Solvent type graphene dispersion liquid and preparation method thereof

Abstract

The invention relates to the technical field of graphene, and discloses a solvent type graphene dispersion liquid and a preparation method thereof. The preparation method comprises the following steps: dissolving dimethylolpropionic acid in N, N-dimethylformamide (DMF), reacting with p-toluenesulfonic acid and ethylenediamine to obtain hyperbranched polyesteramine, and introducing an epoxy group into the hyperbranched polyesteramine to obtain the epoxy hyperbranched polyesteramine. Then, perylene-3, 4, 9, 10-tetracarboxylic dianhydride is dissolved in DMF and reacts with triethylene tetramine and epoxy hyperbranched polyesteramine in sequence, the pH is adjusted, a graphene dispersant precursor is obtained, an adhesion agent is added, a reaction is further conducted, and the graphene dispersant is obtained. And finally, dispersing graphite and the dispersing agent in ethanol, and performing liquid-phase mechanical stripping to obtain the graphene dispersion liquid. According to the preparation method provided by the invention, the graphene dispersion liquid is remarkably improved in the aspects of low viscosity, high solid content, uniform dispersion, long-term stability, conductivity and material compatibility.

Description

Technical Field

[0001] The present invention relates to the technical field of graphene, and more specifically, to a solvent-based graphene dispersion and a preparation method thereof. Background Art

[0002] Graphene is a kind of carbon atom 2 The two-dimensional material with a single-layer honeycomb lattice structure composed of hybrid orbitals has excellent electrical, mechanical, thermal and other properties, and has shown broad application prospects in many fields such as electronic devices, energy storage, composite materials, sensors, etc., and is regarded as one of the revolutionary materials. However, due to its strong π-π stacking effect and van der Waals force, graphene sheets are prone to irreversible agglomeration, which greatly limits the performance of its excellent properties and constitutes an obstacle to practical applications.

[0003] In order to overcome this limitation, graphene dispersions came into being. The methods for dispersing graphene mainly include covalent modification and non-covalent modification. Although covalent modification can improve dispersibility to a certain extent, it will inevitably destroy the original structure of graphene, thereby affecting its inherent electrical and other physical and chemical properties. In contrast, non-covalent modification methods have attracted much attention because they can achieve effective dispersion without damaging the intrinsic properties of graphene. Nevertheless, traditional non-covalent modification methods, such as using surfactants to assist in dispersion, still have shortcomings such as poor dispersion effect and the need for a large amount of additives to maintain stability, which not only increases costs, but also limits the large-scale application of graphene dispersions. In many application scenarios, not only is it necessary for graphene to be evenly and stably dispersed in a solvent, but also strict standards are proposed for the solid content, conductivity and compatibility with other materials of its dispersion, and the dispersion prepared by the existing graphene dispersion technology often cannot reach an ideal state in these key performance indicators. Therefore, the present invention provides a solvent-based graphene dispersion and a preparation method thereof to solve the above-mentioned technical problems. Summary of the invention

[0004] In order to solve the limitations of existing graphene dispersions, the preparation method provided by the present invention achieves significant improvements in the high solid content, uniform dispersion, long-term stability, conductivity and material compatibility of the graphene dispersion.

[0005] The present invention provides a solvent-based graphene dispersion, which adopts the following technical solution:

[0006] A solvent-based graphene dispersion comprises the following raw materials in parts by weight: 7-10 parts of graphite, 1-3 parts of a graphene dispersant and 40-50 parts of ethanol.

[0007] Preferably, the preparation steps of the solvent-based graphene dispersion are:

[0008] S1. Preparation of epoxy hyperbranched polyester amine:

[0009] S11, drying the raw materials, dissolving dimethylolpropionic acid in N,N-dimethylformamide, adding p-toluenesulfonic acid, stirring at 110-120° C. for 4-6 hours, then dropping ethylenediamine solution, continuing the reaction for 6-8 hours, cooling to room temperature, and distilling under reduced pressure to obtain hyperbranched polyesteramine;

[0010] S12, under a nitrogen atmosphere, dissolving the hyperbranched polyester amine in tetrahydrofuran and adding sodium hydroxide, adding allyl alcohol glycidyl ether dropwise at 50-60° C., continuing the reaction for 4-6 hours, pouring the reaction system into water, washing and drying the precipitated product to obtain epoxy hyperbranched polyester amine;

[0011] S2. Preparation of graphene dispersant:

[0012] S21, drying perylene-3,4,9,10-tetracarboxylic dianhydride and dissolving it in N,N-dimethylformamide, adding triethylenetetramine dropwise at 45-50° C. under stirring, reacting for 3-6 hours, adding epoxy hyperbranched polyester amine and potassium carbonate, heating to 60-70° C. and reacting for 6-8 hours, cooling to room temperature, adjusting the pH with formic acid, and obtaining a graphene dispersant precursor;

[0013] S22, adding a reinforcing agent to the graphene dispersant precursor, stirring continuously at 50-60° C. for 2-3 hours, adding polyvinyl pyrrolidone, heating to 65-70° C. for continuous reaction for 4-6 hours, and distilling under reduced pressure to obtain a graphene dispersant;

[0014] S3. Preparation of solvent-based graphene dispersion:

[0015] Graphite and graphene dispersant are uniformly dispersed in ethanol, and a solvent-based graphene dispersion is obtained by liquid phase mechanical exfoliation.

[0016] Preferably, in step S11, the mass ratio of dimethylolpropionic acid, N,N-dimethylformamide, p-toluenesulfonic acid and ethylenediamine solution is 10-14:40-50:0.3-0.5:3-5.

