TW201922940A - Graphene polymer composite material and method for preparing the same comprising a substrate, a plurality of graphene sheets, and a polymer layer - Google Patents

Abstract

A graphene polymer composite material comprises a substrate, a plurality of graphene sheets, and a polymer layer, wherein the substrate has two opposite surfaces, the plurality of graphene sheets are parallel and attached to two surfaces of the substrate, and the polymer layer covers the plurality of graphite sheets and two surfaces of the substrate. Further, the polymer is an epoxy resin, a phenolic resin, a polyester resin or a combination thereof, and the substrate is a carbon fiber fabric, a glass fiber fabric, a Kevlar fiber fabric or a combination thereof. In addition, based on the total weight of the polymer composite material, the plurality of graphene sheets are from 0.01 to 5 wt%, and the polymer layer is from 25 to 55 wt%. The present invention further provides a method for preparing the graphene polymer composite material.

Description

Graphene polymer composite material and preparation method thereof

The invention relates to a graphene polymer composite material with high mechanical strength and a preparation method thereof.

In 2004, Andre Geim and Konstantin Novoselov of the University of Manchester in the United Kingdom succeeded in using a tape to strip graphite to obtain a single layer of graphene. The graphene is mainly composed of a sp ² mixed orbital domain composed of hexagonal honeycomb arrays. 0.335 nm, which is the size of only one carbon atom. Graphene has a specific gravity of only about a quarter of that of steel, and its mechanical strength can be much higher than that of steel. It is the most mechanically strong material, and graphene has excellent properties in terms of electrical conductivity, thermal conductivity and chemical resistance. It is used by industry in different technical fields.

However, the most common problem in practical applications is that graphene sheets are not easily dispersed uniformly, are easy to aggregate, stack and agglomerate, and may agglomerate even after a short dispersion, thus, how to prevent the graphene sheets from being unevenly stacked with each other. Phenomenon, to obtain a uniform dispersion and a small number of layers of graphene powder, has always been the technical bottleneck that the industry needs to solve.

Chinese Patent No. 101864098B discloses a method for preparing a polymer and a graphene composite masterbatch by dispersing graphite oxide in a polymer latex by ultrasonic or grinding in a graphene powder and a solvent, and introducing a reducing agent into the polymer latex. The in-situ reduction of graphene oxide is carried out, and then a solid polymer and a graphene composite master batch are obtained by steps of demulsification, coagulation, and drying. However, in addition to studies that indicate that the ultrasonic method is less suitable for high viscosity liquids (Rasheed Atif, Fawad Inam, Beilstein Jornal of Nanotechnology. 2016, 7, 1174-1196), polymers containing solvents and graphene reduction During the drying process, the graphene is re-agglomerated by the evaporation of the solvent.

Chinese Patent No. 106221128A discloses a method for preparing a carbon fiber composite material, in which a composite resin and a filler (for example, graphene) are preheated to between 30 and 150 degrees Celsius, and the modified filler is dispersed in the matrix resin by ultrasonic waves. After that, the slurry is ground several times, cooled to obtain a modified resin, the modified resin and the carbon fiber are prepared on a hot-melt prepreg, and the carbon fiber prepreg is hot-pressed. Carbon fiber composite material. However, by using graphene as a modified filler in this way, graphene in the matrix resin may agglomerate during cooling, resulting in the modified resin not having the desired performance.

No. 20150333320A1 discloses a method for producing a positive electrode active material and graphene composite particles, which is obtained by combining a graphene oxide having a functional group and a positive electrode active material on a surface of a kneader to obtain precursor particles by thermal reduction. Or the reducing agent graphene oxide to obtain a positive electrode active material and graphene composite particles. Studies have shown that the more surface functional groups of reduced graphene oxide, the higher the oxygen content, the lower the conductivity and thermal conductivity (Naoki Morimoto, Takuya Kubo, Yuta Nishina, Scientific Reports 6, 2016, 21715), therefore, the aforementioned method is required The relative ratio of the functional groups and the oxygen content of the graphene is strictly controlled by the temperature and the reducing atmosphere. Although the graphene having a high oxygen content is less likely to agglomerate, the characteristics of the graphene have been lost.

It can be known from the above-mentioned prior art that the graphene dispersion technology is limited to a specific material form or operating condition, and the short-time dispersed graphene is mixed with other materials or can improve the efficiency, but in practical application, the graphene mixed with other materials must be at least Industrial utilization is only achieved when the state of dispersion is maintained for a certain period of time.

To achieve the above object, the present invention provides a method for preparing a graphene dispersion paste, comprising: mixing and stirring a graphene sheet, a solvent, and a polymer to form a pseudoplastic non-Newtonian fluid, wherein the graphene sheet is composed of 2 to 30 graphene stacked on each other The layer is composed of having a bulk density of 0.005-0.05 g/cm ³ , a thickness of 0.68-10 nm, and a planar transverse dimension of 1-100 μm; and applying a pressure of not less than 10 bar to make the pseudoplastic non-Newtonian fluid passage gap not larger than The slit of 1000 μm is formed at least twice to form a graphene dispersion paste, wherein the viscosity of the pseudoplastic non-Newtonian fluid passing through the slit is between 10 and 10000 cps, and the viscosity of the graphene dispersion paste is between 50,000 and 350,000 cps.

In one embodiment, the graphene sheet comprises 0.05-20 wt% of the pseudoplastic non-Newtonian fluid.

In one embodiment, the surface of the graphene sheet has a functional group of Rx-R'y, and the R is selected from at least one of a benzene ring, a pyridine, and a triazine, and the R' is selected from an amino group. At least one of an alkoxy group, a carbonyl group, a carboxyl group, a decyloxy group, a decylamino group, an alkoxy group, a dimethylamino group and an alkoxycarbonyl group, 1≦x≦4,1≦y≦6.

