High-concentration water-based graphene dispersing agent

Abstract

The invention relates to the technical field of dispersing agents, and particularly discloses a high-concentration water-based graphene dispersing agent. The high-concentration water-based graphene dispersing agent is prepared from the following raw materials in parts by weight: 25 to 30 parts of a modified nonionic surfactant, 8 to 12 parts of sodium lignin sulfonate, 0.4 to 0.8 part of a de-foaming agent and 90 to 100 parts of de-ionized water, the modified nonionic surfactant is prepared by the following steps: carrying out dehydration esterification reaction on 1-pyrene butyric acid and N-hydroxysuccinimide, carrying out nucleophilic substitution reaction on the obtained product and polyethylene glycol monododecyl ether to obtain modified 1-pyrene butyric acid, and finally polymerizing the modified 1-pyrene butyric acid and n-butyl acrylate. The method is easy to operate, graphene does not need to be subjected to oxidation reduction, the integrity of a graphene sheet layer can be completely kept, and the performance of the graphene can be fully exerted; the prepared graphene dispersing agent realizes efficient dispersing effect, excellent stability and environment-friendly safety characteristics, and provides solid technical support for wide application of graphene in multiple fields.

Description

Technical Field

[0001] The present invention relates to the technical field of dispersants, and more specifically, to a high-concentration aqueous graphene dispersant. Background Art

[0002] As a two-dimensional nanomaterial, graphene has great application potential in electronic devices, composite materials, energy storage and other fields due to its excellent mechanical strength, excellent electrical and thermal conductivity, and large specific surface area. Its unique physical and chemical properties make it an ideal material for many high-tech fields. However, the strong π-π interaction and van der Waals force between graphene sheets make them very easy to agglomerate in solvents, making it difficult to form a stable and uniform dispersion system. This agglomeration phenomenon seriously limits the full play of graphene's excellent performance and hinders its large-scale industrial application. In order to solve this problem, researchers have developed a variety of dispersants to improve the dispersibility of graphene. These dispersants can be roughly divided into two categories: organic solvent type and water-based dispersants according to their medium environment.

[0003] Although organic solvent-based dispersants can effectively improve the dispersion effect of graphene in non-polar or weakly polar systems, they are usually accompanied by high costs, poor biocompatibility and environmental unfriendliness. In contrast, water-soluble dispersants have received more attention due to their environmental protection, low cost and good compatibility with biological systems. Most of the existing water-soluble dispersants use surfactants to achieve stable dispersion of graphene. Traditional surfactants often require a large amount when dispersing graphene, and the prepared graphene concentration is low, which is not conducive to the construction of composite materials. At the same time, it will also cause the dispersion stability to decrease due to changes in pH or the presence of electrolytes. In addition, some dispersants need to modify graphene through complex chemical treatments such as redox reactions. This process may damage the original structural integrity of graphene, thereby affecting its inherent electrical and mechanical properties. Therefore, the present invention proposes a high-concentration aqueous graphene dispersant to solve the above-mentioned technical problems. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a high-concentration aqueous graphene dispersant with efficient dispersion effect, excellent stability and environmental protection and safety characteristics; at the same time, the present invention is simple to operate, does not require oxidation and reduction of graphene, can completely maintain the integrity of graphene sheets, and can give full play to the performance of graphene.

[0005] The present invention provides a high-concentration aqueous graphene dispersant, which adopts the following technical solution:

[0006] A high-concentration aqueous graphene dispersant comprises the following raw materials in parts by weight: 25-30 parts of a modified nonionic surfactant, 8-12 parts of sodium lignin sulfonate, 0.4-0.8 parts of a defoaming agent and 90-100 parts of deionized water.

