A solvent-based graphene dispersion liquid and a preparation method thereof

Abstract

The present invention relates to the technical field of graphene, and discloses a solvent-based graphene dispersion liquid and a preparation method thereof. The preparation method includes: first dissolving dimethylolpropionic acid in N,N-dimethylformamide (DMF), reacting with p-toluenesulfonic acid and ethylenediamine to obtain hyperbranched polyesteramine, and then introducing epoxy groups into it to obtain epoxy-group hyperbranched polyesteramine. Then, dissolving perylene-3,4,9,10-tetracarboxylic dianhydride in DMF, reacting with triethylenetetramine and epoxy-group hyperbranched polyesteramine successively, adjusting the pH to obtain a graphene dispersant precursor, and adding a reinforcing agent to further react to obtain a graphene dispersant. Finally, dispersing graphite and the above dispersant in ethanol, and obtaining the graphene dispersion liquid through liquid-phase mechanical exfoliation. The preparation method provided by the present invention realizes significant improvements in the aspects of low viscosity, high solid content, uniform dispersion, long-term stability, conductivity and material compatibility of the graphene dispersion liquid.

Description

Technical Field

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

[0002] Graphene, as a two-dimensional material with a single-layer honeycomb lattice structure composed of carbon atoms with sp 2 hybrid orbitals, has excellent electrical, mechanical, thermal and other properties, and shows 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, irreversible agglomeration easily occurs between graphene sheets, which greatly limits the exertion of its excellent properties and poses an obstacle to practical applications.

[0003] To overcome this limitation, graphene dispersion liquids have emerged. The methods for dispersing graphene mainly include covalent modification and non-covalent modification. Although covalent modification can improve the dispersion to a certain extent, it will inevitably damage the original structure of graphene, thereby affecting its inherent electrical and other physicochemical properties. In contrast, non-covalent modification methods can achieve effective dispersion without damaging the intrinsic properties of graphene and have attracted much attention. Nevertheless, traditional non-covalent modification means such as using surfactants to assist dispersion still have deficiencies such as poor dispersion effect and the need for a large amount of additives to maintain stability. This not only increases the cost but also limits the large-scale application of graphene dispersion liquids. In many application scenarios, not only is it required that graphene can be evenly and stably dispersed in the solvent, but also strict standards are put forward for the solid content, conductivity and compatibility with other materials of its dispersion liquid. The dispersion liquids prepared by existing graphene dispersion technologies often cannot reach the ideal state in these key performance indicators. Therefore, the present invention provides a solvent-based graphene dispersion liquid 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 dispersion liquids, the preparation method provided by the present invention has achieved significant improvements in the high solid content, uniform dispersion, long-term stability, conductivity and material compatibility of the graphene dispersion liquid.

[0005] The present invention provides a solvent-based graphene dispersion liquid, adopting the following technical scheme:

[0006] A solvent-based graphene dispersion liquid, comprising 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.

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

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

[0009] S11. Dry the raw materials, dissolve dimethylolpropionic acid in N,N-dimethylformamide, add p-toluenesulfonic acid, stir at 110 - 120 °C for 4 - 6 h, then dropwise add ethylenediamine solution, continue to react for 6 - 8 h and then cool to room temperature, and obtain hyperbranched polyester amine by vacuum distillation;

[0010] S12. Under a nitrogen atmosphere, dissolve hyperbranched polyester amine in tetrahydrofuran and add sodium hydroxide, dropwise add allyl glycidyl ether at 50 - 60 °C, continue to react for 4 - 6 h, pour the reaction system into water, and obtain epoxy hyperbranched polyester amine after washing and drying the precipitated product;

[0011] S2. Preparation of graphene dispersant:

[0012] S21. Dry perylene-3,4,9,10-tetracarboxylic dianhydride and then dissolve it in N,N-dimethylformamide, dropwise add triethylenetetramine at 45 - 50 °C under stirring, react for 3 - 6 h, add epoxy hyperbranched polyester amine and potassium carbonate, raise the temperature to 60 - 70 °C and react for 6 - 8 h, cool to room temperature, and adjust the pH with formic acid to obtain the precursor of graphene dispersant;

[0013] S22. Add the reinforcing agent to the precursor of graphene dispersant, continuously stir at 50 - 60 °C for 2 - 3 h, then add polyvinylpyrrolidone, raise the temperature to 65 - 70 °C and continuously react for 4 - 6 h, and obtain graphene dispersant by vacuum distillation;

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

[0015] Disperse graphite and graphene dispersant uniformly in ethanol, and obtain solvent-based graphene dispersion 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 hyperbranched polyester amine, tetrahydrofuran, sodium hydroxide and allyl 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 polyamine 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, by weight, it is 1-2 parts of a reinforcing agent, 5-7 parts of a graphene dispersant precursor and 2-4 parts of polyvinylpyrrolidone.

[0022] Preferably, in step S22, the reinforcing agent is composed of diethylenetriaminepropylmethyldimethoxysilane and methoxypolyethylene glycolamine with 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 successively reacted with triethylenetetramine and the prepared epoxy hyperbranched polyamine, and then a reinforcing agent is added to obtain a graphene dispersant. Then, graphite and the dispersant are dispersed in ethanol, and a graphene dispersion is obtained by liquid-phase mechanical exfoliation. The epoxy hyperbranched polyamine provides abundant active sites and a three-dimensional spatial structure, which can enhance the adsorption capacity for graphene sheets, prevent agglomeration, lay a foundation for subsequent chemical bonding, and ensure a high solid content and uniform dispersion of the dispersion. The graphene dispersant is obtained by the reaction of perylene-3,4,9,10-tetracarboxylic dianhydride, triethylenetetramine and epoxy hyperbranched polyamine, and combined with a reinforcing agent and polyvinylpyrrolidone. It has a high molecular weight, good water solubility and graphene-philic properties, can improve the long-term stability and conductivity of the dispersion, maintain the original structure of graphene, and as highly reactive sites, is conducive to the formation of stable chemical bonds between graphene and other materials, enhancing the overall performance of the composite material and broadening the application fields.

[0025] 2. The epoxy hyperbranched polyamine of the present invention is prepared by successively reacting dimethylolpropionic acid with toluenesulfonic acid and ethylenediamine to obtain a hyperbranched polyamine, and then reacting with allyl glycidyl ether. The epoxy hyperbranched polyamine 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 surface functional groups of graphene, and take effect quickly under mild conditions, making the epoxy hyperbranched polyamine molecules approach and adhere to the graphene surface, overcoming part of the attraction between graphene sheets; the epoxy group has high reactivity and can undergo ring-opening reactions with the carboxyl and hydroxyl groups on the graphene surface, and then form covalent bonds. The synergistic effect of the two continuously and efficiently maintains the dispersion of graphene sheets, avoids the agglomeration phenomenon of graphene, and provides a solid guarantee for achieving a high-quality dispersion effect of graphene in the solvent.

[0026] 3. In the present invention, the graphene dispersant is obtained by reacting perylene-3,4,9,10-tetracarboxylic dianhydride with triethylenetetramine and epoxy group hyperbranched polyamine, and then adding a reinforcing agent and polyvinylpyrrolidone. The conjugated planar structure of perylene-3,4,9,10-tetracarboxylic dianhydride combines with the graphene surface through π-π bonding. Its carboxyl group reacts with triethylenetetramine to form an intermediate containing multiple amide bonds, and then reacts with the epoxy groups of epoxy group hyperbranched polyamine to enhance the binding force between the dispersant and graphene, retain the graphene structure, maintain a low resistivity, and be capable of bonding with other materials to broaden the application scope. In the reinforcing agent, diethylenetriaminepropylmethyldimethoxysilane can enhance the interfacial bonding strength, and methoxypolyethylene glycolamine can improve the water solubility and lipophilicity of the dispersant. The two cooperate to improve the mechanical strength and stability of the dispersant. And polyvinylpyrrolidone acts together with other components such as the reinforcing agent to further enhance the overall performance of the dispersion liquid, provide a physical barrier, and enhance the strength and stability of the dispersant through chemical action. Specific Embodiments

