CN108221175A - A kind of preparation method of high-voltage electricity polyvinylidene fluoride composite material - Google Patents

Abstract

The invention discloses a preparation method of a high-voltage electric polyvinylidene fluoride composite material, which relates to the preparation technology of piezoelectric flexible materials. The polyvinylidene fluoride composite material is a composite fiber membrane prepared by electrospinning with polyvinylidene fluoride as the matrix and the core-shell structure formed by nano-barium titanate and carbon nanotubes as the reinforcement. The purpose of the present invention is to overcome the problem that the existing polyvinylidene fluoride piezoelectric fiber membrane is mixed with two kinds of reinforcements unevenly, the two kinds of reinforcements are agglomerated or the content of β crystal phase in the fiber membrane is not high, and the piezoelectric performance is not good. question. The CNT@BaTiO ₃ (core/shell) particles prepared by chemical methods can be uniformly dispersed in the polymer, and the prepared composite fiber membrane has good flexibility and mechanical properties. Its crystallinity is 55%-80%, the content of β crystal phase is 60%-91%, and the piezoelectric constant _D33 is 35-50pC/N, which can be applied to piezoelectric sensors, piezoelectric nanogenerators and other devices.

Description

A kind of preparation method of high voltage polyvinylidene fluoride composite material

technical field

The invention relates to a method for preparing a high-performance polyvinylidene fluoride/CNT@BaTiO ₃ composite piezoelectric flexible device, belonging to the technical field of preparation of new materials.

Background technique

With the development of science and technology and the improvement of people's living standards, flexible wearable devices have attracted more and more attention because of their excellent performance, such as the ability to monitor people's pulse, heart rate, etc., to improve the comfort of people's lives. Polyvinylidene fluoride (PVDF) is a polymer piezoelectric material widely used at present. It has the advantages of strong piezoelectric performance, wide frequency response, high sensitivity and low price. However, PVDF is a typical polymorphic polymer. The energy storage properties are closely related to the crystalline morphology. Previous studies have shown that only the polar zigzag β crystal form exhibits higher piezoelectricity and pyroelectricity. However, the content of β crystal phase in PVDF is very low. Therefore, increasing the content of β crystal phase in PVDF and obtaining a β crystal form with high crystallinity and high orientation is the key to exerting the excellent energy storage performance of PVDF thin films, and it is also a hot research topic today.

The traditional polyvinylidene fluoride piezoelectric film is prepared by firstly preparing the polyvinylidene fluoride film, and then undergoing a process of crystal transformation, and the preparation process is complicated. Many researchers are now working on finding a simpler method to prepare polymer films, which makes the operation simple and the prepared films have excellent properties. Electrospinning is a preparation method that can meet the above requirements, and it is a one-step process for preparing fiber membranes with excellent performance. Moreover, choosing a suitable receiving device can realize high-degree orientation arrangement of fibers, and under the synergistic effect of high-voltage electric field, can increase the β-phase content of the fiber membrane. Another way to increase the β-phase content of PVDF films is to dope nanoparticles or metal inorganic salts in the spinning precursor solution. The additives can be used as nucleating agents or conductive phases in the solution to improve the crystallinity and crystallinity of the polymer. phase content. Barium titanate ceramics is a high dielectric piezoelectric material, but its quality is brittle; the conductivity of polyvinylidene fluoride and barium titanate is not good, adding carbon nanotubes can improve the conductivity of electrospun fibers. However, at present, polyvinylidene fluoride is doped with a single additive (such as carbon nanotubes, barium titanate, TiO ₂ , etc.) . If there are multiple substances in the spinning precursor solution, the whole system will be more complicated, and it is difficult to figure out the relationship between the components in the whole system. Several reports on polyvinylidene fluoride/carbon nanotube/barium titanate thin film first use mechanical mixing to simply mix CNT and BaTiO ₃ , and then add PVDF to prepare the precursor, but the mixing is prone to inhomogeneity, so that In the spinning process, the components are agglomerated separately, which affects the performance of the electrospun fiber membrane; the other is to use chemical vapor deposition (CVD) to grow carbon nanotubes on micron-sized barium titanate, and then deposit this Seed particles are mixed with PVDF to prepare the precursor, but this method requires high equipment and complicated operation. The preparation of two inorganic spinning precursor additives using this simple chemical synthesis method has not been reported.

Contents of the invention

The purpose of the present invention is to overcome the shortcomings of uneven mixing between the two fillers or complicated preparation process when two fillers (carbon nanotubes and nano-barium titanate) are doped in the existing polyvinylidene fluoride composite material, and provide A method for preparing a polyvinylidene fluoride composite piezoelectric fiber membrane that realizes high β crystal phase transformation of PVDF and ordered orientation arrangement of β crystal phase, and the prepared polyvinylidene fluoride composite fiber membrane has a higher β crystal phase transformation And higher piezoelectric strain constant D ₃₃ .

Technical solution of the present invention is:

The preparation method of high voltage electric polyvinylidene fluoride composite fiber membrane, according to the following steps:

1. Preparation of CNT@BaTiO ₃ core-shell structure: specifically including four steps of mixed acid modification of carbon nanotubes, amidation reaction of carbon nanotubes, surface modification of nano-barium titanate, and grafting reaction of CNT@BaTiO ₃ .

(1) Mixed acid modification of carbon nanotubes: prepare a mixed acid of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 1:1-5:1, and cool to room temperature. Then put the original carbon nanotubes into the prepared mixed acid, sonicate at room temperature for 30-60min, then sonicate at 40-80℃ for 4-8h, then cool to room temperature, centrifuge, add deionized water to wash, repeat several times, until PH=7. Then the obtained CNTs were vacuum-dried at 50-120° C. to constant weight for use.

Wherein, the carbon nanotubes are one of multi-walled carbon nanotubes (MWCNTs) or single-walled carbon nanotubes (SWCNTs), and the concentration of CNTs in the mixed acid is 4 mg/mL-20 mg/mL.

(2) Amidation of acid-modified carbon nanotubes: ultrasonically stir the acid-modified carbon nanotubes and 1mol/L HCl for 15-60min, then add excess p-phenylenediamine, and reflux at 60-130°C for 18 -26h, the desired product was obtained. The resultant is centrifuged, washed, and vacuum-dried at 50-120° C. to constant weight to obtain amidated carbon nanotubes CNT-CO-NH-C ₆ H ₄ NH ₂ .

(3) Surface modification of nano-barium titanate: Add nano-BaTiO ₃ particles into ethanol, disperse ultrasonically for 30-120min, then add 0.5-2g KH550 silane coupling agent, stir and react at 50-90℃ for 2-5h , the obtained _BaTiO3 was centrifuged, washed, and vacuum-dried at 50–120 °C to constant weight.