[0017] Preferably, the mass fraction of the ethylenediamine solution in step S11 is 60-65%.

[0018] Preferably, in step S12, the mass ratio of the hyperbranched polyester amine, tetrahydrofuran, sodium hydroxide and allyl alcohol glycidyl ether is 10:50-60:0.1-0.4:1-3.

[0019] Preferably, in step S21, the mass ratio of perylene-3,4,9,10-tetracarboxylic dianhydride, N,N-dimethylformamide, triethylenetetramine, epoxy hyperbranched polyesteramine and potassium carbonate is 10:90-100:15-20:5-10:0.5-1.

[0020] Preferably, in step S21, formic acid is used to adjust the pH to 4-6.

[0021] Preferably, in step S22, the components by weight include 1-2 parts of a reinforcing agent, 5-7 parts of a graphene dispersant precursor, and 2-4 parts of polyvinyl pyrrolidone.

[0022] Preferably, the strengthening agent in step S22 is composed of diethylenetriaminepropylmethyldimethoxysilane and methoxypolyethylene glycolamine in a molar ratio of 1:1-3.

[0023] In summary, the present invention has the following beneficial effects:

[0024] 1. The present invention provides a method for preparing a solvent-based graphene dispersion: perylene-3,4,9,10-tetracarboxylic dianhydride is reacted with triethylenetetramine and prepared epoxy hyperbranched polyester amine in sequence, and a reinforcing agent is added to obtain a graphene dispersant, and then graphite and the dispersant are dispersed in ethanol, and a graphene dispersion is obtained by liquid phase mechanical exfoliation. The epoxy hyperbranched polyester amine provides abundant active sites and a three-dimensional spatial structure, which can enhance the adsorption capacity of graphene sheets, prevent agglomeration, lay the foundation for subsequent chemical bonding, and ensure high solid content and uniform dispersion of the dispersion. The graphene dispersant is made by reacting perylene-3,4,9,10-tetracarboxylic dianhydride, triethylenetetramine and epoxy hyperbranched polyester amine, and combined with a reinforcing agent and polyvinyl pyrrolidone. It has high molecular weight, good water solubility and graphene affinity, can improve the long-term stability and conductivity of the dispersion, maintain the original structure of graphene, and as a highly reactive site, it is beneficial for graphene to form stable chemical bonds with other materials, enhance the overall performance of the composite material, and broaden the application field.

[0025] 2. The epoxy hyperbranched polyester amine of the present invention is obtained by reacting dimethylol propionic acid with toluenesulfonic acid and ethylenediamine to obtain a hyperbranched polyester amine, and then reacting with allyl alcohol glycidyl ether. The epoxy hyperbranched polyester amine introduces a large number of hydroxyl, amino and epoxy groups. The hydroxyl and amino groups form physical adsorption forces such as hydrogen bonds with the functional groups on the surface of graphene, and take effect quickly under mild conditions, so that the epoxy hyperbranched polyester amine molecules approach and adhere to the graphene surface, overcoming the partial attraction between graphene sheets; the epoxy group has high reactivity and can react with the carboxyl and hydroxyl groups on the surface of graphene to form a covalent bond. The two work synergistically to continuously and efficiently maintain the dispersion of graphene sheets, avoid graphene agglomeration, and provide a solid guarantee for achieving high-quality dispersion of graphene in solvents.

[0026] 3. The graphene dispersant in the present invention is obtained by reacting perylene-3,4,9,10-tetracarboxylic dianhydride with triethylenetetramine and epoxy hyperbranched polyester amine, and then adding a reinforcing agent and polyvinyl pyrrolidone. The conjugated planar structure of perylene-3,4,9,10-tetracarboxylic dianhydride is bonded to the graphene surface through π-π, and its carboxyl group reacts with triethylenetetramine to form an intermediate containing multiple amide bonds, which then reacts with the epoxy group of the epoxy hyperbranched polyester amine to enhance the binding force between the dispersant and graphene, retain the graphene structure, maintain low resistivity, and be able to bond with other materials to broaden the scope of application. Diethylenetriaminepropylmethyldimethoxysilane in the reinforcing agent can enhance the interfacial bonding strength, and methoxypolyethylene glycol amine can improve the water solubility and lipophilicity of the dispersant, and the two synergistically improve the mechanical strength and stability of the dispersant. Polyvinyl pyrrolidone works together with other ingredients such as strengthening agents to further enhance the overall performance of the dispersion, provide a physical barrier, and enhance the strength and stability of the dispersant through chemical action. DETAILED DESCRIPTION

[0027] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] The experimental methods in the following examples are conventional methods unless otherwise specified, and the experimental materials used are purchased from conventional biochemical reagent stores unless otherwise specified. The quantitative tests in the following examples were repeated three times, and the data are the average or average ± standard deviation of the three repeated experiments.

[0029] Example 1

[0030] A method for preparing a solvent-based graphene dispersion comprises the following preparation steps:

[0031] S1. Preparation of epoxy hyperbranched polyester amine:

[0032] S11. Dry the raw materials, dissolve dimethylolpropionic acid in N,N-dimethylformamide, add p-toluenesulfonic acid, control the stirring rate to 400 rpm, stir at 110° C. for 6 h, then add dropwise a 60% mass fraction of ethylenediamine solution at a rate of 3 mL / min, continue the reaction for 8 h, then cool to room temperature, and distill under reduced pressure to obtain a hyperbranched polyesteramine, wherein the mass ratio of dimethylolpropionic acid, N,N-dimethylformamide, p-toluenesulfonic acid and ethylenediamine solution is 10:40:0.3:3.

