CN110164588B

CN110164588B - Modified conductive paste and preparation method and application thereof

Info

Publication number: CN110164588B
Application number: CN201910494444.8A
Authority: CN
Inventors: 徐立新; 张博远; 张高乐; 周康
Original assignee: Hangzhou Mingyu Optoelectronics Technology Co ltd; Zhejiang University of Technology ZJUT
Current assignee: Hangzhou Mingyu Optoelectronics Technology Co ltd; Zhejiang University of Technology ZJUT
Priority date: 2019-06-06
Filing date: 2019-06-06
Publication date: 2020-11-06
Anticipated expiration: 2039-06-06
Also published as: CN110164588A

Abstract

The embodiment of the application provides a modified conductive paste and a preparation method and application thereof, and relates to the field of conductive pastes. The modified conductive paste comprises the following raw materials in percentage by mass: 1-90% of carbon-based conductive paste, 5-60% of carbon nanotubes and 5-50% of hyperbranched polyethylene; and a three-dimensional conductive network is formed among the carbon-based conductive paste, the carbon nano tube and the hyperbranched polyethylene. The preparation method of the modified conductive paste mainly comprises the steps of mixing the carbon-based conductive paste and an organic solvent to form a first solution; mixing the carbon nano tube, the hyperbranched polyethylene and the organic solvent to uniformly disperse the carbon nano tube to form a second solution; and uniformly mixing the first solution and the second solution, and removing the organic solvent. The modified conductive paste has high conductivity and low cost, and can be made into a lead; the preparation condition is mild, the process is simple and efficient, and the environment is protected.

Description

Modified conductive paste and preparation method and application thereof

Technical Field

The application relates to the field of conductive paste, in particular to modified conductive paste and a preparation method and application thereof.

Background

Although the metal material is used as the conductive material and is seen everywhere in life, the metal material as the conductive material has a disadvantage that cannot be avoided. For example, because the current value that the unit area of the wire needs to bear is very large, the wire is generally made of metal with high melting point and low resistivity as a conductive material, and the metal material meeting the use requirement after processing not only consumes a lot of energy but also causes great pollution to the environment. Therefore, the development of materials which are easy to process, low in cost, free of pollution and excellent in conductivity is urgent.

The current research finds that the carbon-based conductive paste has certain conductivity, the main components of the carbon-based conductive paste are adhesive and carbon material, the adhesive is non-conductive as an adhesive, and the carbon material plays a conductive role. Although the carbon material is a good non-metallic conductive material, the conductive principle of the carbon-based conductive paste is that the conductive purpose is achieved through the tunnel effect between the carbon materials, specifically, a thin insulating layer (adhesive) is sandwiched between two layers of conductors (the carbon materials) to form an electron tunnel junction, the filler particles are not in contact with each other, and a potential barrier exists. However, the conductivity of the carbon-based conductive paste is still low, and particularly, when the content of the carbon material is low, the conductive effect of the carbon-based conductive paste is poor.

Disclosure of Invention

The embodiment of the application aims to provide the modified conductive paste, the preparation method and the application thereof, the modified conductive paste has high conductivity and low cost, and can be made into a lead; the preparation condition is mild, the process is simple and efficient, and the environment is protected.

In a first aspect, an embodiment of the present application provides a modified conductive paste, which includes, by mass: 1-90% of carbon-based conductive paste, 5-60% of carbon nanotubes and 5-50% of hyperbranched polyethylene; and a three-dimensional conductive network is formed among the carbon-based conductive paste, the carbon nano tube and the hyperbranched polyethylene.

In the above technical solution, the carbon-based conductive paste is used as a main body of the conductive paste, the Carbon Nanotube (CNT) is used as a modified filler, and the hyperbranched polyethylene (HBPE) is used as a dispersing aid, so as to form a three-dimensional network structure.

The carbon nano tube CNT is excellent in conductivity, can be used as a filler to remarkably enhance the conductivity of the carbon-based conductive paste, and can form a three-dimensional conductive network with a carbon material in the carbon-based conductive paste when being used as the filler with a one-dimensional structure. Specifically, the carbon nanotubes are used as a conductive main line, the carbon material in the carbon-based conductive paste plays a role of a support, the carbon nanotubes and the carbon nanotubes are mutually overlapped to form a conductive network, the conductivity of the carbon-based conductive paste is further improved, and particularly the conductivity of the carbon-based conductive paste is greatly improved under the condition of small addition amount of the carbon nanotubes.

The inventor finds that carbon nanotubes are nano-scale fillers, and show a plurality of nano-scale effects after the material reaches the nano-scale, such as zero-dimensional microscopic particles, and after the particle size reaches the nano-scale, the agglomeration effect is remarkably increased, the mutual attraction of the particles in the agglomerate is also remarkably increased, the dispersion difficulty is increased, and the nano-scale fillers show a strong agglomeration effect of nano-powder. Meanwhile, a single carbon nano tube is a fibrous one-dimensional nano material, and the length and diameter are larger, so that the carbon nano tubes are easy to be entangled and bonded together to form a large aggregate. By combining the strong agglomeration effect of the nano powder and the entanglement and bonding phenomenon of the fiber material, the carbon nano tube aggregate is firmer and is more difficult to uniformly disperse. Due to the unique spherical multi-branch structure (namely, the dendritic structure) of the hyperbranched polyethylene, the hyperbranched polyethylene and the carbon nano tubes can generate CH-pi and pi-pi effects, so that the effect of stripping the carbon nano tubes is achieved, the hyperbranched polyethylene and the carbon nano tubes are mixed and dispersed in the solution, and the stably dispersed carbon nano tube solution is obtained.

The hyperbranched polyethylene HBPE can assist in stripping the carbon nano tube to obtain a stably dispersed carbon nano tube solution, more importantly, the hyperbranched polyethylene can also assist in stably and uniformly dispersing the carbon nano tube in the carbon-based conductive paste, namely, the solubility of the hyperbranched polyethylene is related to whether the carbon nano tube is uniformly dispersed in the carbon-based conductive paste or not, because the hyperbranched polyethylene can perform CH-pi action or pi-pi action with a carbon material in the carbon-based conductive paste, the hyperbranched polyethylene adsorbed on the carbon nano tube can also adsorb the carbon material in the carbon-based conductive paste, and at the moment, the carbon material can be uniformly distributed beside the carbon nano tube under the action of the hyperbranched polyethylene, namely, the hyperbranched polyethylene can promote the uniform and stable dispersion of the carbon nano tube in the conductive paste to form a conductive carbon-based bridge, so that the carbon nano tube and the carbon material in the conductive paste form a three-dimensional network structure, the conductivity of the modified conductive paste is obviously enhanced.

In one possible implementation mode, the raw materials comprise the following components in percentage by mass: 72 to 90 percent of carbon-based conductive paste; 5% -14% of carbon nanotubes; and 5 to 14 percent of hyperbranched polyethylene.

