CN106008974B - A kind of preparation method of high hydrophobic fluorinated carbon nano-tube/polyimide composite material - Google Patents

Abstract

The invention discloses a method for preparing a highly hydrophobic fluorinated carbon nanotube/polyimide composite material, which relates to a method for preparing a polyimide composite material. The purpose of the present invention is to reduce the high dielectric constant of pure polyimide, improve its mechanical properties, reduce its moisture absorption in engineering applications, improve its service life, and solve its special application in electrical insulation and power electronics restricted issues. Methods: 1. Prepare fluorinated carbon nanotubes; 2. Obtain highly hydrophobic fluorinated carbon nanotubes/polyimide composites by in-situ polymerization. The preparation method of a highly hydrophobic fluorinated carbon nanotube/polyimide composite material of the present invention can be scaled up industrially, and has huge potential application prospects in the fields of electrical insulation and power electronics in the future, and is new to polyimide The application prospect is of great significance. The invention can obtain a preparation method of highly hydrophobic fluorinated carbon nanotube/polyimide composite material.

Description

A kind of preparation method of highly hydrophobic fluorinated carbon nanotube/polyimide composite material

technical field

The invention relates to a preparation method of a polyimide composite material.

Background technique

Because of its unique electrical properties, excellent mechanical properties, good chemical and thermal stability, and light weight, carbon nanotubes are ideal reinforcements for composite materials. The preparation of polymer/carbon nanotube composites has become a research topic for composite materials. hotspots. However, carbon nanotubes are easy to aggregate into bundles and have low dispersion in common organic solvents, which restricts their application fields. In addition, carbon nanotubes have excellent electrical conductivity. When they are added to polymers as fillers, the electrical conductivity can be greatly improved by adding a small amount, but the composite material after the insulation performance is greatly deteriorated cannot be applied in the field of electrical insulation. The fluorinated carbon nanotubes obtained by fluorinating carbon nanotubes by chemical methods not only retain the original mechanical properties and wear resistance of carbon nanotubes, but also have conductors and become insulators. They are used as fillers to fill polymers. , which can improve the mechanical properties without deteriorating its insulating properties.

As a polymer film material with excellent performance, polyimide has been used in the transmission of electric energy, rail transit, aerospace and energy storage, and its application fields are still expanding. It is one of the highest heat-resistant polymer materials actually used in industry. It has excellent electrical, mechanical, chemical and radiation resistance in an extremely wide temperature range. It is one of the first choice materials for insulation in the electromechanical industry. However, polymer In practical applications, imide materials are easy to absorb water vapor in the air, which will cause premature failure of the material and cause safety hazards.

Contents of the invention

The purpose of the present invention is to further improve the dielectric constant of pure polyimide, improve its electrical insulation and mechanical properties, solve the problem that its application in special fields is limited, and provide a highly hydrophobic fluorinated carbon nanotube/polyimide Preparation method of imide composite material.

A preparation method of highly hydrophobic fluorinated carbon nanotube/polyimide composite material is completed according to the following steps:

1. Preparation of fluorinated carbon nanotubes:

①, the multi-walled carbon nanotubes are placed in an airtight container;

②. Vacuumize the airtight container until the pressure in the airtight container drops below 1Pa; then inject argon into the airtight container until the pressure in the airtight container rises to 10 ⁵ Pa;

③. Repeat step 1 ② 3 to 5 times;

④. Put the mixed gas of argon and fluorine into the airtight container until the pressure in the airtight container rises to 0.5atm~1atm. The heating rate is raised from room temperature to 150°C to 300°C, and then kept at a pressure of 0.5atm to 1atm and a temperature of 150°C to 300°C for 1h to 3h to obtain fluorinated carbon nanotubes;

The ratio of argon and fluorine in the mixed gas of argon and fluorine described in step 1.4 is 1:(1～10);

2. Obtain highly hydrophobic fluorinated carbon nanotubes/polyimide composites by in-situ polymerization:

①. Add the fluorinated carbon nanotubes obtained in step 1 into dimethylacetamide, then stir and react at a stirring speed of 100r/min to 300r/min for 2h to 5h, and then at an ultrasonic power of 100W to 500W Ultrasonic treatment for 12 hours to 24 hours to obtain a dispersion of fluorinated carbon nanotubes with a mass fraction of 0.5% to 5% of fluorinated carbon nanotubes;

②. Add diamine to the fluorinated carbon nanotube dispersion with a mass fraction of 0.5% to 5% of fluorinated carbon nanotubes, and then ultrasonically treat it at an ultrasonic power of 100W to 300W for 2h to 6h, and then stir at a stirring speed of 100r Add dianhydride in 5 times at a temperature of 100r/min to 300r/min at a speed of 100r/min to 300r/min for 12h to 24h to obtain a solution containing polyamic acid and fluorinated carbon nanotubes;

The diamine described in step two ② is 4,4'-diaminodiphenyl ether;

The dianhydride described in step 2 ② is biphenyl dianhydride or isophthalic dianhydride; the biphenyl dianhydride is 3,3',4,4'-biphenyltetracarboxylic dianhydride; the The pyromellitic dianhydride described is pyromellitic dianhydride;

The volume ratio of the mass fraction of the diamine described in step 2 to the fluorinated carbon nanotube dispersion liquid with a mass fraction of 0.5% to 5% of the fluorinated carbon nanotubes is 3g: (50mL to 60mL);

Step 2. The mol ratio of diamine and dianhydride described in 2. is 1:1;

③. Put the solution containing polyamic acid and fluorinated carbon nanotubes in a vacuum box at room temperature for 2h to 8h, then cast, spin coat or lay a film on a clean board, and then heat it at 3 to 6°C Raise the temperature from room temperature to 80°C at a heating rate of /min, and keep at 80°C for 1h;

Then raise the temperature from 80°C to 120°C at a heating rate of 3-6°C/min, and then hold at 120°C for 1 hour;

Then raise the temperature from 120°C to 150°C at a heating rate of 3-6°C/min, and then keep it at 150°C for 1 hour;

Then raise the temperature from 150°C to 210°C at a heating rate of 3-6°C/min, and then keep it at 210°C for 1 hour;

Then raise the temperature from 210°C to 240°C at a heating rate of 3-6°C/min, and keep at 240°C for 1 hour;

Then raise the temperature from 240°C to 300°C at a heating rate of 3-6°C/min, and then hold at 300°C for 1 hour;

Then raise the temperature from 300°C to 350°C at a heating rate of 3-6°C/min, and then hold at 350°C for 1 hour;

Then cool down to room temperature naturally, and demold to obtain highly hydrophobic fluorinated carbon nanotube/polyimide composite material.

