1. A polyvinylpyrrolidone/graphene oxide/polyvinylidene fluoride dielectric composite material is characterized in that: the graphene oxide gel is prepared by taking two-dimensional graphene oxide crystals as a filler, polyvinylidene fluoride as a matrix and polyvinylpyrrolidone as a peptizing agent.

2. The polyvinylpyrrolidone/graphene oxide/polyvinylidene fluoride high dielectric composite material of claim 1, wherein: the mass ratio of the two-dimensional graphene oxide crystal to the polyvinylidene fluoride is 0.2-0.6%: 1, the mass ratio of polyvinylpyrrolidone to polyvinylidene fluoride is 1: 1.

3. a preparation method of a polyvinylpyrrolidone/graphene oxide/polyvinylidene fluoride dielectric composite material is characterized by comprising the following steps:

A. manually mixing 0.2-0.6 wt.% of graphene oxide with polyvinylidene fluoride granules in percentage by weight, and then putting the mixture into 50ml of N, N-dimethylformamide solution to obtain a mixed solution, and carrying out ultrasonic treatment for 6-8 h;

B. adding the polyvinylpyrrolidone granules into the mixed solution, and stirring at 60-70 ℃ for 10-12h to obtain a uniform mixed solution;

C. and pouring the solution into a watch glass, and putting the watch glass into a constant-temperature drying oven to be dried for 8-12h at the temperature of 60 ℃ to obtain the polyvinylpyrrolidone/graphene oxide/polyvinylidene fluoride composite material.

4. The preparation method of the polyvinylpyrrolidone/graphene oxide/polyvinylidene fluoride high dielectric composite material according to claim 1, wherein in the step A, the graphene oxide is prepared by the following method:

a1, uniformly mixing 3g of graphite flake with 18g of potassium permanganate, gradually adding a small amount of mixed dry powder into 360ml of concentrated sulfuric acid, and heating in a water bath at 50 ℃ for 12 hours;

a2, cooling the mixed solution obtained in the step A1 to room temperature by magnetic stirring, slowly adding ice blocks frozen by ultrapure water in advance, controlling the temperature to be lower than 60 ℃, stopping adding ice when the temperature is reduced to 20 ℃, adding about 16ml of hydrogen peroxide, changing the color into yellow and generating a large amount of foam, pouring the ultrapure water after the foam disappears, keeping the constant volume to 1600ml, and stirring at the room temperature for 10-12 hours;

a3, centrifuging graphite oxide, pouring the centrifuged graphite oxide into a beaker again, adding 200m hydrochloric acid after the volume is fixed to 1400ml, changing the color into dark brown, and continuing to centrifuge until the supernatant is neutral;

a4, drying and grinding the precipitate obtained by centrifugation to powder for later use.

5. The preparation method of the polyvinylpyrrolidone/graphene oxide/polyvinylidene fluoride high dielectric composite material according to claim 1, wherein in the step A4, the rotation speed of a centrifuge is 11000rpm, and the centrifugation time is 3 min.

6. The preparation method of polyvinylpyrrolidone/graphene oxide/polyvinylidene fluoride dielectric composite material according to claim 1, characterized by comprising the following steps: and B, the mass ratio of the polyvinylpyrrolidone to the polyvinylidene fluoride is 1: 1.

Background

In recent years, due to rapid development of electronic technology, conductive polymer energy storage materials are widely applied to aerospace, information industry, electronic manufacturing and other fields. With the continuous improvement of the technical requirements of electronic technology, the performance requirements of energy storage components applied in the production and manufacturing process of electronic technology are also continuously improved, and the electronic energy storage components gradually tend to develop in the direction of high performance, high stability and high material quality. However, the traditional single polymer energy storage material is difficult to meet the requirements of the development of modern electronic technology. Researches find that the conductive polymer composite energy storage material formed by compounding different materials realizes the effect of superposing the performances of various single polymer materials, fills the defects of the traditional single polymer energy storage material with the advantages of high stability, miniaturization, low cost and the like, and is fully accepted and widely applied in the industry.