[0007] Preferably, the modified nonionic surfactant is prepared by the following preparation steps:

[0008] S1. Dissolve 1-pyrenebutyric acid, N-hydroxysuccinimide, a catalyst and N,N'-dicyclohexylcarbodiimide in dichloromethane, stir continuously for 10-14 hours at 20-25°C, wash with water, separate the organic phase, dry, filter and distill under reduced pressure to obtain an active ester derivative;

[0009] S2, dissolving the active ester derivative in tetrahydrofuran, adding polyethylene glycol monododecyl ether, stirring continuously at 45-55° C. for 20-24 hours under nitrogen protection, washing, and distilling under reduced pressure to obtain modified 1-pyrenebutyric acid;

[0010] S3. Dissolve the modified 1-pyrenebutyric acid in toluene, add n-butyl acrylate and benzoyl peroxide, and under nitrogen protection, continue stirring at 60-80° C. for 4-6 hours, then wash with water, separate the organic phase, dry, filter and distill under reduced pressure to obtain a modified nonionic surfactant.

[0011] Preferably, the catalyst in step S1 is at least one of 4-dimethylaminopyridine, N,N-diisopropylethylamine and triethylamine.

[0012] Preferably, in step S2, the mass ratio of the active ester derivative, tetrahydrofuran and polyethylene glycol monododecyl ether is 1:6-10:2-4.

[0013] Preferably, the defoaming agent is at least one of polyoxypropylene glyceryl ether, polydimethylsiloxane and gelatin.

[0014] Preferably, in step S3, the mass ratio of modified 1-pyrenebutyric acid, toluene, n-butyl acrylate and benzoyl peroxide is 1:5-10:1-3:0.05-0.08.

[0015] Preferably, the high concentration graphene aqueous dispersant is prepared by the following method:

[0016] Dissolve the modified nonionic surfactant, sodium lignin sulfonate and defoamer in deionized water and stir continuously for 10-15 minutes at room temperature.

[0017] In summary, the present invention has the following beneficial effects:

[0018] The water-based graphene dispersant of the present invention is prepared with modified nonionic surfactant, sodium lignin sulfonate, defoamer and deionized water as raw materials. The modified nonionic surfactant is prepared by dehydration esterification reaction of 1-pyrenebutyric acid and N-hydroxysuccinimide, the obtained product is subjected to nucleophilic substitution reaction with polyethylene glycol monododecyl ether to obtain modified 1-pyrenebutyric acid, and finally polymerized with n-butyl acrylate to obtain the modified 1-pyrenebutyric acid.

[0019] The pyrene ring of 1-pyrenebutyric acid is tightly attached to the graphene carbon plane by virtue of the π-π conjugation effect. This strong specific adsorption not only effectively maintains the integrity of the graphene sheet, but also makes the surfactant molecule have fluorescent properties, which is convenient for monitoring the dispersion. The active ester derivative formed by its reaction with N-hydroxysuccinimide creates conditions for the introduction of subsequent groups. Polyethylene glycol monododecyl ether stretches in the aqueous system by virtue of the hydrophilicity and flexibility of the long chain structure and ether bond, exerting steric hindrance and solubilization efficiency, effectively preventing graphene agglomeration. The reaction with n-butyl acrylate further strengthens the steric hindrance of the molecule and the action site with graphene, improving the adsorption effect and thus achieving efficient dispersion.

[0020] Sodium lignin sulfonate has certain dispersing and adsorption capabilities, and cooperates with modified non-ionic surfactants to significantly enhance the overall dispersibility and stability. The addition of defoaming agent can reduce the bubbles generated by stirring during dispersion, avoid the adverse effects of bubbles on graphene dispersion, and ensure uniform and stable dispersion. Deionized water is used as a solvent to provide a stable aqueous environment for graphene dispersion, eliminate the interference of impurity ions, and ensure the performance of the dispersion system. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. 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.

[0022] Unless otherwise specified, the materials, reagents, etc. used in the examples and comparative examples of the present invention can be obtained from commercial sources.