[0033] S12, under a nitrogen atmosphere, dissolving a hyperbranched polyester amine in tetrahydrofuran and adding sodium hydroxide, controlling the stirring rate to 300 rpm, adding allyl alcohol glycidyl ether dropwise at a rate of 1.5 mL / min at 50 ° C, continuing the reaction for 4 hours, pouring the reaction system into water, washing and drying the precipitated product to obtain an epoxy hyperbranched polyester amine, wherein the mass ratio of the hyperbranched polyester amine, tetrahydrofuran, sodium hydroxide and allyl alcohol glycidyl ether is 10:50:0.1:1;

[0034] S2. Preparation of graphene dispersant:

[0035] S21, after drying perylene-3,4,9,10-tetracarboxylic dianhydride, dissolve it in N,N-dimethylformamide, control the stirring rate to 250rpm, add triethylenetetramine dropwise at 45°C within 6min under stirring, react for 6h, add epoxy hyperbranched polyester amine and potassium carbonate, heat to 60°C and react for 8h, cool to room temperature, adjust the pH to 4 with formic acid, and obtain a graphene dispersant precursor, wherein the mass ratio of perylene-3,4,9,10-tetracarboxylic dianhydride, N,N-dimethylformamide, triethylenetetramine, epoxy hyperbranched polyester amine and potassium carbonate is 10:90:15:5:0.5;

[0036] S22, by weight, adding 1 part of a reinforcing agent to 5 parts of a graphene dispersant precursor, controlling the stirring rate to 250 rpm, stirring continuously at 50° C. for 3 h, then adding 2 parts of polyvinyl pyrrolidone, raising the temperature to 65° C. and reacting continuously for 6 h, and distilling under reduced pressure to obtain a graphene dispersant, wherein the reinforcing agent is composed of diethylenetriaminepropylmethyldimethoxysilane and methoxypolyethylene glycolamine in a molar ratio of 1:1;

[0037] S3. Preparation of solvent-based graphene dispersion:

[0038] By weight, 7 parts of graphite and 1 part of graphene dispersant were uniformly dispersed in 40 parts of ethanol, first stirred at a rate of 800 rpm for 1 hour, and then sheared at a rate of 4000 rpm in a high-speed disperser for 50 minutes, and then the upper layer liquid was taken to obtain a solvent-based graphene dispersion.

[0039] Example 2

[0040] A method for preparing a solvent-based graphene dispersion comprises the following preparation steps:

[0041] S1. Preparation of epoxy hyperbranched polyester amine:

[0042] S11. Dry the raw materials, dissolve dimethylolpropionic acid in N,N-dimethylformamide, add p-toluenesulfonic acid, control the stirring rate to 420rpm, stir at 114°C for 5.5h, then add dropwise 62% ethylenediamine solution at a rate of 4mL / min, continue the reaction for 7.8h, then cool to room temperature, and distill under reduced pressure to obtain a hyperbranched polyesteramine, wherein the mass ratio of dimethylolpropionic acid, N,N-dimethylformamide, p-toluenesulfonic acid and ethylenediamine solution is 11:42:0.4:4.

[0043] S12, under a nitrogen atmosphere, dissolving a hyperbranched polyester amine in tetrahydrofuran and adding sodium hydroxide, controlling the stirring rate to 320 rpm, adding allyl alcohol glycidyl ether dropwise at a rate of 1.6 mL / min at 52 ° C, continuing the reaction for 5.8 h, pouring the reaction system into water, washing and drying the precipitated product to obtain an epoxy hyperbranched polyester amine, wherein the mass ratio of the hyperbranched polyester amine, tetrahydrofuran, sodium hydroxide and allyl alcohol glycidyl ether is 10:52:0.3:2;

[0044] S2. Preparation of graphene dispersant:

[0045] S21, after drying perylene-3,4,9,10-tetracarboxylic dianhydride, dissolve it in N,N-dimethylformamide, control the stirring rate to 260rpm, add triethylenetetramine dropwise at 47°C within 7min under stirring, react for 5.8h, add epoxy hyperbranched polyester amine and potassium carbonate, heat to 62°C and react for 7.8h, cool to room temperature, adjust the pH to 5 with formic acid, and obtain a graphene dispersant precursor, wherein the mass ratio of perylene-3,4,9,10-tetracarboxylic dianhydride, N,N-dimethylformamide, triethylenetetramine, epoxy hyperbranched polyester amine and potassium carbonate is 10:94:16:7:0.6;

[0046] S22, by weight, adding 2 parts of a reinforcing agent to 6 parts of a graphene dispersant precursor, controlling the stirring rate to 270 rpm, stirring continuously at 52° C. for 2.8 h, then adding 3 parts of polyvinyl pyrrolidone, raising the temperature to 67° C. and reacting continuously for 5.8 h, and distilling under reduced pressure to obtain a graphene dispersant, wherein the reinforcing agent is composed of diethylenetriaminepropylmethyldimethoxysilane and methoxypolyethylene glycolamine in a molar ratio of 1:2;

[0047] S3. Preparation of solvent-based graphene dispersion:

[0048] By weight, 8 parts of graphite and 2 parts of graphene dispersant were uniformly dispersed in 42 parts of ethanol, first stirred at a rate of 900 rpm for 0.6 h, and then sheared at a rate of 5000 rpm in a high-speed disperser for 45 min, and then the upper layer liquid was taken to obtain a solvent-based graphene dispersion.