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0028] In the experimental methods in the following embodiments, unless otherwise specified, they are all conventional methods. The test materials used, unless otherwise specified, are all purchased from conventional biochemical reagent stores. In the following embodiments, the quantitative tests are all set with three repeated experiments, and the data are the average values or average values ± standard deviations of the three repeated experiments.

[0029] Example 1

[0030] A preparation method of a solvent-based graphene dispersion liquid includes the following preparation steps:

[0031] S1. Prepare epoxy group hyperbranched polyamine:

[0032] S11. Dry the raw materials. Dissolve dimethylolpropionic acid in N,N-dimethylformamide, add p-toluenesulfonic acid, control the stirring rate at 400 rpm, stir at 110 °C for 6 h, then dropwise add an ethylenediamine solution with a mass fraction of 60% at a rate of 3 mL / min, continue to react for 8 h and then cool to room temperature, and obtain hyperbranched polyamine by vacuum distillation. 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, dissolve hyperbranched poly(ester amine) in tetrahydrofuran and add sodium hydroxide. Control the stirring rate at 300 rpm. Dropwise add allyl glycidyl ether at a rate of 1.5 mL / min at 50 °C and continue the reaction for 4 h. Pour the reaction system into water. After washing and drying the precipitated product, epoxy-functionalized hyperbranched poly(ester amine) is obtained, where the mass ratio of hyperbranched poly(ester amine), tetrahydrofuran, sodium hydroxide, and allyl glycidyl ether is 10:50:0.1:1;

[0034] S2. Prepare a graphene dispersant:

[0035] S21. Dry perylene-3,4,9,10-tetracarboxylic dianhydride and then dissolve it in N,N-dimethylformamide. Control the stirring rate at 250 rpm. Dropwise add triethylenetetramine within 6 min at 45 °C under stirring and react for 6 h. Add epoxy-functionalized hyperbranched poly(ester amine) and potassium carbonate, heat up to 60 °C and react for 8 h. Cool to room temperature and adjust the pH to 4 with formic acid to obtain a graphene dispersant precursor, where the mass ratio of perylene-3,4,9,10-tetracarboxylic dianhydride, N,N-dimethylformamide, triethylenetetramine, epoxy-functionalized hyperbranched poly(ester amine), and potassium carbonate is 10:90:15:5:0.5;

[0036] S22. By weight, add 1 part of an adhesion enhancer to 5 parts of the graphene dispersant precursor. Control the stirring rate at 250 rpm and continuously stir at 50 °C for 3 h. Then add 2 parts of polyvinylpyrrolidone, heat up to 65 °C and continuously react for 6 h. Perform vacuum distillation to obtain the graphene dispersant, and the adhesion enhancer is composed of diethylenetriaminepropylmethyldimethoxysilane and methoxypolyethylene glycol amine with a molar ratio of 1:1;

[0037] S3. Prepare a solvent-based graphene dispersion:

[0038] By weight, uniformly disperse 7 parts of graphite and 1 part of the graphene dispersant in 40 parts of ethanol. First, stir at a rate of 800 rpm for 1 h, and then shear at a rate of 4000 rpm in a high-speed disperser for 50 min, and then take the upper layer liquid to obtain the solvent-based graphene dispersion.