[0023] Sodium lignin sulfonate, brand Nengju Chemical, CAS No. 8061-51-6, was purchased from Shandong Nengju Chemical Co., Ltd.

[0024] Polyethylene glycol monododecyl ether, brand name Perfemiker, CAS number 9002-92-0, was purchased from Shanghai Chuangsai Technology Co., Ltd.

[0025] Polyoxypropylene glycerol ether, brand name Xinghengye, CAS number 25791-96-2, was purchased from Hubei Xinghengye Technology Co., Ltd.

[0026] Polydimethylsiloxane, brand Yingyu, model 201, purchased from Jinan Yingyu Chemical Co., Ltd. Gelatin, brand Huace, CAS number 9000-70-8, purchased from Jiangsu Huace Biotechnology Co., Ltd.

[0027] Example 1

[0028] A high-concentration aqueous graphene dispersant is composed of the following raw materials in parts by weight: 25 parts of a modified nonionic surfactant, 8 parts of sodium lignin sulfonate, 0.4 parts of a defoaming agent, and 90 parts of deionized water;

[0029] The preparation method of the modified nonionic surfactant is as follows:

[0030] S1. Dissolve 8 parts of 1-pyrenebutyric acid, 14 parts of N-hydroxysuccinimide, 0.5 parts of triethylamine and 9 parts of N,N'-dicyclohexylcarbodiimide in 90 parts of dichloromethane according to weight parts, control the stirring speed to 300 rpm, continue stirring at 20°C for 14 hours, wash with water, separate the organic phase, dry the organic phase with anhydrous sodium sulfate, filter and distill under reduced pressure to obtain an active ester derivative;

[0031] S2, dissolving the active ester derivative in tetrahydrofuran at a mass ratio of 1:6:2, adding polyethylene glycol monododecyl ether, controlling the stirring speed to 300 rpm under nitrogen protection, stirring continuously at 45° C. for 24 h, washing with ethanol, and distilling under reduced pressure to obtain modified 1-pyrenebutyric acid;

[0032] S3. Dissolve the modified 1-pyrenebutyric acid in toluene, add n-butyl acrylate and benzoyl peroxide, and under nitrogen protection, control the stirring speed to 300 rpm, stir continuously at 60° C. for 6 hours, wash with water, separate the organic phase, dry the organic phase with anhydrous sodium sulfate, filter and distill under reduced pressure to obtain a modified non-ionic surfactant, wherein the mass ratio of modified 1-pyrenebutyric acid, toluene, n-butyl acrylate and benzoyl peroxide is 1:5:1:0.05.

[0033] A method for preparing a high-concentration graphene aqueous dispersant comprises the following steps: weighing various raw materials according to the formula amount, dissolving a modified nonionic surfactant, sodium lignin sulfonate and a defoamer in deionized water, controlling the stirring speed to 300 rpm, and continuously stirring for 15 minutes at room temperature.

[0034] Example 2

[0035] A high-concentration aqueous graphene dispersant is composed of the following raw materials in parts by weight: 26 parts of a modified nonionic surfactant, 11 parts of sodium lignin sulfonate, 0.5 parts of a defoamer and 93 parts of deionized water;

[0036] The preparation method of the modified nonionic surfactant is as follows:

[0037] S1. Dissolve 9 parts of 1-pyrenebutyric acid, 15 parts of N-hydroxysuccinimide, 0.6 parts of N,N-diisopropylethylamine and 10 parts of N,N'-dicyclohexylcarbodiimide in 95 parts of dichloromethane according to weight parts, control the stirring speed to 320 rpm, continue stirring at 22 ° C for 13 hours, wash with water, separate the organic phase, dry the organic phase with anhydrous sodium sulfate, filter and distill under reduced pressure to obtain an active ester derivative;

[0038] S2, dissolving the active ester derivative in tetrahydrofuran at a mass ratio of 1:8:3, adding polyethylene glycol monododecyl ether, controlling the stirring speed to 320 rpm under nitrogen protection, stirring continuously at 50° C. for 23 h, washing with ethanol, and distilling under reduced pressure to obtain modified 1-pyrenebutyric acid;