In one embodiment, the above pressure is sequentially increased to 10-30 bar, and the gap between the slits is lowered to 10-1000 μm.

In one embodiment, the preparation method further comprises: heating to 30-200 ° C to reduce the viscosity of the graphene dispersion paste to 10,000-50,000 cps, and removing the bubbles in the graphene dispersion paste having a reduced viscosity by centrifugal force.

Based on the above preparation method, the present invention provides a graphene dispersion paste having a viscosity between 50,000 and 350,000 cps and a blade fineness of less than 20 μm, and comprising: a graphene sheet, a solvent, and a first polymer, wherein the graphene sheet The content is between 0.05 and 20 wt%, and has a bulk density of 0.005-0.05 g/cm ³ , a thickness of 0.68-10 nm, and a planar transverse dimension of 1-100 μm.

Based on the above preparation method, the present invention provides a method for using a graphene dispersion paste, comprising: preparing the above graphene dispersion paste; diluting the graphene dispersion paste to form a graphene dispersion having a viscosity of not more than 50,000 cps; and applying a graphene dispersion And depositing the graphene sheet on the surface of the substrate on the substrate; and curing the graphene dispersion, so that the first polymer adheres the graphene sheet to the surface of the substrate.

In one embodiment, the graphene dispersion paste is diluted with a solvent or a second polymer compatible with the first polymer to form a graphene dispersion; after curing the graphene dispersion, the first polymer and the second polymer The polymer adheres the above graphene sheet to the surface of the substrate.

In one embodiment, when the graphene dispersion paste is diluted, a conductive filler is further added to form the graphene dispersion; after the graphene dispersion is cured, the graphene sheet is connected to the conductive filler to form a conductive network.

The invention utilizes the fluid property of the polymer to mix the graphene sheet polymer to form a pseudoplastic non-Newtonian fluid having a viscosity greater than 50,000 cps, and applies a pressure of 10-30 bar to pass the pseudoplastic non-Newtonian fluid through a slit of 10-1000 μm at least two. Secondly, under the high shear force formed by the slit, the viscosity of the polymer drops sharply and the graphene sheet is uniformly dispersed, and the polymer whose original viscosity is restored by the slit can effectively prevent the graphene sheet from agglomerating and can be used for a long time. The dispersed state of the graphene sheets is maintained. When the graphene dispersion paste of the present invention is used, by adjusting the viscosity of the graphene dispersion paste by adding a solvent or a compatible polymer, the direction and rate of flow of the graphene sheet can be controlled, and the graphene sheet can be dispersed and attached to the surface of the material. The graphene dispersion paste can be applied to the technical fields of fiber, rubber, electrochemistry, etc., and has industrial utilization.

The embodiments of the present invention will be described in more detail below with reference to the drawings and the <RTIgt; It should be noted that, in order to clearly illustrate the main features of the present invention, the figures only show the relative relationship or operation mode between the main elements in a schematic manner, and are not drawn according to the actual size, so the thickness, size and shape of the main elements in the figures are not shown. The arrangement, the configuration, and the like are for reference only and are not intended to limit the scope of the invention.

The physical properties of polymer materials change due to factors such as molecular weight, molecular structure, additives, processing conditions, etc. When the fluid polymer flows under force, it exhibits the viscosity of the liquid and the elasticity of the solid, which is different from the general Newton. The viscosity of the fluid is not affected by shear forces. Under the action of high shear force, the viscosity of the polymer will decrease rapidly and the fluidity close to the Newtonian fluid will be obtained. When the shear force disappears, the polymer will restore the original viscosity and exhibit the viscoelasticity of the non-Newtonian fluid. Therefore, the present invention utilizes the fluid properties of the polymer to disperse and preserve the graphene sheets.

Figure 1 is a flow chart showing the steps of the graphene dispersion method of the present invention. As shown in FIG. 1, the graphene dispersion method of the present invention comprises: mixing step S10, mixing a plurality of graphene sheets and at least one polymer forming mixture; stirring step S20, stirring the mixture to form pseudoplastics of graphene sheets and polymers; Newtonian fluid; dispersion step S30, pressurizing the pseudoplastic non-Newtonian fluid to form the graphene dispersion paste at least twice through the slit; and defoaming step S40 to exclude the gas in the graphene dispersion paste.

Fig. 2 is a schematic view showing the mixing step of the graphene dispersion method of the present invention. As shown in FIG. 2, in the mixing step S10, the graphene solution and at least one polymer (not shown) are sequentially added to the mixing device (for example, but not limited to: homogenizer, kneading machine, etc.) to form a viscosity of 100,000. - a non-flowing mixture of 1,000,000 cps.

The graphene solution comprises a graphene sheet and a solvent, wherein the graphene sheet is composed of 2 to 30 graphene layers stacked on each other, having a bulk density of 0.005-0.05 g/cm ³ , a thickness of 0.68-10 nm, and a range of 1-100 μm. Planar transverse dimension; solvents such as, but not limited to, N-methyl pyrrolidinone (NMP), isophorone. The polymer is selected from the group consisting of oily, thermoplastic or thermosetting polymers which are liquid or solvent soluble liquid mixtures having a viscosity of between 300 and 900,000 cps. Due to the high oil absorption of graphene sheets, the viscosity of the mixture is rapidly increased. The higher the viscosity of the selected polymer, the lower the proportion of graphene sheets that can be added to the mixture. Therefore, the graphene sheets are based on the viscosity of the polymer. The proportion in the mixture is between 0.05 and 20 wt%.

