Highly conductive polypyrrole composite material, and preparation method and application thereof

Abstract

The application belongs to the technical field of conductive polymer materials, and particularly relates to a high-conductivity polypyrrole composite material, a preparation method and application thereof. The application uses mercapto graphene oxide as a substrate and metal copper quantum dots as an auxiliary material, so that pyrrole monomers are in-situ polymerized on the surface of the mercapto graphene oxide to form a nanosheet structure, and the mercapto graphene oxide is reduced to form a high-conductivity composite material with polypyrrole and graphene as substrates. After the graphene oxide is modified by mercapto, the copper quantum dots are more uniformly distributed on the surface of the graphene oxide, the stability of the metal copper quantum dots is improved, and the stability of the graphene oxide in the reduction and processing process is improved. The polypyrrole nanosheets in the high-conductivity polypyrrole composite material are vertically distributed on the surface of the graphene, which not only improves the porosity of the composite material, increases the specific surface area, but also improves the mechanical properties of the polypyrrole, and is conducive to maintaining the stability of the polypyrrole morphology in the processing process.

Description

Technical Field

[0001] This invention belongs to the field of conductive polymer materials technology, specifically relating to a highly conductive polypyrrole composite material, its preparation method, and its application. Background Technology

[0002] Conductive polymers, also known as conductive high-performance polymers, refer to a series of polymers with high conductivity due to the continuous conjugated structure in their main chain. These conductive polymers possess unique three-dimensional structures and excellent chemical and electrochemical properties, and are widely used in polymer batteries, sensors, actuators, artificial muscles, solar photovoltaics, functional coatings, and electrochromic displays. As one of these polymers, polypyrrole exhibits greater chemical stability, convenient synthesis methods, high conductivity, and good biocompatibility than other conductive polymers, leading to its wider application in electrode materials, electronic storage, optoelectronic performance, sensors, and bioengineering.

[0003] Like traditional conductive polymers, polypyrrole has a continuous conjugated bond structure in its molecular chain and is widely used in sensors, drug carriers, and transducers. In these specific operating environments, materials often require certain unique structures and physical properties to maximize the function of their functional groups. For example, high specific surface area and suitable porosity and pore diameter can effectively improve the electrical conductivity of polypyrrole and reduce internal resistance. Therefore, to obtain materials with specific properties that meet product requirements, the material often needs to possess suitable microstructures, and this is crucial and depends on the preparation method. Common methods for preparing polypyrrole include in-situ chemical polymerization, electrochemical polymerization, interfacial polymerization, emulsion polymerization, solid-state polymerization, and soluble precursor polymerization. These methods can be broadly categorized into two types based on their reaction conditions and mechanisms: electrochemical deposition and chemical oxidation.

[0004] CN120484256A discloses a method for preparing and applying a conductive polypyrrole composite. The method includes: (1) preparing an emulsion system; (2) adding an oxidant; (3) diluting and adding the monomer pyrrole dropwise to allow the reaction to occur; and (4) washing the product. Then, the polypyrrole composite is mixed with a commercial polyurethane foaming component and foamed in one step to obtain a conductive product. The synthesis of a conductive polypyrrole composite with a nano-scale dendritic structure can achieve better dispersion and reduce the amount of conductive material used; the foamed conductive polyurethane foam is easy to construct, foams instantly, has a high foaming rate, retains more than 50% of the original mechanical properties, and has excellent conductivity. CN117362639A regulates the polymerization rate of polypyrrole by continuously adjusting the temperature of the reaction system, thereby controlling the radial conductivity and dielectric constant distribution of the polypyrrole microspheres. When the reaction system temperature is low, the polymerization rate is relatively slow. The regular arrangement of polypyrrole molecular chains increases the degree of π-conjugation, resulting in strong intra- and inter-chain charge transfer capabilities, high polymer conductivity, and a large dielectric constant. Conversely, as the reaction system temperature increases, the polymerization rate accelerates, causing the molecular chains to not have enough time to arrange themselves regularly, resulting in poorer π-conjugation, lower polymer conductivity, and a smaller dielectric constant. The polypyrrole microspheres provided exhibit radial conductivity and dielectric constant gradients, enabling gradient changes in conductivity and dielectric constant from the microsphere core to the surface. Applied to electromagnetic wave absorption, this provides both excellent impedance matching and dielectric loss performance. CN110698856A also discloses a graphene / polypyrrole / water-soluble polymer ternary composite material and its preparation method. The method involves adding an aqueous dispersion of graphene oxide, pyrrole monomer, morphology control agent, oxidant, and complexing agent to a hydrothermal reactor. After ultrasonic dispersion, the mixture is heated and simultaneously irradiated to obtain a graphene / polypyrrole / water-soluble polymer ternary hybrid hydrogel. The hydrogel is then freeze-dried to obtain the graphene / polypyrrole / water-soluble polymer ternary composite material. This method enables uniform dispersion of graphene and polypyrrole in the polymer matrix, resulting in a composite material with excellent electrical conductivity and mechanical properties. However, the above-mentioned process for preparing special polypyrrole morphologies is relatively complex and lacks a three-dimensional spatial structure, making it difficult to use directly as a conductive filler and limiting its application in the field of polyolefins and other resins. Summary of the Invention

[0005] To address the technical problems of poor morphological controllability and poor compatibility with resins in polypyrrole, this invention provides a highly conductive polypyrrole composite material and its preparation method. Using mercapto-modified graphene oxide as a substrate and copper quantum dots as auxiliary materials, pyrrole monomers are polymerized in situ on the surface of mercapto-modified graphene oxide to form nanosheet structures. After reduction, a three-dimensional highly conductive composite material with polypyrrole and graphene as the matrix is ​​obtained. When the three-dimensional conductive polypyrrole material is mixed with resins such as polyolefins, the vertically distributed polypyrrole nanosheets on the graphene surface increase the interaction area with the matrix resin, thereby increasing the interfacial energy and significantly improving the mechanical strength and conductivity of the polyolefin resin.

[0006] To achieve the above objectives, the present invention provides the following solution:

[0007] A method for preparing a highly conductive polypyrrole composite material includes the following steps:

[0008] (1) Add mercaptosilane coupling agent to graphene oxide dispersion, heat to react, filter, wash and dry to obtain mercapto-modified graphene oxide;

[0009] (2) The mercapto-modified graphene oxide was redispersed in deionized water, and then copper quantum dots were added and stirred evenly to obtain a mixed dispersion.

[0010] (3) Add oxidant to the mixed dispersion and stir evenly to obtain a reaction solution; then add pyrrole monomer to the reaction solution and after reaction, obtain a mercapto-modified graphene oxide / polypyrrole composite dispersion;

[0011] (4) Add a reducing agent to the mercaptoized graphene oxide / polypyrrole composite dispersion to reduce the graphene oxide, filter, wash and dry to obtain the highly conductive polypyrrole composite material.

[0012] As a common conductive polymer material, polypyrrole is often used as a conductive filler for thermoplastic resins such as polyolefins, imparting a certain degree of conductivity to the resin. However, its practical application faces a series of significant drawbacks. First, polypyrrole has a rigid chain structure, resulting in poor compatibility with the non-polar polyolefin matrix. It is prone to phase separation and agglomeration, leading to uneven dispersion and difficulty in forming a conductive network. Although existing technologies enhance the interfacial compatibility between polypyrrole and polyolefins by surface modification, such as introducing alkyl chains, using surfactants, or graft copolymerization, the preparation process is cumbersome, and the mixing process of polypyrrole and resin usually requires mechanical stirring. The modified polypyrrole has reduced mechanical properties and can easily damage the mechanical properties of the matrix resin. In particular, existing technologies generally directly add polypyrrole nanoparticles as conductive fillers. Rigid particles may act as stress concentration points, reducing the toughness, ductility, and other mechanical properties of polyolefins, leading to deterioration of mechanical properties.