In above-mentioned technical scheme, because hyperbranched polyethylene has not only played the effect of peeling off carbon nanotube, has also played the effect of supplementary carbon nanotube stable dispersion in carbon base conductive paste, so the electric conductivity of modified conductive paste can be influenced to the difference of carbon nanotube addition, and the electric conductivity of modified conductive paste can also be influenced to the difference of hyperbranched polyethylene addition, adopts the raw materials by mass percent: 72 to 90 percent of carbon-based conductive paste; 5% -14% of carbon nanotubes; and 5% -14% of hyperbranched polyethylene, and the obtained modified conductive paste has better conductivity.

In one possible implementation mode, the components of the carbon-based conductive paste comprise an adhesive and a carbon material, wherein the mass content of the carbon material is between 30% and 70%; optionally, the carbon-based conductive paste is mainly obtained by grinding, dispersing and modifying an adhesive and a carbon material.

In the technical scheme, the carbon material in the carbon-based conductive paste is a main material playing a role in conducting electricity, so that the mass content of the carbon material in the carbon-based conductive paste is controlled to be 30-70%, and the modified conductive paste obtained by modifying the carbon-based conductive paste through the carbon nano tube and the hyperbranched polyethylene has better conductivity.

In one possible implementation, the carbon nanotubes comprise at least one selected from the group consisting of single-walled carbon nanotubes, double-walled carbon nanotubes, multi-walled carbon nanotubes, highly conductive multi-walled carbon nanotubes, hydroxylated carbon nanotubes, carboxylated carbon nanotubes and aminated carbon nanotubes.

In the technical scheme, the addition of different types of carbon nanotubes has obvious influence on the change of the conductivity of the carbon-based conductive paste, and the modified conductive paste obtained by using the carbon nanotubes as the modified filler has better conductivity.

In a second aspect, an embodiment of the present application provides a method for preparing a modified conductive paste provided in the first aspect, which includes the following steps:

mixing a carbon-based conductive paste and an organic solvent to form a first solution; mixing the carbon nano tube, the hyperbranched polyethylene and the organic solvent to uniformly disperse the carbon nano tube to form a second solution;

and uniformly mixing the first solution and the second solution, and removing the organic solvent.

In the above technical scheme, a certain amount of carbon-based conductive paste is weighed and dissolved in a corresponding organic solvent to form a carbon-based conductive paste solution (i.e., a first solution), and a certain amount of carbon nanotubes and hyperbranched polyethylene are weighed and dissolved in a corresponding organic solvent to uniformly disperse the carbon nanotubes, thereby forming a carbon nanotube/hyperbranched polyethylene mixed solution (a second solution); and mixing the carbon-based conductive paste solution with the carbon nano tube/hyperbranched polyethylene mixed solution to uniformly disperse the carbon nano tube and the hyperbranched polyethylene in the carbon-based conductive paste, and removing the organic solvent to obtain the modified carbon-based conductive paste (namely the modified conductive paste). The preparation method has the advantages of mild conditions, simple process, low price and environmental friendliness, and can improve the conductivity of the carbon-based conductive paste and efficiently prepare the modified conductive paste; the preparation method can also recycle the organic solvent, greatly reduce the cost and avoid the pollution to the environment and the harm to the human body caused by the volatilization of the organic solvent.

The hyperbranched polyethylene can assist the carbon nano tubes to be uniformly dispersed in the carbon-based conductive paste, and the hyperbranched polyethylene can perform CH-pi action or pi-pi action with carbon materials in the carbon-based conductive paste, so that the hyperbranched polyethylene adsorbed on the carbon nano tubes can adsorb the carbon materials in the carbon-based conductive paste, and the carbon nano tubes and the carbon materials in the carbon-based conductive paste form a three-dimensional network structure. The modified conductive paste has low cost, high electric conductivity and high heat conductivity, can be processed and molded at normal temperature (the molding method is various and simple, the shape of the conductive paste can be changed by using a mold at normal temperature), can be recycled, solves the problems that the common carbon-based conductive paste on the market is difficult to mold, has low electric conductivity and can not replace metal wires, and can be applied to wider fields, such as replacing wires in low-power electric appliances and preventing oxidation at joints of two different metal wires.

In one possible implementation, the organic solvent comprises at least one selected from the group consisting of chloroform, tetrahydrofuran, petroleum ether, and diethyl ether; optionally, the organic solvent comprises at least one of chloroform or tetrahydrofuran.

In the above technical solution, there are many organic solvents for dissolving the carbon-based conductive paste and the hyperbranched polyethylene, such as chloroform, tetrahydrofuran THF, petroleum ether, and diethyl ether. The hyperbranched polyethylene is added in the process of modifying the carbon-based conductive paste, the solubility of the hyperbranched polyethylene in chloroform and tetrahydrofuran is better than that of other organic solvents, and the solubility of the hyperbranched polyethylene is related to the uniform degree of dispersion of the carbon nano tube in the carbon-based conductive paste, so that at least one of chloroform and tetrahydrofuran with better solubility of the hyperbranched polyethylene can be selected as the organic solvent to dissolve the carbon-based conductive paste and the hyperbranched polyethylene.

In one possible implementation, the method of mixing the carbon nanotubes, the hyperbranched polyethylene and the organic solvent to uniformly disperse the carbon nanotubes is ultrasonic treatment; optionally, the time of ultrasonic treatment is 0.5-12 h.

In the technical scheme, the carbon nano tubes can be uniformly dispersed in a liquid system through ultrasonic treatment.

In a possible implementation manner, after the carbon nanotubes are uniformly dispersed, the method further comprises the steps of removing part of the hyperbranched polyethylene and then re-uniformly dispersing the carbon nanotubes;

optionally, the method of removing a portion of the hyperbranched polyethylene comprises at least one of high speed centrifugation or vacuum filtration.

In the technical scheme, a certain amount of hyperbranched polyethylene is added for modification, the hyperbranched polyethylene not only plays a role in peeling off the carbon nanotubes, but also plays a role in assisting the carbon nanotubes to be stably dispersed in the carbon-based conductive paste, but the hyperbranched polyethylene is non-conductive, and the more the hyperbranched polyethylene is added, the poorer the conductivity of the modified conductive paste is, so that part of the hyperbranched polyethylene needs to be removed. In addition, due to the fact that CH-pi and pi-pi effects exist between the hyperbranched polyethylene and the carbon nano tubes and cannot be separated, the purpose of removing part of the hyperbranched polyethylene can be achieved simultaneously by removing part of the carbon nano tubes by at least one of high-speed centrifugation or vacuum filtration.

In one possible implementation manner, the method for uniformly mixing the first solution and the second solution is stirring treatment; optionally, the stirring treatment time is 10-240 min;

and/or, the method of removing the organic solvent comprises at least one of rotary evaporation, purging, or drying.

In the technical scheme, the first solution and the second solution are mixed and continuously stirred for 10-240 min to uniformly mix, so that the stably dispersed carbon nanotubes and the carbon-based conductive paste are uniformly mixed. Because the volatile organic solvent with low melting point is selected in the modification process, the organic solvent can be effectively removed by at least one of rotary evaporation, blowing or drying.