Wherein, the ratio of nanometer barium titanate to ethanol is 2.5mg/mL-20mg/mL.

(4) Grafting reaction of CNT@BaTiO ₃ : add 1 mol/L HCl solution and BaTiO ₃ particles modified by silane coupling agent into a single-necked flask, ultrasonically disperse for 0.5-2 h; at the same time, add amidated CNT to Ultrasound-15-60min in the Erlenmeyer flask containing n-hexane, after mixing evenly, also add it to the above single-necked flask containing BaTiO ₃ particles, keep stirring in an ice bath at 1-5°C for 8-15h, and obtain titanic acid Solution of barium grafted amidated carbon nanotubes. After the reaction was completed, it was centrifuged and vacuum-dried at 50-120°C to constant weight to obtain the desired chemically bonded CNT@BaTiO ₃ particles.

Wherein, the mass ratio of modified nano barium titanate to amidated CNT is 1:1-12:1.

2. Preparation of precursor spinning solution: Put the CNT@BaTiO ₃ particles obtained in step 1 into N,N-dimethylformamide (DMF) solvent for ultrasonic dispersion for 1-4 hours to obtain the dispersion of doped particles solution; at the same time, disperse the polyvinylidene fluoride PVDF powder into another DMF organic solvent, stir magnetically at 40-60°C for 1-5h, until the PVDF powder is completely dissolved, then add the prepared CNT@BaTiO ₃ dispersion and acetone , after ultrasonic dispersion for 30 minutes, continue magnetic stirring for 1-3 hours, until the particles are evenly dispersed in the PVDF solution, after standing still, set aside.

The concentration of PVDF is 8wt%-20wt%, the doping amount of CNT@ _BaTiO3 particles is 0.01wt%-2.0wt% (relative to the mass of PVDF), and the volume ratio of organic solvent and acetone is 9:1-5:5 .

3. Preparation of PVDF/CNT@BaTiO ₃ nanocomposite: First, suck 4mL of the prepared precursor solution into a medical syringe, put the syringe on the syringe pump and clamp it, set the injection speed, and then connect the positive pole of the high voltage power supply To the spinning stainless steel needle, the aluminum foil is connected to the negative electrode, the drum is used as the receiving device, the rotating speed of the drum and the high voltage are set, the spinning starts, and the power is turned off after the end. Carefully peel off the aluminum foil from the roller, and dry it in a blast drying oven at 50-100°C for 2-8 hours to evaporate the residual solvent, then transfer the dried fiber film to a sample bag, write a label, and put it in Store in a desiccator until use.

Among them, the spinning voltage is 12-26kV, the injection speed of the syringe pump is 0.5ml/h-3.0ml/h, the selected needle type is 27G-18G, the distance between the needle and the collection device is 10-20cm, the rotation speed of the drum 300-2500rpm.

The crystallinity of the composite material fiber membrane prepared by the invention is 55%-80%, the content of beta crystal phase is 60%-91%, and the piezoelectric constant _d33 is 35-50pC/N.

4. Characterization and performance test of PVDF/CNT@BaTiO ₃ nanocomposite fiber membrane:

The morphology of the fiber membrane was tested by scanning electron microscope (SEM), the crystallization properties of the fiber membrane were measured by X-ray diffractometer (XRD), and the crystallinity and β crystal phase content of the fiber membrane were analyzed and calculated by Peakfit software.

Cut a piece of fiber membrane of 1.5×2cm, put the fiber membrane on the quasi-static instrument, select five points for testing, record the test data, and take the average value to obtain the piezoelectric strain constant D ₃₃ .

Advantages and beneficial effects of the present invention:

A high-voltage polyvinylidene fluoride composite material was invented and prepared. The fiber membrane is prepared by electrospinning with PVDF as the matrix and CNT@BaTiO ₃ (core/shell) as the reinforcement. Firstly, the CNT and _BaTiO3 were treated by chemical methods, so that barium titanate was grafted onto the carbon nanotubes through p-phenylenediamine to form a core-shell structure and increase the uniformity of dispersion of CNT and _BaTiO3 in the solution. Then the PVDF/CNT@BaTiO ₃ solution is prepared, and the PVDF/CNT@BaTiO ₃ composite fiber membrane is prepared by electrospinning. The composite fiber membrane can be coated with electrodes to make sensor devices, and can also be used as battery separators and supercapacitors. Electrodes, etc., are widely used.

Compared with the prior art, the present invention has two reinforcing phases doped in the polymer, and the two reinforcing phases are chemically connected to make it uniformly dispersed in the spinning precursor solution, reducing carbon nanotube and the agglomeration of nano-barium titanate; the second is that the prepared composite fiber membrane has good flexibility, good conductivity, high content of β crystal phase, and good piezoelectric performance.

Description of drawings

Fig. 1 is a scanning electron microscope SEM photo of the composite nanofibrous membrane prepared in Example 1 of the present invention.

Fig. 2 is the XRD pattern of the PVDF/CNT@BaTiO ₃ composite nanofiber membrane prepared in Example 4 of the present invention.

Fig. 3 is an XRD pattern of a pure PVDF nanofiber membrane prepared in a comparative example of the present invention.

Fig. 4 is an XRD peak diagram of the PVDF/CNT@BaTiO ₃ composite nanofiber membrane prepared in Example 4 of the present invention.

Detailed ways

In order to further understand the present invention, the preferred embodiments of the present invention are described below in conjunction with the examples, but it should be understood that these descriptions are only to further illustrate the characteristics and advantages of the present invention, rather than limiting the claims of the present invention.

Example 1

Prepare polyvinylidene fluoride/CNT@BaTiO ₃ composite fiber materials according to the method provided by the invention:

1. Preparation of CNT@BaTiO ₃ core-shell structure

(1) Mixed acid modification of carbon nanotubes: prepare 180 mL of mixed acid of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 3:1, and cool to room temperature. Then put 2g of original MWCNT into the prepared mixed acid, sonicate at room temperature for 30min, 50℃ for 6h, then cool to room temperature, centrifuge, add deionized water to wash, repeat several times until PH = 7, and the obtained CNT Dry in vacuum at 80°C until constant weight.

(2) Amidation of acid-modified carbon nanotubes: ultrasonically stir the acid-modified carbon nanotubes and 200 mL of 1mol/L HCl for 30 min, then add excess p-phenylenediamine, and reflux at 90 ° C for 24 h to obtain the obtained Need product. The resultant was centrifuged, washed, and vacuum-dried at 80° C. to constant weight to obtain amidated carbon nanotubes MWCNTs-CO-NH-C ₆ H ₄ NH ₂ .