[0013] To address the aforementioned issues, the inventors previously employed aramid nanofibers as a carrier for polypyrrole (CN120865606A, CN120867096A) to improve the mechanical stability of polypyrrole. However, aramid nanofibers lack electrical conductivity, offering limited improvement to the resin's conductivity. Unlike simple one-dimensional polypyrrole nanorods or two-dimensional graphene conductive materials, existing three-dimensional conductive materials generally possess a three-dimensional structure, forming macroscopic materials integrated from two-dimensional graphene sheets and conductive nanowires / nanorobars. While inheriting the excellent properties of two-dimensional graphene, such as thinness, high conductivity, superior mechanical strength, flexibility, and elasticity, their porous structure enhances their flexibility and specific surface area compared to traditional two-dimensional graphene, resulting in superior mass transfer performance. However, traditional graphene-based three-dimensional conductive materials are typically composed of one-dimensional nanowires or nanorods combined with two-dimensional graphene. They primarily rely on point-to-point or point-to-surface contact, leading to high contact resistance and fragile pathways. Moreover, the small contact area between one-dimensional conductive materials and graphene makes them prone to breakage during processing, shearing, or external force, requiring a higher filler load to form a conductive network, resulting in poor network stability.

[0014] This invention uses thiolized graphene oxide as a substrate and copper quantum dots as an auxiliary material to polymerize pyrrole monomers in situ on the surface of thiolized graphene oxide to form a nanosheet structure. After reduction, the thiolized graphene oxide forms a three-dimensional highly conductive composite material with polypyrrole and graphene as the matrix.

[0015] In their previous work, the inventors used pure graphene oxide as a carrier for copper quantum dots. Pure graphene oxide mainly loads copper quantum dots through physical adsorption or weak electrostatic interaction. However, copper quantum dots are prone to detachment or aggregation, and the exposed copper quantum dots lack a protective layer, making it easy for the active ingredients to become inactive.

[0016] After thiol modification, graphene oxide exhibits stronger coordination between thiol groups and copper atoms, enabling more robust anchoring of copper quantum dots and preventing their aggregation, detachment, or migration, thereby improving loading stability. The thiol groups on the graphene oxide surface can serve as functionalization sites, resulting in a more uniform distribution of copper quantum dots on the graphene oxide surface, reducing agglomeration, improving the stability of metallic copper quantum dots, and maintaining a high specific surface area and active site density. Simultaneously, the introduction of thiol groups can modulate the electronic structure of graphene oxide, promoting charge transfer between graphene oxide and copper quantum dots, enhancing interfacial coupling, and improving catalytic or sensing performance.

[0017] Furthermore, modification of graphene oxide with mercaptosilane coupling agents can improve its stability during reduction and processing. Direct chemical reduction of graphene oxide often leaves numerous structural defects on the graphene sheets while removing oxygen-containing functional groups. These defects severely disrupt the continuity of the carbon network, resulting in conductivity far below theoretical values. However, after modification with mercaptosilane coupling agents, the agents can act as repair agents during the reduction process, improving the stability of the conductive network. Simultaneously, the presence of the mercaptosilane coupling agent also acts as a separator, preventing the stacking of layers (re-graphitization) caused by π-π interactions and van der Waals forces after the reduction of graphene oxide to graphene. This results in graphene with a higher specific surface area, richer interlayer porosity, and a more open three-dimensional structure, improving the conductivity of the composite material. In addition, introducing mercaptosilane coupling agents into highly conductive polypyrrole composites prepared using mercapto-modified graphene oxide as a raw material can also improve the dispersion performance of highly conductive polypyrrole composites in resins such as polyolefins. When unmodified graphene-polypyrrole nanosheets are mixed with resin, the interaction between the nanosheets and resin is purely physical adsorption, resulting in weak interfacial bonding. Under stress, these nanosheets are prone to debonding, becoming defect sources and leading to decreased toughness and even strength in the composite material. They also tend to aggregate within the polyolefin, forming conductive "islands" requiring high filler content to achieve conductivity. However, after modification with a mercaptosilane coupling agent, the alkyl chains in the coupling agent have similar molecular chain structures and polarities to those of polyolefins, exhibiting excellent compatibility. This transforms the weak interface into a strong one, effectively transferring external forces from the resin matrix to the high-strength, highly conductive polypyrrole composite material. This simultaneously improves the composite material's strength, modulus, and toughness, achieving reinforcement without embrittlement.

[0018] In this invention, the polypyrrole nanosheets in the highly conductive polypyrrole composite material are vertically distributed on the graphene surface. This not only improves the porosity and specific surface area of ​​the composite material but also enhances the mechanical properties of polypyrrole, facilitating the maintenance of stable polypyrrole morphology during machining. Compared to traditional three-dimensional conductive materials composed of graphene-nanorobars / nanowires, the graphene-polypyrrole nanosheet three-dimensional conductive material prepared in this invention can form a multi-face-to-face and edge-to-face interconnected network. The sidewalls of the vertically arranged polypyrrole nanosheets easily contact each other, forming numerous conductive nodes. The wide interface between the polypyrrole nanosheet substrate and graphene results in low interfacial resistance, allowing for easier formation of efficient, low-percolation-threshold conductive pathways within the polymer matrix, leading to superior conductivity. Furthermore, the graphene-polypyrrole nanosheet three-dimensional conductive material possesses a high specific surface area, providing numerous active interfaces for charge storage (for supercapacitors), molecular adsorption (for sensing), or interaction with the polymer matrix, further enhancing the electrochemical activity of polypyrrole. Furthermore, the sheet-like structure of polypyrrole acts like a "nanolock," allowing it to better interpenetrate and entangle with polymer molecular chains, resulting in a stronger mechanical interlocking effect. This not only inhibits filler agglomeration but also effectively transfers stress, leading to better enhancement or retention of the mechanical properties (strength and toughness) of the composite material.

[0019] Specifically, this invention uses thiolized graphene oxide as a substrate because it exhibits good dispersibility in water and can adsorb copper quantum dots through coordination, laying the foundation for subsequent catalyst sites. On the other hand, copper quantum dots, as nanoscale metal particles, typically have a particle size below 10 nm. Their high surface energy easily causes the nanoparticles to aggregate into larger particles, which significantly reduces active sites and lowers catalytic efficiency. However, the surface of thiolized graphene oxide sheets is rich in polar functional groups such as thiol groups. Copper quantum dots can be adsorbed onto the graphene oxide surface through coordination, achieving atomic-level uniform distribution and effectively preventing leaching or migration and aggregation of copper quantum dots during use.