Advantages of the present invention:

1. Compared with the highly hydrophobic fluorinated carbon nanotube/polyimide composite material prepared by the present invention and the polyimide film, its hydrophobic performance has been improved, and its mechanics has been improved, but its insulation performance has not been reduced ;

2. The preparation method of a highly hydrophobic fluorinated carbon nanotube/polyimide composite material of the present invention can be scaled up industrially, and has huge potential application prospects in the fields of electrical insulation and power electronics in the future. For polyimide New application prospects are of great significance;

3. The tensile strength of the highly hydrophobic fluorinated carbon nanotube/polyimide composite material prepared by the present invention is greater than 150MPa;

4. The dielectric constant of the highly hydrophobic fluorinated carbon nanotube/polyimide composite material prepared by the present invention is between 3.8 and 4.5;

5. The contact angle of the highly hydrophobic fluorinated carbon nanotube/polyimide composite material prepared by the present invention is 102°, while that of pure polyimide is 71°.

The invention can obtain a preparation method of highly hydrophobic fluorinated carbon nanotube/polyimide composite material.

Description of drawings

Fig. 1 is the TEM figure of the fluorinated carbon nanotube obtained in step one 4. in embodiment one;

Fig. 2 is the SEM picture of the highly hydrophobic fluorinated carbon nanotube/polyimide composite material that step 2.3 of embodiment 1 obtains;

Fig. 3 is a dielectric property diagram, among Fig. 3, 1 is the dielectric property curve of the highly hydrophobic fluorinated carbon nanotube/polyimide composite material prepared by embodiment one, and 2 is the highly hydrophobic fluorinated carbon prepared by embodiment two The dielectric property curve of the nanotube/polyimide composite material, 3 is the dielectric property curve of the highly hydrophobic fluorinated carbon nanotube/polyimide composite material prepared in embodiment three, and 4 is the highly hydrophobic fluorinated carbon nanotube/polyimide composite material prepared in embodiment four Dielectric property curves of hydrophobic fluorinated carbon nanotubes/polyimide composites;

Fig. 4 is the contact angle figure of the pure polyimide prepared by comparative test;

Fig. 5 is the contact angle diagram of the highly hydrophobic fluorinated carbon nanotube/polyimide composite material prepared in embodiment two;

Fig. 6 is the change curve figure of elongation at break with tensile strength, among Fig. 6, 1 is the change curve of elongation at break of the pure polyimide prepared by comparative test with tensile strength, and 2 is prepared by embodiment one The elongation at break of the highly hydrophobic fluorinated carbon nanotube/polyimide composite material varies with the tensile strength curve, and 3 is the fracture of the highly hydrophobic fluorinated carbon nanotube/polyimide composite material prepared in Example 2 The variation curve of elongation with tensile strength, 4 is the variation curve of elongation at break of the highly hydrophobic fluorinated carbon nanotube/polyimide composite material prepared in embodiment three with tensile strength, and 5 is embodiment four The curve of elongation at break versus tensile strength of the prepared highly hydrophobic fluorinated carbon nanotubes/polyimide composites.

Detailed ways

Embodiment 1: This embodiment is a preparation method of a highly hydrophobic fluorinated carbon nanotube/polyimide composite material, which is completed in the following steps:

1. Preparation of fluorinated carbon nanotubes:

①, the multi-walled carbon nanotubes are placed in an airtight container;

②. Vacuumize the airtight container until the pressure in the airtight container drops below 1Pa; then inject argon into the airtight container until the pressure in the airtight container rises to 10 ⁵ Pa;

③. Repeat step 1 ② 3 to 5 times;

④. Put the mixed gas of argon and fluorine into the airtight container until the pressure in the airtight container rises to 0.5atm~1atm. The heating rate is raised from room temperature to 150°C to 300°C, and then kept at a pressure of 0.5atm to 1atm and a temperature of 150°C to 300°C for 1h to 3h to obtain fluorinated carbon nanotubes;

The ratio of argon and fluorine in the mixed gas of argon and fluorine described in step 1.4 is 1:(1～10);

2. Obtain highly hydrophobic fluorinated carbon nanotubes/polyimide composites by in-situ polymerization:

①. Add the fluorinated carbon nanotubes obtained in step 1 into dimethylacetamide, then stir and react at a stirring speed of 100r/min to 300r/min for 2h to 5h, and then at an ultrasonic power of 100W to 500W Ultrasonic treatment for 12 hours to 24 hours to obtain a dispersion of fluorinated carbon nanotubes with a mass fraction of 0.5% to 5% of fluorinated carbon nanotubes;

②. Add diamine to the fluorinated carbon nanotube dispersion with a mass fraction of 0.5% to 5% of fluorinated carbon nanotubes, and then ultrasonically treat it at an ultrasonic power of 100W to 300W for 2h to 6h, and then stir at a stirring speed of 100r Add dianhydride in 5 times at a temperature of 100r/min to 300r/min at a speed of 100r/min to 300r/min for 12h to 24h to obtain a solution containing polyamic acid and fluorinated carbon nanotubes;

The diamine described in step two ② is 4,4'-diaminodiphenyl ether;

The dianhydride described in step 2 ② is biphenyl dianhydride or isophthalic dianhydride; the biphenyl dianhydride is 3,3',4,4'-biphenyltetracarboxylic dianhydride; the The pyromellitic dianhydride described is pyromellitic dianhydride;

The volume ratio of the mass fraction of the diamine described in step 2 to the fluorinated carbon nanotube dispersion liquid with a mass fraction of 0.5% to 5% of the fluorinated carbon nanotubes is 3g: (50mL to 60mL);

Step 2. The mol ratio of diamine and dianhydride described in 2. is 1:1;

③. Put the solution containing polyamic acid and fluorinated carbon nanotubes in a vacuum box at room temperature for 2h to 8h, then cast, spin coat or lay a film on a clean board, and then heat it at 3 to 6°C Raise the temperature from room temperature to 80°C at a heating rate of /min, and keep at 80°C for 1h;

Then raise the temperature from 80°C to 120°C at a heating rate of 3-6°C/min, and then hold at 120°C for 1 hour;

Then raise the temperature from 120°C to 150°C at a heating rate of 3-6°C/min, and then keep it at 150°C for 1 hour;

Then raise the temperature from 150°C to 210°C at a heating rate of 3-6°C/min, and then keep it at 210°C for 1 hour;

Then raise the temperature from 210°C to 240°C at a heating rate of 3-6°C/min, and keep at 240°C for 1 hour;

Then raise the temperature from 240°C to 300°C at a heating rate of 3-6°C/min, and then hold at 300°C for 1 hour;

Then raise the temperature from 300°C to 350°C at a heating rate of 3-6°C/min, and then hold at 350°C for 1 hour;

Then cool down to room temperature naturally, and demold to obtain highly hydrophobic fluorinated carbon nanotube/polyimide composite material.