In order to increase the dispersibility of the graphene sheet in the polymer, a dispersant or a surface-modified graphene sheet may be further added. The dispersing agent may be selected from the group consisting of a siloxane, a polyvinylpyrrolidone, a sulfate or an ester compound. The surface-modified graphene sheet may be formed by adsorbing at least one surface modifier on the surface of the graphene sheet by a π-π bond stack, and the surface modifier has a chemical formula of Rx-R'y, wherein the R group is selected from the group consisting of benzene. a functional group of at least one hexacyclic ring structure of a ring, a pyridine or a triazine selected from the group consisting of an amino group, an alkoxy group, a carbonyl group, a carboxyl group, a decyloxy group, a decylamino group, and an alkoxy group. At least one functional group of dimethylamino and alkoxycarbonyl, 1≦x≦4,1≦y≦6. The functional group of the surface modifier can repel the graphene sheets in the polymer to improve the stability of the graphene sheet dispersion state, and the functional groups formed by the surface modifier on the surface of the graphene sheet can generate chemical bonds with the polymer. The junction strengthens the interface strength between the graphene and the polymer and increases the mechanical strength of the polymer.

Fig. 3 is a schematic view showing the stirring step of the graphene dispersion method of the present invention. As shown in Fig. 3, the stirring device (such as but not limited to: a three-axis planetary mixer) includes at least one self-rotating homogenizing mechanism and at least one revolution homogenizing mechanism, and the rotation homogenizing mechanism rotates at a speed of 100-30,000 rpm, and the revolving homogenizing mechanism The rotation speed is between 100-30,000 rpm, and the rotation and revolution homogenization mechanisms independently control the rotation speed of the rotation and revolution by the two sets of control units to generate the maximum shear force. In the stirring step S20, the mixture of the graphene sheet and the polymer is placed in a stirring device, and the graphene sheet is preliminarily dispersed in the polymer by the high shear force generated by the stirring device to form a pseudoplastic non-graphene of the graphene sheet and the polymer. Newtonian fluid with a viscosity between 50,000 and 350,000 cps.

Fig. 4 is a schematic view showing the dispersion step of the graphene dispersion method of the present invention. As shown in Fig. 4, the dispersing device (such as but not limited to: a three-roller) can apply a pressure of 10-30 bar to the high-viscosity mixed material to pass the high-viscosity complex material at a flow rate of 0.1-10 L/min. Slots with a gap between 10 and 1000 μm to form a homogeneous mixture. In the dispersing step S30, the pseudoplastic non-Newtonian fluid of the graphene and the polymer is excavated from the stirring device and placed in the dispersing device, and the pseudoplastic non-Newtonian fluid is subjected to a plurality of dispersion processing to form the graphene dispersing paste. Due to the high pressure and the shear force generated by the slit, the viscosity of the pseudoplastic non-Newtonian fluid is rapidly reduced to 10-10000 cps, and the pseudoplastic non-Newtonian fluid with reduced viscosity generates fluidity in the slit and is separated by shearing force. The agglomerated graphene sheet, the separated graphene sheet is further dispersed with the fluid with increasing flow rate; after the fluid passes through the slit, the shearing force disappears, and the pseudoplastic non-Newtonian fluid which returns to the original viscosity can pull the graphene sheet to prevent agglomeration. Thereby forming a stable graphene dispersion paste.

In the dispersing step S30, the pressure and the slit gap can be successively adjusted to further improve the separation and dispersion effect of the graphene sheets. In one embodiment, the conditions of the first dispersion processing are: the pressure is set to 10-25 bar, and the slit gap is 100-1000 μm. Under this condition, the viscosity of the pseudoplastic non-Newtonian fluid passing through the slit is between 100 and 10000 cps. The flow rate through the slit is 0.1-5 L/min, and the slit of the larger gap can be separated by the larger agglomerated graphene sheet to form a smaller agglomerated graphene sheet to avoid clogging; the second dispersion processing Conditions: The pressure is increased to 15-30 bar, and the slit gap is adjusted to 10-200 μm. Under this condition, the viscosity of the pseudoplastic non-Newtonian fluid passing through the slit is between 10 and 1000 cps, and the flow rate through the slit is 0.5- 10 L/min. Gradually increasing shear force can separate the agglomerated graphene sheets from large to small, and the accelerated effect of the gradually narrowing slit can uniformly disperse the graphene sheets, and the high-viscosity pseudoplastic non-Newtonian fluid can be stabilized. The dispersed state of the graphene sheets is maintained.

In the mixing and dispersing process of the graphene sheet and the polymer, gas or bubbles may be retained therein, and FIG. 5 is a schematic diagram of the defoaming step of the graphene dispersion method of the present invention. As shown in Fig. 5, the defoaming device (for example, but not limited to: a centrifugal defoaming machine) has a heating mechanism and a rotating mechanism, and the gas in the high-viscosity material can be removed by heating and centrifugal force. In the defoaming step S40, the graphene dispersion paste is placed in a degassing condition of the exhaust gas or bubbles of the centrifugal defoamer: the temperature is between 30-200 degrees Celsius, the rotation speed is between 200-2000 rpm, and the elevated temperature is used. The viscosity of the graphene dispersion paste is reduced to 10,000 to 50,000 cps, and the centrifugal force is used to promote the discharge of gas or bubbles, thereby avoiding the generation of pores in the application of the graphene dispersion paste.

It should be noted that the graphene dispersion paste of the present invention can maintain the dispersion state and characteristics of the graphene sheets for a long time, and is easy to store and transport. The scraper fineness meter can be used to test the degree of material dispersion of the composite material. The smaller the value, the higher the dispersion degree, and the measured value of the graphene dispersion paste of the present invention is actually less than 20 μm by a scraper fineness meter (for example, 5- 15 μm), and the measured value of the graphene resin dispersed only by the male transfer machine (a certain degree of agglomeration may occur or the graphene sheets may be easily stacked again into graphite due to uneven dispersion) is not less than 25 μm, and thus it is known that The graphene sheets in the graphene dispersion paste of the present invention did not undergo serious agglomeration and were uniformly dispersed.