According to the properties of dielectric materials, dielectric materials can be classified into inorganic ceramic dielectric materials, polymer dielectric materials and conductive polymer composite dielectric materials. The graphene oxide carbon material is widely applied to dielectric fillers of conductive polymer composite dielectric materials due to the characteristics of large action area, excellent heat conduction and electric conductivity, strong dielectric conductivity, low production and manufacturing cost and the like in the using process. Meanwhile, a thermoplastic semicrystalline polyvinylidene fluoride (PVDF) polymer is obtained on the basis of a large amount of experimental researches on the composite material, the high-stability physical property and the high-stability chemical property of the PVDF polymer are obtained on the basis of analyzing the structural characteristics, the physical property and the chemical property of the PVDF polymer, and the formed conductive composite material has a high dielectric constant and is also widely applied to a substrate of a conductive high-molecular composite dielectric material to become a research focus in the research field of the composite high-molecular material.

The research on the graphene/polyvinylidene fluoride high-dielectric composite material, namely the preparation of graphene and the research on the dielectric property of the graphene/PVDF composite material, carried out by Song hong pine and Liu Da Bo, reports that when the using amount of the graphene reaches 0.25 wt.%, the dielectric constant of the composite material at 1000HZ is close to 16, which is improved by 70% compared with pure PVDF. Although the system shows better dielectric properties, the system still has a larger lifting space. And chinese patent 103467894a discloses a polyvinylidene fluoride/graphene composite material and a preparation method thereof, the graphene/polyvinylidene fluoride composite material is prepared by a melt blending method, when the content of graphene is 3 wt.%, although the dielectric constant of the composite material at I000HZ can reach 100, the dielectric loss factor at 1000HZ is as high as 3000, so that the requirements of practical application are difficult to meet. Therefore, how to solve the problem of interface compatibility of the graphene filler and the polyvinylidene fluoride and regulate and control the spatial distribution condition of the graphene in the polyvinylidene fluoride matrix becomes the key for obtaining the composite material with good dielectric property by improving the dielectric constant of the composite material and maintaining a low loss factor.

Disclosure of Invention

The invention aims to provide a polyvinylpyrrolidone/graphene oxide/polyvinylidene fluoride dielectric composite material and a preparation method of the polyvinylpyrrolidone/graphene oxide/polyvinylidene fluoride dielectric composite material, so as to solve the problem that the traditional single material is limited by dielectric properties in use in high-dielectric high-energy storage.

The purpose of the invention is realized by the following technical scheme:

a polyvinylpyrrolidone/graphene oxide/polyvinylidene fluoride high-dielectric composite material is prepared by taking two-dimensional graphene oxide crystals as a filler, taking polyvinylidene fluoride as a matrix and taking polyvinylpyrrolidone (PVP) as a peptizing agent.

Further, the mass ratio of the two-dimensional graphene oxide crystal to the polyvinylidene fluoride is as follows: 0.2-0.6%: 1, the mass ratio of polyvinylpyrrolidone to polyvinylidene fluoride is 1: 1.

a preparation method of a polyvinylpyrrolidone/graphene oxide/polyvinylidene fluoride dielectric composite material comprises the following steps:

A. manually mixing 0.2-0.6 wt.% of graphene oxide with polyvinylidene fluoride granules in percentage by weight, and then putting the mixture into 50ml of N, N-dimethylformamide solution to obtain a mixed solution, and carrying out ultrasonic treatment for 6-8 h;

B. adding the polyvinylpyrrolidone granules into the mixed solution, and stirring at 60-70 ℃ for 10-12h to obtain a uniform mixed solution;

C. and pouring the solution into a watch glass, and putting the watch glass into a constant-temperature drying oven to be dried for 8-12h at the temperature of 60 ℃ to obtain the polyvinylpyrrolidone/graphene oxide/polyvinylidene fluoride composite material.