The advantage of this implementation mode:

1. Compared with the highly hydrophobic fluorinated carbon nanotube/polyimide composite material prepared in this embodiment and/polyimide film, its hydrophobic performance has been improved, and its mechanics has been improved, but its insulation performance has not reduce;

2. The preparation method of a highly hydrophobic fluorinated carbon nanotube/polyimide composite material in this embodiment can be scaled up industrially, and has huge potential application prospects in the fields of electrical insulation and power electronics in the future. The new application prospect of amine is of great significance;

3. The tensile strength of the highly hydrophobic fluorinated carbon nanotube/polyimide composite material prepared in this embodiment is greater than 150 MPa;

4. The dielectric constant of the highly hydrophobic fluorinated carbon nanotube/polyimide composite material prepared in this embodiment is between 3.8 and 4.5;

5. The contact angle of the highly hydrophobic fluorinated carbon nanotube/polyimide composite material prepared in this embodiment is 102°, while that of pure polyimide is 71°.

In this embodiment, a method for preparing a highly hydrophobic fluorinated carbon nanotube/polyimide composite material can be obtained.

Specific embodiment two: the difference between this embodiment and specific embodiment one is: in step 1.4, pass the mixed gas of argon and fluorine gas into the airtight container until the pressure in the airtight container rises to 1 atm, and then the pressure is The temperature was raised from room temperature to 250° C. at a rate of 4° C./min at 1 atm, and then kept at a pressure of 1 atm and a temperature of 250° C. for 2 hours to obtain fluorinated carbon nanotubes. Other steps are the same as in the first embodiment.

Specific embodiment three: the difference between this embodiment and specific embodiment one or two is: in step 2 ①, the fluorinated carbon nanotubes obtained in step 1 are added in dimethylacetamide, and then the stirring speed is Stirring and reacting at 100 r/min for 2 hours, and then sonicating at an ultrasonic power of 300 W for 12 hours to obtain a dispersion of fluorinated carbon nanotubes with a mass fraction of 0.5% of fluorinated carbon nanotubes. Other steps are the same as those in Embodiment 1 or 2.

Embodiment 4: The difference between this embodiment and Embodiment 1 to 3 is that the mass fraction of diamine and fluorinated carbon nanotubes in step 2.2 are 0.5% to 5% carbon fluoride The volume ratio of the nanotube dispersion is 3g:60mL. Other steps are the same as those in Embodiments 1 to 3.

Specific embodiment five: the difference between this embodiment and one of specific embodiments one to four is: in step 2 (3), the solution containing polyamic acid and fluorinated carbon nanotubes is placed in a vacuum box at room temperature for 2 hours, and then Cast, spin-coat or lay a film on a clean plate, then raise the temperature from room temperature to 80°C at a rate of 3°C/min, and keep it at 80°C for 1 hour;

Then raise the temperature from 80°C to 120°C at a heating rate of 3°C/min, and then keep it at 120°C for 1 hour;

Then raise the temperature from 120°C to 150°C at a heating rate of 3°C/min, and keep at 150°C for 1 hour;

Then raise the temperature from 150°C to 210°C at a heating rate of 3°C/min, and keep at 210°C for 1 hour;

Then raise the temperature from 210°C to 240°C at a heating rate of 3°C/min, and keep at 240°C for 1 hour;

Then raise the temperature from 240°C to 300°C at a heating rate of 3°C/min, and keep at 300°C for 1 hour;

Then raise the temperature from 300°C to 350°C at a heating rate of 3°C/min, and then hold at 350°C for 1 hour;

Then cool down to room temperature naturally, and demold to obtain highly hydrophobic fluorinated carbon nanotube/polyimide composite material.

Other steps are the same as those in Embodiments 1 to 4.

Specific embodiment six: the difference between this embodiment and one of specific embodiments one to five is: in step 2 (3), the solution containing polyamic acid and fluorinated carbon nanotubes is placed in a vacuum box at room temperature for 2 hours, and then Cast, spin coat or spread film on a clean plate, then raise the temperature from room temperature to 80°C at a rate of 5°C/min, and keep it at 80°C for 1 hour;

Then raise the temperature from 80°C to 120°C at a heating rate of 5°C/min, and keep at 120°C for 1 hour;

Then raise the temperature from 120°C to 150°C at a heating rate of 5°C/min, and keep at 150°C for 1 hour;

Then raise the temperature from 150°C to 210°C at a heating rate of 5°C/min, and then hold at 210°C for 1 hour;

Then raise the temperature from 210°C to 240°C at a heating rate of 5°C/min, and then keep it at 240°C for 1 hour;

Then raise the temperature from 240°C to 300°C at a heating rate of 5°C/min, and then hold at 300°C for 1 hour;

Then raise the temperature from 300°C to 350°C at a heating rate of 5°C/min, and then hold at 350°C for 1 hour;

Then cool down to room temperature naturally, and demold to obtain highly hydrophobic fluorinated carbon nanotube/polyimide composite material.

Other steps are the same as those in Embodiments 1 to 5.