(3) Surface modification of nano-barium titanate: add 2g nano-BaTiO ₃ particles into 200mL ethanol, disperse ultrasonically for 60min, then add 1gKH550 silane coupling agent, stir at 60°C for 3h, centrifuge the obtained BaTiO ₃ , Wash and dry in vacuum at 80°C to constant weight.

(4) Grafting reaction of CNT@BaTiO ₃ : Add 150 mL of 1mol/L HCl solution and 0.05 g of modified BaTiO ₃ particles into a single-necked flask, ultrasonically disperse for 1 h, and at the same time add 0.05 g of amidated CNT to the containing Sonicate in a Erlenmeyer flask with 30mL of n-hexane for 60min, after mixing evenly, add it to the above single-necked flask containing BaTiO ₃ particles, react in an ice bath at 1-5°C for 8h, centrifuge, wash, and vacuum dry at 80°C until constant Heavy. Save for later use. Where CNT:BaTiO ₃ =1:1(w/w)

2. Preparation of precursor spinning solution: Disperse 2.41g of PVDF powder in 12ml of DMF, stir magnetically at 50°C for 2h, then weigh 0.002410g of CNT@BaTiO ₃ particles into 8mL of acetone and ultrasonically disperse at 50°C for 1h. The sonicated CNT@BaTiO ₃ dispersion was poured into the PVDF solution, and after 30 min of sonication, it was magnetically stirred for 2 h to obtain the PVDF/CNT@BaTiO ₃ spinning solution precursor. The concentration of PVDF is 12wt%, and the concentration of CNT@ _BaTiO3 is 0.1wt% (relative to the mass of PVDF).

3. Preparation of PVDF/CNT@BaTiO ₃ nanocomposites: spinning voltage 22kV, injection speed 1mL/h, needle type 22G, distance from needle to receiving device 15cm, drum (diameter 200mm) speed 1500rpm, prepared Contains doped polyvinylidene fluoride composite fibers.

4. Performance test of PVDF/CNT@BaTiO ₃ nanocomposite fiber membrane:

Use the scanning electron microscope (SEM) to test the morphology of the fiber membrane, the SEM figure is shown in Figure 1, measure the crystallization properties of the fiber membrane by X-ray diffractometer (XRD), and then analyze and calculate the crystallinity and β crystallinity of the fiber membrane by Peakfit software phase content. Cut a piece of fiber membrane of 1.5×2cm, put the fiber membrane on the quasi-static instrument, select five points to test, record the test data, and take the average value to obtain the piezoelectric constant D ₃₃ .

The crystallinity of the obtained fiber membrane is 64%, the β crystal phase content is 76.9%, and the piezoelectric constant D ₃₃ is 40pC/N.

Example 2

Prepare polyvinylidene fluoride/CNT@BaTiO ₃ composite fiber materials according to the method provided by the invention:

1. Preparation of CNT@BaTiO ₃ core-shell structure

(1) Mixed acid modification of carbon nanotubes: prepare 180 mL of mixed acid with a volume ratio of 1:1 concentrated sulfuric acid and concentrated nitric acid, and cool to room temperature. Then put 2g of original multi-walled carbon nanotubes into the prepared mixed acid, ultrasonicate at room temperature for 60min, then ultrasonically at 80°C for 8h, then cool to room temperature, centrifuge, add deionized water to wash, repeat several times until PH = 7. The obtained CNTs were then vacuum-dried at 80°C to constant weight for further use.

(2) Amidation of acid-modified carbon nanotubes: ultrasonically stir the acid-modified carbon nanotubes and 200 mL of 1mol/L HCl for 60 min, then add excess p-phenylenediamine, and reflux at 130 ° C for 24 h to obtain the Need product. The resultant was centrifuged, washed, and vacuum-dried at 120° C. to constant weight to obtain amidated carbon nanotubes MWCNTs-CO-NH-C ₆ H ₄ NH ₂ .

(3) Surface modification of nano-barium titanate: add 2g nano-BaTiO ₃ particles into 400mL ethanol, disperse ultrasonically for 30min, then add 0.5g KH550 silane coupling agent, stir and react at 50°C for 5h, and the obtained BaTiO _3. Centrifuge, wash, and dry under vacuum at 50°C until constant weight.

(4) Grafting reaction of CNT@BaTiO ₃ : Add 200 mL of 1mol/L HCl solution and 0.3 g of modified BaTiO ₃ particles into a single-necked flask, ultrasonically disperse for 0.5 h, and at the same time add 0.05 g of amidated CNT to Sonicate in a Erlenmeyer flask containing 30mL of n-hexane for 60min, mix evenly, and then add it to the above single-necked flask containing BaTiO ₃ particles, react in an ice bath at 1-5°C for 15h, centrifuge, wash, and vacuum dry at 120°C to constant weight. Save for later use. where CNT:BaTiO ₃ =1:6(w/w)

2. Preparation of precursor spinning solution: Disperse 2.41g of PVDF powder in 12mL of DMF, stir magnetically at 50°C for 2h, then weigh 0.002410g of CNT@BaTiO ₃ particles into 8mL of acetone and ultrasonically disperse at 50°C for 1h. The sonicated CNT@BaTiO ₃ dispersion was poured into the PVDF solution, and after 30 min of sonication, it was magnetically stirred for 2 h to obtain the PVDF/CNT@BaTiO ₃ spinning solution precursor. The concentration of PVDF is 12wt%, and the concentration of CNT@ _BaTiO3 is 0.1wt% (relative to the mass of PVDF).

3. Preparation of PVDF/CNT@BaTiO ₃ nanocomposite: spinning voltage 16kV, injection speed 0.5mL/h, needle type 27G, distance from needle to receiving device 20cm, drum (diameter 200mm) speed 300rpm, preparation A doped polyvinylidene fluoride composite fiber was obtained.

4. Characterization and performance test of PVDF/CNT@BaTiO ₃ nanocomposite fiber membrane:

The morphology of the fiber membrane was tested by scanning electron microscope (SEM), the crystallization properties of the fiber membrane were measured by X-ray diffractometer (XRD), and then the crystallinity and β crystal phase content of the fiber membrane were analyzed and calculated by Peakfit software.

Cut a piece of fiber membrane of 1.5×2cm, put the fiber membrane on the quasi-static instrument, select five points to test, record the test data, and take the average value to obtain the piezoelectric constant D ₃₃ .

The crystallinity of the obtained fiber membrane is 66%, the content of β crystal phase is 78%, and the piezoelectric constant D ₃₃ is 48pC/N.