[0020] In previous work, the inventors had used single copper quantum dots or quantum dots modified with mercaptosilane coupling agents as catalysts to prepare spherical polyacrylamide (CN119219836A, CN119119360A, CN119176912A, CN119219839A, etc.). The polymerization of pyrrole monomers is typically an oxidative polymerization process, requiring an oxidant to capture electrons from the pyrrole monomers, generating free radical cations, which then initiate chain growth. Copper quantum dots not only possess a large specific surface area and abundant active sites, but also exhibit excellent electron supply and acceptance capabilities. They can be uniformly anchored on mercapto-modified graphene oxide sheets, becoming numerous and evenly distributed polymerization "nucleation centers." This ensures that polypyrrole can grow uniformly on the surface of mercapto-modified graphene oxide, rather than agglomerating into large particles, thus forming an ideal vertical nanosheet structure.

[0021] In the presence of an oxidant, high-surface-energy copper quantum dots can act as a "catalytic platform," enriching the oxidant and promoting the transfer of electrons from pyrrole monomers to the oxidant. This leads to a localized increase in reactant concentration, optimized reaction pathways, and a significant reduction in the activation energy of the polymerization reaction, allowing polymerization to proceed rapidly under milder conditions. Unlike traditional free radical initiators, copper quantum dots do not initiate pyrrole polymerization "alone," but through catalysis, they synergistically work with the main oxidant to efficiently catalyze the oxidative polymerization of pyrrole. Copper quantum dots act as nanoscale "seeds," guiding the in-situ polymerization and uniform growth of polypyrrole on the surface of thiolized graphene oxide. The uniform distribution of copper quantum dots on the graphene oxide sheets serves as the "nucleation centers" for pyrrole polymerization. Pyrrole monomers are first oxidized and polymerized into oligomers around the copper quantum dots. Subsequently, polymer chains radiate outward from the copper quantum dots, generating vertical nanosheet structures that tightly adhere to the thiolized graphene oxide sheets and are ultimately embedded in the surface of the thiolized graphene oxide. Through physicochemical interactions, this enhances the structural stability and conductivity of the composite material. After the polymerization reaction is complete, the oxygen-containing functional groups on the surface of the mercapto-modified graphene oxide are removed by a reduction process, and it is converted into reduced graphene oxide, thus obtaining a three-dimensional polypyrrole conductive material.

[0022] Thiol-modified graphene oxide is not only a "stabilizer" preventing the aggregation and oxidation of copper quantum dots, but also a "nanoplatform" guiding their uniform distribution and catalytic function, and ultimately a "structural foundation" for constructing high-performance three-dimensional composite materials. This integrated "carrier-catalyst" design is key to obtaining highly conductive functional materials. In this way, the high activity of copper quantum dots can be fully utilized and maintained for a long time, while the excellent performance of graphene oxide / reduced graphene oxide is activated and enhanced by the introduction of copper quantum dots and polypyrrole.

[0023] In one embodiment, the graphene oxide dispersion in step (1) is a deionized water dispersion of graphene oxide with a concentration of 0.5-10 mg / mL. Specifically, it can be 0.5 mg / mL, 1 mg / mL, 2 mg / mL, 3 mg / mL, 4 mg / mL, 5 mg / mL, 6 mg / mL, 7 mg / mL, 8 mg / mL, 9 mg / mL, or 10 mg / mL. In particular, it can be 1-3 mg / mL.

[0024] In one embodiment, the mercaptosilane coupling agent in step (1) is at least one of 3-mercaptopropyltrimethoxysilane and 3-mercaptopropyltriethoxysilane.

[0025] In one embodiment, the mass ratio of mercaptosilane coupling agent to graphene oxide in step (1) is 4-10:1. Specifically, the mass ratio of mercaptosilane coupling agent to graphene oxide can be 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, or 10:1. In particular, it can be 5-9:1 or 6-8:1.

[0026] In one embodiment, in step (1), after adding mercaptosilane coupling agent to the graphene oxide dispersion, ultrasonic dispersion treatment is performed, with an ultrasonic power of 100-200W.

[0027] In one embodiment, the heating reaction temperature in step (1) is 60-75°C, and the time is 8-12 hours. Further, the heating reaction temperature is 65-70°C, and the time is 9-10 hours.

[0028] In one embodiment, the stirring rate in step (2) is 300-500 rpm. Further, the stirring time is 0.1-1 h. Stirring promotes the dispersion of copper quantum dots and mercapto-modified graphene oxide, improving the dispersion degree of the raw materials.

[0029] In one embodiment, the mass ratio of copper quantum dots to thiolized graphene oxide in step (2) is 0.1%-1%. Specifically, it can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, or 1%. In particular, it can be 0.1%-0.6% or 0.2%-0.4%. An appropriate amount of copper quantum dots can be uniformly dispersed on the surface of thiolized graphene oxide. As a carrier for copper quantum dots, thiolized graphene oxide can not only improve the stability of copper quantum dots, but also promote their dispersion and prevent them from agglomerating and annihilating.

[0030] In one embodiment, the concentration of the thiolized graphene oxide dispersion obtained by redispersing the thiolized graphene oxide in deionized water in step (2) is 0.5-10 mg / mL. Compared to graphene, thiolized graphene oxide contains a large number of polar functional groups, is highly hydrophilic, and can be stably dispersed in solvents such as water and alcohol, facilitating solution processing and making it suitable for large-scale production. More importantly, the surface of thiolized graphene oxide sheets is rich in polar functional groups such as thiol groups, allowing copper quantum dots to be adsorbed onto the surface of graphene oxide through coordination, achieving atomic-level uniform distribution and improving the stability of copper quantum dots.

[0031] In one embodiment, the oxidant in step (3) is one or more of ammonium persulfate, potassium persulfate, sodium bisulfite, and azobisisobutyronitrile. By adding the oxidant to the mercapto-modified graphene oxide mixed dispersion loaded with copper quantum dots, it is beneficial for the oxidant to be adsorbed and enriched in advance. Subsequently, the added pyrrole monomer is preferentially oxidized around the copper quantum dots and polymerized into oligomers. Then, the polymer chains radiate outward from the copper quantum dots as the center to generate a vertical nanosheet structure.

[0032] In one embodiment, the stirring rate in step (3) is 300-500 rpm. Further, the stirring time is 0.1-1 h.

[0033] In one embodiment, the mass ratio of pyrrole monomer to thiolated graphene oxide in step (3) is (3-8):1. Specifically, the mass ratio of pyrrole monomer to thiolated graphene oxide is 3:1, 4:1, 5:1, 6:1, 7:1, or 8:1. In particular, the mass ratio of pyrrole monomer to thiolated graphene oxide is (4-6):1. A suitable amount of pyrrole monomer can ensure the integrity of the sheet structure and avoid the phenomenon of excessive growth of nanosheets and mutual adhesion caused by excessive polypyrrole. The thiolated graphene oxide sheets serve as a flexible two-dimensional conductive framework, and the polypyrrole nanosheets serve as fillers and bridging components dispersed on the surface of graphene oxide to construct an interpenetrating network structure, which greatly reduces the overall resistance.

[0034] In one embodiment, the mass ratio of oxidant to pyrrole monomer in step (3) is (0.5-5):1. Specifically, it can be 0.5:1, 1:1, 2:1, 3:1, 4:1, or 5:1. If the amount of oxidant is too small, a large amount of pyrrole monomer cannot be oxidized, resulting in low reaction conversion rate and poor structural strength. If the amount of oxidant is too large, it may lead to over-oxidation of the polypyrrole backbone, producing defects such as carbonyl groups, destroying the conjugated structure, and thus reducing conductivity.