Specific embodiment seven: the difference between this embodiment and one of specific embodiments one to six is: in step 2 (3), the solution containing polyamic acid and fluorinated carbon nanotubes is placed in a vacuum box at room temperature for 2 hours, and then Cast, spin-coat or lay a film on a clean plate, then raise the temperature from room temperature to 80°C at a rate of 6°C/min, and keep it at 80°C for 1 hour;

Then raise the temperature from 80°C to 120°C at a heating rate of 6°C/min, and then hold at 120°C for 1 hour;

Then raise the temperature from 120°C to 150°C at a heating rate of 6°C/min, and then keep it at 150°C for 1 hour;

Then raise the temperature from 150°C to 210°C at a heating rate of 6°C/min, and keep at 210°C for 1 hour;

Then raise the temperature from 210°C to 240°C at a heating rate of 6°C/min, and then keep it at 240°C for 1 hour;

Then raise the temperature from 240°C to 300°C at a heating rate of 6°C/min, and then hold at 300°C for 1 hour;

Then raise the temperature from 300°C to 350°C at a heating rate of 6°C/min, and keep at 350°C for 1 hour;

Then cool down to room temperature naturally, and demold to obtain highly hydrophobic fluorinated carbon nanotube/polyimide composite material.

Other steps are the same as those in Embodiments 1 to 6.

Embodiment 8: The difference between this embodiment and Embodiments 1 to 7 is that in Step 2 ①, the fluorinated carbon nanotubes obtained in Step 1 are added to dimethylacetamide, and then the stirring speed is 100r Stirring and reacting at 1/min for 2 hours, and then sonicating for 12 hours at an ultrasonic power of 500 W, to obtain a dispersion of fluorinated carbon nanotubes with a mass fraction of 1% of fluorinated carbon nanotubes. Other steps are the same as those in Embodiments 1 to 7.

Specific embodiment nine: the difference between this embodiment and specific embodiment one to eight is: in step 2 ①, the fluorinated carbon nanotubes obtained in step 1 are added to dimethylacetamide, and then the stirring speed is 100r The mixture was stirred and reacted for 2 hours at 1/min, and then ultrasonically treated for 12 hours at an ultrasonic power of 300 W to obtain a fluorinated carbon nanotube dispersion with a mass fraction of 3% fluorinated carbon nanotubes. Other steps are the same as those in Embodiments 1 to 8.

Embodiment 10: The difference between this embodiment and Embodiment 1 to Embodiment 9 is that in Step 2 ①, the fluorinated carbon nanotubes obtained in Step 1 are added to dimethylacetamide, and then the stirring speed is 100r The mixture was stirred and reacted for 2 h at 1/min, and then ultrasonically treated for 12 h at an ultrasonic power of 500 W to obtain a dispersion of fluorinated carbon nanotubes with a mass fraction of 5% of the fluorinated carbon nanotubes. Other steps are the same as those in Embodiments 1 to 9.

Adopt the following examples to verify the beneficial effects of the present invention:

Embodiment 1: a kind of preparation method of highly hydrophobic fluorinated carbon nanotube/polyimide composite material is completed according to the following steps:

A preparation method of highly hydrophobic fluorinated carbon nanotube/polyimide composite material is completed according to the following steps:

1. Preparation of fluorinated carbon nanotubes:

①, the multi-walled carbon nanotubes are placed in an airtight container;

②. Vacuumize the airtight container until the pressure in the airtight container drops below 0.5 Pa; then feed argon into the airtight container until the pressure in the airtight container rises to 10 ⁵ Pa;

③. Repeat steps 1 and ② 5 times;

④. Introduce the mixed gas of argon and fluorine into the airtight container until the pressure in the airtight container rises to 1atm, then raise the temperature from room temperature to 250°C at a rate of 4°C/min under the pressure of 1atm, and then The pressure is 1 atm and the temperature is 250 ° C for 2 hours to obtain fluorinated carbon nanotubes;

The ratio of argon and fluorine in the mixed gas of argon and fluorine described in step 1.4 is 1:5;

2. Obtain highly hydrophobic fluorinated carbon nanotubes/polyimide composites by in-situ polymerization:

①. Add the fluorinated carbon nanotubes obtained in step 1 into dimethylacetamide, then stir and react at a stirring speed of 100r/min for 2h, and then ultrasonically treat at an ultrasonic power of 300W for 12h to obtain fluorinated carbon The mass fraction of nanotubes is 0.5% fluorinated carbon nanotube dispersion;

②. Add diamine to the fluorinated carbon nanotube dispersion with a mass fraction of 0.5% of fluorinated carbon nanotubes, then ultrasonically treat it for 2 hours at an ultrasonic power of 300W, and then add it in 5 times at a stirring speed of 200r/min Dianhydride, then stirred at a stirring speed of 200r/min for 12h to obtain a solution containing polyamic acid and fluorinated carbon nanotubes;

The diamine described in step two ② is 4,4'-diaminodiphenyl ether;

The dianhydride described in step two (2) is a phthalic dianhydride; the phthalic dianhydride is pyromellitic dianhydride;

The volume ratio of the mass fraction of the diamine described in step 2 ② to the fluorinated carbon nanotube dispersion liquid with a mass fraction of 0.5% of the fluorinated carbon nanotubes is 3g:60mL;

Step 2. The mol ratio of diamine and dianhydride described in 2. is 1:1;

③. Put the solution containing polyamic acid and fluorinated carbon nanotubes in a vacuum box at room temperature for 2 hours, then spin-coat it on a clean plate, and then raise the temperature from room temperature to 80°C at a rate of 3°C/min. ℃, and keep warm at 80℃ for 1h;

Then raise the temperature from 80°C to 120°C at a heating rate of 3°C/min, and then keep it at 120°C for 1 hour;

Then raise the temperature from 120°C to 150°C at a heating rate of 3°C/min, and keep at 150°C for 1 hour;

Then raise the temperature from 150°C to 210°C at a heating rate of 3°C/min, and keep at 210°C for 1 hour;

Then raise the temperature from 210°C to 240°C at a heating rate of 3°C/min, and keep at 240°C for 1 hour;

Then raise the temperature from 240°C to 300°C at a heating rate of 3°C/min, and keep at 300°C for 1 hour;

Then raise the temperature from 300°C to 350°C at a heating rate of 3°C/min, and then hold at 350°C for 1 hour;

Then cool down to room temperature naturally, and demold to obtain highly hydrophobic fluorinated carbon nanotube/polyimide composite material.