Example 3

Prepare polyvinylidene fluoride/CNT@BaTiO ₃ composite fiber materials according to the method provided by the invention:

1. Preparation of CNT@BaTiO ₃ core-shell structure

(1) Mixed acid modification of carbon nanotubes: prepare 300 mL of mixed acid of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 3:1, and cool to room temperature. Then put 2g of original multi-walled carbon nanotubes into the prepared mixed acid, ultrasonic at room temperature for 45min, then ultrasonic at 40°C for 4h, then cool to room temperature, centrifuge, add deionized water to wash, repeat several times until PH = 7. The resulting CNTs were then vacuum-dried at 120°C to constant weight for further use.

(2) Amidation of acid-modified carbon nanotubes: ultrasonically stir the acid-modified carbon nanotubes and 200 mL of 1mol/L HCl for 30 min, then add excess p-phenylenediamine, and reflux at 60 ° C for 26 h to obtain the obtained Need product. The resultant was centrifuged, washed, and vacuum-dried at 50° C. to constant weight to obtain amidated carbon nanotubes MWCNTs-CO-NH-C ₆ H ₄ NH ₂ .

(3) Surface modification of nano-barium titanate: Add 2g of nano-BaTiO ₃ particles into 200mL ethanol, disperse by ultrasonic for 60min, then add 1g of KH550 silane coupling agent, stir and react at 60°C for 3h, and the obtained BaTiO ₃ Centrifuge, wash, and vacuum-dry at 120°C until constant weight.

(4) Grafting reaction of CNT@BaTiO ₃ : Add 150 mL of 1mol/L HCl solution and 0.6 g of modified BaTiO ₃ particles into a single-necked flask, ultrasonically disperse for 0.5 h, and at the same time add 0.05 g of amidated CNT to Sonicate in a Erlenmeyer flask containing 30mL of n-hexane for 60min, mix evenly, and then add it to the single-necked flask above containing BaTiO ₃ particles, react in an ice bath at 1-5°C for 15h, centrifuge, wash, and vacuum dry at 120°C to constant weight. Save for later use. Where CNT:BaTiO ₃ =1:12(w/w)

2. Preparation of precursor spinning solution: Disperse 2.41g PVDF powder in 12mL DMF, stir magnetically at 50°C for 2h, then weigh 0.002410g CNT@BaTiO ₃ particles into 8mL acetone and ultrasonically disperse at 50°C for 1h. The CNT@BaTiO ₃ dispersion liquid was poured into the PVDF solution, and after ultrasonication for 30 min, magnetic stirring was performed for 2 h to obtain the PVDF/CNT@BaTiO ₃ spinning solution precursor. The concentration of PVDF is 12wt%, and the concentration of CNT@ _BaTiO3 is 0.1wt% (relative to the mass of PVDF).

3. Preparation of PVDF/CNT@BaTiO ₃ nanocomposites: spinning voltage 22kV, injection speed 1mL/h, needle type 22G, distance from needle to receiving device 15cm, drum (diameter 200mm) speed 1500rpm, prepared Contains doped polyvinylidene fluoride composite fibers.

4. Performance test of PVDF/CNT@BaTiO ₃ nanocomposite fiber membrane:

The morphology of the fiber membrane was tested by scanning electron microscope (SEM), the crystallization properties of the fiber membrane were measured by X-ray diffractometer (XRD), and then the crystallinity and β crystal phase content of the fiber membrane were analyzed and calculated by Peakfit software.

Cut a piece of fiber membrane of 1.5×2cm, put the fiber membrane on the quasi-static instrument, select five points to test, record the test data, and take the average value to obtain the piezoelectric constant D ₃₃ .

The crystallinity of the obtained fiber membrane is 63%, the β crystal phase content is 78%, and the piezoelectric constant D ₃₃ is 49pC/N.

Example 4

Prepare polyvinylidene fluoride/CNT@BaTiO ₃ composite fiber materials according to the method provided by the invention:

1. Preparation of CNT@BaTiO ₃ core-shell structure

(1) Mixed acid modification of carbon nanotubes: prepare 180 mL of mixed acid of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 3:1, and cool to room temperature. Then put 2g of original multi-walled carbon nanotubes into the prepared mixed acid, sonicate at room temperature for 30min, then sonicate at 50°C for 6h, then cool to room temperature, centrifuge, add deionized water to wash, repeat several times until PH = 7. The obtained CNTs were then vacuum-dried at 80°C to constant weight for further use.

(2) Amidation of acid-modified carbon nanotubes: ultrasonically stir the acid-modified carbon nanotubes and 200 mL of 1mol/L HCl for 30 min, then add excess p-phenylenediamine, and reflux at 90 ° C for 24 h to obtain the obtained Need product. The resultant was centrifuged, washed, and vacuum-dried at 80° C. to constant weight to obtain amidated carbon nanotubes MWCNTs-CO-NH-C ₆ H ₄ NH ₂ .

(3) Surface modification of nano-barium titanate: Add 2g of nano-BaTiO ₃ particles into 200mL ethanol, ultrasonically disperse for 60min, then add 2g of KH550 silane coupling agent, stir and react at 60°C for 3h, and centrifuge the obtained BaTiO ₃ , washed, and vacuum-dried at 80°C to constant weight.

(4) Grafting reaction of CNT@BaTiO ₃ : Add 150 mL of 1mol/L HCl solution and 0.1 g of modified BaTiO ₃ particles into a single-necked flask, ultrasonically disperse for 2 h, and at the same time add 0.05 g of amidated CNT to the container Sonicate in a Erlenmeyer flask with 30mL of n-hexane for 15min, mix evenly, add it to the above single-necked flask containing BaTiO ₃ particles, react in ice bath at 1-5°C for 12h, centrifuge, wash, and vacuum dry at 80°C until constant Heavy. Save for later use. Wherein CNT:BaTiO ₃ =1:2 (w/w).

2. Preparation of precursor spinning solution: Disperse 2.41g of PVDF powder in 12mL of DMF, stir magnetically at 50°C for 2h, then weigh 0.000241g of CNT@BaTiO ₃ particles into 8mL of acetone and ultrasonically disperse at 50°C for 1h. The CNT@BaTiO ₃ dispersion liquid was poured into the PVDF solution, and after ultrasonication for 30 min, magnetic stirring was performed for 2 h to obtain the PVDF/CNT@BaTiO ₃ spinning solution precursor. The concentration of PVDF is 12wt%, and the concentration of CNT@ _BaTiO3 is 0.01wt% (relative to the mass of PVDF).

3. Preparation of PVDF/CNT@BaTiO ₃ nanocomposites: spinning voltage 26kV, injection speed 3.0mL/h, needle type 22G, distance from needle to receiving device 15cm, drum (diameter 200mm) speed 2500rpm, preparation A doped polyvinylidene fluoride composite fiber was obtained.