[0035] In one embodiment, the reaction temperature in step (3) is 0-5°C and the reaction time is 8-12h. After the reaction begins, the pyrrole monomer polymerizes and grows in situ, firmly "stitching" together the originally easily stacked thiolized graphene oxide sheets, which not only prevents the re-aggregation of thiolized graphene oxide, but also enhances the structural toughness.

[0036] In one embodiment, the reducing agent in step (4) is one or more of hydrazine hydrate, hydroiodic acid, ascorbic acid, and sodium borohydride. Compared with thermal reduction, chemical reduction using a reducing agent can restore the conductive network of graphene more efficiently and controllably under milder conditions, and is more compatible with hydrophobic polyolefin matrices without damaging the structure of the three-dimensional conductive network.

[0037] In one embodiment, the mass ratio of the reducing agent to the mercaptoized graphene oxide in step (4) is (0.5-10):1.

[0038] In one embodiment, the reduction in step (4) is carried out at a temperature of 80-90°C for 3.5-6 hours.

[0039] In one embodiment, the washing in step (4) is performed by alternating washing with ethanol and deionized water, and the drying is performed by drying in a vacuum drying oven.

[0040] On the other hand, this invention also provides applications of highly conductive polypyrrole composite materials in the preparation of battery materials, sensor materials, capacitor materials, detector materials, conductive sheets, conductive pipes, and grouting materials. The highly conductive polypyrrole composite material not only possesses excellent electrical conductivity but also a rich porous structure, making it widely applicable in the field of high conductivity technology. Specifically, two-dimensional graphene sheets and vertically grown polypyrrole nanosheets together construct a three-dimensional interpenetrating network. This structure is more likely to form efficient conductive pathways with low filler content than single graphene sheets or polypyrrole nanosheets. Polypyrrole adheres tightly to the graphene surface through in-situ polymerization, reducing interfacial contact resistance. Simultaneously, the surface properties of graphene and polypyrrole modified with mercaptosilane coupling agents facilitate interfacial compatibility or physical entanglement with hydrophobic polyolefin resins. Overall, graphene provides high conductivity and excellent mechanical properties, while polypyrrole provides good electrochemical activity and easily tunable surface morphology. By constructing a three-dimensional hierarchical conductive network, the transformation of resins such as polyolefins from insulators to conductors or semiconductors can be achieved with extremely low filler loads, while maintaining good processability and mechanical properties.

[0041] Furthermore, this invention provides a polyolefin composite material comprising the following components in parts by weight: 50-150 parts polyolefin resin, 1-30 parts highly conductive polypyrrole composite material, and 1-10 parts processing aids. This polyolefin composite material possesses high mechanical strength and high electrical conductivity, and can be applied in battery current collectors, packaging films, sensors, electromagnetic shielding materials, conductive materials, and other technical fields, showing broad application prospects. The type of raw material for the composite material is not particularly limited. Specifically, this invention uses recycled polyolefins as the base material to reduce costs. Processing aids may include lubricants, antioxidants, flow modifiers, light stabilizers, UV absorbers, coupling agents, colorants, heat stabilizers, anti-hydrolysis agents, etc. The polyolefin may include common types such as polyethylene, polypropylene, polystyrene, ethylene-vinyl alcohol copolymers, and ethylene-vinyl acetate copolymers. In particular, the raw materials used in this invention are all common types and can be prepared, purchased, or recycled materials. For example, graphene oxide can be prepared using the Hummers method, which is common in this field; quantum dots can be selected from Benro copper quantum dots; polypropylene can be selected from Maoming Petrochemical T30S; and antioxidants can be selected from BASF antioxidant 1010, etc.

[0042] Beneficial effects:

[0043] (1) After thiol modification, graphene oxide has a stronger coordination ability with copper atoms, which can more firmly anchor copper quantum dots and prevent them from agglomerating, falling off or migrating, thereby improving the load stability. At the same time, the presence of thiol silane coupling agent also plays a spacer role, preventing the stacking phenomenon after graphene oxide is reduced to graphene, so that the obtained graphene has a higher specific surface area, more abundant interlayer pores and a more open three-dimensional structure, thus improving the conductivity of the composite material.

[0044] (2) Thiolized graphene oxide supported on copper quantum dots provides a "micro-reaction platform" for the polymerization of pyrrole monomers. Pyrrole monomers can be enriched around copper quantum dots, achieving high concentrations locally and greatly improving catalytic efficiency. Thiolized graphene oxide sheets themselves are ideal frameworks for constructing three-dimensional networks. After being loaded with copper quantum dots, they become the core of structure guidance in subsequent polymerization, ultimately forming a stable three-dimensional conductive composite material with graphene as the framework and polypyrrole as the connecting points. This structure is more likely to form efficient conductive pathways with low filler content than single graphene sheets or polypyrrole nanosheets. Polypyrrole adheres tightly to the graphene surface through in-situ polymerization, reducing interfacial contact resistance. Overall, graphene provides high conductivity and excellent mechanical properties, while polypyrrole provides good electrochemical activity and easily tunable surface morphology. By constructing a three-dimensional hierarchical conductive network, the transformation of resins such as polyolefins from insulators to conductors or semiconductors can be achieved with extremely low filler loading, while maintaining good processability and mechanical properties. Using this composite material as a conductive filler for resin, its electrical conductivity is further improved while maintaining the high mechanical properties of the resin, thus solving the technical problem that the addition of ordinary conductive fillers leads to a decrease in the mechanical properties of the composite material. Attached Figure Description

[0045] Figure 1 and Figure 2 The images shown are transmission electron microscope (TEM) and scanning electron microscope (SEM) images of the highly conductive polypyrrole composite material prepared in Example 11.

[0046] Figure 3 and Figure 4 The images shown are transmission electron microscope (TEM) and scanning electron microscope (SEM) images of the polypyrrole composite material prepared in Comparative Example 1. Detailed Implementation

[0047] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application. Unless otherwise specified, the raw material types of the following embodiments and comparative examples are the same.

[0048] Performance Testing: A polypropylene composite material comprising the following components by weight: 100 parts polypropylene resin, 12 parts polypyrrole composite material (prepared in Examples 1-11 and Comparative Examples 1-2, respectively), 2 parts antioxidant 1010, and 2 parts polyethylene wax lubricant. The above components were added to a twin-screw extruder and melt-extruded into granules (extruder temperature 190°C). Standard samples were then prepared, and their mechanical and electrical properties were tested. Tensile strength was measured according to ASTM D638, flexural strength according to ASTM D790, and the volume resistivity of the samples was measured using a ohmmeter.

[0049] Example 1

[0050] A method for preparing a highly conductive polypyrrole composite material includes the following steps:

[0051] (1) Add mercaptosilane coupling agent 3-mercaptopropyltrimethoxysilane to a graphene oxide deionized water dispersion with a concentration of 1 mg / mL, and sonicate at 100 W for 15 min; then heat at 60 °C for 12 h, filter, wash, and dry to obtain mercapto-modified graphene oxide; the mass ratio of mercaptosilane coupling agent to graphene oxide is 4:1;

[0052] (2) The mercapto-modified graphene oxide was redispersed in deionized water to obtain a deionized water dispersion of mercapto-modified graphene oxide. Then, copper quantum dots were added and stirred at 300 rpm for 1 h to obtain a mixed dispersion. The mass ratio of copper quantum dots to mercapto-modified graphene oxide was 0.1%. The concentration of the deionized water dispersion of mercapto-modified graphene oxide was 0.8 mg / mL.