[0049] Example 3

[0050] A method for preparing a solvent-based graphene dispersion comprises the following preparation steps:

[0051] S1. Preparation of epoxy hyperbranched polyester amine:

[0052] S11. Dry the raw materials, dissolve dimethylolpropionic acid in N,N-dimethylformamide, add p-toluenesulfonic acid, control the stirring rate to 500 rpm, stir at 120° C. for 4 h, then add dropwise a 65% mass fraction ethylenediamine solution at a rate of 6 mL / min, continue the reaction for 6 h, then cool to room temperature, and distill under reduced pressure to obtain a hyperbranched polyesteramine, wherein the mass ratio of dimethylolpropionic acid, N,N-dimethylformamide, p-toluenesulfonic acid and ethylenediamine solution is 14:50:0.5:5.

[0053] S12, under a nitrogen atmosphere, dissolving a hyperbranched polyester amine in tetrahydrofuran and adding sodium hydroxide, controlling the stirring rate to 400 rpm, adding allyl alcohol glycidyl ether dropwise at a rate of 3 mL / min at 60 ° C, continuing the reaction for 4 hours, pouring the reaction system into water, washing and drying the precipitated product to obtain an epoxy hyperbranched polyester amine, wherein the mass ratio of the hyperbranched polyester amine, tetrahydrofuran, sodium hydroxide and allyl alcohol glycidyl ether is 10:60:0.4:3;

[0054] S2. Preparation of graphene dispersant:

[0055] S21, after drying perylene-3,4,9,10-tetracarboxylic dianhydride, dissolve it in N,N-dimethylformamide, control the stirring rate to 350rpm, add triethylenetetramine dropwise at 50°C within 10min under stirring, react for 3h, add epoxy hyperbranched polyester amine and potassium carbonate, heat to 70°C and react for 6h, cool to room temperature, adjust the pH to 6 with formic acid, and obtain a graphene dispersant precursor, wherein the mass ratio of perylene-3,4,9,10-tetracarboxylic dianhydride, N,N-dimethylformamide, triethylenetetramine, epoxy hyperbranched polyester amine and potassium carbonate is 10:100:20:10:1;

[0056] S22, by weight, adding 2 parts of a reinforcing agent to 7 parts of a graphene dispersant precursor, controlling the stirring rate to 350 rpm, stirring continuously at 60° C. for 2 h, then adding 4 parts of polyvinyl pyrrolidone, heating to 70° C. and reacting continuously for 4 h, and distilling under reduced pressure to obtain a graphene dispersant, wherein the reinforcing agent is composed of diethylenetriaminepropylmethyldimethoxysilane and methoxypolyethylene glycolamine in a molar ratio of 1:3;

[0057] S3. Preparation of solvent-based graphene dispersion:

[0058] By weight, 10 parts of graphite and 3 parts of graphene dispersant were uniformly dispersed in 50 parts of ethanol, first stirred at a rate of 1000 rpm for 0.5 h, and then sheared at a rate of 7000 rpm in a high-speed disperser for 30 min, and then the upper layer liquid was taken to obtain a solvent-based graphene dispersion.

[0059] Example 4

[0060] A method for preparing a solvent-based graphene dispersion comprises the following preparation steps:

[0061] S1. Preparation of epoxy hyperbranched polyester amine:

[0062] S11, drying the raw materials, dissolving dimethylolpropionic acid in N,N-dimethylformamide, adding p-toluenesulfonic acid, controlling the stirring rate to 500 rpm, stirring at 120° C. for 4.5 h, then dropping a 64% mass fraction ethylenediamine solution at a rate of 5 mL / min, continuing the reaction for 7 h, then cooling to room temperature, and distilling under reduced pressure to obtain a hyperbranched polyesteramine, wherein the mass ratio of dimethylolpropionic acid, N,N-dimethylformamide, p-toluenesulfonic acid and ethylenediamine solution is 14:48:0.5:4.

[0063] S12, under a nitrogen atmosphere, dissolving a hyperbranched polyester amine in tetrahydrofuran and adding sodium hydroxide, controlling the stirring rate to 400 rpm, adding allyl alcohol glycidyl ether dropwise at a rate of 2 mL / min at 60 ° C, continuing the reaction for 4 hours, pouring the reaction system into water, washing and drying the precipitated product to obtain an epoxy hyperbranched polyester amine, wherein the mass ratio of the hyperbranched polyester amine, tetrahydrofuran, sodium hydroxide and allyl alcohol glycidyl ether is 10:58:0.4:3;

[0064] S2. Preparation of graphene dispersant:

[0065] S21, after drying perylene-3,4,9,10-tetracarboxylic dianhydride, dissolve it in N,N-dimethylformamide, control the stirring rate to 350rpm, add triethylenetetramine dropwise at 50°C within 10min under stirring, react for 3h, add epoxy hyperbranched polyester amine and potassium carbonate, heat to 70°C and react for 6h, cool to room temperature, adjust the pH to 6 with formic acid, and obtain a graphene dispersant precursor, wherein the mass ratio of perylene-3,4,9,10-tetracarboxylic dianhydride, N,N-dimethylformamide, triethylenetetramine, epoxy hyperbranched polyester amine and potassium carbonate is 10:100:20:10:0.8;

[0066] S22, by weight, adding 2 parts of a reinforcing agent to 6 parts of a graphene dispersant precursor, controlling the stirring rate to 350 rpm, stirring continuously at 60° C. for 2 h, then adding 4 parts of polyvinyl pyrrolidone, heating to 70° C. and reacting continuously for 4 h, and distilling under reduced pressure to obtain a graphene dispersant, wherein the reinforcing agent is composed of diethylenetriaminepropylmethyldimethoxysilane and methoxypolyethylene glycolamine in a molar ratio of 1:3;

[0067] S3. Preparation of solvent-based graphene dispersion:

[0068] By weight, 10 parts of graphite and 3 parts of graphene dispersant were uniformly dispersed in 48 parts of ethanol, first stirred at a rate of 1000 rpm for 0.5 h, and then sheared at a rate of 7000 rpm in a high-speed disperser for 35 min, and then the upper layer liquid was taken to obtain a solvent-based graphene dispersion.