In a third aspect, the embodiments of the present application provide an application of the modified conductive paste provided in the first aspect, and the modified conductive paste is used as a conductive material for manufacturing a conductive wire.

In the technical scheme, the modified conductive paste has the advantages of low cost, low filler content, high conductivity and the like, and can be used for manufacturing a wire, can replace a metal wire, and can be specifically manufactured into a wire for a low-power electric appliance or a joint between two different metal wires.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments of the present application will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and that those skilled in the art can also obtain other related drawings based on the drawings without inventive efforts.

Fig. 1 is a flow chart of a process for preparing a modified conductive paste according to an embodiment of the present disclosure;

FIG. 2 is a schematic diagram of the principle of hyperbranched polyethylene assisted dispersion of carbon nanotubes into a carbon nanotube solution;

FIG. 3 is a schematic structural diagram of a three-dimensional conductive network formed by dispersing hyperbranched polyethylene-assisted carbon nanotubes in carbon-based conductive paste;

fig. 4 is a diagram illustrating the effect of different amounts of carbon nanotubes on the conductivity of carbon-based conductive paste.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

The following describes the modified conductive paste of the embodiments of the present application, and its preparation method and application.

In a first aspect, an embodiment of the present application provides a modified conductive paste, which includes, by mass: 1-90% of carbon-based conductive paste, 5-60% of carbon nanotubes and 5-50% of hyperbranched polyethylene; and a three-dimensional conductive network is formed among the carbon-based conductive paste, the carbon nano tube and the hyperbranched polyethylene. Optionally, the raw materials comprise, by mass: 72 to 90 percent of carbon-based conductive paste, 5 to 14 percent of carbon nano tube and 5 to 14 percent of hyperbranched polyethylene; further optionally, the raw materials comprise, by mass: 72 to 80 percent of carbon-based conductive paste, 8 to 14 percent of carbon nano tube and 8 to 14 percent of hyperbranched polyethylene.

In the embodiment, the carbon-based conductive paste has various selected types, and as an implementation mode, the main components of the carbon-based conductive paste are an adhesive and a carbon material, wherein the mass content of the carbon material is 30-70%, the carbon material content is different, and the conductivity of the corresponding carbon-based conductive paste is also different; optionally, the carbon-based conductive paste is a soft paste obtained by grinding, dispersing and modifying an adhesive and a carbon material. The carbon-based conductive paste is characterized in that the adhesive plays a role of adhesion but is not conductive, the main component of the adhesive is base oil and special additive, the base oil comprises at least one of mineral oil, synthetic ester oil and silicone oil, and the special additive comprises at least one of antioxidant, anticorrosive agent and arc inhibitor. Illustratively, the carbon-based conductive paste is one or at least two of a DY-6 product manufactured by Nanjing Xilite Adhesion Limited, a DDG-A product manufactured by Wuhan Yangtze river electromechanics and a 801 product manufactured by KunLun Kunlun.

In this embodiment, the carbon nanotubes have a variety of specifications to be selected from, and optionally, the carbon nanotubes include at least one selected from the group consisting of single-walled carbon nanotubes SWCNTs, double-walled carbon nanotubes DWCNTs, multi-walled carbon nanotubes MWCNTs, highly conductive multi-walled carbon nanotubes hemcnts, hydroxylated carbon nanotubes (e.g., multi-walled carbon nanotubes grafted with hydroxyl groups), carboxylated carbon nanotubes (e.g., multi-walled carbon nanotubes grafted with carboxyl groups), and aminated carbon nanotubes (e.g., multi-walled carbon nanotubes grafted with amino groups). For example, the carbon nanotube is one of a single-walled carbon nanotube, a double-walled carbon nanotube, a multi-walled carbon nanotube, a highly conductive multi-walled carbon nanotube, a hydroxylated carbon nanotube, a carboxylated carbon nanotube, and an aminated carbon nanotube.

In this embodiment, the hyperbranched polyethylene may be obtained by catalyzing ethylene with a Pd-diimine catalyst and using a one-step "chain removal" copolymerization mechanism, and the specific preparation process includes the following steps:

under the protection of nitrogen, adding ethylene gas into a reaction vessel, ensuring that no oxygen or water exists in the reaction vessel, ensuring that the whole reaction vessel is filled with the ethylene gas, using an anhydrous solvent as a solvent, controlling the temperature to be 5-35 ℃, then adding a Pd-diimine catalyst dissolved in the anhydrous solvent, stirring and reacting for 6-72 hours under the conditions of the temperature of 5-35 ℃ and the ethylene pressure of 0.01-0.8 MPa, pouring the obtained product into acidified methanol after the polymerization is finished to terminate the polymerization, and separating and purifying the obtained polymerization reaction mixture to obtain the hyperbranched polyethylene.

Optionally, the anhydrous grade solvent comprises at least one selected from the group consisting of anhydrous dichloromethane, anhydrous chloroform, or anhydrous chlorobenzene; optionally, the dosage of the Pd-diimine catalyst and the total volume of the anhydrous solvent are 0.5-10.0 g/L; optionally, the Pd-diimine catalyst is an acetonitrile group Pd-diimine catalyst

Or hexatomic cyclic Pd-diimine catalyst containing carbomethoxy

The above-mentioned separation and purification of the polymerization reaction mixture can be carried out according to the following steps:

(a) removing the solvent from the polymerization reaction mixture;

(b) dissolving the obtained product in tetrahydrofuran, adding acetone to precipitate the product, removing supernatant liquid to obtain a polymerization product again; repeating the process for 2-3 times;

(c) dissolving the obtained product in tetrahydrofuran again, adding a small amount of hydrochloric acid and hydrogen peroxide (for example, 5-10 drops of each), stirring for 1-5 hours to dissolve a small amount of Pd particles contained in the product, and then adding methanol or acetone to precipitate the product;

(d) and (3) carrying out vacuum drying on the obtained product at the temperature of 50-80 ℃ for 24-48 h to obtain the hyperbranched polyethylene.

In this embodiment, different types and different addition amounts of the carbon nanotubes and different addition amounts of the hyperbranched polyethylene may affect the performance of the modified conductive paste. The addition of carbon nanotubes with different parameters can obviously change the conductivity of the carbon-based conductive paste, wherein the influence factors of the carbon nanotubes include the types, lengths, conductivities, specific surface areas, purities, outer diameters, functional group contents, preparation processes and the like of the carbon nanotubes.

The embodiment of the application also provides a preparation method of the modified conductive paste, which comprises the following steps:

step one, mixing carbon-based conductive paste and an organic solvent to form a carbon-based conductive paste solvent, namely a first solution.

