CN105623136B - A kind of composite conducting polymer material and preparation method thereof - Google Patents

Abstract

The invention provides a polymer conductive composite material, which is composed of a one-dimensional conductive nanowire, a two-dimensional graphene and a spherical polymer matrix, combining the advantages of a one-dimensional conductive nanowire material and a two-dimensional graphene, By combining two-dimensional graphene with a polymer matrix and then compounding it with a high aspect ratio one-dimensional conductive nanowire with excellent electrical properties, the dispersion uniformity of the conductive filler in the polymer matrix is improved, and the polymer composite is increased. The contact opportunities between conductive fillers in the material, utilizing the synergistic effect of one-dimensional conductive nanowires and two-dimensional graphene, constructs an efficient conductive pathway network and improves the conductivity of polymer composites. In addition, the invention also provides a preparation method of the polymer conductive composite material.

Description

A kind of polymer conductive composite material and preparation method thereof

technical field

The invention relates to the technical field of conductive composite materials, in particular to a polymer conductive composite material and a preparation method thereof.

Background technique

Polymer-based conductive composite materials are widely used in electromagnetic shielding materials, anti-static materials, electronic tags, solar cell electrodes, etc. It has important application value in other fields. Polymer-based conductive composites usually consist of conductive fillers and a polymer matrix. Commonly used conductive fillers include metal conductive fillers (mainly gold, silver, copper, nickel, etc., which can be granular, spherical, linear, etc.) and carbon-based conductive fillers (carbon black, carbon nanotubes, graphene, etc.). According to the conductive percolation theory, it can be known that the two-dimensional structure sheet-like conductive filler and the one-dimensional structure nanowire conductive filler are more conducive to obtaining a low percolation threshold and high conductivity than conventional granular and spherical conductive fillers.

Among the conductive fillers with two-dimensional structures, graphene has attracted extensive attention due to its excellent electrical properties, thermal properties, and large specific surface area. How to effectively and uniformly disperse graphene in the polymer matrix and avoid the sharp decline in performance caused by the strong van der Waals agglomeration of graphene is one of the key issues in the preparation of conductive composite materials using graphene as a conductive filler.

In order to realize the effective dispersion of graphene, the patent CN 102964713 A disperses graphene oxide with N, N-dimethylformamide solvent, and disperses polystyrene with chloromethyl ether, through the blending of the two, suction filtration, washing and drying The functionalized graphene core-shell nano-hybrid material was prepared by other steps. Although this method achieves a uniform dispersion of graphene in the polymer, it uses a large amount of toxic solvents. In order to avoid the use of toxic solvents, the patent CN 104261403 A uses the electrostatic interaction between the polystyrene template and graphene oxide to form a uniform aqueous dispersion. Patent CN 104650521 A composites cationic polystyrene and graphene oxide, which can inhibit the self-polymerization of graphene and induce graphene to selectively distribute on the surface of polymer particles to form a perfect three-dimensional graphene network skeleton. The prepared composite material It shows extremely low conductivity and high conductivity. Patent CN103554702 A covers polystyrene with graphene, and prepares a graphene polymer composite material in which graphene is networked by casting or compression molding.

The one-dimensional nanowire material has a high aspect ratio, and it can be used as a conductive filler to reduce the percolation threshold and increase the conductivity. Patent CN1873838 A uses silver nanowire and silver powder as composite filler and acrylic resin as polymer matrix to prepare polymer composite conductive material with high conductivity. Patent CN 104974500 A discloses a polymer-based conductive composite material containing metal nanowires and graphene oxide and its preparation method, by adding a small amount of sheet-shaped non-conductive graphene oxide to the polymer-based composite material of metal nanowires On the one hand, it prevents the agglomeration of metal nanowires, and on the other hand, it can prevent the sinking of metal nanowires, so the dispersion of metal nanowires is more uniform, so that the conductivity is improved. However, this method is only suitable for water-soluble polymer matrix, which has great limitations. At the same time, graphene oxide only acts as a stable dispersant and does not have conductivity. In order to combine the advantages of two-dimensional and one-dimensional conductive fillers, patent CN104992781A prepared a graphene-based The ternary composite transparent conductive film improves the photoelectric performance of the graphene-based transparent conductive film, but the material is a conductive film rather than a bulk conductive composite material.

Contents of the invention

In view of this, in order to overcome the defects and problems of the prior art, the present invention provides a polymer conductive composite material.