Embodiment two: a kind of preparation method of highly hydrophobic fluorinated carbon nanotube/polyimide composite material is finished according to the following steps:

1. Preparation of fluorinated carbon nanotubes:

①, the multi-walled carbon nanotubes are placed in an airtight container;

②. Vacuumize the airtight container until the pressure in the airtight container drops to 0.5 Pa; then inject argon into the airtight container until the pressure in the airtight container rises to 10 ⁵ Pa;

③. Repeat steps 1 and ② 5 times;

④. Introduce the mixed gas of argon and fluorine into the airtight container until the pressure in the airtight container rises to 1atm, then raise the temperature from room temperature to 250°C at a rate of 4°C/min under the pressure of 1atm, and then The pressure is 1 atm and the temperature is 250 ° C for 2 hours to obtain fluorinated carbon nanotubes;

The ratio of argon and fluorine in the mixed gas of argon and fluorine described in step 1.4 is 1:5;

2. Obtain highly hydrophobic fluorinated carbon nanotubes/polyimide composites by in-situ polymerization:

①. Add the fluorinated carbon nanotubes obtained in step 1 into dimethylacetamide, then stir and react at a stirring speed of 100r/min for 2h, and then ultrasonically treat at an ultrasonic power of 500W for 12h to obtain fluorinated carbon The mass fraction of nanotubes is 1% fluorinated carbon nanotube dispersion;

②. Add diamine to the fluorinated carbon nanotube dispersion with a mass fraction of 1% of fluorinated carbon nanotubes, and then ultrasonically treat it for 2 hours at an ultrasonic power of 300W, and then add it in 5 times at a stirring speed of 200r/min. Dianhydride, then stirred at a stirring speed of 200r/min for 12h to obtain a solution containing polyamic acid and fluorinated carbon nanotubes;

The diamine described in step two ② is 4,4'-diaminodiphenyl ether;

The dianhydride described in step two (2) is a phthalic dianhydride; the phthalic dianhydride is pyromellitic dianhydride;

The volume ratio of the mass fraction of the diamine described in step 2 ② to the fluorinated carbon nanotube dispersion liquid with a mass fraction of fluorinated carbon nanotubes of 1% is 3g:60mL;

Step 2. The mol ratio of diamine and dianhydride described in 2. is 1:1;

③. Put the solution containing polyamic acid and fluorinated carbon nanotubes in a vacuum box at room temperature for 2 hours, then spin-coat it on a clean plate, and then raise the temperature from room temperature to 80°C at a rate of 5°C/min. ℃, and keep warm at 80℃ for 1h;

Then raise the temperature from 80°C to 120°C at a heating rate of 5°C/min, and keep at 120°C for 1 hour;

Then raise the temperature from 120°C to 150°C at a heating rate of 5°C/min, and keep at 150°C for 1 hour;

Then raise the temperature from 150°C to 210°C at a heating rate of 5°C/min, and then hold at 210°C for 1 hour;

Then raise the temperature from 210°C to 240°C at a heating rate of 5°C/min, and then keep it at 240°C for 1 hour;

Then raise the temperature from 240°C to 300°C at a heating rate of 5°C/min, and then hold at 300°C for 1 hour;

Then raise the temperature from 300°C to 350°C at a heating rate of 5°C/min, and then hold at 350°C for 1 hour;

Then cool down to room temperature naturally, and demold to obtain highly hydrophobic fluorinated carbon nanotube/polyimide composite material.

Embodiment three: a kind of preparation method of highly hydrophobic fluorinated carbon nanotube/polyimide composite material is finished according to the following steps:

1. Preparation of fluorinated carbon nanotubes:

①, the multi-walled carbon nanotubes are placed in an airtight container;

②. Vacuumize the airtight container until the pressure in the airtight container drops to 0.5 Pa; then inject argon into the airtight container until the pressure in the airtight container rises to 10 ⁵ Pa;

③. Repeat steps 1 and ② 5 times;

④. Introduce the mixed gas of argon and fluorine into the airtight container until the pressure in the airtight container rises to 1atm, then raise the temperature from room temperature to 250°C at a rate of 4°C/min under the pressure of 1atm, and then The pressure is 1 atm and the temperature is 250 ° C for 2 hours to obtain fluorinated carbon nanotubes;

The ratio of argon and fluorine in the mixed gas of argon and fluorine described in step 1.4 is 1:5;

2. Obtain highly hydrophobic fluorinated carbon nanotubes/polyimide composites by in-situ polymerization:

①. Add the fluorinated carbon nanotubes obtained in step 1 into dimethylacetamide, then stir and react at a stirring speed of 100r/min for 2h, and then ultrasonically treat at an ultrasonic power of 300W for 12h to obtain fluorinated carbon The mass fraction of nanotubes is 3% fluorinated carbon nanotube dispersion;

②. Add diamine to the fluorinated carbon nanotube dispersion with a mass fraction of 3% fluorinated carbon nanotubes, then ultrasonically treat it for 2 hours at an ultrasonic power of 100W, and then add it in 5 times at a stirring speed of 200r/min Dianhydride, then stirred at a stirring speed of 200r/min for 12h to obtain a solution containing polyamic acid and fluorinated carbon nanotubes;

The diamine described in step two ② is 4,4'-diaminodiphenyl ether;

The dianhydride described in step two (2) is a phthalic dianhydride; the phthalic dianhydride is pyromellitic dianhydride;

The volume ratio of the mass fraction of the diamine described in step 2 ② to the fluorinated carbon nanotube dispersion liquid with a mass fraction of fluorinated carbon nanotubes of 3% is 3g:60mL;

Step 2. The mol ratio of diamine and dianhydride described in 2. is 1:1;

③. Put the solution containing polyamic acid and fluorinated carbon nanotubes in a vacuum box at room temperature for 2 hours, then spin-coat it on a clean plate, and then raise the temperature from room temperature to 80°C at a rate of 5°C/min. ℃, and keep warm at 80℃ for 1h;

Then raise the temperature from 80°C to 120°C at a heating rate of 5°C/min, and keep at 120°C for 1 hour;

Then raise the temperature from 120°C to 150°C at a heating rate of 5°C/min, and keep at 150°C for 1 hour;

Then raise the temperature from 150°C to 210°C at a heating rate of 5°C/min, and then hold at 210°C for 1 hour;

Then raise the temperature from 210°C to 240°C at a heating rate of 5°C/min, and then keep it at 240°C for 1 hour;

Then raise the temperature from 240°C to 300°C at a heating rate of 5°C/min, and then hold at 300°C for 1 hour;

Then raise the temperature from 300°C to 350°C at a heating rate of 5°C/min, and then hold at 350°C for 1 hour;

Then cool down to room temperature naturally, and demold to obtain highly hydrophobic fluorinated carbon nanotube/polyimide composite material.