Mixing the carbon nano tube, the hyperbranched polyethylene and the organic solvent to uniformly disperse the carbon nano tube to form a carbon nano tube/hyperbranched polyethylene mixed solution, namely a second solution, wherein in the initial mixed solution formed by uniformly mixing the carbon nano tube, the hyperbranched polyethylene and the organic solvent, the concentration of the carbon nano tube is 0.5-500 mg/mL, and the mass ratio of the hyperbranched polyethylene to the carbon nano tube is 0.005-10: 1.

in this embodiment, the organic solvent contains at least one selected from the group consisting of chloroform, tetrahydrofuran, petroleum ether, and diethyl ether; optionally, the organic solvent comprises at least one of chloroform or tetrahydrofuran. The organic solvents for forming the first solution and the second solution are not particularly limited in this embodiment, and different organic solvents may be used to form the first solution and the second solution, respectively, or the same organic solvent may be used to form the first solution and the second solution, respectively, and for example, chloroform, tetrahydrofuran, petroleum ether, or diethyl ether may be used as the organic solvent to form the first solution and the second solution, respectively.

Optionally, the method for uniformly dispersing the carbon nanotubes by mixing the carbon nanotubes, the hyperbranched polyethylene and the organic solvent is ultrasonic treatment, and the ultrasonic treatment time can be 0.5-12 hours. The hyperbranched polyethylene and the carbon nano tube are mixed in an organic solvent and the carbon nano tube solution with stable dispersion can be obtained under the assistance of ultrasonic waves.

Optionally, after the carbon nanotubes are uniformly dispersed, the method further comprises the steps of removing part of the hyperbranched polyethylene and re-uniformly dispersing the carbon nanotubes. Wherein the method for removing part of the hyperbranched polyethylene comprises at least one of high-speed centrifugation or vacuum filtration. For example, the mixed solution is subjected to ultrasonic treatment to uniformly disperse the carbon nanotubes, then vacuum filtration is carried out, and the filtrate is added with an organic solvent for ultrasonic treatment to uniformly disperse the carbon nanotubes again; or, carrying out ultrasonic treatment on the mixed solution to uniformly disperse the carbon nano tubes, then carrying out high-speed centrifugation, and collecting the bottom layer solution of the layered solution.

And step two, uniformly mixing the first solution and the second solution, wherein the method for uniformly mixing the first solution and the second solution can be stirring for 10-240 min, and removing the organic solvent.

Optionally, the method for removing the organic solvent comprises at least one of rotary evaporation, blowing or drying, and the blowing is further divided into cold air blowing and hot air blowing. The organic solvent can be removed by adopting rotary evaporation, blowing or drying modes, and the organic solvent can also be removed by adopting a combination of two modes in the above modes; illustratively, after most of the organic solvent is removed by a cold air blowing method, a hot air blowing method or a vacuum rotary evaporation method, the crude product is put into a vacuum box for vacuum treatment for 4-48 hours, so as to completely remove the organic solvent.

Fig. 1 is a flow chart of a process for preparing a modified conductive paste according to this embodiment.

When the hyperbranched polyethylene is used as the dispersing auxiliary agent to form the second solution, the hyperbranched polyethylene non-covalently assists in dispersing the carbon nanotubes based on the synergistic effect of CH-pi and pi-pi, so as to obtain a uniformly dispersed and stable carbon nanotube solution, and the schematic diagram of the principle of the forming process is shown in FIG. 2. The schematic structural diagram of the three-dimensional conductive network is shown in fig. 3, and the carbon nanotubes are used as filler, the carbon nanotubes are uniformly dispersed in the carbon-based conductive paste and are mutually overlapped to form the conductive network, the carbon-based conductive paste also contains a large amount of carbon crystals, and the carbon crystals are dispersed around the carbon nanotubes to play a role of a bridge, so that the carbon nanotubes and the carbon nanotubes are connected to form the conductive network. Therefore, the conductivity of the modified carbon-based conductive paste is greatly improved, the carbon-based conductive paste can be formed at normal temperature, welding is not needed, and the carbon-based conductive paste is high in installation efficiency and safer.

The embodiment of the application also provides application of the modified conductive paste, and the modified conductive paste is used as a conductive material for manufacturing a lead.

The features and properties of the present application are described in further detail below with reference to examples.

Influence of different types of carbon-based conductive paste on sample performance

1. Preparation of samples

(1) Example 1 provides a sample of a modified conductive paste prepared as follows:

the first step is as follows: at normal temperature, 4.5g of carbon-based conductive paste (the carbon-based conductive paste manufacturer is Nanjing Xilite adhesive Co., Ltd., model DY-6) is weighed and dissolved in 30ml of chloroform to form a carbon-based conductive paste solution.

The second step is that: 0.25g of carbon nanotubes (5% of the total amount of the raw materials) was weighed and dissolved in 80ml of chloroform.

The third step: 0.25g of hyperbranched polyethylene (hyperbranched polyethylene accounting for 5% of the total amount of the starting material) was weighed out and dissolved in 20ml of chloroform.

The fourth step: and mixing the solution obtained in the second step with the solution obtained in the third step, and performing ultrasonic treatment in an ultrasonic instrument for 2 hours to form a carbon nano tube/hyperbranched polyethylene mixed solution.

The fifth step: and mixing the carbon nano tube/hyperbranched polyethylene mixed solution with the carbon-based conductive paste solution, stirring to uniformly disperse the carbon nano tubes in the carbon-based conductive paste solution, stirring for 10min, and blowing the solution by using a blower to remove the organic solvent chloroform.

And a sixth step: and after the chloroform is volatilized, putting the crude product in a vacuum box for vacuum treatment for 8 hours to completely remove the organic solvent chloroform, thereby obtaining the modified conductive paste.

(2) Embodiment 2 provides a modified conductive paste sample, which has a preparation method substantially the same as that of embodiment 1, and is not described herein again, except that:

the carbon-based conductive paste used in this example was a modified conductive paste obtained by a manufacturer of electromechanical, model DDG-a, wuhan changjiang river.

(3) Embodiment 3 provides a modified conductive paste sample, which has a preparation method substantially the same as that of embodiment 1, and is not described herein again, except that:

the carbon-based conductive paste used in this example was manufactured by KunLun, model 801, and finally, the modified conductive paste was obtained.

2. Characterization and testing

Testing conductivity

Before testing, in order to make experimental data more convincing, the carbon-based conductive paste and the modified conductive paste of examples 1-3 need to be respectively filled into a mold with the diameter of 0.5cm and the length of 1cm and compacted to be correspondingly made into a lead, and the modified conductive paste prepared by the embodiment has good plasticity, so the carbon-based conductive paste can be molded by using the mold at normal temperature and normal pressure. The conducting wires made of the carbon-based conductive paste and the modified conductive paste (i.e., the modified carbon-based conductive paste) in the embodiments 1 to 3 are connected to the conducting wires of the LED bulb to replace the original conducting wires, the testing temperature is room temperature, the conducting circuit is connected, and the conducting performance of the carbon-based conductive paste and the modified conductive paste can be visually observed according to the brightness difference of the LED bulb.