A polymer conductive composite material is composed of a one-dimensional structure of conductive nanowires, a two-dimensional structure of graphene and a spherical polymer matrix, and the mass ratio of each component is as follows:

Conductive nanowires with one-dimensional structure 5-40 parts

Graphene with two-dimensional structure 0.5 to 5 parts

Spherical polymer matrix 55-90 parts.

In some embodiments, the conductive nanowire is one of silver nanowires, copper nanowires, gold nanowires, nickel nanowires, aluminum nanowires, iron nanowires, single-walled carbon nanotubes, and multi-walled carbon nanotubes. species or several.

In some embodiments, the length of the conductive nanowire is 5-500 μm, and the diameter is 30-300 nm.

In some embodiments, the spherical polymer matrix is a spherical polystyrene, polymethacrylate, polyacrylate, styrene-acrylate copolymer, acrylic-methacrylate copolymer , polyacrylamide, polyethylene, phenolic resin, polysiloxane, polyphenylsiloxane or one or more.

In some embodiments, the diameter of the spherical polymer is 200 nm-10 μm.

In addition, the present invention also provides a preparation method of polymer conductive composite material, comprising the following steps:

Step S10: preparing a graphene-coated polymer polymer/graphene composite

mixing an aqueous dispersion of graphene oxide with an aqueous dispersion of a spherical polymer, so that the graphene oxide is uniformly coated on the surface of the spherical polymer to obtain a composite material of the graphene oxide-coated polymer;

Then carry out in-situ chemical reduction to the composite material of described graphene oxide coated polymer, obtain the composite material of reduced graphene oxide coated polymer;

After washing to remove unreacted impurities, it is redispersed in deionized water to obtain a polymer/graphene composite material coated with graphene;

Step S20: Prepare a polymer/graphene/conductive nanowire mixture with a multidimensional hybrid structure

Add the aqueous dispersion of the conductive nanowires to the aqueous dispersion of the polymer/graphene composite material prepared in step (1), and mix uniformly to obtain a multidimensional hybrid structure of polymer/graphene/conductive nanowires. line mixed dispersion;

Remove the aqueous medium by suction filtration, and then dry to obtain a polymer/graphene/conductive nanowire mixture with a multidimensional hybrid structure;

Step S30: preparing a polymer-based conductive composite material with a multi-dimensional hybrid structure

The polymer/graphene/conductive nanowire mixture of the multidimensional hybrid structure prepared in step (2) is molded to obtain a polymer-based conductive composite material with a multidimensional hybrid structure, and in the polymer conductive composite material with a multidimensional hybrid structure The mass ratio of each component is as follows:

Conductive nanowires with one-dimensional structure 5-40 parts

Graphene with two-dimensional structure 0.5 to 5 parts

Spherical polymer matrix 55-90 parts.

In some embodiments, in step S10, the polymer/graphene composite material of graphene-coated polymer is prepared, specifically comprising the following steps:

Mix the aqueous dispersion of graphene oxide with the aqueous dispersion of the spherical polymer, use the cationic spherical polymer or adjust the pH of the solution to 1-6 so that the graphene oxide is uniformly coated on the surface of the spherical polymer, and the graphene oxide coating is obtained. Polymer-coated composites.

In some embodiments, in step S10, the in-situ reduction method of graphene oxide is chemical reduction, and the reducing agent is hydrazine hydrate, dimethylhydrazine, hydroiodic acid, sodium borohydride, potassium borohydride, vitamin C, and hydrazine in concentrated ammonia water. A sort of.

In some embodiments, in step S30, the compression molding is cold pressing or heating molding, and the cold pressing conditions are: the temperature is room temperature, the pressure is 1-30MPa, and the time is 10min-3h; the pressurizing conditions are: temperature (Tg+ 10)～(Tg+50)℃, Tg is the glass transition temperature of the polymer, the pressure is 1-30MPa, and the time is 2min～2h.

Compared with the prior art, the polymer conductive composite material provided by the present invention is composed of a one-dimensional conductive nanowire, a two-dimensional graphene and a spherical polymer matrix, and combines a one-dimensional conductive nanowire material with a two-dimensional graphite Based on the advantages of graphene, the two-dimensional graphene is compounded with the polymer matrix and then compounded with the high aspect ratio one-dimensional conductive nanowire with excellent electrical properties, thereby improving the dispersion uniformity of the conductive filler in the polymer matrix and increasing the The contact opportunities between conductive fillers in polymer composites are eliminated, and the synergistic effect of one-dimensional conductive nanowires and two-dimensional graphene is used to construct an efficient conductive pathway network and improve the conductivity of polymer composites.