[0069] Comparative Example 1

[0070] A method for preparing a solvent-based graphene dispersion comprises the following preparation steps:

[0071] S1. Preparation of hyperbranched polyester amine:

[0072] The raw materials were dried, dimethylolpropionic acid was dissolved in N,N-dimethylformamide, p-toluenesulfonic acid was added, the stirring rate was controlled to 500 rpm, and the mixture was stirred at 120° C. for 4.5 h. Then, a 64% mass fraction ethylenediamine solution was added dropwise at a rate of 5 mL / min, and the mixture was cooled to room temperature after continuing the reaction for 7 h. The hyperbranched polyester amine was obtained by distillation under reduced pressure, wherein the mass ratio of dimethylolpropionic acid, N,N-dimethylformamide, p-toluenesulfonic acid and ethylenediamine solution was 14:48:0.5:4.

[0073] S2. Preparation of graphene dispersant:

[0074] S21, after drying perylene-3,4,9,10-tetracarboxylic dianhydride, dissolve it in N,N-dimethylformamide, control the stirring rate to 350rpm, add triethylenetetramine dropwise at 50°C within 10min under stirring, react for 3h, add hyperbranched polyesteramine and potassium carbonate, heat to 70°C and react for 6h, cool to room temperature, adjust the pH to 6 with formic acid, and obtain a graphene dispersant precursor, wherein the mass ratio of perylene-3,4,9,10-tetracarboxylic dianhydride, N,N-dimethylformamide, triethylenetetramine, hyperbranched polyesteramine and potassium carbonate is 10:100:20:10:0.8;

[0075] S22, by weight, adding 2 parts of a reinforcing agent to 6 parts of a graphene dispersant precursor, controlling the stirring rate to 350 rpm, stirring continuously at 60° C. for 2 h, then adding 4 parts of polyvinyl pyrrolidone, heating to 70° C. and reacting continuously for 4 h, and distilling under reduced pressure to obtain a graphene dispersant, wherein the reinforcing agent is composed of diethylenetriaminepropylmethyldimethoxysilane and methoxypolyethylene glycolamine in a molar ratio of 1:3;

[0076] S3. Preparation of solvent-based graphene dispersion:

[0077] By weight, 10 parts of graphite and 3 parts of graphene dispersant were uniformly dispersed in 48 parts of ethanol, first stirred at a rate of 1000 rpm for 0.5 h, and then sheared at a rate of 7000 rpm in a high-speed disperser for 35 min, and then the upper layer liquid was taken to obtain a solvent-based graphene dispersion.

[0078] Comparative Example 2

[0079] A method for preparing a solvent-based graphene dispersion comprises the following preparation steps:

[0080] S1. Preparation of graphene dispersant:

[0081] S11, after drying perylene-3,4,9,10-tetracarboxylic dianhydride, dissolving it in N,N-dimethylformamide, controlling the stirring rate to 350 rpm, adding triethylenetetramine dropwise at 50° C. within 10 min under stirring, reacting for 3 h and then cooling to room temperature, adjusting the pH to 6 with formic acid, to obtain a graphene dispersant precursor, wherein the mass ratio of perylene-3,4,9,10-tetracarboxylic dianhydride, N,N-dimethylformamide and triethylenetetramine is 10:100:20:;

[0082] S12, S22, by weight, adding 2 parts of a reinforcing agent to 6 parts of a graphene dispersant precursor, controlling the stirring rate to 350 rpm, stirring continuously at 60° C. for 2 hours, then adding 4 parts of polyvinyl pyrrolidone, heating to 70° C. and reacting continuously for 4 hours, and distilling under reduced pressure to obtain a graphene dispersant, wherein the reinforcing agent is composed of diethylenetriaminepropylmethyldimethoxysilane and methoxypolyethylene glycolamine in a molar ratio of 1:3;

[0083] S2. Preparation of solvent-based graphene dispersion:

[0084] By weight, 10 parts of graphite and 3 parts of graphene dispersant were uniformly dispersed in 48 parts of ethanol, first stirred at a rate of 1000 rpm for 0.5 h, and then sheared at a rate of 7000 rpm in a high-speed disperser for 35 min, and then the upper layer liquid was taken to obtain a solvent-based graphene dispersion.

[0085] Comparative Example 3

[0086] A method for preparing a solvent-based graphene dispersion comprises the following preparation steps:

[0087] S1. Preparation of epoxy hyperbranched polyester amine:

[0088] S11, drying the raw materials, dissolving dimethylolpropionic acid in N,N-dimethylformamide, adding p-toluenesulfonic acid, controlling the stirring rate to 500 rpm, stirring at 120° C. for 4.5 h, then dropping a 64% mass fraction ethylenediamine solution at a rate of 5 mL / min, continuing the reaction for 7 h, then cooling to room temperature, and distilling under reduced pressure to obtain a hyperbranched polyesteramine, wherein the mass ratio of dimethylolpropionic acid, N,N-dimethylformamide, p-toluenesulfonic acid and ethylenediamine solution is 14:48:0.5:4.