[0039] S3. Dissolve the modified 1-pyrenebutyric acid in toluene, add n-butyl acrylate and benzoyl peroxide, and under nitrogen protection, control the stirring speed to 320 rpm, continue stirring at 70°C for 5 hours, wash with water, separate the organic phase, dry the organic phase with anhydrous sodium sulfate, filter and distill under reduced pressure to obtain a modified non-ionic surfactant, wherein the mass ratio of modified 1-pyrenebutyric acid, toluene, n-butyl acrylate and benzoyl peroxide is 1:6:2:0.06.

[0040] A method for preparing a high-concentration graphene aqueous dispersant comprises the following steps: weighing various raw materials according to the formula amount, dissolving a modified nonionic surfactant, sodium lignin sulfonate and a defoamer in deionized water, controlling the stirring speed to 320 rpm, and continuously stirring for 13 minutes at room temperature.

[0041] Example 3

[0042] A high-concentration aqueous graphene dispersant is composed of the following raw materials in parts by weight: 30 parts of a modified nonionic surfactant, 12 parts of sodium lignin sulfonate, 0.8 parts of a defoaming agent, and 100 parts of deionized water;

[0043] The preparation method of the modified nonionic surfactant is as follows:

[0044] S1. Dissolve 12 parts of 1-pyrenebutyric acid, 17 parts of N-hydroxysuccinimide, 0.8 parts of 4-dimethylaminopyridine and 14 parts of N,N'-dicyclohexylcarbodiimide in 100 parts of dichloromethane according to weight parts, control the stirring speed to 400 rpm, continue stirring at 25°C for 10 hours, wash with water, separate the organic phase, dry the organic phase with anhydrous sodium sulfate, filter and distill under reduced pressure to obtain an active ester derivative;

[0045] S2, dissolving the active ester derivative in tetrahydrofuran at a mass ratio of 1:10:4, adding polyethylene glycol monododecyl ether, controlling the stirring speed to 400 rpm under nitrogen protection, stirring continuously at 55° C. for 20 h, washing with ethanol, and distilling under reduced pressure to obtain modified 1-pyrenebutyric acid;

[0046] S3. Dissolve the modified 1-pyrenebutyric acid in toluene, add n-butyl acrylate and benzoyl peroxide, and under nitrogen protection, control the stirring speed to 400 rpm, stir continuously at 80°C for 4 hours, wash with water, separate the organic phase, dry the organic phase with anhydrous sodium sulfate, filter and distill under reduced pressure to obtain a modified non-ionic surfactant, wherein the mass ratio of modified 1-pyrenebutyric acid, toluene, n-butyl acrylate and benzoyl peroxide is 1:10:3:0.08.

[0047] A method for preparing a high-concentration graphene aqueous dispersant comprises the following steps: weighing various raw materials according to the formula amount, dissolving a modified nonionic surfactant, sodium lignin sulfonate and a defoamer in deionized water, controlling the stirring speed to 400 rpm, and continuously stirring for 10 minutes at room temperature.

[0048] Example 4

[0049] A high-concentration aqueous graphene dispersant, composed of the following raw materials in parts by weight: 30 parts of a modified nonionic surfactant, 12 parts of sodium lignin sulfonate, 0.6 parts of a defoamer and 95 parts of deionized water;

[0050] The preparation method of the modified nonionic surfactant is as follows:

[0051] S1. Dissolve 12 parts of 1-pyrenebutyric acid, 16 parts of N-hydroxysuccinimide, 0.6 parts of 4-dimethylaminopyridine and 14 parts of N,N'-dicyclohexylcarbodiimide in 95 parts of dichloromethane according to weight parts, control the stirring speed to 380 rpm, continue stirring at 25°C for 10 hours, wash with water, separate the organic phase, dry the organic phase with anhydrous sodium sulfate, filter and distill under reduced pressure to obtain an active ester derivative;