3. Comparison and analysis of test results

The difference between the embodiments 1-3 lies in that the carbon-based conductive pastes are different, and tests show that the brightness of the LED connected with the small bulb is very low when the three carbon-based conductive pastes are directly used as wires, which indicates that the existing carbon-based conductive pastes have poor conductivity, i.e., if the existing carbon-based conductive pastes are directly used, the purpose of replacing metal wires cannot be achieved. Tests show that the brightness of the bulb is obviously improved compared with the brightness of the bulb directly adopting the corresponding carbon-based conductive paste after the LED bulb is communicated by adopting the modified conductive pastes of the examples 1-3 as the conducting wires.

Analysis finds that the reason of poor conductivity of the unmodified carbon-based conductive paste is that the conductive principle of the carbon-based conductive paste is that the conductive purpose is achieved through the tunnel effect among carbon materials, and the conductive effect is poor when the content of the carbon materials is low. The reason for the increased conductivity of the modified conductive paste is as follows: 1) the added carbon nano tube has excellent conductivity, and the conductivity of the carbon-based conductive paste can be well increased. 2) The hyperbranched polyethylene can generate CH-pi action or pi-pi action with the carbon nano tube to assist in stripping the carbon nano tube to obtain uniformly dispersed and stable carbon nano tube solution, and meanwhile, the hyperbranched polyethylene can also assist in uniformly dispersing the carbon nano tube in the carbon-based conductive paste, because the hyperbranched polyethylene can also generate CH-pi action or pi-pi action with the carbon material in the carbon-based conductive paste, the hyperbranched polyethylene adsorbed on the carbon nano tube can also adsorb the carbon material in the carbon-based conductive paste, so that the carbon nano tube and the carbon material in the carbon-based conductive paste form a three-dimensional network structure, and the electrical conductivity of the carbon-based conductive paste is greatly improved under the action of the hyperbranched polyethylene and the carbon nano tube.

Secondly, the influence of different types of carbon nano tubes on the performance of the sample

1. Preparation of samples

(1) Example 4 provides a modified conductive paste sample prepared as follows:

the first step is as follows: 3.6g of carbon-based conductive paste (the carbon-based conductive paste manufacturer is Nanjing Xilite adhesive Co., Ltd., model DY-6) is weighed at normal temperature and dissolved in 24ml of chloroform to form a carbon-based conductive paste solution.

The second step is that: and simultaneously weighing 0.7g of single-walled carbon nanotube SWCNT (the single-walled carbon nanotube accounts for 14.3 percent of the total amount of the raw materials, the parameters of the single-walled carbon nanotube are that the outer diameter is less than 2nm, the purity is more than 95 weight percent, the length is 5-30microns, the specific surface area is more than 490 square meters per gram, and the electric conductivity is more than 100s/cm), and dissolving the single-walled carbon nanotube SWCNT in 224ml of chloroform.

The third step: 0.7g of hyperbranched polyethylene (hyperbranched polyethylene accounting for 14.3% of the total amount of the starting materials) was weighed out and dissolved in 56ml of chloroform.

The fourth step: and mixing the solution obtained in the second step with the solution obtained in the third step, and performing ultrasonic treatment in an ultrasonic instrument for 2 hours to form a single-walled carbon nanotube/hyperbranched polyethylene mixed solution.

The fifth step: and mixing the single-walled carbon nanotube/hyperbranched polyethylene mixed solution with the carbon-based conductive paste solution, stirring to uniformly disperse the single-walled carbon nanotubes in the carbon-based conductive paste solution, stirring for 10min, and blowing the solution by using a blower to remove the organic solvent chloroform.

(2) Embodiment 5 provides a modified conductive paste sample, which has a preparation method substantially the same as that of embodiment 4, and is not described herein again, except that:

the carbon nano tube is double-wall carbon nano tube DWCNT, and the parameters of the double-wall carbon nano tube are as follows: the external diameter is 2-4 nm, the purity is more than 60 wt%, the length is 10-50microns, the specific surface area is more than 340 square meters per gram, the electric conductivity is more than 100s/cm, and finally the modified conductive paste is obtained.

(3) Embodiment 6 provides a modified conductive paste sample, which has a preparation method substantially the same as that of embodiment 4, and is not described herein again, except that:

the carbon nano-tube is a multi-wall carbon nano-tube MWCNT, and the parameters of the multi-wall carbon nano-tube are as follows: the external diameter is 2-4 nm, the purity is more than 90 wt%, the length is less than 10microns, the specific surface area is 500-700 square meters per gram, the electric conductivity is more than 100s/cm, and finally the modified conductive paste is obtained.

(4) Example 7 provides a modified conductive paste sample, which has a preparation method substantially the same as that of example 4, and is not described herein again, except that:

the carbon nano-tube is a high-conductivity multi-wall carbon nano-tube HEMWCNT, and the parameters of the high-conductivity multi-wall carbon nano-tube are as follows: the external diameter is 10-20 nm, the purity is more than 90 wt%, the length is less than 30microns, the specific surface area is 230-280 square meters per gram, the electric conductivity is more than 100s/cm, and finally the modified conductive paste is obtained.

(5) Embodiment 8 provides a modified conductive paste sample, which has a preparation method substantially the same as that of embodiment 4, and is not described herein again, except that:

the carbon nano tube is a multi-wall carbon nano tube MWCNT connected with hydroxyl, and the parameters of the multi-wall carbon nano tube connected with the hydroxyl are as follows: the external diameter is less than 10-20 nm, the purity is more than 90 wt%, the length is less than 30microns, the specific surface area is 230-280 square meters per gram, the electric conductivity is more than 100s/cm, the-OH content is 3.06 wt%, and finally the modified conductive paste is obtained.

(6) Example 9 provides a modified conductive paste sample, which has a preparation method substantially the same as that of example 4, and is not described herein again, except that:

the carbon nano tube is a multi-wall carbon nano tube MWCNT connected with carboxyl, and the parameters of the multi-wall carbon nano tube connected with the carboxyl are as follows: the external diameter is less than 10-20 nm, the purity is more than 90 wt%, the length is less than 30microns, the specific surface area is 230-280 square meters per gram, the electric conductivity is more than 100s/cm, the-COOH content is 2.00 wt%, and finally the modified conductive paste is obtained.

(7) Embodiment 10 provides a modified conductive paste sample, which has a preparation method substantially the same as that of embodiment 4, and is not described herein again, except that:

the carbon nano tube is a multi-wall carbon nano tube MWCNT connected with amino, and the parameters of the multi-wall carbon nano tube connected with amino are as follows: outer diameter<10-20 nm, purity>90 wt% length<30microns, the specific surface area of 230-280 square meters per gram, and the electric conductionRate of change>100s/cm，-NH₃The content was 2.67 wt%, and finally, a modified conductive paste was obtained.

2. Characterization and testing

Testing conductivity

See test method in test one.