The graphene dispersion paste of the invention can be widely applied to the technical fields of fiber composite materials, rubber composite materials, electrochemical element current collecting layers, electrochemical element electrode material conductive additives, antistatic coatings and anti-corrosion coatings.

6A, 6B and 6C are schematic views showing the steps of the method for using the graphene dispersion paste of the present invention. As shown in FIG. 6A, the graphene dispersion paste 1 is prepared according to the above preparation method, and the graphene dispersion paste 1 comprises a plurality of graphene sheets 11 and a first polymer 12, and the graphene sheets 11 are uniformly dispersed in the first polymer 12, graphite. The viscosity of the olefin dispersion paste 1 is not less than 50,000 cps.

As shown in FIG. 6B, the graphene dispersion 1' having a viscosity of not more than 5000 cps is formed by using a solvent or a second polymer-diluted graphene dispersion paste 1 compatible with the first polymer; and a graphene dispersion 1' is applied. In the substrate 100, the graphene dispersion 1' is expanded along the surface of the substrate 100, and the first polymer (or the first polymer and the second polymer) 12' which recovers the fluidity is dispersed and sedimented. Without agglomeration, the moving distance of each graphene sheet 11 parallel to the surface of the substrate 100 is proportional to its vertical distance from the surface of the substrate 100 (as shown by the dotted arrow), so that the plurality of graphene sheets 11 can be uniformly distributed on the base. The surface of the material 100.

As shown in FIG. 6C, the graphene dispersion 1' is cured by heating or light irradiation to form a graphene polymer composite structure 10 in which the graphene sheets 11 distributed on the surface of the substrate 100 form a graphene layer 110, which is high in solidification. The molecular layer 120 adheres the graphene layer 110 to the surface of the substrate 100. The graphene layer 110 can greatly increase the properties of the conductive layer, the heat dissipation, or the mechanical strength of the polymer layer 120 and the substrate 100. Therefore, the graphene polymer composite structure 10 can be combined with the substrate 100 to produce a superiority to the conventional graphene composite material. efficacy.

The specific application of the graphene dispersion paste of the present invention will be more clearly understood by those skilled in the art, and the practical application method will be described in detail below by way of exemplary embodiments.

The invention provides a graphene resin fiber composite material comprising: a fiber cloth, a plurality of graphene sheets and a resin layer, each graphene sheet is attached to opposite surfaces of the fiber cloth, and the resin layer is coated on the graphene sheet. The fiber cloth may be any one or a combination of a carbon fiber cloth, a glass fiber cloth, or a Kevlar fiber cloth. The resin layer may be formed by a polymerization reaction or a crosslinking reaction by heating or ultraviolet light irradiation of a resin, and the material of the resin layer is, for example, an epoxy resin, a phenol resin or a polyester resin, or a combination thereof. Based on the total weight of the graphene resin fiber composite, the resin layer accounts for 25-55 wt%, the graphene sheet accounts for 0.01-5 wt%, and the ratio of the planar transverse dimension to the fiber diameter of each graphene sheet is between 0.1-10. .

Example 1: Graphene Resin Fiber Composite

Preparation step: 8 wt% graphene sheets and 92 wt% epoxy resin were added to a homogenizer, mixed for 1 hour to form a mixture having a viscosity of more than 200,000 cps; a mixture of graphene sheets and epoxy resin was placed in a revolutionary autorotation mixer. The rotation speed is 2000 rpm, the revolution speed is 500 rpm, and the operation is continued for 3 hours to form a pseudoplastic non-Newtonian fluid; the pseudoplastic non-Newtonian fluid of the graphene sheet and the epoxy resin is placed in the dispersing device, and the first dispersion processing is set to a pressure of 5 bar. And a 200 μm slit, the pseudoplastic non-Newtonian fluid passes through the slit at a flow rate of 0.5 L/min, the second dispersion process sets a pressure of 22 bar and a slit of 50 μm, and the pseudoplastic non-Newtonian fluid is 2.0 L/min. The flow rate was passed through the slit to obtain a graphene dispersion paste; the graphene dispersion paste was placed in a deaerator, set at a rotation speed of 1000 rpm, and the temperature was removed at 60 degrees Celsius.

Pre-dipping step: diluting the graphene dispersion paste to a weight ratio of graphene sheets by epoxy resin to 1 wt%; adding isophorone solvent to adjust the viscosity of the diluted graphene dispersion paste to about 1000 cps, forming Graphene dispersion; immersed in a graphene dispersion of Formosa TC12K36 carbon fiber cloth; remove the pre-soaked carbon fiber cloth and let it stand at room temperature, dry and dry, and the weight ratio of the resin contained therein is 42%.

Molding step: 6 pieces of prepreg carbon fiber cloth were placed in a mold, vacuumed to 160 ° C and subjected to pressure molding at 1000 Kg/cm ² to obtain a graphene resin carbon fiber composite material.

After the same ratio of graphene sheets and epoxy resin were dispersed only through the first-stage revolution-rotating agitator, only the pre-dip step was carried out to prepare a graphene pre-impregnated carbon fiber cloth. Cutting a graphene-free resin fiber composite material by a CNC, a graphene resin fiber composite material prepared by using the graphene dispersion paste of the present invention, and a graphene resin prepreg carbon fiber cloth dispersed only by a public-rotation stirrer, The material dispersion of the three fiber composites was tested by a squeegee fineness meter, and the tensile strength, tensile modulus, and flexural modulus of each sample were tested in accordance with the test method of ASTM D3039, and the results are shown in Table 1.

Table 1
The epoxy resin with reduced viscosity can drive the graphene sheet to be uniformly dispersed on the surface of the carbon fiber, and the cured epoxy resin can adhere the graphene sheet to the surface of the carbon fiber, as shown in Table 1, which is not contained in Comparative Example 1-1. The graphene resin fiber composite material, the graphene resin fiber composite material of the embodiment 1 can increase the mechanical strength by an average of 15-20%; since the graphene sheets in the comparative example 1-2 graphene resin prepreg carbon fiber cloth are not uniformly dispersed, The fineness of the squeegee is markedly increased, and significant unevenness in the coated surface of the carbon fiber cloth is observed during the coating or prepreg process, so that the subsequent molding step cannot be continued.