Embodiment four: a kind of preparation method of highly hydrophobic fluorinated carbon nanotube/polyimide composite material is finished according to the following steps:

1. Preparation of fluorinated carbon nanotubes:

①, the multi-walled carbon nanotubes are placed in an airtight container;

②. Vacuumize the airtight container until the pressure in the airtight container drops to 0.5 Pa; then inject argon into the airtight container until the pressure in the airtight container rises to 10 ⁵ Pa;

③. Repeat steps 1 and ② 5 times;

④. Introduce the mixed gas of argon and fluorine into the airtight container until the pressure in the airtight container rises to 1atm, then raise the temperature from room temperature to 250°C at a rate of 4°C/min under the pressure of 1atm, and then The pressure is 1 atm and the temperature is 250 ° C for 2 hours to obtain fluorinated carbon nanotubes;

The ratio of argon and fluorine in the mixed gas of argon and fluorine described in step 1.4 is 1:5;

2. Obtain highly hydrophobic fluorinated carbon nanotubes/polyimide composites by in-situ polymerization:

①. Add the fluorinated carbon nanotubes obtained in step 1 into dimethylacetamide, then stir and react at a stirring speed of 100r/min for 2h, and then ultrasonically treat at an ultrasonic power of 500W for 12h to obtain fluorinated carbon The mass fraction of nanotubes is 5% fluorinated carbon nanotube dispersion;

②. Add diamine to the fluorinated carbon nanotube dispersion with a mass fraction of 5% fluorinated carbon nanotubes, and then ultrasonically treat it for 2 hours at an ultrasonic power of 300W, and then add it in 5 times at a stirring speed of 200r/min. Dianhydride, then stirred at a stirring speed of 200r/min for 12h to obtain a solution containing polyamic acid and fluorinated carbon nanotubes;

The diamine described in step two ② is 4,4'-diaminodiphenyl ether;

The dianhydride described in step two (2) is a phthalic dianhydride; the phthalic dianhydride is pyromellitic dianhydride;

The volume ratio of the mass fraction of the diamine described in step 2 to the fluorinated carbon nanotube dispersion liquid in which the mass fraction of the fluorinated carbon nanotubes is 0.5% to 5% is 3g:60mL;

Step 2. The mol ratio of diamine and dianhydride described in 2. is 1:1;

③. Put the solution containing polyamic acid and fluorinated carbon nanotubes in a vacuum box at room temperature for 2 hours, then spin-coat it on a clean plate, and then increase the temperature from room temperature at a rate of 3-6°C/min to 80°C, and keep warm at 80°C for 1h;

Then raise the temperature from 80°C to 120°C at a heating rate of 6°C/min, and then hold at 120°C for 1 hour;

Then raise the temperature from 120°C to 150°C at a heating rate of 6°C/min, and then keep it at 150°C for 1 hour;

Then raise the temperature from 150°C to 210°C at a heating rate of 6°C/min, and keep at 210°C for 1 hour;

Then raise the temperature from 210°C to 240°C at a heating rate of 6°C/min, and then keep it at 240°C for 1 hour;

Then raise the temperature from 240°C to 300°C at a heating rate of 6°C/min, and then hold at 300°C for 1 hour;

Then raise the temperature from 300°C to 350°C at a heating rate of 6°C/min, and keep at 350°C for 1 hour;

Then cool down to room temperature naturally, and demold to obtain highly hydrophobic fluorinated carbon nanotube/polyimide composite material.

Comparative test: a kind of method for preparing polyimide is specifically finished according to the following steps:

1. Add diamine to dimethylacetamide, then add dianhydride in 5 times at a stirring speed of 200r/min, and then stir for 12 hours at a stirring speed of 200r/min to obtain a solution containing polyamic acid;

The diamine described in step 1 is 4,4'-diaminodiphenyl ether;

The dianhydride described in the step 1 is a phthalic dianhydride; the phthalic dianhydride is a pyromellitic dianhydride;

The mass of diamine described in step 1 and the volume ratio of dimethylacetamide are 3g:60mL;

Step 2. The mol ratio of diamine and dianhydride described in 2. is 1:1;

2. Put the solution containing polyamic acid and fluorinated carbon nanotubes in a vacuum box at room temperature for 2 hours, then spin-coat it on a clean plate, and then raise the temperature from room temperature to 80°C at a rate of 5°C/min , and kept at 80°C for 1h;

Then raise the temperature from 80°C to 120°C at a heating rate of 5°C/min, and keep at 120°C for 1 hour;

Then raise the temperature from 120°C to 150°C at a heating rate of 5°C/min, and keep at 150°C for 1 hour;

Then raise the temperature from 150°C to 210°C at a heating rate of 5°C/min, and then hold at 210°C for 1 hour;

Then raise the temperature from 210°C to 240°C at a heating rate of 5°C/min, and then keep it at 240°C for 1 hour;

Then raise the temperature from 240°C to 300°C at a heating rate of 5°C/min, and then hold at 300°C for 1 hour;

Then raise the temperature from 300°C to 350°C at a heating rate of 5°C/min, and then hold at 350°C for 1 hour;

Then cool down to room temperature naturally, and demold to obtain pure polyimide.

Fig. 1 is the TEM figure of the fluorinated carbon nanotube obtained in step one 4. in embodiment one;

It can be seen from Figure 1 that the diameter of the fluorinated carbon nanotubes is about tens of nanometers and the length is several micrometers;

Fig. 2 is the SEM picture of the highly hydrophobic fluorinated carbon nanotube/polyimide composite material that step 2.3 of embodiment 1 obtains;

As can be seen from Figure 2, the fluorinated carbon nanotubes are uniformly dispersed in the polyimide-based composite material;

Fig. 3 is a dielectric property diagram, among Fig. 3, 1 is the dielectric property curve of the highly hydrophobic fluorinated carbon nanotube/polyimide composite material prepared by embodiment one, and 2 is the highly hydrophobic fluorinated carbon prepared by embodiment two The dielectric property curve of the nanotube/polyimide composite material, 3 is the dielectric property curve of the highly hydrophobic fluorinated carbon nanotube/polyimide composite material prepared in embodiment three, and 4 is the highly hydrophobic fluorinated carbon nanotube/polyimide composite material prepared in embodiment four Dielectric property curves of hydrophobic fluorinated carbon nanotubes/polyimide composites;

It can be seen from Figure 3 that the dielectric constant of polyimide composites filled with fluorinated carbon nanotubes with different contents is between 3.8 and 4.5;

Fig. 4 is the contact angle figure of the pure polyimide prepared by comparative test;

Fig. 5 is the contact angle diagram of the highly hydrophobic fluorinated carbon nanotube/polyimide composite material prepared in embodiment two;

It can be seen from Figure 4 and Figure 5 that the contact angle of the pure polyimide prepared in the comparative test is 71°, and the contact angle of the highly hydrophobic fluorinated carbon nanotube/polyimide composite material prepared in Example 2 is 102°.