[0089] S12, under a nitrogen atmosphere, dissolving a hyperbranched polyester amine in tetrahydrofuran and adding sodium hydroxide, controlling the stirring rate to 400 rpm, adding allyl alcohol glycidyl ether dropwise at a rate of 2 mL / min at 60 ° C, continuing the reaction for 4 hours, pouring the reaction system into water, washing and drying the precipitated product to obtain an epoxy hyperbranched polyester amine, wherein the mass ratio of the hyperbranched polyester amine, tetrahydrofuran, sodium hydroxide and allyl alcohol glycidyl ether is 10:58:0.4:3;

[0090] S2. Preparation of graphene dispersant:

[0091] S21, after drying perylene-3,4,9,10-tetracarboxylic dianhydride, dissolve it in N,N-dimethylformamide, control the stirring rate to 350rpm, add triethylenetetramine dropwise at 50°C within 10min under stirring, react for 3h, add epoxy hyperbranched polyester amine and potassium carbonate, heat to 70°C and react for 6h, cool to room temperature, adjust the pH to 6 with formic acid, and obtain a graphene dispersant precursor, wherein the mass ratio of perylene-3,4,9,10-tetracarboxylic dianhydride, N,N-dimethylformamide, triethylenetetramine, epoxy hyperbranched polyester amine and potassium carbonate is 10:100:20:10:0.8;

[0092] S22, by weight, adding 2 parts of diethylenetriaminepropylmethyldimethoxysilane to 6 parts of graphene dispersant precursor, controlling the stirring rate to 350 rpm, stirring continuously at 60° C. for 2 h, then adding 4 parts of polyvinylpyrrolidone, heating to 70° C. and reacting continuously for 4 h, and distilling under reduced pressure to obtain a graphene dispersant;

[0093] S3. Preparation of solvent-based graphene dispersion:

[0094] By weight, 10 parts of graphite and 3 parts of graphene dispersant were uniformly dispersed in 48 parts of ethanol, first stirred at a rate of 1000 rpm for 0.5 h, and then sheared at a rate of 7000 rpm in a high-speed disperser for 35 min, and then the upper layer liquid was taken to obtain a solvent-based graphene dispersion.

[0095] Comparative Example 4

[0096] A method for preparing a solvent-based graphene dispersion comprises the following preparation steps:

[0097] S1. Preparation of epoxy hyperbranched polyester amine:

[0098] S11, drying the raw materials, dissolving dimethylolpropionic acid in N,N-dimethylformamide, adding p-toluenesulfonic acid, controlling the stirring rate to 500 rpm, stirring at 120° C. for 4.5 h, then dropping a 64% mass fraction ethylenediamine solution at a rate of 5 mL / min, continuing the reaction for 7 h, then cooling to room temperature, and distilling under reduced pressure to obtain a hyperbranched polyesteramine, wherein the mass ratio of dimethylolpropionic acid, N,N-dimethylformamide, p-toluenesulfonic acid and ethylenediamine solution is 14:48:0.5:4.

[0099] S12, under a nitrogen atmosphere, dissolving a hyperbranched polyester amine in tetrahydrofuran and adding sodium hydroxide, controlling the stirring rate to 400 rpm, adding allyl alcohol glycidyl ether dropwise at a rate of 2 mL / min at 60 ° C, continuing the reaction for 4 hours, pouring the reaction system into water, washing and drying the precipitated product to obtain an epoxy hyperbranched polyester amine, wherein the mass ratio of the hyperbranched polyester amine, tetrahydrofuran, sodium hydroxide and allyl alcohol glycidyl ether is 10:58:0.4:3;

[0100] S2. Preparation of graphene dispersant:

[0101] S21, after drying perylene-3,4,9,10-tetracarboxylic dianhydride, dissolve it in N,N-dimethylformamide, control the stirring rate to 350rpm, add triethylenetetramine dropwise at 50°C within 10min under stirring, react for 3h, add epoxy hyperbranched polyester amine and potassium carbonate, heat to 70°C and react for 6h, cool to room temperature, adjust the pH to 6 with formic acid, and obtain a graphene dispersant precursor, wherein the mass ratio of perylene-3,4,9,10-tetracarboxylic dianhydride, N,N-dimethylformamide, triethylenetetramine, epoxy hyperbranched polyester amine and potassium carbonate is 10:100:20:10:0.8;

[0102] S22, by weight, adding 2 parts of methoxypolyethylene glycol amine to 6 parts of graphene dispersant precursor, controlling the stirring rate to 350 rpm, stirring continuously at 60° C. for 2 h, then adding 4 parts of polyvinyl pyrrolidone, heating to 70° C. and reacting continuously for 4 h, and distilling under reduced pressure to obtain a graphene dispersant;

[0103] S3. Preparation of solvent-based graphene dispersion:

[0104] By weight, 10 parts of graphite and 3 parts of graphene dispersant were uniformly dispersed in 48 parts of ethanol, first stirred at a rate of 1000 rpm for 0.5 h, and then sheared at a rate of 7000 rpm in a high-speed disperser for 35 min, and then the upper layer liquid was taken to obtain a solvent-based graphene dispersion.