[0053] (3) Add ammonium persulfate as an oxidant to the mixed dispersion and stir at 300 rpm for 1 h to obtain a reaction solution; then add pyrrole monomer to the reaction solution and react at 0℃ for 8 h to obtain a mercapto-modified graphene oxide / polypyrrole composite dispersion; the mass ratio of oxidant to pyrrole monomer is 2.8:1; the mass ratio of pyrrole monomer to mercapto-modified graphene oxide is 8:1;

[0054] (4) Add ascorbic acid as a reducing agent to the mercapto-modified graphene oxide / polypyrrole composite dispersion, react at 80℃ for 6 hours, filter, wash alternately with ethanol and deionized water, and dry in a vacuum drying oven to obtain the highly conductive polypyrrole composite material; the mass ratio of reducing agent to mercapto-modified graphene oxide is 1:1. The corresponding polypropylene composite material was tested and found to have a tensile strength of 34.6 MPa, a flexural strength of 40.1 MPa, and a volume resistivity of 8.2 × 10⁻⁶ MPa. 6 Ω·m.

[0055] Example 2

[0056] A method for preparing a highly conductive polypyrrole composite material includes the following steps:

[0057] (1) Add mercaptosilane coupling agent 3-mercaptopropyltrimethoxysilane to a deionized water dispersion of graphene oxide with a concentration of 1 mg / mL, and sonicate at 200 W for 15 min; then heat at 75 °C for 8 h, filter, wash, and dry to obtain mercapto-modified graphene oxide; the mass ratio of mercaptosilane coupling agent to graphene oxide is 8:1;

[0058] (2) The mercapto-modified graphene oxide was redispersed in deionized water to obtain a deionized water dispersion of mercapto-modified graphene oxide. Then, copper quantum dots were added and stirred at 500 rpm for 0.5 h to obtain a mixed dispersion. The mass ratio of copper quantum dots to mercapto-modified graphene oxide was 0.5%. The concentration of the deionized water dispersion of mercapto-modified graphene oxide was 2.2 mg / mL.

[0059] (3) Add ammonium persulfate as an oxidant to the mixed dispersion and stir at 500 rpm for 0.5 h to obtain a reaction solution; then add pyrrole monomer to the reaction solution and react at 0℃ for 12 h to obtain a mercapto-modified graphene oxide / polypyrrole composite dispersion; the mass ratio of oxidant to pyrrole monomer is 3.5:1; the mass ratio of pyrrole monomer to mercapto-modified graphene oxide is 3:1;

[0060] (4) Add ascorbic acid as a reducing agent to the mercapto-modified graphene oxide / polypyrrole composite dispersion, react at 90℃ for 3.6 h, filter, wash alternately with ethanol and deionized water, and dry in a vacuum drying oven to obtain the highly conductive polypyrrole composite material; the mass ratio of reducing agent to mercapto-modified graphene oxide is 4:1. The corresponding polypropylene composite material was tested and found to have a tensile strength of 35.1 MPa, a flexural strength of 39.4 MPa, and a volume resistivity of 5.5 × 10⁻⁶ MPa. 5 Ω·m.

[0061] Example 3

[0062] A method for preparing a highly conductive polypyrrole composite material includes the following steps:

[0063] (1) Add mercaptosilane coupling agent 3-mercaptopropyltrimethoxysilane to a deionized water dispersion of graphene oxide with a concentration of 1 mg / mL, and sonicate at 150 W for 20 min; then heat at 70 °C for 10 h, filter, wash, and dry to obtain mercapto-modified graphene oxide; the mass ratio of mercaptosilane coupling agent to graphene oxide is 9:1;

[0064] (2) The mercapto-modified graphene oxide was redispersed in deionized water to obtain a deionized water dispersion of mercapto-modified graphene oxide. Then, copper quantum dots were added and stirred at 400 rpm for 0.8 h to obtain a mixed dispersion. The mass ratio of copper quantum dots to mercapto-modified graphene oxide was 0.4%. The concentration of the deionized water dispersion of mercapto-modified graphene oxide was 1 mg / mL.

[0065] (3) Add ammonium persulfate as an oxidant to the mixed dispersion and stir at 400 rpm for 0.8 h to obtain a reaction solution; then add pyrrole monomer to the reaction solution and react at 0 °C for 10 h to obtain a mercapto-modified graphene oxide / polypyrrole composite dispersion; the mass ratio of oxidant to pyrrole monomer is 3:1; the mass ratio of pyrrole monomer to mercapto-modified graphene oxide is 5:1;

[0066] (4) Add ascorbic acid as a reducing agent to the mercapto-modified graphene oxide / polypyrrole composite dispersion, react at 85℃ for 5 hours, filter, wash alternately with ethanol and deionized water, and dry in a vacuum drying oven to obtain the highly conductive polypyrrole composite material; the mass ratio of reducing agent to mercapto-modified graphene oxide is 3:1. The corresponding polypropylene composite material was tested and found to have a tensile strength of 35.5 MPa, a flexural strength of 41.4 MPa, and a volume resistivity of 6.8 × 10⁻⁶. 6 Ω·m.

[0067] Example 4

[0068] A method for preparing a highly conductive polypyrrole composite material includes the following steps:

[0069] (1) Add mercaptosilane coupling agent 3-mercaptopropyltrimethoxysilane to a graphene oxide deionized water dispersion with a concentration of 1 mg / mL, and sonicate at 100 W for 15 min; then heat at 60 °C for 8 h, filter, wash, and dry to obtain mercapto-modified graphene oxide; the mass ratio of mercaptosilane coupling agent to graphene oxide is 7:1;

[0070] (2) The mercapto-modified graphene oxide was redispersed in deionized water to obtain a deionized water dispersion of mercapto-modified graphene oxide. Then, copper quantum dots were added and stirred at 300 rpm for 0.5 h to obtain a mixed dispersion. The mass ratio of copper quantum dots to mercapto-modified graphene oxide was 0.15%. The concentration of the deionized water dispersion of mercapto-modified graphene oxide was 2 mg / mL.

[0071] (3) Add ammonium persulfate as an oxidant to the mixed dispersion and stir at 500 rpm for 1 h to obtain a reaction solution; then add pyrrole monomer to the reaction solution and react at 0℃ for 8 h to obtain a mercapto-modified graphene oxide / polypyrrole composite dispersion; the mass ratio of oxidant to pyrrole monomer is 3.2:1; the mass ratio of pyrrole monomer to mercapto-modified graphene oxide is 5.5:1;

[0072] (4) Add ascorbic acid as a reducing agent to the mercapto-modified graphene oxide / polypyrrole composite dispersion, react at 80℃ for 3.6 h, filter, wash alternately with ethanol and deionized water, and dry in a vacuum drying oven to obtain the highly conductive polypyrrole composite material; the mass ratio of reducing agent to mercapto-modified graphene oxide is 1.5:1. The corresponding polypropylene composite material was tested and found to have a tensile strength of 34.7 MPa, a flexural strength of 38.8 MPa, and a volume resistivity of 9.8 × 10⁻⁶ MPa. 5 Ω·m.