4. Characterization and performance test of PVDF/CNT@BaTiO ₃ nanocomposite fiber membrane:

Use a scanning electron microscope (SEM) to test the morphology of the fiber membrane, and measure the crystallinity of the fiber membrane by X-ray diffractometer (XRD). The crystallinity and β crystal phase content, the specific peak fitting diagram is shown in Figure 4.

Cut a piece of fiber membrane of 1.5×2cm, put the fiber membrane on the quasi-static instrument, select five points to test, record the test data, and take the average value to obtain the piezoelectric constant D ₃₃ .

The crystallinity of the obtained fiber membrane is 59%, the content of β crystal phase is 70.3%, and the piezoelectric constant D ₃₃ is 35pC/N.

Example 5

Prepare polyvinylidene fluoride/CNT@BaTiO ₃ composite fiber materials according to the method provided by the invention:

1. Preparation of CNT@BaTiO ₃ core-shell structure

(1) Mixed acid modification of carbon nanotubes: prepare 180 mL of mixed acid of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 5:1, and cool to room temperature. Then put 2g of original multi-walled carbon nanotubes into the prepared mixed acid, ultrasonicate at room temperature for 60min, then ultrasonically at 80°C for 8h, then cool to room temperature, centrifuge, add deionized water to wash, repeat several times until PH = 7. The resulting CNTs were then vacuum-dried at 120°C to constant weight for further use.

(2) Amidation of acid-modified carbon nanotubes: ultrasonically stir the acid-modified carbon nanotubes and 200 mL of 1mol/L HCl for 60 min, then add excess p-phenylenediamine, and reflux at 130 ° C for 26 h to obtain the Need product. The resultant was centrifuged, washed, and vacuum-dried at 60° C. to constant weight to obtain amidated carbon nanotubes MWCNTs-CO-NH-C ₆ H ₄ NH ₂ .

(3) Surface modification of nano-barium titanate: Add 2g of nano-BaTiO ₃ particles into 200mL ethanol, ultrasonically disperse for 60min, then add 2g of KH550 silane coupling agent, stir and react at 60°C for 3h, and centrifuge the obtained BaTiO ₃ , washed, and vacuum-dried at 80°C to constant weight.

(4) Grafting reaction of CNT@BaTiO ₃ : Add 150 mL of 1mol/L HCl solution and 0.1 g of modified BaTiO ₃ particles into a single-necked flask, ultrasonically disperse for 0.5 h, and simultaneously add 0.05 g of amidated CNT to Sonicate in a Erlenmeyer flask containing 30mL of n-hexane for 60min, mix evenly, and then add it to the above single-necked flask containing BaTiO ₃ particles, react in an ice bath at 1-5°C for 12h, centrifuge, wash, and vacuum dry at 80°C to constant weight. Save for later use. where CNT:BaTiO ₃ =1:2(w/w)

2. Preparation of precursor spinning solution: Disperse 2.41g of PVDF powder in 12mL of DMF, stir magnetically at 50°C for 2h, then weigh 0.0482g of CNT@BaTiO ₃ particles into 8mL of acetone and ultrasonically disperse at 50°C for 1h. The CNT@BaTiO ₃ dispersion liquid was poured into the PVDF solution, and after ultrasonication for 30 min, magnetic stirring was performed for 2 h to obtain the PVDF/CNT@BaTiO ₃ spinning solution precursor. The concentration of PVDF is 12wt%, and the concentration of CNT@ _BaTiO3 is 2wt% (relative to the mass of PVDF).

3. Preparation of PVDF/CNT@BaTiO ₃ nanocomposites: spinning voltage 12kV, injection speed 0.5mL/h, needle type 18G, distance from needle to receiver 10cm, drum (diameter 200mm) speed 1500rpm, preparation A doped polyvinylidene fluoride composite fiber was obtained.

4. Performance test of PVDF/CNT@BaTiO ₃ nanocomposite fiber membrane:

The morphology of the fiber membrane was tested by scanning electron microscope (SEM), the crystallization properties of the fiber membrane were measured by X-ray diffractometer (XRD), and then the crystallinity and β crystal phase content of the fiber membrane were analyzed and calculated by Peakfit software.

Cut a piece of fiber membrane of 1.5×2cm, put the fiber membrane on the quasi-static instrument, select five points to test, record the test data, and take the average value to obtain the piezoelectric constant D ₃₃ .

The crystallinity of the obtained fiber membrane is 64%, the content of β crystal phase is 69.3%, and the piezoelectric constant D ₃₃ is 38pC/N.

Example 6

Prepare polyvinylidene fluoride/CNT@BaTiO ₃ composite fiber materials according to the method provided by the invention:

1. Preparation of CNT@BaTiO ₃ core-shell structure

(1) Mixed acid modification of carbon nanotubes: prepare 500 mL of mixed acid of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 3:1, and cool to room temperature. Then put 2g of original multi-walled carbon nanotubes into the prepared mixed acid, ultrasonicate at room temperature for 30min, and then ultrasonically at 50°C for 6h, then cool to room temperature, centrifuge, add deionized water to wash, repeat several times until PH = 7. The obtained CNTs were then vacuum-dried at 80°C to constant weight for further use.

(2) Amidation of acid-modified carbon nanotubes: ultrasonically stir the acid-modified carbon nanotubes and 200 mL of 1mol/L HCl for 30 min, then add excess p-phenylenediamine, and reflux at 90 ° C for 24 h to obtain the obtained Need product. The resultant was centrifuged, washed, and vacuum-dried at 80° C. to constant weight to obtain amidated carbon nanotubes MWCNTs-CO-NH-C ₆ H ₄ NH ₂ .

(3) Surface modification of nano-barium titanate: add 2g nano-BaTiO ₃ particles into 200mL ethanol, disperse by ultrasonic for 60min, then add 1gKH550 silane coupling agent, stir and react at 60°C for 3h, centrifuge the obtained BaTiO ₃ , washed, and vacuum-dried at 80°C to constant weight.

(4) Grafting reaction of CNT@BaTiO ₃ : Add 150 mL of 1mol/L HCl solution and 0.1 g of modified BaTiO ₃ particles into a single-necked flask, ultrasonically disperse for 0.5 h, and simultaneously add 0.05 g of amidated CNT to Sonicate in a Erlenmeyer flask containing 30mL of n-hexane for 60min, mix evenly, and then add it to the above single-necked flask containing BaTiO ₃ particles, react in an ice bath at 1-5°C for 12h, centrifuge, wash, and vacuum dry at 80°C to constant weight. Save for later use. Wherein CNT:BaTiO ₃ =1:2 (w/w).