[0105] Comparative Example 5

[0106] A method for preparing a solvent-based graphene dispersion comprises the following preparation steps:

[0107] S1. Preparation of epoxy hyperbranched polyester amine:

[0108] S11, drying the raw materials, dissolving dimethylolpropionic acid in N,N-dimethylformamide, adding p-toluenesulfonic acid, controlling the stirring rate to 500 rpm, stirring at 120° C. for 4.5 h, then dropping a 64% mass fraction ethylenediamine solution at a rate of 5 mL / min, continuing the reaction for 7 h, then cooling to room temperature, and distilling under reduced pressure to obtain a hyperbranched polyesteramine, wherein the mass ratio of dimethylolpropionic acid, N,N-dimethylformamide, p-toluenesulfonic acid and ethylenediamine solution is 14:48:0.5:4.

[0109] S12, under a nitrogen atmosphere, dissolving a hyperbranched polyester amine in tetrahydrofuran and adding sodium hydroxide, controlling the stirring rate to 400 rpm, adding allyl alcohol glycidyl ether dropwise at a rate of 2 mL / min at 60 ° C, continuing the reaction for 4 hours, pouring the reaction system into water, washing and drying the precipitated product to obtain an epoxy hyperbranched polyester amine, wherein the mass ratio of the hyperbranched polyester amine, tetrahydrofuran, sodium hydroxide and allyl alcohol glycidyl ether is 10:58:0.4:3;

[0110] S2. Preparation of graphene dispersant:

[0111] S21, after drying perylene-3,4,9,10-tetracarboxylic dianhydride, dissolve it in N,N-dimethylformamide, control the stirring rate to 350rpm, add triethylenetetramine dropwise at 50°C within 10min under stirring, react for 3h, add epoxy hyperbranched polyester amine and potassium carbonate, heat to 70°C and react for 6h, cool to room temperature, adjust the pH to 6 with formic acid, and obtain a graphene dispersant precursor, wherein the mass ratio of perylene-3,4,9,10-tetracarboxylic dianhydride, N,N-dimethylformamide, triethylenetetramine, epoxy hyperbranched polyester amine and potassium carbonate is 10:100:20:10:0.8;

[0112] S22, adding 2 parts of a reinforcing agent to 6 parts of a graphene dispersant precursor by weight, controlling the stirring rate to 350 rpm, stirring continuously for 2 hours at 60° C., and then distilling under reduced pressure to obtain a graphene dispersant, wherein the reinforcing agent is composed of diethylenetriaminepropylmethyldimethoxysilane and methoxypolyethylene glycolamine in a molar ratio of 1:3;

[0113] S3. Preparation of solvent-based graphene dispersion:

[0114] By weight, 10 parts of graphite and 3 parts of graphene dispersant were uniformly dispersed in 48 parts of ethanol, first stirred at a rate of 1000 rpm for 0.5 h, and then sheared at a rate of 7000 rpm in a high-speed disperser for 35 min, and then the upper layer liquid was taken to obtain a solvent-based graphene dispersion.

[0115] Comparative Example 6

[0116] A method for preparing a solvent-based graphene dispersion comprises the following preparation steps:

[0117] S1. Preparation of epoxy hyperbranched polyester amine:

[0118] S11, drying the raw materials, dissolving dimethylolpropionic acid in N,N-dimethylformamide, adding p-toluenesulfonic acid, controlling the stirring rate to 500 rpm, stirring at 120° C. for 4.5 h, then dropping a 64% mass fraction ethylenediamine solution at a rate of 5 mL / min, continuing the reaction for 7 h, then cooling to room temperature, and distilling under reduced pressure to obtain a hyperbranched polyesteramine, wherein the mass ratio of dimethylolpropionic acid, N,N-dimethylformamide, p-toluenesulfonic acid and ethylenediamine solution is 14:48:0.5:4.

[0119] S12, under a nitrogen atmosphere, dissolving a hyperbranched polyester amine in tetrahydrofuran and adding sodium hydroxide, controlling the stirring rate to 400 rpm, adding allyl alcohol glycidyl ether dropwise at a rate of 2 mL / min at 60 ° C, continuing the reaction for 4 hours, pouring the reaction system into water, washing and drying the precipitated product to obtain an epoxy hyperbranched polyester amine, wherein the mass ratio of the hyperbranched polyester amine, tetrahydrofuran, sodium hydroxide and allyl alcohol glycidyl ether is 10:58:0.4:3;

[0120] S2. Preparation of graphene dispersant:

[0121] After drying perylene-3,4,9,10-tetracarboxylic dianhydride, dissolve it in N,N-dimethylformamide, control the stirring rate to 350 rpm, add triethylenetetramine dropwise at 50° C. within 10 min under stirring, react for 3 h, add epoxy hyperbranched polyester amine and potassium carbonate, heat to 70° C. and react for 6 h, cool to room temperature, adjust the pH to 6 with formic acid, and obtain a graphene dispersant, wherein the mass ratio of perylene-3,4,9,10-tetracarboxylic dianhydride, N,N-dimethylformamide, triethylenetetramine, epoxy hyperbranched polyester amine and potassium carbonate is 10:100:20:10:0.8;

[0122] S3. Preparation of solvent-based graphene dispersion:

[0123] By weight, 10 parts of graphite and 3 parts of graphene dispersant were uniformly dispersed in 48 parts of ethanol, first stirred at a rate of 1000 rpm for 0.5 h, and then sheared at a rate of 7000 rpm in a high-speed disperser for 35 min, and then the upper layer liquid was taken to obtain a solvent-based graphene dispersion.