The invention provides a graphene antistatic rubber, comprising: 10-60 wt% of rubber, carbon black, zinc oxide, cotton yarn and 0.001-6 wt% of graphene sheets as a whole, and the planar transverse dimension of the graphene sheet and The diameter ratio of the cotton yarn fibers is between 0.1 and 10. The rubber can be formed by heating or ultraviolet light to irradiate the raw material for polymerization or cross-linking reaction, for example: nitrile rubber, hydrogenated nitrile rubber, tantalum rubber, fluorine rubber, EPDM rubber, fluorine rubber, styrene-butadiene rubber Any one or combination of neoprene, acrylate rubber, natural rubber, chlorosulfonated polyethylene gum, butyl rubber or polyurethane rubber.

Example 2: Graphene antistatic rubber

Preparation steps: Add 8 wt% graphene sheets and 92 wt% aromatic oil to a homogenizer, mix for 1 hour to form a mixture with a viscosity greater than 50,000 cps; put a mixture of graphene sheets and aromatic oil into a revolutionary autorotator, rotation speed 2000 rpm , the revolution speed is 500 rpm, and the operation is continued for 3 hours to form a pseudoplastic non-Newtonian fluid; the pseudoplastic non-Newtonian fluid of the graphene sheet and the aromatic oil is placed in the dispersing device, and the first dispersion processing is set to a pressure of 20 bar and a narrowness of 200 μm. Slot, pseudoplastic non-Newtonian fluid passes through the slit at a flow rate of 0.5 L/min, the second dispersion process sets a pressure of 24 bar and a slit of 50 μm, and the pseudoplastic non-Newtonian fluid passes through the slit at a flow rate of 2.0 L/min. A graphene dispersion paste was obtained; the graphene dispersion paste was placed in a deaerator, the rotation speed was set at 1000 rpm, and the temperature was removed at 60 degrees Celsius.

Mixing step: dilute the viscosity of the graphene dispersion paste to 10,000 cps with an aromatic oil and a decane to form a graphene dispersion; add 100 parts by weight of chloroprene rubber, 60 parts by weight of reinforcing carbon black, and 5 parts by weight. Zinc oxide, put into a revolutionary rotation mixer, rotation speed 2000 rpm, revolution speed 500 rpm, continuous operation for 0.5 hours to form a raw material dispersion; dilute the raw material dispersion with aromatic oil and decane to a viscosity of 3000 cps; finally add 15 parts by weight The cotton yarn forms an antistatic rubber material, wherein the graphene sheet accounts for 1-6 wt% of the whole.

Curing step: heating causes the antistatic rubber raw material to undergo polymerization or crosslinking reaction to form a graphene antistatic rubber. Due to the decrease of the viscosity of the antistatic rubber raw material, the binding force of the diluted rubber on the graphene sheet is reduced during the polymerization or crosslinking process, the graphene sheet will gradually settle on the surface of the cotton yarn, and the electron migration network is formed by reinforcing the carbon black. This improves the electrical conductivity of the cotton yarn, thereby improving the antistatic properties of the rubber. Resistance test results of graphene rubber made of graphene-free rubber, graphene antistatic rubber prepared according to the method of the present invention, and graphene sheet dispersed only by homogenizer and revolutionary autorotation mixer Table 2.

Table 2
As shown in Table 2, the rubbers containing the graphene sheets of Examples 2-1 and 2-2 had an excellent antistatic effect as compared with the rubber containing no graphene of Comparative Example 2-1; although Comparative Example 2-2 The graphene rubber contains the same content of the graphene sheet as the graphene rubber of Example 3-1, and the graphene sheet is not uniformly dispersed, resulting in a resistance value higher than that of the embodiment 2-1, and does not have the example 2-1 and 2-2 antistatic effect.

The invention provides a graphene antistatic coating comprising: a carrier resin, a graphene sheet and an additive, and the graphene sheet accounts for 0.01-5 wt% of the whole. The carrier resin is selected from the group consisting of polyvinylidene fluoride, polymethyl methacrylate, polyethylene terephthalate, polyurethane, polyethylene oxide, polyacrylonitrile, polypropylene decylamine, polymethyl acrylate, polymethyl methacrylate. , polyvinyl acetate, polyvinyl pyrrolidone, polytetraethylene glycol diacrylate, polyimine, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, ethyl cellulose, cyanoethyl cellulose, At least one of cyanoethyl polyvinyl alcohol, carboxymethyl cellulose, polyvinyl chloride, polyolefin, and anthrone resin. The additive is selected from the group consisting of a conductive auxiliary agent, a surfactant, a viscosity modifying agent, a coupling agent, and a thixotropic agent.

Example 3: Graphene antistatic coating

Preparation step: adding 30 wt% graphene sheets and 70 wt% phthalate to a homogenizer, mixing for 1 hour to form a mixture having a viscosity greater than 50,000 cps; placing a mixture of graphene sheets and phthalates Into the revolution rotary mixer, the rotation speed of 2000 rpm, the revolution speed of 500 rpm, continuous operation for 3 hours to form a pseudoplastic non-Newtonian fluid; the graphene sheet and the phthalate pseudoplastic non-Newtonian fluid into the dispersion device, the first The secondary dispersion process sets a pressure of 15 bar and a slit of 200 μm. The pseudoplastic non-Newtonian fluid passes through the slit at a flow rate of 0.5 L/min. The second dispersion process sets a pressure of 22 bar and a slit of 50 μm. The non-Newtonian fluid was passed through the slit at a flow rate of 2.0 L/min to obtain a graphene dispersion paste; the graphene dispersion paste was placed in a deaerator, set at a rotation speed of 1000 rpm, and the temperature was removed at 60 degrees Celsius.