[0052] S2, dissolving the active ester derivative in tetrahydrofuran at a mass ratio of 1:10:3, adding polyethylene glycol monododecyl ether, controlling the stirring speed to 380 rpm under nitrogen protection, stirring continuously at 54° C. for 20 h, washing with ethanol, and distilling under reduced pressure to obtain modified 1-pyrenebutyric acid;

[0053] S3. Dissolve the modified 1-pyrenebutyric acid in toluene, add n-butyl acrylate and benzoyl peroxide, and under nitrogen protection, control the stirring speed to 380 rpm, stir continuously at 80°C for 4 hours, wash with water, separate the organic phase, dry the organic phase with anhydrous sodium sulfate, filter and distill under reduced pressure to obtain a modified non-ionic surfactant, wherein the mass ratio of modified 1-pyrenebutyric acid, toluene, n-butyl acrylate and benzoyl peroxide is 1:8:3:0.07.

[0054] A method for preparing a high-concentration graphene aqueous dispersant comprises the following steps: weighing various raw materials according to the formula amount, dissolving a modified nonionic surfactant, sodium lignin sulfonate and a defoamer in deionized water, controlling the stirring speed to 380 rpm, and continuously stirring for 14 minutes at room temperature.

[0055] Comparative Example 1

[0056] A high-concentration aqueous graphene dispersant, composed of the following raw materials in parts by weight: 30 parts of sodium dodecyl sulfate, 12 parts of sodium lignin sulfonate, 0.6 parts of a defoamer and 95 parts of deionized water;

[0057] A method for preparing a high-concentration graphene aqueous dispersant comprises the following steps: weighing various raw materials according to the formula amount, dissolving sodium dodecyl sulfate, sodium lignin sulfonate and a defoamer in deionized water, controlling the stirring speed to 380 rpm, and continuously stirring for 14 minutes at room temperature.

[0058] Comparative Example 2

[0059] A high-concentration aqueous graphene dispersant, composed of the following raw materials in parts by weight: 30 parts of a modified nonionic surfactant, 12 parts of sodium lignin sulfonate, 0.6 parts of a defoamer and 95 parts of deionized water;

[0060] The preparation method of the modified nonionic surfactant is as follows: according to parts by weight, 12 parts of 1-pyrenebutyric acid, 16 parts of N-hydroxysuccinimide, 0.6 parts of 4-dimethylaminopyridine and 14 parts of N,N'-dicyclohexylcarbodiimide are dissolved in 95 parts of dichloromethane, the stirring speed is controlled to be 380 rpm, and the mixture is continuously stirred at 25°C for 10 hours, followed by washing with water, separating the organic phase, drying the organic phase with anhydrous sodium sulfate, filtering and distilling under reduced pressure to obtain the modified nonionic surfactant;

[0061] A method for preparing a high-concentration graphene aqueous dispersant comprises the following steps: weighing various raw materials according to the formula amount, dissolving a modified nonionic surfactant, sodium lignin sulfonate and a defoamer in deionized water, controlling the stirring speed to 380 rpm, and continuously stirring for 14 minutes at room temperature.

[0062] Comparative Example 3

[0063] A high-concentration aqueous graphene dispersant, composed of the following raw materials in parts by weight: 30 parts of a modified nonionic surfactant, 12 parts of sodium lignin sulfonate, 0.6 parts of a defoamer and 95 parts of deionized water;

[0064] The preparation method of the modified nonionic surfactant is as follows:

[0065] S1. Dissolve 12 parts of 1-pyrenebutyric acid, 16 parts of N-hydroxysuccinimide, 0.6 parts of 4-dimethylaminopyridine and 14 parts of N,N'-dicyclohexylcarbodiimide in 95 parts of dichloromethane according to weight parts, control the stirring speed to 380 rpm, continue stirring at 25°C for 10 hours, wash with water, separate the organic phase, dry the organic phase with anhydrous sodium sulfate, filter and distill under reduced pressure to obtain an active ester derivative;