In addition, the present invention also provides a method for preparing a polymer conductive composite material, by preparing a graphene-coated polymer polymer/graphene composite material, and then preparing a multi-dimensional hybrid structure polymer/graphene/conductive nanowire mixture , and finally a polymer-based conductive composite material with a multi-dimensional hybrid structure is prepared. The preparation method has a simple process, does not need to use toxic and harmful solvents in the composite process, is environmentally friendly, and the prepared composite material has high quality and good conductivity.

At the same time, since the two-dimensional structure of graphene oxide is uniformly dispersed in the spherical polymer matrix and reduced in situ, a networked conductive path is formed, which is beneficial to improve the conductivity of the polymer composite; the one-dimensional structure of conductive nanowires and reduction Graphene oxide is uniformly dispersed and in close contact, and the synergistic effect of the two promotes the further improvement of the conductivity of the polymer composite.

Description of drawings

Figure 1 Schematic diagram of the polymer-based conductive composite material with multi-dimensional hybrid structure and its preparation process.

FIG. 2 is an SEM image of a polymer/graphene/conductive nanowire mixture with a multidimensional hybrid structure prepared in Example 1. FIG.

3 is a partially enlarged SEM image of the polymer/graphene/conductive nanowire mixture with a multi-dimensional hybrid structure prepared in Example 1.

FIG. 4 is a cross-sectional SEM image of the polymer-based conductive material with a multi-dimensional hybrid structure prepared in Example 1. FIG.

Detailed ways

In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the associated drawings. Preferred embodiments of the invention are shown in the accompanying drawings. The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process conversion made by using the description of the present invention and the contents of the accompanying drawings, or directly or indirectly used in other related technical fields , are all included in the scope of patent protection of the present invention in the same way.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field of the invention. The terminology used herein in the description of the present invention is only for the purpose of describing specific embodiments, and is not intended to limit the present invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The polymer conductive composite material provided by the present invention is composed of conductive nanowires with a one-dimensional structure, graphene with a two-dimensional structure and a spherical polymer matrix. The mass ratio of each component is as follows:

Conductive nanowires with one-dimensional structure 5-40 parts

Graphene with two-dimensional structure 0.5 to 5 parts

Spherical polymer matrix 55-90 parts.

Preferably, the conductive nanowires are one or more of silver nanowires, copper nanowires, gold nanowires, nickel nanowires, aluminum nanowires, iron nanowires, single-walled carbon nanotubes and multi-walled carbon nanotubes. kind.

Preferably, the length of the conductive nanowire is 5-500 μm, and the diameter is 30-300 nm.

Preferably, the spherical polymer matrix is spherical polystyrene, polymethacrylate, polyacrylate, styrene-acrylate copolymer, acrylic-methacrylate copolymer, polypropylene One or more of amide, polyethylene, phenolic resin, polysiloxane, polyphenylsiloxane.

Preferably, the spherical polymer has a diameter of 200 nm-10 μm.

It can be understood that the polymer conductive composite material provided by the present invention is composed of a one-dimensional conductive nanowire, a two-dimensional graphene and a spherical polymer matrix, and combines the advantages of a one-dimensional conductive nanowire material and a two-dimensional graphene. , by combining two-dimensional graphene with a polymer matrix and then compounding it with a high aspect ratio one-dimensional conductive nanowire with excellent electrical properties, the dispersion uniformity of the conductive filler in the polymer matrix is improved, and the polymer The contact opportunities between conductive fillers in the composites, utilizing the synergistic effect of 1D conductive nanowires and 2D graphene, constructs an efficient conductive pathway network and improves the conductivity of polymer composites.