2. Preparation of precursor spinning solution: Disperse 4.41g of PVDF powder in 12mL of DMF, stir magnetically at 50°C for 2h, then weigh 0.02205g of CNT@BaTiO ₃ particles into 8mL of acetone and ultrasonically disperse at 50°C for 1h. The CNT@BaTiO ₃ dispersion liquid was poured into the PVDF solution, and after ultrasonication for 30 min, magnetic stirring was performed for 2 h to obtain the PVDF/CNT@BaTiO ₃ spinning solution precursor. The concentration of PVDF is 20wt%, and the concentration of CNT@BaTiO ₃ is 0.05wt% (relative to the mass of PVDF).

3. Preparation of PVDF/CNT@BaTiO ₃ nanocomposites: spinning voltage 22kV, injection speed 1mL/h, needle type 22G, distance from needle to receiver 15cm, drum (diameter 200mm) speed 1500rpm, prepared Contains doped polyvinylidene fluoride composite fibers.

4. Characterization and performance test of PVDF/CNT@BaTiO ₃ nanocomposite fiber membrane:

The morphology of the fiber membrane was tested by scanning electron microscopy (SEM), the crystallization properties of the fiber membrane were measured by X-ray diffractometer (XRD), and then the crystallinity and β crystal phase content of the fiber membrane were analyzed and calculated by Peakfit software.

Cut a piece of fiber membrane of 1.5×2cm, put the fiber membrane on the quasi-static instrument, select five points to test, record the test data, and take the average value to obtain the piezoelectric constant D ₃₃ .

The crystallinity of the obtained fiber membrane is 54%, the β crystal phase content is 73%, and the piezoelectric constant D ₃₃ is 33pC/N.

Example 7

Prepare polyvinylidene fluoride/CNT@BaTiO ₃ composite fiber materials according to the method provided by the invention:

1. Preparation of CNT@BaTiO ₃ core-shell structure

(1) Mixed acid modification of carbon nanotubes: prepare 100 mL of mixed acid of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 3:1, and cool to room temperature. Then put 2g of original multi-walled carbon nanotubes into the prepared mixed acid, ultrasonicate at room temperature for 60min, then ultrasonically at 80°C for 4h, then cool to room temperature, centrifuge, add deionized water to wash, repeat several times until PH = 7. The resulting CNTs were then vacuum-dried at 50°C to constant weight for further use.

(2) Amidation of acid-modified carbon nanotubes: ultrasonically stir the acid-modified carbon nanotubes and 200 mL of 1mol/L HCl for 30 min, then add excess p-phenylenediamine, and reflux at 130 ° C for 18 h to obtain the obtained Need product. The resultant was centrifuged, washed, and vacuum-dried at 50° C. to constant weight to obtain amidated carbon nanotubes MWCNTs-CO-NH-C ₆ H ₄ NH ₂ .

(3) Surface modification of nano-barium titanate: add 2g nano-BaTiO ₃ particles into 100mL ethanol, disperse by ultrasonic for 60min, then add 1gKH550 silane coupling agent, stir and react at 60°C for 3h, and centrifuge the obtained BaTiO ₃ , washed, and vacuum-dried at 80°C to constant weight.

(4) Grafting reaction of CNT@BaTiO ₃ : Add 150 mL of 1mol/L HCl solution and 0.1 g of modified BaTiO ₃ particles into a single-necked flask, ultrasonically disperse for 0.5 h, and simultaneously add 0.05 g of amidated CNT to Sonicate in a Erlenmeyer flask containing 30mL of n-hexane for 60min, mix evenly, and then add it to the above single-necked flask containing BaTiO ₃ particles, react in an ice bath at 1-5°C for 15h, centrifuge, wash, and vacuum dry at 80°C to constant weight. Save for later use. where CNT:BaTiO ₃ =1:2(w/w)

2. Preparation of precursor spinning solution: Disperse 2.41g of PVDF powder in 12mL of DMF, stir magnetically at 50°C for 2h, then weigh 0.001205g of CNT@BaTiO ₃ particles into 8mL of acetone and ultrasonically disperse at 50°C for 1h. The CNT@BaTiO ₃ dispersion liquid was poured into the PVDF solution, and after ultrasonication for 30 min, magnetic stirring was performed for 2 h to obtain the PVDF/CNT@BaTiO ₃ spinning solution precursor. The concentration of PVDF is 12wt%, and the concentration of CNT@ _BaTiO3 is 0.05wt% (relative to the mass of PVDF).

3. Preparation of PVDF/CNT@BaTiO ₃ nanocomposites: spinning voltage 22kV, injection speed 1mL/h, needle type 22G, distance from needle to receiving device 15cm, drum (diameter 200mm) speed 1500rpm, prepared Contains doped polyvinylidene fluoride composite fibers.

4. Performance test of PVDF/CNT@BaTiO ₃ nanocomposite fiber membrane:

The morphology of the fiber membrane was tested by scanning electron microscope (SEM), the crystallization properties of the fiber membrane were measured by X-ray diffractometer (XRD), and then the crystallinity and β crystal phase content of the fiber membrane were analyzed and calculated by Peakfit software.

Cut a piece of fiber membrane of 1.5×2cm, put the fiber membrane on the quasi-static instrument, select five points to test, record the test data, and take the average value to obtain the piezoelectric constant D ₃₃ .

The crystallinity of the obtained fiber membrane is 63%, the content of β crystal phase is 81%, and the piezoelectric constant D ₃₃ is 41pC/N.

Example 8

Prepare polyvinylidene fluoride/CNT@BaTiO ₃ composite fiber materials according to the method provided by the invention:

1. Preparation of CNT@BaTiO ₃ core-shell structure

(1) Mixed acid modification of carbon nanotubes: prepare 180 mL of mixed acid of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 3:1, and cool to room temperature. Then put 2g of original single-walled carbon nanotubes into the prepared mixed acid, ultrasonic at room temperature for 30min, then ultrasonic at 50°C for 6h, then cool to room temperature, centrifuge, add deionized water to wash, repeat several times until PH = 7. The obtained CNTs were then vacuum-dried at 80°C to constant weight for further use.

(2) Amidation of acid-modified carbon nanotubes: ultrasonically stir the acid-modified carbon nanotubes and 200 mL of 1mol/L HCl for 30 min, then add excess p-phenylenediamine, and reflux at 90 ° C for 24 h to obtain the obtained Need product. The resultant was centrifuged, washed, and vacuum-dried at 80° C. to constant weight to obtain amidated carbon nanotube SWCNT-CO-NH-C ₆ H ₄ NH ₂ .

(3) Surface modification of nano-barium titanate: Add 2g of nano-BaTiO ₃ particles into 800mL ethanol, ultrasonically disperse for 120min, then add 2g of KH550 silane coupling agent, stir and react at 90°C for 2h, and centrifuge the obtained BaTiO ₃ , washed, and vacuum-dried at 50°C to constant weight.