3. Comparison and analysis of test results

Examples 4 to 10 differ in the kind of carbon nanotubes added, example 4 using a common single-walled carbon nanotube SWCNT, examples 5 to 7 using a double-walled carbon nanotube DWCNT, a multi-walled carbon nanotube MWCNT, and a highly conductive multi-walled carbon nanotube hemcnt, respectively, and examples 8 to 10 using a multi-walled carbon nanotube MWCNT grafted with a functional group. The single-walled carbon nanotube SWCNT is the most expensive, the modification effect is better, the double-walled carbon nanotube DWCNT and the multi-walled carbon nanotube MWCNT can be well compatible with the carbon-based conductive paste under the auxiliary action of the hyperbranched polyethylene HBPE, and the conductivity of the carbon-based conductive paste can be improved to a great extent; compared with the carbon nanotubes, the high-conductivity multi-wall carbon nanotube HEMCNT can greatly improve the conductivity of the carbon-based conductive paste under the condition of small addition amount due to different parameters; the carbon nanotubes with functional groups have a poor modification effect compared to the previous carbon nanotubes, and the conductivity is relatively poor because the original structure is damaged.

Influence of different amount of nanotubes on sample performance

1. Preparation of samples

(1) The preparation method of the modified conductive paste sample provided in example 1 is not described in detail.

(2) Example 11 provides a modified conductive paste sample prepared as follows:

the first step is as follows: 4.2g of carbon-based conductive paste was weighed at normal temperature and dissolved in 28ml of chloroform to form a carbon-based conductive paste solution.

The second step is that: 0.4g of carbon nanotubes (8% of the total amount of the raw materials) was weighed and dissolved in 138ml of chloroform.

The third step: 0.4g of hyperbranched polyethylene (hyperbranched polyethylene accounting for 8% of the total amount of the starting materials) was weighed out and dissolved in 32ml of chloroform.

The fifth step: and mixing the carbon nano tube/hyperbranched polyethylene mixed solution with the carbon-based conductive paste solution, stirring to uniformly disperse the carbon nano tubes in the carbon-based conductive paste solution, stirring for 10min, and blowing the solution by using a blower to remove the organic solvent.

And a sixth step: and after the organic solvent is volatilized, putting the crude product in a vacuum box for vacuum treatment for 8 hours to completely remove the organic solvent, thereby obtaining the modified conductive paste.

2. Characterization and testing

Testing of electrical conductivity

See test method in test one.

3. Comparison and analysis of test results

The difference between the embodiment 1 and the embodiment 11 is that the amount of the carbon nanotubes added is different, the left graph in fig. 4 is the luminance graph of the LED bulb with the modified conductive paste of the embodiment 1, and the right graph in fig. 4 is the luminance graph of the LED bulb with the modified conductive paste of the embodiment 11. As shown in fig. 4, the black ball and the portion connected with the conducting wire are modified conductive paste, and can be molded into various shapes at normal temperature, and the LED bulb adopts a series circuit, so that the circled portion in fig. 4 is the brightness of the bulb in a normal circuit, and the dark color portion is the brightness of the bulb corresponding to the modified conductive paste; comparing the brightness of the LED bulb in the left and right images, it can be observed that the brightness of the LED bulb in the right image in FIG. 4 is higher, that is, the brightness of the LED bulb is higher along with the increase of the content of the carbon nano tube, and the conductivity of the carbon-based conductive paste is enhanced.

Fourth, influence of hyperbranched polyethylene on sample performance

1. Preparation of samples

(2) Comparative example 1 provides a modified conductive paste sample, which was prepared as follows:

the first step is as follows: 4.5g of carbon-based conductive paste is weighed at normal temperature and dissolved in 30ml of chloroform to form a carbon-based conductive paste solution.

The second step is that: 0.25g of carbon nanotubes was weighed and dissolved in 80ml of chloroform.

The third step: and (4) carrying out ultrasonic treatment on the solution obtained in the second step in an ultrasonic instrument for 2 hours to form a carbon nano tube solution.

The fourth step: and mixing the carbon nanotube solution and the carbon-based conductive paste solution, stirring to uniformly disperse the carbon nanotubes in the carbon-based conductive paste solution, stirring for 10min, and blowing the solution by using a blower to remove the organic solvent.

The fifth step: and after the organic solvent is volatilized, putting the crude product in a vacuum box for vacuum treatment for 8 hours to completely remove the organic solvent, thereby obtaining the modified conductive paste.

2. Characterization and testing

Testing of electrical conductivity

See test method in test one.

3. Comparison and analysis of test results

The difference between example 1 and comparative example 1 is that in comparative example 1, hyperbranched polyethylene is not used as an auxiliary agent, and the conductive performance of the modified conductive paste of example 1 is obviously better than that of the modified conductive paste of comparative example 1, and the important function of the hyperbranched polyethylene is also proved.

Influence of different amounts of hyperbranched polyethylene on sample performance

1. Preparation of samples

(1) The preparation method of the modified conductive paste sample provided in example 7 is not described in detail.

(2) Example 12 provides a sample of a modified conductive paste prepared as follows:

the first step is as follows: 3.3g of carbon-based conductive paste was weighed at normal temperature and dissolved in 22ml of chloroform to form a carbon-based conductive paste solution.

The second step is that: 0.7g of highly conductive multi-walled carbon nanotubes (HEMWCNT, which is 14.3% of the total amount of the raw material) were weighed out and dissolved in 224ml of chloroform.

The third step: 1g of hyperbranched polyethylene (hyperbranched polyethylene accounts for 20% of the total amount of the raw materials) was weighed out and dissolved in 80ml of chloroform.

The fourth step: and mixing the solution obtained in the second step with the solution obtained in the third step, and performing ultrasonic treatment in an ultrasonic instrument for 2 hours to form the high-conductivity multi-walled carbon nanotube/hyperbranched polyethylene mixed solution.

The fifth step: and mixing the high-conductivity multi-walled carbon nanotube/hyperbranched polyethylene mixed solution with the carbon-based conductive paste solution, stirring to uniformly disperse the high-conductivity multi-walled carbon nanotube in the carbon-based conductive paste solution, stirring for 10min, and blowing the solution by using a blower to remove the organic solvent.

2. Characterization and testing

(1) Testing of electrical conductivity

See test method in test one.

(2) Measurement of tack

One of the characteristics of the modified conductive paste is that it is easily molded at room temperature, and thus the modified conductive paste is required to have a certain viscosity and plasticity, and the flexibility of the modified conductive paste can be observed.

3. Comparison and analysis of test results

The difference between example 7 and example 12 is that the content of the hyperbranched polyethylene is different, the hyperbranched polyethylene can assist in dispersing the carbon nanotubes to form a stable carbon nanotube dispersion, and meanwhile, the viscosity of the hyperbranched polyethylene is great, so that the viscosity of the carbon-based conductive paste can be increased. Therefore, the viscosity of the modified conductive paste of example 7 is lower than that of the modified conductive paste of example 12, but the conductivity of the modified conductive paste of example 7 is better than that of example 12 because the hyperbranched polyethylene can assist in dispersing the carbon nanotubes and can increase the viscosity of the carbon-based conductive paste, but the hyperbranched polyethylene itself is not conductive, and a large amount of the hyperbranched polyethylene can reduce the conductivity of the modified conductive paste.