Please refer to Fig. 1, the polymer-based conductive composite material and its preparation process schematic diagram of the preparation method of the polymer conductive composite material provided by the present invention, including the following steps:

Step S10: preparing a graphene-coated polymer polymer/graphene composite

mixing an aqueous dispersion of graphene oxide with an aqueous dispersion of a spherical polymer, so that the graphene oxide is uniformly coated on the surface of the spherical polymer to obtain a composite material of the graphene oxide-coated polymer;

Then carry out in-situ chemical reduction to the composite material of described graphene oxide coated polymer, obtain the composite material of reduced graphene oxide coated polymer;

After washing to remove unreacted impurities, it is redispersed in deionized water to obtain a polymer/graphene composite material coated with graphene;

Step S20: Prepare a polymer/graphene/conductive nanowire mixture with a multidimensional hybrid structure

Add the aqueous dispersion of the conductive nanowires to the aqueous dispersion of the polymer/graphene composite material prepared in step (1), and mix uniformly to obtain a multidimensional hybrid structure of polymer/graphene/conductive nanowires. line mixed dispersion;

Remove the aqueous medium by suction filtration, and then dry to obtain a polymer/graphene/conductive nanowire mixture with a multidimensional hybrid structure;

Step S30: preparing a polymer-based conductive composite material with a multi-dimensional hybrid structure

The multi-dimensional hybrid structure polymer/graphene/conductive nanowire mixture prepared in step (2) is molded to obtain a multi-dimensional hybrid structure polymer-based conductive composite material.

It can be understood that the above-mentioned preparation method of the present invention is due to the use of graphene oxide with a two-dimensional structure uniformly dispersed in the spherical polymer matrix and reduced in situ to form a networked conductive path, which is beneficial to improve the conductivity of the polymer composite material; the one-dimensional structure The conductive nanowires and the reduced graphene oxide are uniformly dispersed and in close contact, and the synergistic effect of the two promotes the further improvement of the conductivity of the polymer composite.

Example 1:

Take 10mL of 5mg/mL (1 mass part) graphene oxide aqueous dispersion, add to 89mL 5wt% (89 mass parts) polystyrene ball water dispersion with a particle diameter of about 440nm, magnetically stir evenly, slowly drop hydrochloric acid solution, adjust the pH of the mixed solution to 2, and mix for 30 minutes under stirring to obtain a mixed solution of graphene oxide-coated spherical polystyrene composite material; place the above mixed solution in a water bath at 80°C, add 5ml of 85% hydrazine hydrate, and magnetically The reaction was completed after stirring for 3 hours, and a mixed solution of redox graphene-coated polystyrene composite material was obtained. After the mixed solution was suction-filtered and washed several times to remove unreacted impurities, it was re-dispersed into 100 mL of deionized water, and then 10 mL of 5 wt % (10 parts by mass) silver nanowire aqueous dispersion was added thereto, stirred and dispersed evenly to obtain multidimensional Mixed dispersion solution of polystyrene/graphene/silver nanowires with hybrid structure. Remove the water medium by suction filtration, dry in an oven at 60°C, put the dried powder into a mold, and press at 180°C and 15MPa for 10 minutes to obtain a polymer-based conductive composite material with a multi-dimensional hybrid structure. The mass ratio of the one-dimensional structure of silver nanowires and the two-dimensional structure of graphene to the polymer matrix in the polymer-based conductive composite material of the multi-dimensional hybrid structure prepared in this example is 10:1:89, and the conductivity is about 250S /m.

Please refer to Figure 2, Figure 3 and Figure 4, which are the SEM images of the polymer/graphene/conductive nanowire mixture of the multidimensional hybrid structure prepared in Example 1, and the polymer/graphene/conductive nanowire of the multidimensional hybrid structure Partially enlarged SEM image of the mixture and cross-sectional SEM image of the polymer-based conductive material with multidimensional hybrid structure.

Example 2:

Get 30mL of 5mg/mL (3 parts by mass) of graphene oxide aqueous dispersion, add to 70mL of 5wt% (70 parts by mass) of polymethyl methacrylate microspheres with a particle diameter of about 2.2 μm in water dispersion, magnetically stir Evenly, slowly add hydrochloric acid solution dropwise, adjust the pH of the mixed solution to 3, and mix for 30 minutes under stirring to obtain a mixed solution of graphene oxide-coated spherical polymethyl methacrylate composite material; put the above mixed solution in a water bath at 100 ° C, 5ml of 45% hydroiodic acid was added, and the reaction was completed after 10h under magnetic stirring to obtain a mixed solution of redox graphene-coated polymethyl methacrylate composite material. After the mixed solution was suction-filtered and washed several times to remove unreacted impurities, it was re-dispersed into 100 mL of deionized water, and then 27 mL of 5 wt % (27 parts by mass) copper nanowire aqueous dispersion was added thereto, stirred and dispersed evenly to obtain a multidimensional hybrid Structured polymethyl methacrylate/graphene/copper nanowire mixed dispersion solution. Remove the water medium by suction filtration, dry in a vacuum oven at 40°C, put the dried powder into a mold, and press at room temperature and 30MPa for 30min to obtain a polymer-based conductive composite material with a multi-dimensional hybrid structure. The mass ratio of the one-dimensional structure of silver nanowires and the two-dimensional structure of graphene to the polymer matrix in the polymer-based conductive composite material of the multi-dimensional hybrid structure prepared in this example is 27:3:70, and the conductivity is about 1080S /m.