Fig. 6 is the change curve figure of elongation at break with tensile strength, among Fig. 6, 1 is the change curve of elongation at break of the pure polyimide prepared by comparative test with tensile strength, and 2 is prepared by embodiment one The elongation at break of the highly hydrophobic fluorinated carbon nanotube/polyimide composite material varies with the tensile strength curve, and 3 is the fracture of the highly hydrophobic fluorinated carbon nanotube/polyimide composite material prepared in Example 2 The variation curve of elongation with tensile strength, 4 is the variation curve of elongation at break of the highly hydrophobic fluorinated carbon nanotube/polyimide composite material prepared in embodiment three with tensile strength, and 5 is embodiment four The curve of elongation at break versus tensile strength of the prepared highly hydrophobic fluorinated carbon nanotubes/polyimide composites.

It can be seen from Figure 6 that the tensile strength of the polyimide-based composite material doped with fluorinated carbon nanotubes has been greatly improved.

Claims (10)

1. a kind of preparation method of high hydrophobic fluorinated carbon nano-tube/polyimide composite material, it is characterised in that a kind of high hydrophobic The preparation method of carbon fluoride nano-tube/composite polyimide material is completed according to the following steps：

First, carbon fluoride nano-tube is prepared：

1., multi-walled carbon nanotube is placed in closed container；

2., to being vacuumized in closed container, until closed container in pressure be down to below 1Pa；Again into closed container Argon gas is passed through, until pressure rises to 10 in closed container⁵Pa；

3., repeat step one 2. 3 times~5 times；

4., be passed through into closed container the mixed gas of argon gas and fluorine gas, the pressure into closed container rise to 0.5atm~ 1atm, then pressure be 0.5atm~1atm under with the heating rate of 3 DEG C/min~5 DEG C/min from room temperature to 150 DEG C~ 300 DEG C, then 1h~3h is kept the temperature in the case where pressure is 0.5atm~1atm and temperature is 150 DEG C~300 DEG C, obtain fluorocarbons nanometer Pipe；

4. the ratio of argon gas and fluorine gas is 1 to step 1 in the mixed gas of the argon gas and fluorine gas:(1~10)；

2nd, situ aggregation method obtains high hydrophobic fluorinated carbon nano-tube/polyimide composite material：

1., the carbon fluoride nano-tube obtained in step 1 is added in dimethylacetylamide, then low whipping speed is 100r/ Stirring reaction 2h~5h under min~300r/min, then 12h~24h is ultrasonically treated in the case where ultrasonic power is 100W~500W, obtain The mass fraction of carbon fluoride nano-tube is 0.5%~5% carbon fluoride nano-tube dispersion liquid；

2., to carbon fluoride nano-tube mass fraction be 0.5%~5% carbon fluoride nano-tube dispersion liquid add diamines, then Ultrasonic power is that 2h~6h, then low whipping speed are ultrasonically treated under 100W~300W as lower point of 100r/min~300r/min 5 times Dianhydride is added, then low whipping speed is that 12h~24h is stirred under 100r/min~300r/min, is obtained containing polyamic acid and fluorine The solution of carbon nano tube；

Step 2 2. described in diamines be 4,4 '-diaminodiphenyl ether；

Step 2 2. described in dianhydride be equal benzene-type dianhydride；The equal benzene-type dianhydride is pyromellitic acid anhydride；

Step 2 2. described in diamines quality and carbon fluoride nano-tube mass fraction be 0.5%~5% fluorocarbons receive The volume ratio of mitron dispersion liquid is 3g:(50mL~60mL)；

Step 2 2. described in diamines and dianhydride molar ratio be 1:1；

3., the solution containing polyamic acid and carbon fluoride nano-tube existed, 2h~8h is stood in vacuum tank at room temperature, then flow Prolong, spin coating or plastic film mulch on clean plate, then with the heating rate of 3~6 DEG C/min from room temperature to 80 DEG C, and at 80 DEG C Keep the temperature 1h；

120 DEG C are warming up to from 80 DEG C with the heating rate of 3~6 DEG C/min again, then 1h is kept the temperature at 120 DEG C；

150 DEG C are warming up to from 120 DEG C with the heating rate of 3~6 DEG C/min again, then 1h is kept the temperature at 150 DEG C；

210 DEG C are warming up to from 150 DEG C with the heating rate of 3~6 DEG C/min again, then 1h is kept the temperature at 210 DEG C；

240 DEG C are warming up to from 210 DEG C with the heating rate of 3~6 DEG C/min again, then 1h is kept the temperature at 240 DEG C；

300 DEG C are warming up to from 240 DEG C with the heating rate of 3~6 DEG C/min again, then 1h is kept the temperature at 300 DEG C；

350 DEG C are warming up to from 300 DEG C with the heating rate of 3~6 DEG C/min again, then 1h is kept the temperature at 350 DEG C；

Room temperature is naturally cooling to again, is demoulded, and obtains high hydrophobic fluorinated carbon nano-tube/polyimide composite material.

2. a kind of preparation method of high hydrophobic fluorinated carbon nano-tube/polyimide composite material according to claim 1, its The mixed gas of argon gas and fluorine gas is passed through in being characterized in that step 1 4. into closed container, the pressure into closed container rises to 1atm, then in the case where pressure is 1atm with the heating rate of 4 DEG C/min from room temperature to 250 DEG C, then in pressure be 1atm and temperature Spend to keep the temperature 2h at 250 DEG C, obtain carbon fluoride nano-tube.

3. a kind of preparation method of high hydrophobic fluorinated carbon nano-tube/polyimide composite material according to claim 1, its The carbon fluoride nano-tube obtained in step 1 is added in dimethylacetylamide in being characterized in that step 2 1., then in stirring speed Spend and react 2h for stirring under 100r/min, then 12h is ultrasonically treated in the case where ultrasonic power is 300W, obtain the matter of carbon fluoride nano-tube Measure the carbon fluoride nano-tube dispersion liquid that fraction is 0.5%.