(4) Grafting reaction of CNT@BaTiO ₃ : Add 150 mL of 1mol/L HCl solution and 0.1 g of modified BaTiO ₃ particles into a single-necked flask, ultrasonically disperse for 0.5 h, and simultaneously add 0.05 g of amidated CNT to Sonicate in a Erlenmeyer flask containing 30mL of n-hexane for 60min, mix evenly, and then add it to the above single-necked flask containing BaTiO ₃ particles, react in an ice bath at 1-5°C for 15h, centrifuge, wash, and vacuum dry at 80°C to constant weight. Save for later use. where CNT:BaTiO ₃ =1:2(w/w)

2. Preparation of precursor spinning solution: Disperse 1.54g of PVDF powder in 12mL of DMF, stir magnetically at 50°C for 2h, then weigh 0.00077g of CNT@BaTiO ₃ particles into 8mL of acetone and ultrasonically disperse at 50°C for 1h. The CNT@BaTiO ₃ dispersion liquid was poured into the PVDF solution, and after ultrasonication for 30 min, magnetic stirring was performed for 2 h to obtain the PVDF/CNT@BaTiO ₃ spinning solution precursor. The concentration of PVDF is 8 wt%, and the concentration of CNT@BaTiO ₃ is 0.05 wt% (relative to the mass of PVDF).

3. Preparation of PVDF/CNT@BaTiO ₃ nanocomposites: spinning voltage 22kV, injection speed 1mL/h, needle type 22G, distance from needle to receiving device 15cm, drum (diameter 200mm) speed 1500rpm, prepared Contains doped polyvinylidene fluoride composite fibers.

4. Performance test of PVDF/CNT@BaTiO ₃ nanocomposite fiber membrane:

The morphology of the fiber membrane was tested by scanning electron microscope (SEM), the crystallization properties of the fiber membrane were measured by X-ray diffractometer (XRD), and then the crystallinity and β crystal phase content of the fiber membrane were analyzed and calculated by Peakfit software.

Cut a piece of fiber membrane of 1.5×2cm, put the fiber membrane on the quasi-static instrument, select five points to test, record the test data, and take the average value to obtain the piezoelectric constant D ₃₃ .

The crystallinity of the obtained fiber membrane is 62%, the content of β crystal phase is 82.1%, and the piezoelectric constant D ₃₃ is 43pC/N.

Example 9

Prepare polyvinylidene fluoride/CNT@BaTiO ₃ composite fiber materials according to the method provided by the invention:

1. Preparation of CNT@BaTiO ₃ core-shell structure

(1) Mixed acid modification of carbon nanotubes: prepare 180 mL of mixed acid of concentrated sulfuric acid and concentrated nitric acid with a volume ratio of 3:1, and cool to room temperature. Then put 2g of original single-walled carbon nanotubes into the prepared mixed acid, ultrasonic at room temperature for 30min, then ultrasonic at 50°C for 6h, then cool to room temperature, centrifuge, add deionized water to wash, repeat several times until PH = 7. The obtained CNTs were then vacuum-dried at 80°C to constant weight for further use.

(2) Amidation of acid-modified carbon nanotubes: ultrasonically stir the acid-modified carbon nanotubes and 200 mL of 1mol/L HCl for 30 min, then put in excess p-phenylenediamine, and reflux at 90° C. for 24 h to obtain the Need product. The resultant was centrifuged, washed, and vacuum-dried at 80° C. to constant weight to obtain amidated single-walled carbon nanotubes SWCNT-CO-NH-C ₆ H ₄ NH ₂ .

(3) Surface modification of nano-barium titanate: add 2g nano-BaTiO ₃ particles into 200mL ethanol, disperse by ultrasonic for 60min, then add 1gKH550 silane coupling agent, stir and react at 60°C for 3h, centrifuge the obtained BaTiO ₃ , washed, and vacuum-dried at 80°C to constant weight.

(4) Grafting reaction of CNT@BaTiO ₃ : Add 150 mL of 1mol/L HCl solution and 0.1 g of modified BaTiO ₃ particles into a single-necked flask, ultrasonically disperse for 0.5 h, and simultaneously add 0.05 g of amidated CNT to Sonicate in a Erlenmeyer flask containing 30mL of n-hexane for 60min, mix evenly, and then add it to the above single-necked flask containing BaTiO ₃ particles, react in an ice bath at 1-5°C for 15h, centrifuge, wash, and vacuum dry at 80°C to constant weight. Save for later use. Wherein CNT:BaTiO ₃ =1:2 (w/w).

2. Preparation of precursor spinning solution: Disperse 2.06g of PVDF powder in 18ml of DMF, stir magnetically at 50°C for 2h, then weigh 0.001103g of CNT@BaTiO ₃ particles into 2ml of acetone and ultrasonically disperse at 50°C for 1h. The sonicated CNT@BaTiO ₃ dispersion was poured into the PVDF solution, and after 30 min of sonication, it was magnetically stirred for 2 h to obtain the PVDF/CNT@BaTiO ₃ spinning solution precursor. The concentration of PVDF is 12wt%, and the concentration of CNT@ _BaTiO3 is 0.05wt% (relative to the mass of PVDF).

3. Electrospinning: spinning voltage 22kV, injection speed 1ml/h, needle type 22G, distance from the needle to the receiving device 15cm, drum (diameter 200mm) speed of 1500rpm, prepared polyvinylidene fluoride containing doping Composite fibers.

4. Performance test of PVDF/CNT@BaTiO ₃ nanocomposite fiber membrane:

The morphology of the fiber membrane was tested by scanning electron microscopy (SEM), the crystallization properties of the fiber membrane were measured by X-ray diffractometer (XRD), and then the crystallinity and β crystal phase content of the fiber membrane were analyzed and calculated by jade software.

Cut a piece of fiber membrane of 1.5×2cm, put the fiber membrane on the quasi-static instrument, select five points to test, record the test data, and take the average value to obtain the piezoelectric constant D ₃₃ .

The crystallinity of the obtained fiber membrane is 59%, the β crystal phase content is 74%, and the piezoelectric constant D ₃₃ is 36pC/N.

comparative example

Prepare polyvinylidene fluoride nanofiber material according to the method provided by the present invention, and compare it with PVDF/CNT@BaTiO ₃ composite material:

(1) Preparation of precursor spinning solution: Disperse 2.412g of PVDF powder in 12ml of DMF and 8ml of acetone, and stir magnetically at 50°C for 2h to obtain a PVDF spinning solution precursor. Wherein the concentration of PVDF is 12wt%,

(2) Preparation of pure PVDF nanomaterials: spinning voltage 22kV, injection speed 1ml/h, needle type 22G, the distance from the needle to the receiving device 15cm, the rotating speed of the drum (200mm in diameter) is 1500rpm, and polyvinylidene fluoride is prepared nanofibrous membrane.