[0124] Performance Testing

[0125] The paint films formed by the ship anticorrosion coatings prepared in Examples 1-4 and Comparative Examples 1-6 were subjected to performance tests:

[0126] 1. Stability test: The solvent-based graphene dispersions obtained in Examples 1-4 and Comparative Examples 1-6 were allowed to stand for one week, and then centrifuged at 7000 r / min for 10 min. The state of the dispersions after centrifugation was observed. The test results are shown in Table 1.

[0127] 2. Solid content test: Weigh an empty watch glass, record the weight as m1, apply the solvent-based graphene dispersion on the surface of the watch glass, weigh it, record the weight as m2, put the watch glass coated with the solvent-based graphene dispersion into a 140°C oven, bake for 0.5h, cool to room temperature and weigh it again, record the weight as m3, then the solid content = (m3-m1) / (m2-m1)×100%. The test results are shown in Table 1.

[0128] 3. Viscosity test: Mechanically stir at 800 rpm for 3 minutes, insert the 4# rotor of the rotational viscometer into the solvent-based graphene at room temperature, and test at 12 rpm. Read the numbers on the viscometer after they stabilize. The test results are shown in Table 1.

[0129] 4. Resistivity test: The solvent-based graphene dispersion prepared in Examples 1-4 and Comparative Examples 1-6 was coated on the PI film using a 200 μm coating scraper, dried at 140°C for 1 h, and then tested using a four-probe tester model RTS-8. Five points were taken symmetrically, and the average resistivity measured at the five points was the obtained value. The test results are shown in Table 1.

[0130] Table 1

[0131]

[0132]

[0133] From the results shown in Table 1 above, it can be seen that the comprehensive performance of the solvent-based graphene dispersions prepared in Examples 1-4 of the present invention is far better than that of Comparative Examples 1-6.

[0134] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A solvent-based graphene dispersion, characterized in that: The invention comprises the following raw materials in parts by weight: 7-10 parts of graphite, 1-3 parts of graphene dispersant and 40-50 parts of ethanol.

2. A method for preparing a solvent-based graphene dispersion, for preparing the solvent-based graphene dispersion according to claim 1, characterized in that: The preparation method comprises the following steps: S1. Preparation of epoxy hyperbranched polyester amine: S11, drying the raw materials, dissolving dimethylolpropionic acid in N,N-dimethylformamide, adding p-toluenesulfonic acid, stirring at 110-120° C. for 4-6 hours, then dropping ethylenediamine solution, continuing the reaction for 6-8 hours, cooling to room temperature, and distilling under reduced pressure to obtain hyperbranched polyesteramine; S12, under a nitrogen atmosphere, dissolving the hyperbranched polyester amine in tetrahydrofuran and adding sodium hydroxide, adding allyl alcohol glycidyl ether dropwise at 50-60° C., continuing the reaction for 4-6 hours, pouring the reaction system into water, washing and drying the precipitated product to obtain epoxy hyperbranched polyester amine; S2. Preparation of graphene dispersant: S21, drying perylene-3,4,9,10-tetracarboxylic dianhydride and dissolving it in N,N-dimethylformamide, adding triethylenetetramine dropwise at 45-50° C. under stirring, reacting for 3-6 hours, adding epoxy hyperbranched polyester amine and potassium carbonate, heating to 60-70° C. and reacting for 6-8 hours, cooling to room temperature, adjusting the pH with formic acid, and obtaining a graphene dispersant precursor; S22, adding a reinforcing agent to the graphene dispersant precursor, stirring continuously at 50-60° C. for 2-3 hours, adding polyvinyl pyrrolidone, heating to 65-70° C. for continuous reaction for 4-6 hours, and distilling under reduced pressure to obtain a graphene dispersant; S3. Preparation of solvent-based graphene dispersion: Graphite and graphene dispersant are uniformly dispersed in ethanol, and a solvent-based graphene dispersion is obtained by liquid phase mechanical exfoliation.

3. The method for preparing a solvent-based graphene dispersion according to claim 2, wherein: In the step S11, the mass ratio of dimethylolpropionic acid, N,N-dimethylformamide, p-toluenesulfonic acid and ethylenediamine solution is 10-14:40-50:0.3-0.5:3-5.

4. The method for preparing a solvent-based graphene dispersion according to claim 2, wherein: The mass fraction of the ethylenediamine solution in step S11 is 60-65%.

5. The method for preparing a solvent-based graphene dispersion according to claim 2, wherein: In the step S12, the mass ratio of the hyperbranched polyester amine, tetrahydrofuran, sodium hydroxide and allyl alcohol glycidyl ether is 10:50-60:0.1-0.4:1-3.

6. The method for preparing a solvent-based graphene dispersion according to claim 2, characterized in that: In the step S21, the mass ratio of perylene-3,4,9,10-tetracarboxylic dianhydride, N,N-dimethylformamide, triethylenetetramine, epoxy hyperbranched polyester amine and potassium carbonate is 10:90-100:15-20:5-10:0.5-1.

7. The method for preparing a solvent-based graphene dispersion according to claim 2, characterized in that: In the step S21, formic acid is used to adjust the pH to 4-6.

8. The method for preparing a solvent-based graphene dispersion according to claim 2, characterized in that: In the step S22, the components by weight include 1-2 parts of a reinforcing agent, 5-7 parts of a graphene dispersant precursor, and 2-4 parts of polyvinyl pyrrolidone.

9. The method for preparing a solvent-based graphene dispersion according to claim 2, characterized in that: In the step S22, the strengthening agent is composed of diethylenetriaminepropylmethyldimethoxysilane and methoxypolyethylene glycolamine in a molar ratio of 1:1-3.

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