Sixthly, whether the influence of part of hyperbranched polyethylene on the performance of the sample is removed

1. Preparation of samples

(1) The preparation method of the modified conductive paste sample provided in example 12 is not described in detail.

(2) Example 13 provides a modified conductive paste sample prepared according to the following steps:

The fifth step: and carrying out vacuum filtration on the high-conductivity multi-walled carbon nanotube/hyperbranched polyethylene mixed solution.

And a sixth step: and putting the high-conductivity multi-walled carbon nanotube/hyperbranched polyethylene mixed solution subjected to suction filtration into 80ml of chloroform again for returning and overtaking for 2 hours.

The seventh step: mixing the super-fine high-conductivity multi-walled carbon nanotube/hyperbranched polyethylene mixed solution with the carbon-based conductive paste solution, stirring to uniformly disperse the high-conductivity multi-walled carbon nanotube in the carbon-based conductive paste solution, stirring for 10min, and blowing the solution by using a blower to remove the organic solvent.

Eighth step: and after the organic solvent is volatilized, putting the crude product in a vacuum box for vacuum treatment for 8 hours to completely remove the organic solvent, thereby obtaining the modified conductive paste.

2. Characterization and testing

Testing of electrical conductivity

See test method for test one.

3. Comparison and analysis of test results

The difference between the embodiment 12 and the embodiment 13 is that the embodiment 13 performs suction filtration treatment on the carbon nanotube/hyperbranched polyethylene mixed solution, the suction filtration can remove most of the hyperbranched polyethylene in the mixed solution, because the hyperbranched polyethylene and the carbon nanotubes have the CH-pi and pi-pi effects, so that the hyperbranched polyethylene cannot be separated, the suction filtration treatment can remove part of the carbon nanotubes and the hyperbranched polyethylene, and about 20% of the hyperbranched polyethylene remains in the filtrate after the suction filtration treatment. The modified conductive paste of example 13 was superior in conductive performance to the modified conductive paste of example 12 in that the hyperbranched polyethylene was not conductive, and the more the amount thereof was added, the worse the conductive performance of the modified conductive paste was.

Influence of different organic solvents on sample performance

1. Preparation of samples

(1) Example 14 provides a sample of a modified conductive paste prepared as follows:

the first step is as follows: 4.5g of carbon-based conductive paste was weighed at normal temperature and dissolved in 30ml of chloroform to form a carbon-based conductive paste solution.

The second step is that: 0.25g of the highly conductive multi-walled carbon nanotube HEMMWCNT (highly conductive multi-walled carbon nanotube accounts for 5% of the total amount) was weighed out and dissolved in 80ml of chloroform.

The third step: 0.25g of hyperbranched polyethylene was weighed out and dissolved in 20ml of chloroform.

The fifth step: and mixing the high-conductivity multi-walled carbon nanotube/hyperbranched polyethylene mixed solution with the carbon-based conductive paste solution, stirring to uniformly disperse the high-conductivity multi-walled carbon nanotube in the carbon-based conductive paste solution, stirring for 10min, and blowing the solution by using a blower to remove the organic solvent chloroform.

And a sixth step: and after the chloroform is volatilized, putting the crude product in a vacuum box for vacuum treatment for 8 hours to completely remove the organic solvent, thereby obtaining the modified conductive paste.

(2) Example 15 provides a modified conductive paste sample, which has a preparation method substantially the same as that of example 14, and is not described herein again, except that:

tetrahydrofuran is adopted to replace chloroform, and finally the modified conductive paste is obtained.

2. Characterization and testing

(1) Testing the solubility of the carbon-based conductive paste in different solvents:

taking 4.5g of each of two carbon-based conductive pastes, respectively filling the two carbon-based conductive pastes into beakers, respectively filling 30ml of each of chloroform and tetrahydrofuran into the two beakers, marking, filling a stirrer and stirring, wherein the carbon-based conductive paste can be dissolved quickly by stirring, simultaneously sealing the mouth of the beaker by using a preservative film to prevent the volatilization of an organic solvent, standing for 1h after stirring for 30min, and then observing the solubility of the carbon-based conductive paste in the beaker.

(2) Testing of electrical conductivity

See test method for test one.

3. Comparison and analysis of test results

Example 14 differs from example 15 in that the organic solvent used is different, and the solubility of the carbon-based conductive paste affects the subsequent mixing of the multi-walled carbon nanotubes with the carbon-based conductive paste solution. After adding various organic solvents and stirring and standing, it was observed that the carbon-based conductive paste in example 14 was rapidly dissolved in chloroform and formed a stable solution, while in example 15, it was observed that the carbon-based conductive paste was slowly dissolved and had incompletely dissolved carbon-based conductive paste therein. Meanwhile, by comparing the conductive properties of the modified conductive pastes of example 14 and example 15, it is understood that the use of chloroform as an organic solvent is superior to the use of tetrahydrofuran as an organic solvent.

Eighthly, influence of different amounts of organic solvents on sample performance

1. Preparation of samples

(1) Example 16 provides a modified conductive paste sample prepared according to the following steps:

The second step is that: 0.25g of the highly conductive multi-walled carbon nanotube HEMMWCNT (highly conductive multi-walled carbon nanotube accounts for 5% of the total amount of the raw materials) was weighed out and dissolved in 80ml of chloroform.

And a sixth step: and putting the filtered high-conductivity multi-walled carbon nanotube/hyperbranched polyethylene mixed solution into 80ml of chloroform as an organic solvent again for returning super-treatment for 2 h.

Eighth step: and after the organic solvent is volatilized, putting the crude product in a vacuum box for vacuum treatment for 8 hours to completely remove the organic solvent in the conductive paste, thereby obtaining the modified conductive paste.

(2) Example 17 provides a modified conductive paste sample prepared by the steps of:

The second step is that: 0.25g of the highly conductive multi-walled carbon nanotube HEMMWCNT (highly conductive multi-walled carbon nanotube accounts for 5% of the total amount) was weighed out and dissolved in 200ml of chloroform.

The third step: 0.25g of hyperbranched polyethylene (hyperbranched polyethylene accounting for 5% of the total amount) was weighed out and dissolved in 20ml of chloroform.

The fifth step: and centrifuging the high-conductivity multi-walled carbon nanotube/hyperbranched polyethylene mixed solution for 20min at a centrifugation speed of 8000 rad/min.

And a sixth step: and removing supernatant of the centrifuged layered solution, and collecting the bottom high-conductivity multi-walled carbon nanotube/hyperbranched polyethylene mixed solution.