(3) Performance test of PVDF fiber membrane:

The morphology of the fiber membrane was tested by a scanning electron microscope (SEM), and the crystallization properties of the fiber membrane were measured by an X-ray diffractometer (XRD). The XRD spectrum is shown in FIG. 3 . Then, the crystallinity and β crystal phase content of the fiber membrane were analyzed and calculated by Peakfit software. Cut a piece of fiber membrane of 1.5×2cm, put the fiber membrane on the quasi-static instrument, select five points for testing, record the test data, and take the average value to obtain the piezoelectric constant D ₃₃ .

The crystallinity of the obtained fiber membrane is 46.3%, the β crystal phase content is 49%, and the piezoelectric constant D ₃₃ is 25pC/N.

Claims (9)

1. a kind of preparation method of high-voltage electricity polyvinylidene fluoride composite material, which is characterized in that this method using PVDF as matrix, CNT@BaTiO₃Core/shell structure is reinforcement, is prepared using the method for electrostatic spinning, concrete operations include the following steps：

First, CNT@BaTiO₃The preparation of nucleocapsid

(1) nitration mixture of carbon nanotube is modified：Dose volume ratio is 1:1-5:1 concentrated sulfuric acid and the nitration mixture of concentrated nitric acid, by original carbon Nanotube is put into the nitration mixture prepared, first room temperature ultrasound 30-60min, rear 40-80 DEG C of ultrasound 4-8h, and deionized water is used in centrifugation Washing, is repeated several times, until PH=7；Gained CNT is dried under vacuum to constant weight at 50-120 DEG C；

(2) amidation of sour modified carbon nano-tube：By upper step acid modified carbon nano-tube and the HCl ultrasound 15-60min of 1mol/L, Excessive p-phenylenediamine is placed into, flow back 18-26h at 60-130 DEG C, centrifuges, washing, and is dried under vacuum in 50-120 DEG C Constant weight obtains amidated carbon nanotube；

(3) surface of nano barium phthalate is modified：By nanometer BaTiO₃Particle is added in ethyl alcohol, ultrasonic disperse 30-120min, then 0.5-2g KH550 silane coupling agents are added in, after being stirred to react 2-5h at 50-90 DEG C, centrifugation, 50-120 DEG C is dried under vacuum to Constant weight；

(4)CNT@BaTiO₃Graft reaction：The BaTiO that the HCl of 1mol/L and step 1 (3) were modified₃Particle is added to appearance In device, ultrasonic disperse 0.5-2h, then step 1 (2) amidated CNT is added to ultrasound 15- in the conical flask for fill n-hexane 60min is uniformly mixed, and is poured into modified BaTiO₃In solution, 1-5 DEG C of condition of ice bath stirring 8-15h is kept, is centrifuged, washing, Constant weight is dried under vacuum at 50-120 DEG C, obtains the CNT BaTiO of required chemistry key connection₃Particle；

2nd, the preparation of presoma spinning solution：The CNT@BaTiO that step 1 is obtained₃Particle is put into N,N-dimethylformamide (DMF) organic solvent for ultrasonic dispersion 1-4h obtains CNT@BaTiO₃Dispersion liquid, while by Kynoar (PVDF) powder with having Solvent magnetic agitation 1-5h at 40-60 DEG C is all dissolved to PVDF powder, adds prepared CNT@BaTiO₃Dispersion Liquid and acetone, ultrasonic disperse 30min, magnetic agitation 1-3h treat that particle is uniformly dispersed in PVDF solution, spare after standing；

3rd .PVDF/CNT@BaTiO₃The preparation of nanocomposite：First the prepared precursor solution of 4mL step 2 is sucked In injector for medical purpose, syringe clamps on syringe pump, connects syringe and syringe needle, sets injection speed, then will High-voltage power cathode is connected on spinning stainless steel syringe needle, and aluminium foil connects cathode, chooses reception device, sets spinning parameter, Start spinning, after, it powers off；Aluminium foil from reception device is carefully taken off, is put into 50-100 DEG C of air dry oven Middle dry 2-8h makes remaining solvent volatilize, then dry tunica fibrosa is gone in sample sack, finishes writing label, is put into drying It is preserved in device for use.

2. the preparation method of high-voltage electricity polyvinylidene fluoride composite material according to claim 1, it is characterised in that step 1 (1) carbon nanotube described in is one kind in multi-walled carbon nanotube (MWCNTs) or single-walled carbon nanotube (SWCNT).

3. the preparation method of high-voltage electricity polyvinylidene fluoride composite material according to claim 1, it is characterised in that step 1 (1) a concentration of 4mg/mL-20mg/mL of the carbon nanotube in nitration mixture described in.

4. the preparation method of high-voltage electricity polyvinylidene fluoride composite material according to claim 1, it is characterised in that step 1 (3) ratio of nano barium phthalate and amount of alcohol described in is 2.5mg/mL-20mg/mL.

5. the preparation method of high-voltage electricity polyvinylidene fluoride composite material according to claim 1, it is characterised in that step 1 (4) the modified nano barium phthalate and the mass ratio of amidated carbon nanotube are 1:1-12:1.

6. the preparation method of high-voltage electricity polyvinylidene fluoride composite material according to claim 1, it is characterised in that step 2 The common a concentration of 8wt%-20wt% of Kynoar, CNT@BaTiO₃A concentration of 0.01wt%- of particle The volume ratio of 2.0wt%, organic solvent and acetone is 9:1-5:5.

7. the preparation method of high-voltage electricity polyvinylidene fluoride composite material according to claim 1, it is characterised in that step 3 The voltage of electrostatic spinning is 12-26kV, and the injection speed of syringe pump is 0.5mL/h-3.0mL/h, selected syringe needle model 27G- 18G, syringe needle to the distance between collection device are 10-20cm, and using roller as collection device, the rotating speed of roller is 300- 2500rpm。

8. the preparation method of high-voltage electricity polyvinylidene fluoride composite material according to claim 1, it is characterised in that preparation The crystallinity of composite fiber film is 55%-80%, and the content of β crystalline phases is 60%-91%, piezoelectric constant d₃₃For 35-50pC/ N。

9. the preparation method of high-voltage electricity polyvinylidene fluoride composite material according to claim 1, which is characterized in that gather inclined fluorine CNT@BaTiO in ethylene composite material precursor₃The preparation of additive is to make two kinds of nano inorganic particle knots by chemical method It is combined, reduces the agglomeration of two kinds of particles, make CNT@BaTiO₃It can be uniformly distributed in a polymer solution, spinning can It is smoothed out.