Mixing step: dilute the viscosity of the graphene dispersion paste to 10,000 cps with epoxy resin, phenolic resin or phthalate to form a graphene dispersion; mix polyvinyl chloride, epoxy resin, phenolic resin, orthophthalic acid Formate, barium stearate, triphenyl phosphate, cerium oxide and graphene dispersion form antistatic coatings, in which polyvinyl chloride, epoxy resin and phenolic resin are used as carrier resin, phthalate as viscosity The adjusting agent, barium stearate, triphenyl phosphate and ceria are used as adhesion enhancers.

Curing step: the antistatic coating is applied to the surface of the glass substrate by a doctor blade, and the antistatic coating is heated and baked at 150 degrees Celsius for 30 minutes to form a graphene antistatic coating with a thickness of 30 μm, wherein the polyvinyl chloride 60 wt%, epoxy resin accounted for 10 wt%, phenolic resin accounted for 10 wt%, phthalate accounted for 10%, barium stearate accounted for 2 wt%, triphenyl phosphate accounted for 2.5 wt%, calcium carbonate 2 wt%, cerium oxide 2 wt%, graphene sheet 1.5 wt%. The binding force of the diluted resin on the graphene sheet is lowered, and the graphene sheet covers the surface of the glass substrate to form an electron migration network.

Electrostatic measuring machine and surface impedance testing machine were used to test the antistatic coating containing no graphene, the antistatic coating of graphene, and the same content of graphene sheets dispersed by homogenizer and revolutionary agitator as in Example 3. The surface resistance of the graphene antistatic coating was as shown in Table 3.

table 3
As shown in Table 3, the graphene antistatic coating of Example 3 had an excellent antistatic effect compared to the antistatic coating containing no graphene of Comparative Example 3-1; although Comparative Example 3-2 was included in the implementation. In the same amount of graphene sheets of Example 3, the graphene sheets were unevenly dispersed, resulting in a higher electric resistance value than in Example 3, and the transmittance was also slightly lower than that in Example 3.

The invention provides a graphene conductive coating comprising: a graphene sheet, a carrier resin and a conductive filler, wherein the graphene sheet is connected with the conductive filler to form a conductive network on the substrate, the carrier resin covers the graphene sheet and the conductive filler, and the graphene sheet The total amount is 0.1-30% by weight, the conductive filler accounts for 10-50% by weight of the whole, and the carrier resin accounts for 10-50% by weight of the whole. The substrate may be selected from an insulating material or a metal foil, and the insulating material may be selected from any of polyethylene terephthalate, polyimide, epoxy resin and phenolic resin, and the metal foil is selected from the group consisting of aluminum foil, copper foil and titanium. Any of foil and nickel foil. The electrically conductive filler is selected from the group consisting of electrically conductive carbon black, carbon nanotubes, or combinations thereof.

Example 4: Graphene current collecting layer

Preparation steps: adding graphene sheets, conductive fillers and N-methyl pyrrolidinone (NMP) to a homogenizer to form a mixture of graphene sheets and conductive fillers; mixing graphene sheets and conductive fillers with carrier resin Put into a revolutionary agitator, rotate at 1000 rpm, rotate at 400 rpm, and continue to run for 1 hour to form a pseudoplastic non-Newtonian fluid with a viscosity greater than 200,000 cps; place the pseudoplastic non-Newtonian fluid of graphene sheets, conductive filler and carrier resin. Dispersing device, the first dispersion process sets the pressure of 20 bar and the slit of 150 μm. The pseudoplastic non-Newtonian fluid passes through the slit at a flow rate of 1 L/min. The second dispersion process sets the pressure of 24 bar and the narrowness of 30 μm. The slit, pseudoplastic non-Newtonian fluid was passed through the slit at a flow rate of 2.0 L/min to obtain a graphene dispersion paste.

Dilution step: N-methylpyrrolidone (NMP) and graphene dispersion paste are added to the centrifuge, and the graphene dispersion paste is diluted to a viscosity of not more than 1000 cps by a centrifuge to form a graphene dispersion. The rotation speed of the centrifuge is 200. -2000 rpm.

Curing step: The graphene dispersion is applied to an aluminum foil substrate, and the N-methylpyrrolidone (NMP) therein is volatilized by heating to form a graphene conductive coating having a thickness of 0.1 to 5 μm. The binding force of the diluted carrier resin on the graphene sheet is lowered, and the graphene sheet recovers the fluidity. In addition to preventing the graphene sheet from agglomerating, the conductive filler can also be connected with the graphene sheet to form a conductive network.

The graphene conductive coating was tested by a 3M model 600 and 610 tape (adhesion), and the adhesion strength of the graphene conductive coating to the substrate was ≧4B. The resistance values of the graphene conductive coatings of different compositions and thicknesses were measured by a four-point probe, wherein Examples 4-1 to 4-5 were selected from polyvinylidene fluoride (PVDF) as a carrier resin, and Example 4- 6 and 4-7 use epoxy resin as the carrier resin. Comparative Examples 4-1 and 4-2 used graphene sheets, conductive fillers, and N-methyl pyrrolidinone (NMP) in the same ratio as in Examples 4-5 and 4-7, respectively, and were mixed only by a homogenizer. The graphene conductive coating is formed without subsequent dispersion processing, and the graphene conductive coating is applied and cured on the substrate to form a graphene current collecting layer. The test results are shown in Table 4.