[0073] Example 5

[0074] A method for preparing a highly conductive polypyrrole composite material includes the following steps:

[0075] (1) Add mercaptosilane coupling agent 3-mercaptopropyltrimethoxysilane to a graphene oxide deionized water dispersion with a concentration of 1 mg / mL, and sonicate at 150 W for 20 min; then heat at 70 °C for 10 h, filter, wash, and dry to obtain mercapto-modified graphene oxide; the mass ratio of mercaptosilane coupling agent to graphene oxide is 6:1;

[0076] (2) The mercapto-modified graphene oxide was redispersed in deionized water to obtain a deionized water dispersion of mercapto-modified graphene oxide. Then, copper quantum dots were added and stirred at 400 rpm for 0.8 h to obtain a mixed dispersion. The mass ratio of copper quantum dots to mercapto-modified graphene oxide was 0.6%. The concentration of the deionized water dispersion of mercapto-modified graphene oxide was 1 mg / mL.

[0077] (3) Add ammonium persulfate as an oxidant to the mixed dispersion and stir at 400 rpm for 0.8 h to obtain a reaction solution; then add pyrrole monomer to the reaction solution and react at 0 °C for 10 h to obtain a mercapto-modified graphene oxide / polypyrrole composite dispersion; the mass ratio of oxidant to pyrrole monomer is 3:1; the mass ratio of pyrrole monomer to mercapto-modified graphene oxide is 5:1;

[0078] (4) Add ascorbic acid as a reducing agent to the mercapto-modified graphene oxide / polypyrrole composite dispersion, react at 85℃ for 5 hours, filter, wash alternately with ethanol and deionized water, and dry in a vacuum drying oven to obtain the highly conductive polypyrrole composite material; the mass ratio of reducing agent to mercapto-modified graphene oxide is 3:1. The corresponding polypropylene composite material was tested and found to have a tensile strength of 34.8 MPa, a flexural strength of 40.3 MPa, and a volume resistivity of 7.3 × 10⁻⁶ MPa. 6 Ω·m.

[0079] Example 6

[0080] A method for preparing a highly conductive polypyrrole composite material includes the following steps:

[0081] (1) Add mercaptosilane coupling agent 3-mercaptopropyltrimethoxysilane to a deionized water dispersion of graphene oxide with a concentration of 1 mg / mL, and sonicate at 120 W for 25 min; then heat at 63 °C for 11 h, filter, wash, and dry to obtain mercapto-modified graphene oxide; the mass ratio of mercaptosilane coupling agent to graphene oxide is 5:1;

[0082] (2) The mercapto-modified graphene oxide was redispersed in deionized water to obtain a deionized water dispersion of mercapto-modified graphene oxide. Then, copper quantum dots were added and stirred at 350 rpm for 0.8 h to obtain a mixed dispersion. The mass ratio of copper quantum dots to mercapto-modified graphene oxide was 0.2%. The concentration of the deionized water dispersion of mercapto-modified graphene oxide was 1.2 mg / mL.

[0083] (3) Add ammonium persulfate as an oxidant to the mixed dispersion and stir at 350 rpm for 0.8 h to obtain a reaction solution; then add pyrrole monomer to the reaction solution and react at 0℃ for 9 h to obtain a mercapto-modified graphene oxide / polypyrrole composite dispersion; the mass ratio of oxidant to pyrrole monomer is 3:1; the mass ratio of pyrrole monomer to mercapto-modified graphene oxide is 4:1;

[0084] (4) Add ascorbic acid as a reducing agent to the mercapto-modified graphene oxide / polypyrrole composite dispersion, react at 83℃ for 4 hours, filter, wash alternately with ethanol and deionized water, and dry in a vacuum drying oven to obtain the highly conductive polypyrrole composite material; the mass ratio of reducing agent to mercapto-modified graphene oxide is 2.5:1. The corresponding polypropylene composite material was tested and found to have a tensile strength of 34.2 MPa, a flexural strength of 39.7 MPa, and a volume resistivity of 9.6 × 10⁻⁶. 5 Ω·m.

[0085] Example 7

[0086] A method for preparing a highly conductive polypyrrole composite material includes the following steps:

[0087] (1) Add mercaptosilane coupling agent 3-mercaptopropyltrimethoxysilane to a graphene oxide deionized water dispersion with a concentration of 1 mg / mL, and sonicate at 150 W for 20 min; then heat at 70 °C for 10 h, filter, wash, and dry to obtain mercapto-modified graphene oxide; the mass ratio of mercaptosilane coupling agent to graphene oxide is 6:1;

[0088] (2) The mercapto-modified graphene oxide was redispersed in deionized water to obtain a deionized water dispersion of mercapto-modified graphene oxide. Then, copper quantum dots were added and stirred at 400 rpm for 0.8 h to obtain a mixed dispersion. The mass ratio of copper quantum dots to mercapto-modified graphene oxide was 0.4%. The concentration of the deionized water dispersion of mercapto-modified graphene oxide was 1 mg / mL.

[0089] (3) Add ammonium persulfate as an oxidant to the mixed dispersion and stir at 400 rpm for 0.8 h to obtain a reaction solution; then add pyrrole monomer to the reaction solution and react at 0 °C for 10 h to obtain a mercapto-modified graphene oxide / polypyrrole composite dispersion; the mass ratio of oxidant to pyrrole monomer is 3:1; the mass ratio of pyrrole monomer to mercapto-modified graphene oxide is 8:1;

[0090] (4) Add ascorbic acid as a reducing agent to the mercapto-modified graphene oxide / polypyrrole composite dispersion, react at 85℃ for 5 hours, filter, wash alternately with ethanol and deionized water, and dry in a vacuum drying oven to obtain the highly conductive polypyrrole composite material; the mass ratio of reducing agent to mercapto-modified graphene oxide is 3:1. The corresponding polypropylene composite material was tested and found to have a tensile strength of 34.2 MPa, a flexural strength of 41.1 MPa, and a volume resistivity of 9.8 × 10⁻⁶ MPa. 6 Ω·m.

[0091] Example 8

[0092] A method for preparing a highly conductive polypyrrole composite material includes the following steps:

[0093] (1) Add mercaptosilane coupling agent 3-mercaptopropyltrimethoxysilane to a graphene oxide deionized water dispersion with a concentration of 1 mg / mL, and sonicate at 180 W for 25 min; then heat at 70 °C for 9 h, filter, wash, and dry to obtain mercapto-modified graphene oxide; the mass ratio of mercaptosilane coupling agent to graphene oxide is 7.5:1;

[0094] (2) The mercapto-modified graphene oxide was redispersed in deionized water to obtain a deionized water dispersion of mercapto-modified graphene oxide. Then, copper quantum dots were added and stirred at 450 rpm for 0.6 h to obtain a mixed dispersion. The mass ratio of copper quantum dots to mercapto-modified graphene oxide was 0.45%. The concentration of the deionized water dispersion of mercapto-modified graphene oxide was 1.6 mg / mL.

[0095] (3) Add ammonium persulfate as an oxidant to the mixed dispersion and stir at 450 rpm for 0.6 h to obtain a reaction solution; then add pyrrole monomer to the reaction solution and react at 0 °C for 10.5 h to obtain a mercapto-modified graphene oxide / polypyrrole composite dispersion; the mass ratio of oxidant to pyrrole monomer is 3.3:1; the mass ratio of pyrrole monomer to mercapto-modified graphene oxide is 6.5:1;

[0096] (4) Add ascorbic acid as a reducing agent to the mercapto-modified graphene oxide / polypyrrole composite dispersion, react at 88℃ for 4.5 h, filter, wash alternately with ethanol and deionized water, and dry in a vacuum drying oven to obtain the highly conductive polypyrrole composite material; the mass ratio of reducing agent to mercapto-modified graphene oxide is 3.5:1. The corresponding polypropylene composite material was tested and found to have a tensile strength of 36.2 MPa, a flexural strength of 41.3 MPa, and a volume resistivity of 5.3 × 10⁻⁶ MPa. 6 Ω·m.