The seventh step: and mixing the collected high-conductivity multi-walled carbon nanotube/hyperbranched polyethylene mixed solution with a carbon-based conductive paste solution, stirring to uniformly disperse the high-conductivity multi-walled carbon nanotube in the carbon-based conductive paste solution, stirring for 10min, and blowing the solution by using a blower to remove the organic solvent.

2. Characterization and testing

Testing of electrical conductivity

See test method of test one.

3. Comparison and analysis of test results

Example 16 differs from example 17 in that more organic solvent is added in example 17, i.e., the concentration of carbon nanotubes is lower, which favors the formation of a stable dispersed solution with the hyperbranched polyethylene. The purpose of the centrifugation treatment was to remove a portion of the hyperbranched polyethylene from the mixed solution, and most of the hyperbranched polyethylene remained in the solvent for the reasons described in test six for the analysis of examples 12 and 13. The conductive performance of the modified conductive paste obtained in example 17 was superior to that of the modified conductive paste obtained in example 16.

Ninth, the Effect of different ultrasound times on sample Properties

1. Preparation of samples

(1) Example 18 provides a modified conductive paste sample prepared according to the following steps:

The fourth step: and mixing the solution obtained in the second step with the solution obtained in the third step, and performing ultrasonic treatment in an ultrasonic instrument for 8 hours to form the high-conductivity multi-walled carbon nanotube/hyperbranched polyethylene mixed solution.

The seventh step: and mixing the collected high-conductivity multi-walled carbon nanotube/hyperbranched polyethylene mixed solution with a carbon-based conductive paste solution, stirring to uniformly disperse the high-conductivity multi-walled carbon nanotube in the carbon-based conductive paste solution, stirring for 10min, and blowing the solution by a blower to remove the organic solvent by cold air blowing.

(2) The preparation method of the modified conductive paste sample provided in example 14 is not described in detail.

2. Characterization and testing

Testing of electrical conductivity

See test method for test one.

3. Comparison and analysis of test results

The sonication time for the mixed solution in example 18 was longer than that in example 14, and example 18 was performed by centrifuging the mixed solution. The extension of the ultrasonic time is beneficial to the combination of the carbon nano tube and the hyperbranched polyethylene, and the formed mixed solution is more uniform. The more stable and uniform the dispersion of carbon nanotubes, the more easily the carbon nanotubes form a conductive network in the carbon-based conductive paste with a small amount of addition. Since the carbon nanotube solution was centrifuged in example 18, the resistivity of the modified conductive paste in example 18 was lower than that of the modified conductive paste in example 14.

Ten, removing the influence of the organic solvent on the performance of the sample by adopting different methods

1. Preparation of samples

(1) Example 19 provides a modified conductive paste sample prepared according to the following steps:

And a sixth step: and removing the supernatant of the layered solution, and collecting the bottom layer of the high-conductivity multi-walled carbon nanotube/hyperbranched polyethylene mixed solution.

(2) Embodiment 20 provides a modified conductive paste sample, which has a preparation method substantially the same as that of embodiment 19, and is not described herein again, except that:

the blower was turned on to hot-air purge the solution to remove the organic solvent. And after the organic solvent is volatilized, collecting the substances in the beaker, thereby obtaining the modified conductive paste.

2. Characterization and testing

Testing of electrical conductivity

See test method for test one.

3. Comparison and analysis of test results

Example 19 differs from example 20 in the way of treating the organic solvent, in example 19, cold air blowing was used and the crude product after blowing was subjected to vacuum treatment, and in example 20, the solvent removal method was hot air blowing. The conductive performance of the modified conductive paste of example 19 is better than that of the modified conductive paste of example 20, the removal of the organic solvent by cold air blowing takes a long time, and the organic solvent can be further removed by vacuum treatment; the method for removing the organic solvent by hot air blowing is easy to cause the agglomeration of the carbon nano tubes, and the uniform distribution of the carbon nano tubes in the carbon-based conductive paste can be influenced by the agglomeration of the carbon nano tubes, so that the conductivity of the modified conductive paste is influenced. In example 20, the crude product was not subjected to vacuum treatment, and the obtained modified conductive paste had an offensive odor due to incomplete removal of chloroform, which was toxic, and many potential safety hazards were caused if not all of the chloroform was removed. Therefore, the treatment process for the organic solvent in example 19 is superior to that in example 20.

In summary, the modified conductive paste of the embodiment of the application has high conductivity and low cost, and can be made into a wire; the preparation condition is mild, the process is simple and efficient, and the environment is protected.

The above description is only an example of the present application and is not intended to limit the scope of the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. The modified conductive paste is characterized by comprising the following raw materials in percentage by mass: 72% -90% of carbon-based conductive paste, 5% -14% of carbon nanotubes and 5% -14% of hyperbranched polyethylene, wherein the components of the carbon-based conductive paste comprise an adhesive and a carbon material, the mass content of the carbon material is 30% -70%, and the carbon material is a graphite material; the carbon-based conductive paste is mainly obtained by grinding, dispersing and modifying the adhesive and the carbon material; and a three-dimensional conductive network is formed among the carbon-based conductive paste, the carbon nano tube and the hyperbranched polyethylene.

2. The modified conductive paste of claim 1, wherein the carbon nanotubes comprise at least one selected from the group consisting of single-walled carbon nanotubes, double-walled carbon nanotubes, multi-walled carbon nanotubes, hydroxylated carbon nanotubes, carboxylated carbon nanotubes and aminated carbon nanotubes.

3. A method for preparing a modified conductive paste according to any one of claims 1 to 2, comprising the steps of:

mixing the carbon-based conductive paste and an organic solvent to form a first solution; mixing the carbon nano tube, the hyperbranched polyethylene and an organic solvent to uniformly disperse the carbon nano tube to form a second solution;

4. The method of manufacturing a modified conductive paste according to claim 3, wherein the organic solvent contains at least one selected from the group consisting of chloroform, tetrahydrofuran, petroleum ether, and diethyl ether.

5. The method of claim 4, wherein the organic solvent comprises at least one of chloroform and tetrahydrofuran.

6. The method of claim 3, wherein the carbon nanotubes, the hyperbranched polyethylene, and an organic solvent are mixed, and the carbon nanotubes are uniformly dispersed by ultrasonic treatment.

7. The preparation method of the modified conductive paste according to claim 6, wherein the time of the ultrasonic treatment is 0.5-12 h.

8. The method according to claim 3, further comprising the step of removing a portion of the hyperbranched polyethylene and re-dispersing the carbon nanotubes uniformly after the carbon nanotubes are uniformly dispersed.

9. The method of claim 8, wherein the removing the portion of the hyperbranched polyethylene comprises at least one of high speed centrifugation or vacuum filtration.

10. The method for preparing the modified conductive paste according to claim 3, wherein the method of uniformly mixing the first solution and the second solution is a stirring treatment; the stirring treatment time is 10-240 min;

the method of removing the organic solvent comprises at least one of rotary evaporation, purging, or drying.

11. Use of the modified conductive paste according to any one of claims 1 to 2 as a conductive material for making a wire.