Table 4
As shown in Table 4, the conductive networks formed by the graphene sheets and the conductive fillers in Examples 4-1 to 4-7 have extremely low electrical resistance, which can greatly improve the conductivity of the current collecting layer, and the carrier resin can enhance the conductive network pair. The adhesion strength of the substrate and the interface resistance between the current collecting layer and the electrode active material are effectively reduced; the current collecting layer resistance obtained by applying the comparative examples 4-1 and 4-2 graphene conductive coating is significantly better than that of the embodiment 4-5. And 4-7 is 2 to 3 times higher, and the graphene dispersion paste of the present invention is used for the advantage of constructing a conductive network.

Fig. 7 is a schematic view showing the structure of a supercapacitor to which the current collecting layer of the present invention is applied. As shown in FIG. 7, the supercapacitor 7 includes a current collecting layer 71 and an active material layer 72, wherein the composition of the current collecting layer 71 is as shown in Embodiment 4-3 of Table 4, and the thickness of the aluminum foil 711 is 15-16 μm. The thickness of the graphene conductive coating 712 is 1-2 μm; the material of the active material layer 72 is activated carbon. The capacitance of the current collecting layer of the present invention and a conventional supercapacitor using only aluminum foil as a current collecting layer was applied at different current density tests to compare the charge and discharge performance of the two.

Fig. 8 is a current density versus capacitance dot plot of a conventional supercapacitor to which the current collecting layer of the present invention is applied and which uses only aluminum foil as a current collecting layer. As shown in Figure 8, under the test conditions that the current density is increased from 0.5 A/g to 10 A/g, the capacitance of the conventional supercapacitor is severely attenuated. When the current density exceeds 4 A/g, the capacitance decays to zero. The supercapacitor to which the current collecting layer of the present invention is applied, the current density is increased from 0.5 A/g to 10 A/g, and the capacitance can be maintained at more than 80% of the highest value. The AC impedance of the conventional supercapacitor using the current collecting layer of the present invention and only the aluminum foil as the current collecting layer was further tested to analyze the difference in charge and discharge performance between the two.

Figure 9 is a diagram of the impedance (Z') versus impedance (Z') dotted line of a conventional supercapacitor using the current collecting layer of the present invention and an aluminum foil only as a current collecting layer. As shown in Fig. 11, In the supercapacitor, the interface impedance between the active material layer and the current collecting layer is too large, and polarization occurs at the interface under the operation of large current density, resulting in inoperability; in view of the use of the graphene current collecting layer of the present invention, the supercapacitor, graphene The interface impedance between the conductive coating and the active material layer is greatly reduced by about 40 times than the interface impedance of the conventional supercapacitor. From the difference in the impedance values of the two, it can be known that the use of the graphene current collecting layer of the present invention can greatly improve the supercapacitor. The operating range of current density.

The present invention provides a graphene electrode material comprising: a graphene sheet, a conductive filler, a solvent, and a resin. The graphene sheet and the conductive filler are dispersed in a solvent, the resin is bonded to the graphene sheet and the conductive filler, the graphene sheet accounts for 0.1-20 wt% of the whole, the conductive filler accounts for 1-30 wt% of the whole, and the solvent accounts for 50-95 wt% of the whole. %, the resin accounts for 0.01-5 wt% of the whole. The conductive filler may be selected from conductive carbon black, carbon nanotubes or a combination thereof, and the ratio of the particle diameter of the conductive filler to the thickness of the graphene sheet is between 2 and 1000.

Example 5: Graphene electrode material

Preparation steps: adding graphene sheets, conductive fillers and N-methyl pyrrolidinone (NMP) to a homogenizer to form a mixture of graphene sheets and conductive fillers; mixing graphene sheets and conductive fillers with polyposition Polyvinylidene fluoride (PVDF) was placed in a revolutionary autorotator, rotating at 800 rpm, 300 rpm, and running for 1 hour to form a pseudoplastic non-Newtonian fluid with a viscosity greater than 200,000 cps; graphene sheets, conductive fillers and geodesic The pseudoplastic non-Newtonian fluid of vinyl fluoride was placed in a dispersing device. The first dispersion process set a pressure of 18 bar and a slit of 200 μm. The pseudoplastic non-Newtonian fluid passed through the slit at a flow rate of 2 L/min, the second dispersion. A pressure of 24 bar and a slit of 50 μm were processed, and a pseudoplastic non-Newtonian fluid was passed through the slit at a flow rate of 2.5 L/min to obtain a graphene dispersion paste.

Mixing step: N-methylpyrrolidone (NMP) and graphene dispersion paste are added to the centrifuge, and the graphene dispersion paste is diluted to a viscosity of not more than 500 cps to form a graphene dispersion, and the speed of the centrifuge is between 200 and 2000 rpm. The graphene dispersion is uniformly mixed with a battery active material (a lithium ion compound such as lithium nickel cobalt manganese oxide, NCM) by a centrifugal defoamer to form a graphene electrode material.

Curing step: coating a graphene electrode material on a substrate, and vacuum heating to volatilize N-methylpyrrolidone (NMP) in the graphene electrode material to form an electrode. Lithium nickel cobalt manganese half-cells were fabricated using graphene electrode materials and carbon nanotube (CNT) electrode materials, respectively, and the battery capacity of the two were measured for charge-discharge rate and cycle life (at 1C rate). Figures 10 and 11 are shown.

In this embodiment, the dispersed graphene sheet is attached to the surface of the electrode active material, and is connected to the conductive filler to form a charge and discharge network of the electrode active material. The resin has the function of dispersing the graphene sheet and bonding the charge and discharge network, such as the 10th. As shown in FIG. 11 , the graphene electrode material of the present invention can effectively improve the charge and discharge efficiency and cycle life of the electrode compared to the carbon nanotube electrode material.