[0097] Example 9

[0098] A method for preparing a highly conductive polypyrrole composite material includes the following steps:

[0099] (1) Add mercaptosilane coupling agent 3-mercaptopropyltrimethoxysilane to a deionized water dispersion of graphene oxide with a concentration of 1 mg / mL, and sonicate at 160 W for 15 min; then heat at 66 °C for 9.5 h, filter, wash, and dry to obtain mercapto-modified graphene oxide; the mass ratio of mercaptosilane coupling agent to graphene oxide is 5.5:1;

[0100] (2) The mercapto-modified graphene oxide was redispersed in deionized water to obtain a deionized water dispersion of mercapto-modified graphene oxide. Then, copper quantum dots were added and stirred at 350 rpm for 0.7 h to obtain a mixed dispersion. The mass ratio of copper quantum dots to mercapto-modified graphene oxide was 0.3%. The concentration of the deionized water dispersion of mercapto-modified graphene oxide was 1.3 mg / mL.

[0101] (3) Add ammonium persulfate as an oxidant to the mixed dispersion and stir at 400 rpm for 0.7 h to obtain a reaction solution; then add pyrrole monomer to the reaction solution and react at 0℃ for 9 h to obtain a mercapto-modified graphene oxide / polypyrrole composite dispersion; the mass ratio of oxidant to pyrrole monomer is 3.4:1; the mass ratio of pyrrole monomer to mercapto-modified graphene oxide is 7:1;

[0102] (4) Add ascorbic acid as a reducing agent to the mercapto-modified graphene oxide / polypyrrole composite dispersion, react at 86℃ for 5.2 h, filter, wash alternately with ethanol and deionized water, and dry in a vacuum drying oven to obtain the highly conductive polypyrrole composite material; the mass ratio of reducing agent to mercapto-modified graphene oxide is 3.3:1. The corresponding polypropylene composite material was tested and found to have a tensile strength of 35.7 MPa, a flexural strength of 40.5 MPa, and a volume resistivity of 4.7 × 10⁻⁶. 6 Ω·m.

[0103] Example 10

[0104] A method for preparing a highly conductive polypyrrole composite material includes the following steps:

[0105] (1) Add mercaptosilane coupling agent 3-mercaptopropyltrimethoxysilane to a graphene oxide deionized water dispersion with a concentration of 1 mg / mL, and sonicate at 180 W for 25 min; then heat at 70 °C for 9 h, filter, wash, and dry to obtain mercapto-modified graphene oxide; the mass ratio of mercaptosilane coupling agent to graphene oxide is 6.5:1;

[0106] (2) The mercapto-modified graphene oxide was redispersed in deionized water to obtain a deionized water dispersion of mercapto-modified graphene oxide. Then, copper quantum dots were added and stirred at 300 rpm for 0.8 h to obtain a mixed dispersion. The mass ratio of copper quantum dots to mercapto-modified graphene oxide was 0.35%. The concentration of the deionized water dispersion of mercapto-modified graphene oxide was 1.6 mg / mL.

[0107] (3) Add ammonium persulfate as an oxidant to the mixed dispersion and stir at 450 rpm for 0.6 h to obtain a reaction solution; then add pyrrole monomer to the reaction solution and react at 0 °C for 10 h to obtain a mercapto-modified graphene oxide / polypyrrole composite dispersion; the mass ratio of oxidant to pyrrole monomer is 3.5:1; the mass ratio of pyrrole monomer to mercapto-modified graphene oxide is 6:1;

[0108] (4) Add ascorbic acid as a reducing agent to the mercapto-modified graphene oxide / polypyrrole composite dispersion, react at 86℃ for 4.8h, filter, wash alternately with ethanol and deionized water, and dry in a vacuum drying oven to obtain the highly conductive polypyrrole composite material; the mass ratio of reducing agent to mercapto-modified graphene oxide is 2.8:1. The corresponding polypropylene composite material was tested and found to have a tensile strength of 34.4MPa, a flexural strength of 39.6MPa, and a volume resistivity of 6.3×10⁻⁶. 6 Ω·m.

[0109] Example 11

[0110] A method for preparing a highly conductive polypyrrole composite material includes the following steps:

[0111] (1) Add mercaptosilane coupling agent 3-mercaptopropyltrimethoxysilane to a graphene oxide deionized water dispersion with a concentration of 1 mg / mL, and sonicate at 150 W for 20 min; then heat at 70 °C for 10 h, filter, wash, and dry to obtain mercapto-modified graphene oxide; the mass ratio of mercaptosilane coupling agent to graphene oxide is 6:1;

[0112] (2) The mercapto-modified graphene oxide was redispersed in deionized water to obtain a deionized water dispersion of mercapto-modified graphene oxide. Then, copper quantum dots were added and stirred at 400 rpm for 0.8 h to obtain a mixed dispersion. The mass ratio of copper quantum dots to mercapto-modified graphene oxide was 0.4%. The concentration of the deionized water dispersion of mercapto-modified graphene oxide was 1 mg / mL.

[0113] (3) Add ammonium persulfate as an oxidant to the mixed dispersion and stir at 400 rpm for 0.8 h to obtain a reaction solution; then add pyrrole monomer to the reaction solution and react at 0 °C for 10 h to obtain a mercapto-modified graphene oxide / polypyrrole composite dispersion; the mass ratio of oxidant to pyrrole monomer is 3:1; the mass ratio of pyrrole monomer to mercapto-modified graphene oxide is 5:1;

[0114] (4) Add ascorbic acid as a reducing agent to the mercapto-modified graphene oxide / polypyrrole composite dispersion, react at 85℃ for 5 hours, filter, wash alternately with ethanol and deionized water, and dry in a vacuum drying oven to obtain the highly conductive polypyrrole composite material; the mass ratio of reducing agent to mercapto-modified graphene oxide is 3:1. The corresponding polypropylene composite material was tested and found to have a tensile strength of 37.3 MPa, a flexural strength of 41.0 MPa, and a volume resistivity of 4.9 × 10⁻⁶ MPa. 5 Ω·m.

[0115] Comparative Example 1

[0116] A method for preparing a polypyrrole composite material includes the following steps:

[0117] (1) Add mercaptosilane coupling agent 3-mercaptopropyltrimethoxysilane to a graphene oxide deionized water dispersion with a concentration of 1 mg / mL, and sonicate at 150 W for 20 min; then heat at 70 °C for 10 h, filter, wash, and dry to obtain mercapto-modified graphene oxide; the mass ratio of mercaptosilane coupling agent to graphene oxide is 6:1;

[0118] (2) The mercapto-modified graphene oxide was redispersed in deionized water to obtain a deionized water dispersion of mercapto-modified graphene oxide. Then, copper quantum dots were added and stirred at 400 rpm for 0.8 h to obtain a mixed dispersion. The mass ratio of copper quantum dots to mercapto-modified graphene oxide was 0.4%. The concentration of the deionized water dispersion of mercapto-modified graphene oxide was 1 mg / mL.