[0039] Example 2

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

[0041] S1. Prepare epoxy-functionalized hyperbranched poly(ester amine):

[0042] S11. Dry the raw materials, dissolve dimethylolpropionic acid in N,N-dimethylformamide, add p-toluenesulfonic acid, control the stirring rate at 420 rpm, stir at 114 °C for 5.5 h, then dropwise add an ethylenediamine solution with a mass fraction of 62% at a rate of 4 mL / min, continue to react for 7.8 h and then cool to room temperature, and obtain hyperbranched poly(ester amine) by vacuum distillation. 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, dissolve hyperbranched poly(ester amine) in tetrahydrofuran and add sodium hydroxide, control the stirring rate at 320 rpm, dropwise add allyl glycidyl ether at a rate of 1.6 mL / min at 52 °C, continue to react for 5.8 h, pour the reaction system into water, and obtain epoxy-group-containing hyperbranched poly(ester amine) after washing and drying the precipitated product. The mass ratio of hyperbranched poly(ester amine), tetrahydrofuran, sodium hydroxide and allyl glycidyl ether is 10:52:0.3:2;

[0044] S2. Prepare a graphene dispersant:

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

[0046] S22. By weight, add 2 parts of a reinforcing agent to 6 parts of the graphene dispersant precursor, control the stirring rate at 270 rpm, continuously stir at 52 °C for 2.8 h, then add 3 parts of polyvinylpyrrolidone, raise the temperature to 67 °C and continuously react for 5.8 h, and obtain the graphene dispersant by vacuum distillation. The reinforcing agent consists of diethylenetriaminepropylmethyldimethoxysilane and methoxypolyethylene glycolamine with a molar ratio of 1:2;

[0047] S3. Prepare a solvent-based graphene dispersion:

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

[0049] Example 3

[0050] A preparation method of a solvent-based graphene dispersion liquid, comprising the following preparation steps:

[0051] S1. Prepare epoxy-based hyperbranched polyester amine:

[0052] S11. Dry the raw materials, dissolve dimethylolpropionic acid in N,N-dimethylformamide, add p-toluenesulfonic acid, control the stirring rate at 500 rpm, stir at 120 °C for 4 h, then dropwise add an ethylenediamine solution with a mass fraction of 65% at a rate of 6 mL / min, continue to react for 6 h and then cool to room temperature, and obtain hyperbranched polyester amine by vacuum distillation. 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, dissolve the hyperbranched polyester amine in tetrahydrofuran and add sodium hydroxide, control the stirring rate at 400 rpm, dropwise add allyl glycidyl ether at a rate of 3 mL / min at 60 °C, continue to react for 4 h, pour the reaction system into water, and obtain epoxy-based hyperbranched polyester amine after the precipitated product is washed and dried. The mass ratio of hyperbranched polyester amine, tetrahydrofuran, sodium hydroxide and allyl glycidyl ether is 10:60:0.4:3;

[0054] S2. Prepare a graphene dispersant:

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

[0056] S22. By weight, add 2 parts of an adhesion promoter to 7 parts of the graphene dispersant precursor, control the stirring rate at 350 rpm, continuously stir at 60 °C for 2 h, then add 4 parts of polyvinylpyrrolidone, raise the temperature to 70 °C and continuously react for 4 h, and obtain the graphene dispersant by vacuum distillation. The adhesion promoter is composed of diethylenetriaminepropylmethyldimethoxysilane and methoxypolyethylene glycol amine with a molar ratio of 1:3;

[0057] S3. Prepare a solvent-based graphene dispersion liquid:

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

[0059] Example 4

[0060] A preparation method of a solvent-based graphene dispersion, comprising the following preparation steps:

[0061] S1. Prepare epoxy hyperbranched polyesteramine:

[0062] S11. Dry the raw materials, dissolve dimethylolpropionic acid in N,N-dimethylformamide, add p-toluenesulfonic acid, control the stirring rate at 500 rpm, stir at 120 °C for 4.5 h, then dropwise add an ethylenediamine solution with a mass fraction of 64% at a rate of 5 mL / min, continue the reaction for 7 h, and then cool to room temperature. Perform vacuum distillation to obtain hyperbranched polyesteramine, where 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, dissolve hyperbranched polyesteramine in tetrahydrofuran and add sodium hydroxide. Control the stirring rate at 400 rpm, and dropwise add allyl glycidyl ether at a rate of 2 mL / min at 60 °C. Continue the reaction for 4 h, pour the reaction system into water, and after washing and drying the precipitated product, obtain epoxy hyperbranched polyesteramine, where the mass ratio of hyperbranched polyesteramine, tetrahydrofuran, sodium hydroxide, and allyl glycidyl ether is 10:58:0.4:3;

[0064] S2. Prepare graphene dispersant:

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

[0066] S22. Add 2 parts of adhesion enhancer to 6 parts of graphene dispersant precursor by weight, control the stirring rate at 350 rpm, continuously stir at 60 °C for 2 h, then add 4 parts of polyvinylpyrrolidone, raise the temperature to 70 °C and continuously react for 4 h, and obtain the graphene dispersant by vacuum distillation. The adhesion enhancer is composed of diethylenetriaminepropylmethyldimethoxysilane and methoxypolyethylene glycolamine with a molar ratio of 1:3;

[0067] S3. Prepare a solvent-based graphene dispersion:

[0068] Disperse 10 parts of graphite and 3 parts of graphene dispersant evenly in 48 parts of ethanol by weight. First, stir at a rate of 1000 rpm for 0.5 h, and then shear at a rate of 7000 rpm in a high-speed disperser for 35 min, and then take the upper layer liquid to obtain the solvent-based graphene dispersion.

[0069] Comparative Example 1

[0070] A preparation method of a solvent-based graphene dispersion includes the following preparation steps:

[0071] S1. Prepare hyperbranched poly(ester amine):

[0072] Dry the raw materials, dissolve dimethylolpropionic acid in N,N-dimethylformamide, add p-toluenesulfonic acid, control the stirring rate at 500 rpm, stir at 120 °C for 4.5 h, then dropwise add an ethylenediamine solution with a mass fraction of 64% at a rate of 5 mL / min, continue to react for 7 h, and then cool to room temperature, and obtain the hyperbranched poly(ester amine) by vacuum distillation. The mass ratio of dimethylolpropionic acid, N,N-dimethylformamide, p-toluenesulfonic acid and ethylenediamine solution is 14:48:0.5:4.

[0073] S2. Prepare graphene dispersant:

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

[0075] S22. Add 2 parts of adhesion enhancer to 6 parts of graphene dispersant precursor by weight, control the stirring rate at 350 rpm, continuously stir at 60 °C for 2 h, then add 4 parts of polyvinylpyrrolidone, raise the temperature to 70 °C and continuously react for 4 h, and obtain the graphene dispersant by vacuum distillation. The adhesion enhancer is composed of diethylenetriaminepropylmethyldimethoxysilane and methoxypolyethylene glycolamine with a molar ratio of 1:3;

[0076] S3. Prepare a solvent-based graphene dispersion:

[0077] Disperse 10 parts of graphite and 3 parts of graphene dispersant evenly in 48 parts of ethanol by weight. First, stir at a rate of 1000 rpm for 0.5 h, and then shear at a rate of 7000 rpm in a high-speed disperser for 35 min, and then take the upper layer liquid to obtain the solvent-based graphene dispersion.