The above-mentioned embodiments only express several implementation modes of the present invention, and the description thereof is relatively specific and detailed, but should not be construed as limiting the patent scope of the present invention. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention should be based on the appended claims.

Claims (6)

1. a kind of preparation method of composite conducting polymer material, which is characterized in that include the following steps：

Step S10：Prepare the polymer/graphene composite material of graphene coated polymer

The aqueous dispersions of graphene oxide with the aqueous dispersions of spherical polymer are mixed, graphene oxide is made to be evenly coated at ball Shape polymer surfaces obtain the composite material of graphene oxide coated polymer；

Then in-situ chemical reduction is carried out to the composite material of the graphene oxide coated polymer, obtains reduction-oxidation graphite The composite material of alkene coated polymer；

It by washing, after removing unreacted impurity, is dispersed in deionized water again, obtains the poly- of graphene coated polymer Close object/graphene composite material；

Step S20：Prepare polymer/graphene/conducting nanowires mixture of multidimensional hybrid structure

The aqueous dispersions of the conducting nanowires are added to the polymer/graphene composite material of step (1) preparation In aqueous dispersions, it is uniformly mixed, obtains polymer/graphene/conducting nanowires mixed dispersion liquid of multidimensional hybrid structure；

Filter removal aqueous medium, then polymer/graphene/conducting nanowires mixture through being dried to obtain multidimensional hybrid structure；

Step S30：Prepare the polymerization based conductive composite material of multidimensional hybrid structure

Polymer/graphene/conducting nanowires mixture compression molding of multidimensional hybrid structure prepared by step (2), obtains The polymerization based conductive composite material of multidimensional hybrid structure, each component in the composite conducting polymer material of the multidimensional hybrid structure Quality proportioning it is as follows：

5~40 parts of the conducting nanowires of one-dimentional structure

0.5~5 part of the graphene of two-dimensional structure

55~90 parts of spherical polymer matrix；

In step S10, the polymer/graphene composite material of graphene coated polymer is prepared, specifically includes following step：

The aqueous dispersions of graphene oxide with the aqueous dispersions of spherical polymer are mixed, using cationic spherical polymer or are led to Overregulating pH value of solution makes graphene oxide be evenly coated at spherical polymer surface to 1~6, obtains graphene oxide cladding polymerization The composite material of object；

In step S30, the compression molding is for cold pressing or heating and mould pressing, cold pressing condition：Temperature is room temperature, pressure 1- 30MPa, time 10min~3h；Pressurized conditions are：Temperature (Tg+10)~(Tg+50) DEG C, Tg are polymer glass transition temperature Degree, pressure 1-30MPa, time 2min~2h.

2. the preparation method of composite conducting polymer material as described in claim 1, which is characterized in that the conducting nanowires For nano silver wire, copper nano-wire, nanowires of gold, nickel nano wire, aluminium nano wire, Fe nanowire, single-walled carbon nanotube and multi wall carbon One or more of nanotube.

3. the preparation method of composite conducting polymer material as claimed in claim 2, which is characterized in that the conducting nanowires Length is 5~500 μm, 30~300nm of diameter.

4. the preparation method of composite conducting polymer material as described in claim 1, which is characterized in that the spherical polymer Matrix is spherical polystyrene type, polymethacrylate, polyacrylate, cinnamic acrylic ester analog copolymer, Acrylic acid-methacrylic acid lipin polymer, polyacrylamide, polyethylene, phenolic resin, polysiloxanes, phenyl silicone One or more of.

5. the preparation method of composite conducting polymer material as claimed in claim 4, which is characterized in that the spherical polymer A diameter of 200nm~10 μm.

6. the preparation method of composite conducting polymer material as described in claim 1, which is characterized in that in step S10, oxidation Graphene in-situ reducing method be electronation, reducing agent for hydrazine hydrate, Dimethylhydrazine, hydroiodic acid, sodium borohydride, potassium borohydride, One kind in vitamin C, concentrated ammonia liquor.