogen atmosphere, adding a catalyst sodium ascorbate and a cocatalyst copper sulfate in a mass ratio of 100:0.2:0.05:0.04, reacting for 24 hours, performing reduced pressure distillation to remove the solvent, washing with distilled water, and drying to prepare the high-strength carbon nano-tube modified phenolic resin flame-retardant material, namely comparative 1.

The limiting oxygen index of the high-strength carbon nanotube modified phenolic resin flame-retardant materials in the examples and the comparative examples is tested by using an hc-2 limiting oxygen index tester, and the test standard is GB/T2406.1-2008.

The tensile strength and the elastic modulus of the material are tested by using a WDW-300H universal tester, and the test standard is GB/T25253-2010.