[0078] Comparative Example 2

[0079] A preparation method of a solvent-based graphene dispersion, comprising the following preparation steps:

[0080] S1. Prepare graphene dispersant:

[0081] S11. Dry perylene-3,4,9,10-tetracarboxylic dianhydride and then dissolve it in N,N-dimethylformamide. Control the stirring rate at 350 rpm, and dropwise add triethylenetetramine within 10 min at 50 °C under stirring. After reacting for 3 h, cool to room temperature, and adjust the pH to 6 with formic acid to obtain the graphene dispersant precursor, where the mass ratio of perylene-3,4,9,10-tetracarboxylic dianhydride, N,N-dimethylformamide, and triethylenetetramine is 10:100:20;

[0082] S12. S22. Add 2 parts of adhesion enhancer to 6 parts of graphene dispersant precursor by weight, control the stirring rate at 350 rpm, continuously stir at 60 °C for 2 h, then add 4 parts of polyvinylpyrrolidone, raise the temperature to 70 °C and continuously react for 4 h, and obtain the graphene dispersant by vacuum distillation. The adhesion enhancer is composed of diethylenetriaminepropylmethyldimethoxysilane and methoxypolyethylene glycolamine with a molar ratio of 1:3;

[0083] S2. Prepare a solvent-based graphene dispersion:

[0084] Disperse 10 parts of graphite and 3 parts of graphene dispersant evenly in 48 parts of ethanol by weight. First, stir at a rate of 1000 rpm for 0.5 h, and then shear at a rate of 7000 rpm in a high-speed disperser for 35 min, and then take the upper layer liquid to obtain the solvent-based graphene dispersion.

[0085] Comparative Example 3

[0086] A preparation method of a solvent-based graphene dispersion liquid, comprising the following preparation steps:

[0087] S1. Prepare epoxy group hyperbranched polyester amine:

[0088] S11. Dry the raw materials, dissolve dimethylolpropionic acid in N,N-dimethylformamide, add p-toluenesulfonic acid, control the stirring rate at 500 rpm, stir at 120 °C for 4.5 h, then dropwise add an ethylenediamine solution with a mass fraction of 64% at a rate of 5 mL / min, continue to react for 7 h, and then cool to room temperature. Obtain hyperbranched polyester amine by vacuum distillation, where 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, dissolve hyperbranched polyester amine in tetrahydrofuran and add sodium hydroxide, control the stirring rate at 400 rpm, dropwise add allyl glycidyl ether at a rate of 2 mL / min at 60 °C, continue to react for 4 h, pour the reaction system into water, and obtain epoxy group hyperbranched polyester amine after washing and drying the precipitated product, where the mass ratio of hyperbranched polyester amine, tetrahydrofuran, sodium hydroxide, and allyl glycidyl ether is 10:58:0.4:3;

[0090] S2. Prepare a graphene dispersant:

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

[0092] S22. By weight, add 2 parts of diethylenetriaminepropylmethyldimethoxysilane to 6 parts of the graphene dispersant precursor, control the stirring rate at 350 rpm, continuously stir at 60 °C for 2 h, then add 4 parts of polyvinylpyrrolidone, raise the temperature to 70 °C and continuously react for 4 h, and obtain the graphene dispersant by vacuum distillation;

[0093] S3. Prepare a solvent-based graphene dispersion liquid:

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

[0095] Comparative Example 4

[0096] A preparation method of a solvent-based graphene dispersion, comprising the following preparation steps:

[0097] S1. Prepare epoxy hyperbranched polyamine:

[0098] S11. Dry the raw materials, dissolve dimethylolpropionic acid in N,N-dimethylformamide, add p-toluenesulfonic acid, control the stirring rate at 500 rpm, stir at 120 °C for 4.5 h, then dropwise add an ethylenediamine solution with a mass fraction of 64% at a rate of 5 mL / min, continue to react for 7 h, and then cool to room temperature. After vacuum distillation, hyperbranched polyamine is obtained. 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, dissolve the hyperbranched polyamine in tetrahydrofuran and add sodium hydroxide. Control the stirring rate at 400 rpm, dropwise add allyl glycidyl ether at a rate of 2 mL / min at 60 °C, continue to react for 4 h, pour the reaction system into water, and after washing and drying the precipitated product, epoxy hyperbranched polyamine is obtained. The mass ratio of hyperbranched polyamine, tetrahydrofuran, sodium hydroxide, and allyl glycidyl ether is 10:58:0.4:3;