4. a kind of preparation method of high hydrophobic fluorinated carbon nano-tube/polyimide composite material according to claim 1, its The quality of diamines described in being characterized in that step 2 2. and the fluorination that the mass fraction of carbon fluoride nano-tube is 0.5%~5% The volume ratio of carbon nano tube dispersion liquid is 3g:60mL.

5. a kind of preparation method of high hydrophobic fluorinated carbon nano-tube/polyimide composite material according to claim 1, its The solution containing polyamic acid and carbon fluoride nano-tube is existed in being characterized in that step 2 3., is stood in vacuum tank at room temperature 2h, then will be cast, spin coating or plastic film mulch on clean plate, then with the heating rate of 3 DEG C/min from room temperature to 80 DEG C, and 1h is kept the temperature at 80 DEG C；

120 DEG C are warming up to from 80 DEG C with the heating rate of 3 DEG C/min again, then 1h is kept the temperature at 120 DEG C；

150 DEG C are warming up to from 120 DEG C with the heating rate of 3 DEG C/min again, then 1h is kept the temperature at 150 DEG C；

210 DEG C are warming up to from 150 DEG C with the heating rate of 3 DEG C/min again, then 1h is kept the temperature at 210 DEG C；

240 DEG C are warming up to from 210 DEG C with the heating rate of 3 DEG C/min again, then 1h is kept the temperature at 240 DEG C；

300 DEG C are warming up to from 240 DEG C with the heating rate of 3 DEG C/min again, then 1h is kept the temperature at 300 DEG C；

350 DEG C are warming up to from 300 DEG C with the heating rate of 3 DEG C/min again, then 1h is kept the temperature at 350 DEG C；

Room temperature is naturally cooling to again, is demoulded, and obtains high hydrophobic fluorinated carbon nano-tube/polyimide composite material.

6. a kind of preparation method of high hydrophobic fluorinated carbon nano-tube/polyimide composite material according to claim 1, its The solution containing polyamic acid and carbon fluoride nano-tube is existed in being characterized in that step 2 3., is stood in vacuum tank at room temperature 2h, then will be cast, spin coating or plastic film mulch on clean plate, then with the heating rate of 5 DEG C/min from room temperature to 80 DEG C, and 1h is kept the temperature at 80 DEG C；

120 DEG C are warming up to from 80 DEG C with the heating rate of 5 DEG C/min again, then 1h is kept the temperature at 120 DEG C；

150 DEG C are warming up to from 120 DEG C with the heating rate of 5 DEG C/min again, then 1h is kept the temperature at 150 DEG C；

210 DEG C are warming up to from 150 DEG C with the heating rate of 5 DEG C/min again, then 1h is kept the temperature at 210 DEG C；

240 DEG C are warming up to from 210 DEG C with the heating rate of 5 DEG C/min again, then 1h is kept the temperature at 240 DEG C；

300 DEG C are warming up to from 240 DEG C with the heating rate of 5 DEG C/min again, then 1h is kept the temperature at 300 DEG C；

350 DEG C are warming up to from 300 DEG C with the heating rate of 5 DEG C/min again, then 1h is kept the temperature at 350 DEG C；

Room temperature is naturally cooling to again, is demoulded, and obtains high hydrophobic fluorinated carbon nano-tube/polyimide composite material.

7. a kind of preparation method of high hydrophobic fluorinated carbon nano-tube/polyimide composite material according to claim 1, its The solution containing polyamic acid and carbon fluoride nano-tube is existed in being characterized in that step 2 3., is stood in vacuum tank at room temperature 2h, then will be cast, spin coating or plastic film mulch on clean plate, then with the heating rate of 6 DEG C/min from room temperature to 80 DEG C, and 1h is kept the temperature at 80 DEG C；

120 DEG C are warming up to from 80 DEG C with the heating rate of 6 DEG C/min again, then 1h is kept the temperature at 120 DEG C；

150 DEG C are warming up to from 120 DEG C with the heating rate of 6 DEG C/min again, then 1h is kept the temperature at 150 DEG C；

210 DEG C are warming up to from 150 DEG C with the heating rate of 6 DEG C/min again, then 1h is kept the temperature at 210 DEG C；

240 DEG C are warming up to from 210 DEG C with the heating rate of 6 DEG C/min again, then 1h is kept the temperature at 240 DEG C；

300 DEG C are warming up to from 240 DEG C with the heating rate of 6 DEG C/min again, then 1h is kept the temperature at 300 DEG C；

350 DEG C are warming up to from 300 DEG C with the heating rate of 6 DEG C/min again, then 1h is kept the temperature at 350 DEG C；

Room temperature is naturally cooling to again, is demoulded, and obtains high hydrophobic fluorinated carbon nano-tube/polyimide composite material.

8. a kind of preparation method of high hydrophobic fluorinated carbon nano-tube/polyimide composite material according to claim 1, its The carbon fluoride nano-tube obtained in step 1 is added in dimethylacetylamide in being characterized in that step 2 1., then in stirring speed Spend and react 2h for stirring under 100r/min, then 12h is ultrasonically treated in the case where ultrasonic power is 500W, obtain the matter of carbon fluoride nano-tube Measure the carbon fluoride nano-tube dispersion liquid that fraction is 1%.

9. a kind of preparation method of high hydrophobic fluorinated carbon nano-tube/polyimide composite material according to claim 1, its The carbon fluoride nano-tube obtained in step 1 is added in dimethylacetylamide in being characterized in that step 2 1., then in stirring speed Spend and react 2h for stirring under 100r/min, then 12h is ultrasonically treated in the case where ultrasonic power is 300W, obtain the matter of carbon fluoride nano-tube Measure the carbon fluoride nano-tube dispersion liquid that fraction is 3%.

10. a kind of preparation method of high hydrophobic fluorinated carbon nano-tube/polyimide composite material according to claim 1, It is characterized in that step 2 1. in the carbon fluoride nano-tube obtained in step 1 is added in dimethylacetylamide, then stirring Speed is stirring reaction 2h under 100r/min, then is ultrasonically treated 12h in the case where ultrasonic power is 500W, obtains carbon fluoride nano-tube Mass fraction is 5% carbon fluoride nano-tube dispersion liquid.