Further, step a, the graphene oxide is prepared by the following method:

a1, uniformly mixing 3g of graphite flake with 18g of potassium permanganate, gradually adding a small amount of mixed dry powder into 360ml of concentrated sulfuric acid, and heating in a water bath at 50 ℃ for 12 hours;

a2, cooling the mixed solution obtained in the step A1 to room temperature by magnetic stirring, slowly adding ice blocks frozen by ultrapure water in advance, controlling the temperature to be lower than 60 ℃, stopping adding ice when the temperature is reduced to 20 ℃, adding about 16ml of hydrogen peroxide, changing the color into yellow and generating a large amount of foam, pouring the ultrapure water after the foam disappears, keeping the constant volume to 1600ml, and stirring at the room temperature for 10-12 hours;

a3, centrifuging graphite oxide, pouring the centrifuged graphite oxide into a beaker again, adding 200m hydrochloric acid after the volume is fixed to 1400ml, changing the color into dark brown, and continuing to centrifuge until the supernatant is neutral;

a4, drying and grinding the precipitate obtained by centrifugation to powder for later use.

Further, in step A4, the rotation speed of the centrifuge is 11000rpm, and the centrifugation time is 3 min.

Further, in the step B, the mass ratio of the polyvinylpyrrolidone to the polyvinylidene fluoride is 1: 1.

compared with the prior art, the invention has the beneficial effects that:

according to the polyvinylpyrrolidone/graphene oxide/polyvinylidene fluoride high-dielectric composite material and the preparation method thereof, the polyvinylpyrrolidone is added, and due to the special molecular structure property of the polyvinylpyrrolidone, the polyvinylpyrrolidone has strong binding property, film forming property under a higher temperature condition and compatibility among organic polymers, and meanwhile, due to the viscosity and the gluey property of the polyvinylpyrrolidone, the organic binding of the graphene oxide filler and the polyvinylidene fluoride matrix is realized. Compared with pure polyvinylidene fluoride, the polyvinylpyrrolidone/graphene oxide/polyvinylidene fluoride composite material prepared by the invention has the advantages that the dielectric constant is obviously improved, and the dielectric loss factor is lower, so that the polyvinylpyrrolidone/graphene oxide/polyvinylidene fluoride composite material is suitable for the fields of embedded capacitors, high-energy-density energy storage devices and the like.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

Fig. 1 is a scanning electron microscope image of the polyvinylpyrrolidone/graphene oxide/polyvinylidene fluoride composite film in example 4;

FIG. 2 is a graph showing the dielectric constant and dielectric dissipation factor of the materials obtained in example 4 and comparative example as a function of frequency.

Detailed Description

The invention is further illustrated by the following examples:

the present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures. Meanwhile, in the description of the present invention, the terms "first", "second", and the like are used only for distinguishing the description, and are not to be construed as indicating or implying relative importance.

The polyvinylidene fluoride/graphene oxide/polyvinylpyrrolidone dielectric composite material is prepared by using a two-dimensional graphene oxide crystal with outstanding conductivity and low production cost as a filler, using polyvinylidene fluoride as a main matrix and using polyvinylpyrrolidone (PVP) as a peptizing agent.

The invention relates to a polyvinylpyrrolidone/graphene oxide/polyvinylidene fluoride dielectric composite material and a preparation method thereof, and the preparation method comprises the following specific operation steps:

step 1, manually mixing 0.2-0.6 wt.% of graphene oxide with polyvinylidene fluoride granules in percentage by weight, and then putting the mixture into 50ml of N, N-dimethylformamide solution to obtain a mixed solution, and carrying out ultrasonic treatment for 6-8 h.

Step 2, putting the polyvinylpyrrolidone granules into the mixed solution, and stirring for 10-12h at 60-70 ℃ to obtain a uniform mixed solution, wherein the mass ratio of polyvinylpyrrolidone to polyvinylidene fluoride is 1: 1.

and 3, pouring the solution into a watch glass, and putting the watch glass into a constant-temperature drying oven to be dried for 8-12h at the temperature of 60 ℃ to obtain the polyvinylpyrrolidone/graphene oxide/polyvinylidene fluoride composite material.

Wherein the graphene oxide is prepared by the following method:

1. 3g of graphite flakes and 18g of potassium permanganate are uniformly mixed and poured into a 2L beaker filled with 360ml of concentrated sulfuric acid, a small amount of mixed dry powder is added by a little bit (about 30 minutes) by using a spoon tip while stirring, and the beaker with the added medicine is placed into a big water bath kettle and stirred for 12 hours in a water bath at 50 ℃.