[0100] S2. Prepare graphene dispersant:

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

[0102] S22. By weight, add 2 parts of methoxypolyethylene glycol amine to 6 parts of graphene dispersant precursor. Control the stirring rate at 350 rpm, continuously stir at 60 °C for 2 h, then add 4 parts of polyvinylpyrrolidone, raise the temperature to 70 °C and continuously react for 4 h, and then perform vacuum distillation to obtain graphene dispersant;

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

[0104] By weight, disperse 10 parts of graphite and 3 parts of graphene dispersant evenly in 48 parts of ethanol. First, stir at a rate of 1000 rpm for 0.5 h, then shear at a rate of 7000 rpm in a high-speed disperser for 35 min, and then take the upper layer liquid to obtain the solvent-based graphene dispersion.

[0105] Comparative Example 5

[0106] A preparation method of a solvent-based graphene dispersion, comprising the following preparation steps:

[0107] S1. Preparation of epoxy-based hyperbranched poly(ester amine):

[0108] S11. Dry the raw materials, dissolve dimethylolpropionic acid in N,N-dimethylformamide, add p-toluenesulfonic acid, control the stirring rate at 500 rpm, stir at 120 °C for 4.5 h, then dropwise add an ethylenediamine solution with a mass fraction of 64% at a rate of 5 mL / min, continue the reaction for 7 h, and then cool to room temperature. After vacuum distillation, hyperbranched poly(ester amine) is obtained. 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, dissolve the hyperbranched poly(ester amine) in tetrahydrofuran and add sodium hydroxide. Control the stirring rate at 400 rpm, dropwise add allyl glycidyl ether at a rate of 2 mL / min at 60 °C, continue the reaction for 4 h, pour the reaction system into water, and after washing and drying the precipitated product, epoxy-based hyperbranched poly(ester amine) is obtained. The mass ratio of hyperbranched poly(ester amine), tetrahydrofuran, sodium hydroxide, and allyl glycidyl ether is 10:58:0.4:3;

[0110] S2. Preparation of graphene dispersant:

[0111] S21. Dry perylene-3,4,9,10-tetracarboxylic dianhydride and then dissolve it in N,N-dimethylformamide. Control the stirring rate at 350 rpm, and dropwise add triethylenetetramine within 10 min at 50 °C under stirring. React for 3 h, add epoxy-based hyperbranched poly(ester amine) and potassium carbonate, raise the temperature to 70 °C and react for 6 h, cool to room temperature, and adjust the pH to 6 with formic acid to obtain the graphene dispersant precursor. The mass ratio of perylene-3,4,9,10-tetracarboxylic dianhydride, N,N-dimethylformamide, triethylenetetramine, epoxy-based hyperbranched poly(ester amine), and potassium carbonate is 10:100:20:10:0.8;

[0112] S22. Add 2 parts of the strengthening agent by weight to 6 parts of the graphene dispersant precursor, control the stirring rate at 350 rpm, continuously stir at 60 °C for 2 h, and then perform vacuum distillation to obtain the graphene dispersant. The strengthening agent is composed of diethylenetriaminepropylmethyldimethoxysilane and methoxypolyethylene glycolamine with a molar ratio of 1:3;

[0113] S3. Prepare a solvent-based graphene dispersion:

[0114] Disperse 10 parts of graphite and 3 parts of the graphene dispersant evenly in 48 parts of ethanol by weight. First, stir at a rate of 1000 rpm for 0.5 h, and then shear at a rate of 7000 rpm in a high-speed disperser for 35 min. Then take the upper layer liquid to obtain the solvent-based graphene dispersion.