[0066] S2, dissolving the active ester derivative in tetrahydrofuran at a mass ratio of 1:10:3, adding polyethylene glycol monododecyl ether, controlling the stirring speed to 380 rpm under nitrogen protection, stirring continuously at 54° C. for 20 h, washing with ethanol, and distilling under reduced pressure to obtain a modified nonionic surfactant;

[0067] A method for preparing a high-concentration graphene aqueous dispersant comprises the following steps: weighing various raw materials according to the formula amount, dissolving a modified nonionic surfactant, sodium lignin sulfonate and a defoamer in deionized water, controlling the stirring speed to 380 rpm, and continuously stirring for 14 minutes at room temperature.

[0068] Comparative Example 4

[0069] A high-concentration aqueous graphene dispersant, composed of the following raw materials in parts by weight: 30 parts of a modified nonionic surfactant, 12 parts of sodium lignin sulfonate, 0.6 parts of a defoamer and 95 parts of deionized water;

[0070] The preparation method of the modified nonionic surfactant is as follows:

[0071] S1. Dissolve 12 parts of 1-pyrenebutyric acid, 16 parts of N-hydroxysuccinimide, 0.6 parts of 4-dimethylaminopyridine and 14 parts of N,N'-dicyclohexylcarbodiimide in 95 parts of dichloromethane according to weight parts, control the stirring speed to 380 rpm, continue stirring at 25°C for 10 hours, wash with water, separate the organic phase, dry the organic phase with anhydrous sodium sulfate, filter and distill under reduced pressure to obtain an active ester derivative;

[0072] S3. Dissolve the active ester derivative in toluene, add n-butyl acrylate and benzoyl peroxide, and under nitrogen protection, control the stirring speed to 380 rpm, continue stirring at 80°C for 4 hours, wash with water, separate the organic phase, dry the organic phase with anhydrous sodium sulfate, filter and distill under reduced pressure to obtain a modified non-ionic surfactant, wherein the mass ratio of the active ester derivative, toluene, n-butyl acrylate and benzoyl peroxide is 1:8:3:0.07.

[0073] A method for preparing a high-concentration graphene aqueous dispersant comprises the following steps: weighing various raw materials according to the formula amount, dissolving a modified nonionic surfactant, sodium lignin sulfonate and a defoamer in deionized water, controlling the stirring speed to 380 rpm, and continuously stirring for 14 minutes at room temperature.

[0074] Comparative Example 5

[0075] A high-concentration aqueous graphene dispersant is composed of the following raw materials in parts by weight: 30 parts of a modified nonionic surfactant, 0.6 parts of a defoaming agent, and 95 parts of deionized water;

[0076] The preparation method of the modified nonionic surfactant is as follows:

[0077] S1. Dissolve 12 parts of 1-pyrenebutyric acid, 16 parts of N-hydroxysuccinimide, 0.6 parts of 4-dimethylaminopyridine and 14 parts of N,N'-dicyclohexylcarbodiimide in 95 parts of dichloromethane according to weight parts, control the stirring speed to 380 rpm, continue stirring at 25°C for 10 hours, wash with water, separate the organic phase, dry the organic phase with anhydrous sodium sulfate, filter and distill under reduced pressure to obtain an active ester derivative;

[0078] S2, dissolving the active ester derivative in tetrahydrofuran at a mass ratio of 1:10:3, adding polyethylene glycol monododecyl ether, controlling the stirring speed to 380 rpm under nitrogen protection, stirring continuously at 54° C. for 20 h, washing with ethanol, and distilling under reduced pressure to obtain modified 1-pyrenebutyric acid;

[0079] S3. Dissolve the modified 1-pyrenebutyric acid in toluene, add n-butyl acrylate and benzoyl peroxide, and under nitrogen protection, control the stirring speed to 380 rpm, stir continuously at 80°C for 4 hours, wash with water, separate the organic phase, dry the organic phase with anhydrous sodium sulfate, filter and distill under reduced pressure to obtain a modified non-ionic surfactant, wherein the mass ratio of modified 1-pyrenebutyric acid, toluene, n-butyl acrylate and benzoyl peroxide is 1:8:3:0.07.