[0119] (3) Add pyrrole monomer to the mixed dispersion and stir at 400 rpm for 0.8 h to obtain a reaction solution; then add ammonium persulfate oxidant to the reaction solution and react at 0℃ for 10 h to obtain a mercapto-modified graphene oxide / polypyrrole composite dispersion; the mass ratio of oxidant to pyrrole monomer is 3:1; the mass ratio of pyrrole monomer to mercapto-modified graphene oxide is 5:1;

[0120] (4) Add ascorbic acid as a reducing agent to the mercapto-modified graphene oxide / polypyrrole composite dispersion, react at 85℃ for 5 hours, filter, wash alternately with ethanol and deionized water, and dry in a vacuum drying oven to obtain the polypyrrole composite material; the mass ratio of reducing agent to mercapto-modified graphene oxide is 3:1. The corresponding polypropylene composite material was tested and found to have a tensile strength of 30.4 MPa, a flexural strength of 36.2 MPa, and a volume resistivity of 9.3 × 10⁻⁶ MPa. 8 Ω·m.

[0121] Comparative Example 2

[0122] A method for preparing a polypyrrole composite material includes the following steps:

[0123] (1) Add mercaptosilane coupling agent 3-mercaptopropyltrimethoxysilane to a graphene deionized water dispersion with a concentration of 1 mg / mL, and ultrasonically disperse at 150 W for 20 min; then heat at 70 °C for 10 h, filter, wash, and dry to obtain mercaptographene; the mass ratio of mercaptosilane coupling agent to graphene is 6:1.

[0124] (2) The mercaptographene was redispersed in deionized water to obtain a deionized water dispersion of mercaptographene. Then, copper quantum dots were added and stirred at 400 rpm for 0.8 h to obtain a mixed dispersion. The mass ratio of copper quantum dots to mercaptographene was 0.4%. The concentration of the deionized water dispersion of mercaptographene was 1 mg / mL.

[0125] (3) Add ammonium persulfate as an oxidant to the mixed dispersion and stir at 400 rpm for 0.8 h to obtain a reaction solution; then add pyrrole monomer to the reaction solution and react at 0 °C for 10 h to obtain a mercaptographene / polypyrrole composite dispersion; the mass ratio of oxidant to pyrrole monomer is 3:1; the mass ratio of pyrrole monomer to mercaptographene is 5:1;

[0126] (4) After filtration, alternating washing with ethanol and deionized water, and drying in a vacuum drying oven, the polypyrrole composite material was obtained. The corresponding polypropylene composite material was tested and found to have a tensile strength of 31.2 MPa, a flexural strength of 36.8 MPa, and a volume resistivity of 1.4 × 10⁻⁶ MPa. 8 Ω·m.

[0127] Figure 1 and Figure 2 The images shown are transmission electron microscopy (TEM) and scanning electron microscopy (SEM) images of the highly conductive polypyrrole composite material prepared in Example 11. Figure 1 Transmission electron microscopy (TEM) images show that after polymerization, the graphene exhibits a relatively regular sheet-like structure, indicating that pyrrole monomers underwent uniform polymerization on the surface of thiolized graphene oxide, and no polypyrrole agglomeration occurred. Figure 2It is evident that the graphene surface exhibits a vertically aligned nanosheet structure with relatively uniform size, forming a planar network structure that interconnects with each other and with the graphene substrate. Furthermore, the polypyrrole nanosheets create numerous pores, which not only increase the specific surface area of ​​the conductive material but also facilitate resin wetting during melt processing, thereby enhancing the interfacial interaction between the conductive filler and the resin. Figure 3 and Figure 4 The images shown are transmission electron microscopy (TEM) and scanning electron microscopy (SEM) images of the polypyrrole composite material prepared in Comparative Example 1. Figure 3 The transmission electron microscopy (TEM) images show that the prepared polypyrrole composite material exhibits a distinct bulk structure, indicating that pyrrole monomers agglomerated on the graphene surface, affecting the dispersion of the graphene. Figure 4 Scanning electron microscopy (SEM) images also show that no polypyrrole nanosheets formed on the graphene surface; instead, rod-shaped polypyrrole coatings were formed. Furthermore, combining the data from the examples and comparative examples, it can be seen that: compared to Example 11, Comparative Example 1 first added pyrrole monomers and then added an oxidant. The addition of a large amount of pyrrole monomers affected the enrichment of the oxidant near the copper quantum dots, which was detrimental to the growth of polypyrrole nanosheets. Instead, a coating structure was formed on the graphene oxide surface, which not only hindered the formation of the graphene-polypyrrole double-sheet structure but also impeded the reduction process of graphene oxide, leading to a decrease in the structural strength and electrical conductivity of the composite material. Compared to Example 11, Comparative Example 2 used graphene as the starting carbon material. Compared to graphene oxide, graphene lacks oxygen-containing functional groups on its surface, resulting in poor dispersibility in solution. This was detrimental to the adhesion of copper quantum dots and the uniform polymerization of pyrrole monomers, leading to a decrease in the mechanical strength and electrical conductivity of the composite material.

[0128] The above embodiments are not intended to limit the content of the composition of the present invention. Any minor modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention or the composition or content of the composition shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a high-conductivity polypyrole composite material, characterized in that , comprising the following steps: (1) adding mercapto silane coupling agent to graphene oxide dispersion, heating reaction, filtering, washing, drying to obtain mercapto graphene oxide; the mass ratio of mercapto silane coupling agent and graphene oxide is 4-10:1; (2) dispersing mercapto graphene oxide in deionized water again, then adding copper quantum dots, stirring to obtain a mixed dispersion; (3) adding oxidant to the mixed dispersion, stirring to obtain a reaction solution; then adding pyrrole monomer to the reaction solution, after reaction, obtaining mercapto graphene oxide / poly pyrrole composite dispersion; the mass ratio of pyrrole monomer and mercapto graphene oxide is (3-8):1; (4) adding reducing agent to the mercapto graphene oxide / poly pyrrole composite dispersion to reduce graphene oxide, filtering, washing, drying to obtain high-conductivity poly pyrrole composite material.

2. The method for preparing a highly conductive polypyrrole composite material as described in claim 1, characterized in that... , the mercapto silane coupling agent in step (1) is at least one of 3-mercaptopropyl trimethoxysilane and 3-mercaptopropyl triethoxysilane.

3. The method for preparing a highly conductive polypyrrole composite material as described in claim 1, characterized in that... , in step (1), after adding mercapto silane coupling agent to graphene oxide dispersion, ultrasonic dispersion treatment is carried out, and the ultrasonic power is 100-200 W.

4. The method for preparing a highly conductive polypyrrole composite material as described in claim 1, characterized in that... , in step (1), the heating reaction temperature is 60-75℃, and the time is 8-12h.

5. The method for preparing a highly conductive polypyrrole composite material as described in claim 1, characterized in that... , in step (3), the reaction temperature is 0-5℃, and the reaction time is 8-12h.

6. The method for preparing a highly conductive polypyrrole composite material as described in claim 1, characterized in that... , in step (4), the reduction temperature is 80-90℃, and the time is 3.5-6h.

7. A high conductive polypyrole composite material, characterized by 8. The application of a high-conductivity poly pyrrole composite material according to claim 7 in the field of battery materials, sensor materials, capacitor materials, detector materials, conductive plate materials, conductive pipe materials, and grouting materials. , comprising the following components by weight: 50-150 parts of polyolefin resin, 1-30 parts of the high-conductivity poly pyrrole composite material according to claim 7, and 1-10 parts of processing aid.

9. A polyolefin composite material, characterized by ​

Images