In summary, the present invention utilizes the fluid properties of the polymer to form a pseudo-plastic non-Newtonian fluid having a viscosity greater than 200,000 cps by mixing the graphene sheets with a polymer, and applying a pressure of 10-30 bar to pass the pseudoplastic non-Newtonian fluid through 10-1000 μm. The slit is at least twice, and the viscosity of the polymer is suddenly dropped under the high shear force formed by the slit to uniformly disperse the graphene sheet, and the polymer which restores the original viscosity through the slit can effectively prevent the graphene sheet from agglomerating. And the dispersion state of the graphene sheets can be maintained for a long time. When the graphene dispersion paste of the present invention is used, the viscosity of the graphene dispersion paste is adjusted by adding a solvent or a compatible polymer, and the direction and rate of flow of the graphene sheet are controlled, so that the graphene sheet is dispersedly attached to the surface of the material, thereby Graphene dispersion paste can be applied to the technical fields of fiber, rubber, electrochemistry, etc., and has industrial applicability.

The above-described embodiments are merely illustrative of the principles of the invention and its effects, and are not intended to limit the invention. Modifications and variations of the above-described embodiments can be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, all equivalent modifications and changes may be made without departing from the spirit and scope of the invention as disclosed in the appended claims.

1‧‧‧Graphene dispersion paste

1'‧‧‧Graphene dispersion

7‧‧‧Supercapacitors

10‧‧‧ Graphene polymer composite structure

11‧‧‧ Graphene sheets

12‧‧‧First polymer

12'‧‧‧ diluted first polymer

71‧‧‧current collecting layer

72‧‧‧Active material layer

110‧‧‧graphene layer

120‧‧‧ polymer layer

100‧‧‧Substrate

711‧‧‧Aluminum foil

712‧‧‧Graphene conductive coating

S10, S20, S30, S40‧‧ steps

1 is a flow chart showing the steps of a method for preparing a graphene dispersion paste of the present invention;

2 is a schematic view showing a mixing step of a method for preparing a graphene dispersion paste of the present invention;

3 is a schematic view showing a stirring step of a method for preparing a graphene dispersion paste of the present invention;

4 is a schematic view showing a dispersion step of a method for preparing a graphene dispersion paste of the present invention;

5 is a schematic view showing a defoaming step of a method for preparing a graphene dispersion paste of the present invention;

6A, 6B and 6C are schematic views showing the steps of the method for using the graphene dispersion paste of the present invention;

Figure 7 is a schematic view showing the structure of a supercapacitor to which the current collecting layer of the present invention is applied;

Figure 8 is a current density versus capacitance dot plot of a conventional supercapacitor to which the current collecting layer of the present invention is applied and which uses only aluminum foil as a current collecting layer;

Figure 9 is a diagram of the impedance (Z') versus impedance (Z') dot plot of a conventional supercapacitor using the current collecting layer of the present invention and a conventional supercapacitor using only aluminum foil as a current collecting layer;

10 is a dotted line diagram of a battery capacity versus charge and discharge rate of a graphene electrode material to which the present invention is applied and a half cell using a carbon nanotube (CNT) electrode material;

Figure 11 is a dot plot of battery capacity versus cycle life for a 1C rate using a graphene electrode material of the present invention and a half cell using a carbon nanotube (CNT) electrode material.

Claims (10)

A method for preparing a graphene polymer composite material, comprising: mixing a plurality of graphene sheets, a solvent and a polymer to form a pseudoplastic non-Newtonian fluid, wherein each of the graphene sheets is composed of 2 to 30 graphene layers stacked on each other, a bulk density of 0.005 to 0.05 g/cm ³ , a thickness of 0.68 to 10 nm, and a planar transverse dimension of 1 to 100 μm; applying a pressure of not less than 10 bar to pass the pseudoplastic non-Newtonian fluid through a gap of not more than 1000 μm Sewing at least twice to form a graphene dispersion paste having a viscosity of 50,000 to 350,000 cps, wherein the pseudoplastic non-Newtonian fluid has a viscosity of 10 to 10000 cps when passing through the slit; diluting the polymer and the solvent a graphene dispersion paste to form a graphene dispersion having a viscosity of 500 to 3000 cps; applying the graphene dispersion to a substrate to uniformly distribute the graphene sheets on a surface of the substrate; and curing the graphene dispersion The liquid forms a graphene polymer composite material. The method for preparing a graphene polymer composite according to claim 1, wherein the polymer is selected from the group consisting of an epoxy resin, a phenol resin, and a polyester resin, or a combination thereof. The method for preparing a graphene polymer composite according to claim 1, wherein the substrate is selected from the group consisting of carbon fiber cloth, glass fiber cloth and kewei fiber cloth, or a combination thereof. The method for preparing a graphene polymer composite according to claim 1, wherein the step of applying the graphene dispersion to the substrate comprises: dipping the substrate into the graphene dispersion, dispersing from the graphene The substrate was taken out from the liquid, and the substrate was allowed to stand to dry at room temperature. The method for preparing a graphene polymer composite according to claim 1, wherein the step of curing the graphene dispersion comprises: stacking the plurality of substrates coated with the graphene dispersion in a mold, and vacuum heating It is more than 160 degrees Celsius and pressurized to 1000 Kg/cm ² or more. A graphene polymer composite material, comprising a substrate having opposite surfaces; a plurality of graphene sheets, parallel and attached to the two surfaces of the substrate, and a polymer layer covering the graphene sheets and the two surfaces of the substrate. The graphene polymer composite material according to claim 6, wherein the substrate is selected from the group consisting of carbon fiber cloth, glass fiber cloth and kewei fiber cloth, or a combination thereof. The graphene polymer composite material according to claim 7, wherein a ratio of a planar transverse dimension of each of the graphene sheets to a fiber diameter of the substrate is between 0.1 and 10. The graphene polymer composite material according to claim 6, wherein the material of the polymer layer is selected from any one of epoxy resin, phenol resin and polyester resin or a combination thereof. The graphene polymer composite material according to claim 6 , wherein the graphene sheet accounts for 0.01 to 5 wt%, and the polymer layer accounts for 25 to 55, based on the total weight of the graphene polymer composite material. Wt%.