[0080] A method for preparing a high-concentration graphene aqueous dispersant comprises the following steps: weighing various raw materials according to the formula amount, dissolving a modified nonionic surfactant and a defoaming agent in deionized water, controlling the stirring speed to 380 rpm, and continuously stirring for 14 minutes at room temperature.

[0081] Comparative Example 6

[0082] A high-concentration aqueous graphene dispersant, composed of the following raw materials in parts by weight: 30 parts of a modified nonionic surfactant, 12 parts of sodium lignin sulfonate, 0.6 parts of a defoamer and 95 parts of deionized water;

[0083] The preparation method of the modified nonionic surfactant is as follows:

[0084] S1. Dissolve 12 parts of 1-pyrenebutyric acid, 16 parts of N-hydroxysuccinimide, 0.6 parts of 4-dimethylaminopyridine and 14 parts of N,N'-dicyclohexylcarbodiimide in 95 parts of dichloromethane according to weight parts, control the stirring speed to 380 rpm, continue stirring at 25°C for 10 hours, wash with water, separate the organic phase, dry the organic phase with anhydrous sodium sulfate, filter and distill under reduced pressure to obtain an active ester derivative;

[0085] S2, dissolving the active ester derivative in tetrahydrofuran at a mass ratio of 1:10:3, adding polyethylene glycol monomethyl ether, controlling the stirring speed to 380 rpm under nitrogen protection, stirring continuously at 54° C. for 20 h, washing with ethanol, and distilling under reduced pressure to obtain modified 1-pyrenebutyric acid;

[0086] S3. Dissolve the modified 1-pyrenebutyric acid in toluene, add n-butyl acrylate and benzoyl peroxide, and under nitrogen protection, control the stirring speed to 380 rpm, stir continuously at 80°C for 4 hours, wash with water, separate the organic phase, dry the organic phase with anhydrous sodium sulfate, filter and distill under reduced pressure to obtain a modified non-ionic surfactant, wherein the mass ratio of modified 1-pyrenebutyric acid, toluene, n-butyl acrylate and benzoyl peroxide is 1:8:3:0.07.

[0087] A method for preparing a high-concentration graphene aqueous dispersant comprises the following steps: weighing various raw materials according to the formula amount, dissolving a modified nonionic surfactant, sodium lignin sulfonate and a defoamer in deionized water, controlling the stirring speed to 380 rpm, and continuously stirring for 14 minutes at room temperature.

[0088] Performance Testing

[0089] By weight, 6 parts of graphite were uniformly dispersed in 1 part of high-concentration graphene aqueous dispersant, 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 high-concentration aqueous graphene dispersion.

[0090] The following performance tests were performed on the high concentration aqueous graphene dispersion prepared above:

[0091] 1. Stability test: The high-concentration aqueous 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.

[0092] 2. Solid content test: Weigh an empty watch glass, record the weight as m1, apply a high concentration aqueous graphene dispersion on the surface of the watch glass, weigh it, record the weight as m2, put the watch glass coated with the high concentration aqueous 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.

[0093] 3. Resistivity test: The high concentration aqueous 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.