2. Taking out the large beaker, placing the large beaker on a magnetic stirrer for stirring, slowly cooling to room temperature, slowly adding ice blocks frozen by ultrapure water into the large beaker, constantly observing and controlling the temperature below 60 ℃ by using a thermometer, stopping adding ice when the temperature is reduced to about 20 ℃, adding about 16ml of hydrogen peroxide, changing the color into yellow and generating a large amount of foam, pouring the ultrapure water after the foam disappears, fixing the volume to 1600ml, and stirring for 10-12h at the room temperature.

3. Centrifuging graphite oxide (11000rpm, 3min), pouring the centrifuged graphite oxide into a 2L beaker again, metering to 1400ml, and adding 200m hydrochloric acid until the color becomes dark brown. Centrifugation was then continued until the supernatant was neutral.

4. Drying and grinding the precipitate obtained by centrifugation to powder for later use.

Example 1

In the embodiment, graphene oxide is used as a dielectric functional material to prepare the polyvinylpyrrolidone/graphene oxide/polyvinylidene fluoride composite material with the graphene oxide content of 0.2%.

Step 1, manually mixing 0.2% of graphene oxide with polyvinylidene fluoride granules in percentage by weight, and then putting the mixture into 50ml of N, N-dimethylformamide solution to obtain a mixed solution, and carrying out ultrasonic treatment for 6-8 h.

Step 2, putting the polyvinylpyrrolidone granules into the mixed solution, and stirring for 10-12h at 60-70 ℃ to obtain a uniform mixed solution, wherein the mass ratio of polyvinylpyrrolidone to polyvinylidene fluoride is 1: 1.

and 3, pouring the solution into a watch glass, putting the watch glass into a constant-temperature drying oven, drying for 8-12 hours to obtain the polyvinylpyrrolidone/graphene oxide/polyvinylidene fluoride composite material, measuring the dielectric property of the polyvinylpyrrolidone/graphene oxide/polyvinylidene fluoride composite material by using an impedance analyzer HP4294a, and measuring the dielectric constant of the polyvinylpyrrolidone/graphene oxide/polyvinylidene fluoride composite material at 1000Hz and the dielectric loss factor of 0.0338.

Example 2

The preparation and test methods were the same as in example 1, except that a polyvinylpyrrolidone/graphene oxide/polyvinylidene fluoride composite material having a graphene oxide content of 0.3 wt.% was prepared, and the composite material was found to have a dielectric constant of 12.8 and a dielectric dissipation factor of 0.0507 at 1000 Hz.

Example 3

The preparation and test methods were the same as in example 1, except that a polyvinylpyrrolidone/graphene oxide/polyvinylidene fluoride composite material having a graphene oxide content of 0.4 wt.% was prepared, and the dielectric constant at 1000Hz of the composite material was 13.9 and the dielectric dissipation factor was 0.0664.

Example 4

The preparation and test methods were the same as in example 1, except that a polyvinylpyrrolidone/graphene oxide/polyvinylidene fluoride composite material having a graphene oxide content of 0.6 wt.% was prepared, and the dielectric constant at 1000Hz of the composite material was measured to be 19.1, and the dielectric loss factor was measured to be 0.2661.

Comparative example

And (3) carrying out hot pressing on the pure polyvinylidene fluoride granules for 4 minutes under the conditions that the temperature is 180 ℃ and the pressure is 12 MPa to obtain a polyvinylidene fluoride hot-pressed film, measuring the dielectric property of the polyvinylidene fluoride hot-pressed film by using an impedance analyzer, and measuring that the dielectric constant of the pure polyvinylidene fluoride hot-pressed film at l000HZ is 8.6 and the dielectric loss factor is 0.0271. Wherein the dielectric constant and dielectric loss factor of the pure polyvinylidene fluoride hot-pressed film are shown in the graph 2 along with the change rule of frequency.

Through a large number of researches, the composite material formed by adopting the composite technology of two or more materials is mutually superposed by utilizing the performance advantages of each single material to form the polymer-based dielectric composite material with high dielectric constant, high stability, high mechanical property and miniaturization, can effectively solve the problems of the traditional single material in high dielectric and high energy storage, and is an effective way for adapting to the development of electronic science and technology.

It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.