[0094] Table 1

[0095] Test items Initial state Dispersion changes Solid content / % Resistivity / Ω.m Example 1 Uniform without precipitation Uniform without precipitation 58.89 36 Example 2 Uniform without precipitation Uniform without precipitation 59.11 37 Example 3 Uniform without precipitation Uniform without precipitation 59.85 40 Example 4 Uniform without precipitation Uniform without precipitation 60.12 41 Comparative Example 1 A small amount of precipitation Layered, with a lot of sediment at the bottom 47.59 83 Comparative Example 2 Uniform without precipitation Layered, with a lot of sediment at the bottom 50.68 75 Comparative Example 3 Uniform without precipitation No obvious stratification, partial sedimentation at the bottom 52.09 72 Comparative Example 4 Uniform without precipitation No obvious stratification, partial sedimentation at the bottom 53.65 70 Comparative Example 5 Uniform without precipitation No obvious stratification, a small amount of sediment at the bottom 55.49 68 Comparative Example 6 Uniform without precipitation No obvious stratification, a small amount of sediment at the bottom 56.22 65

[0096] From the results shown in Table 1 above, it can be seen that the comprehensive performance of the high-concentration water-soluble graphene dispersants prepared in Examples 1-4 of the present invention is far better than that of Comparative Examples 1-6.

[0097] 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 high concentration aqueous graphene dispersant, characterized in that: The invention comprises the following raw materials in parts by weight: 25-30 parts of modified nonionic surfactant, 8-12 parts of sodium lignin sulfonate, 0.4-0.8 parts of defoaming agent and 90-100 parts of deionized water.

2. The high concentration aqueous graphene dispersant according to claim 1, characterized in that The modified nonionic surfactant is prepared by the following preparation steps: S1. Dissolve 1-pyrenebutyric acid, N-hydroxysuccinimide, a catalyst and N,N'-dicyclohexylcarbodiimide in dichloromethane, stir continuously for 10-14 hours at 20-25°C, wash with water, separate the organic phase, dry, filter and distill under reduced pressure to obtain an active ester derivative; S2, dissolving the active ester derivative in tetrahydrofuran, adding polyethylene glycol monododecyl ether, stirring continuously at 45-55° C. for 20-24 hours under nitrogen protection, washing, and distilling under reduced pressure to obtain modified 1-pyrenebutyric acid; S3. Dissolve the modified 1-pyrenebutyric acid in toluene, add n-butyl acrylate and benzoyl peroxide, and under nitrogen protection, continue stirring at 60-80° C. for 4-6 hours, then wash with water, separate the organic phase, dry, filter and distill under reduced pressure to obtain a modified nonionic surfactant.

3. The high concentration aqueous graphene dispersant according to claim 2, characterized in that In step S1, the components by weight include 8-12 parts of 1-pyrenebutyric acid, 14-17 parts of N-hydroxysuccinimide, 0.5-0.8 parts of a catalyst, 9-14 parts of N,N'-dicyclohexylcarbodiimide and 90-100 parts of dichloromethane.

4. The high concentration aqueous graphene dispersant according to claim 2, characterized in that The catalyst in step S1 is at least one of 4-dimethylaminopyridine, N,N-diisopropylethylamine and triethylamine.

5. The high concentration aqueous graphene dispersant according to claim 2, characterized in that: In the step S2, the mass ratio of the active ester derivative, tetrahydrofuran and polyethylene glycol monododecyl ether is 1:6-10:2-4.

6. The high concentration aqueous graphene dispersant according to claim 1, characterized in that The defoaming agent is at least one of polyoxypropylene glyceryl ether, polydimethylsiloxane and gelatin.

7. The high-concentration graphene aqueous dispersant according to claim 2, characterized in that: In the step S3, the mass ratio of modified 1-pyrenebutyric acid, toluene, n-butyl acrylate and benzoyl peroxide is 1:5-10:1-3:0.05-0.

08.

8. The high-concentration graphene aqueous dispersant according to claim 1, characterized in that: The preparation method is as follows: the modified nonionic surfactant, sodium lignin sulfonate and defoamer are dissolved in deionized water, and stirred continuously for 10-15 minutes at room temperature.