[0115] Comparative Example 6

[0116] A preparation method of a solvent-based graphene dispersion, including the following preparation steps:

[0117] S1. Prepare an epoxy group hyperbranched polyesteramine:

[0118] S11. Dry the raw materials. Dissolve dimethylolpropionic acid in N,N-dimethylformamide, add p-toluenesulfonic acid, control the stirring rate at 500 rpm, stir at 120 °C for 4.5 h, then dropwise add an ethylenediamine solution with a mass fraction of 64% at a rate of 5 mL / min, continue to react for 7 h, and then cool to room temperature. Perform vacuum distillation to obtain the hyperbranched polyesteramine. The mass ratio of dimethylolpropionic acid, N,N-dimethylformamide, p-toluenesulfonic acid, and the ethylenediamine solution is 14:48:0.5:4.

[0119] S12. Under a nitrogen atmosphere, dissolve the hyperbranched polyesteramine in tetrahydrofuran and add sodium hydroxide. Control the stirring rate at 400 rpm, dropwise add allyl glycidyl ether at a rate of 2 mL / min at 60 °C, continue to react for 4 h, pour the reaction system into water, and after washing and drying the precipitated product, obtain the epoxy group hyperbranched polyesteramine. The mass ratio of the hyperbranched polyesteramine, tetrahydrofuran, sodium hydroxide, and allyl glycidyl ether is 10:58:0.4:3;

[0120] S2. Prepare a graphene dispersant:

[0121] The perylene-3,4,9,10-tetracarboxylic dianhydride is dried and then dissolved in N,N-dimethylformamide. The stirring rate is controlled at 350 rpm. Triethylenetetramine is added dropwise within 10 min at 50 °C under stirring, and the reaction is carried out for 3 h. Epoxy hyperbranched polyamine and potassium carbonate are added, and the temperature is raised to 70 °C for reaction for 6 h. It is cooled to room temperature, and the pH is adjusted to 6 with formic acid to obtain a graphene dispersant, where the mass ratio of perylene-3,4,9,10-tetracarboxylic dianhydride, N,N-dimethylformamide, triethylenetetramine, epoxy hyperbranched polyamine 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 are uniformly dispersed in 48 parts of ethanol. First, it is 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 is taken to obtain a solvent-based graphene dispersion.

[0124] Performance testing

[0125] The paint films formed by the ship anti-corrosion coatings prepared in Examples 1-4 and Comparative Examples 1-6 are subjected to performance testing:

[0126] 1. Stability test: After the solvent-based graphene dispersions obtained in Examples 1-4 and Comparative Examples 1-6 are left standing for one week, they are centrifuged at 7000 r / min for 10 min, and the state of the dispersion after centrifugation is observed. The test results are shown in Table 1.

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

[0128] 3. Viscosity test: Stir mechanically at 800 rpm for 3 min. At room temperature, insert the 4# rotor of the rotational viscometer into the solvent-based graphene, and test it under the condition of 12 rpm. Read the value after the number on the viscosity meter scale is stable. The test results are shown in Table 1.

[0129] 4. Resistivity test: Use a 200-μm coating knife to coat the homogenized slurry of the solvent-based graphene dispersions prepared in Examples 1-4 and Comparative Examples 1-6 on the PI film, dry it at 140 °C for 1 h, and then use a four-probe tester of model RTS-8 to test. Symmetrically take 5 points, and the average value of the resistivities measured at the 5 points is the obtained value. The test results are shown in Table 1.

[0130] Table 1

[0131]

[0132]

[0133] As can be seen from the results shown in Table 1 above, the comprehensive performance of the solvent-based graphene dispersion prepared in Examples 1-4 of the present invention is far superior to that of Comparative Examples 1-6.

[0134] The above content is only an example and illustration of the present invention. Those skilled in the art of this technology can make various modifications or supplements to the specific embodiments described or use similar methods to replace them. As long as they do not deviate from the invention or exceed the scope defined by this claim book, they should all fall within the protection scope of the present invention.

Claims

1. A preparation method of a solvent-based graphene dispersion for preparing a solvent-based graphene dispersion, the solvent-based graphene dispersion comprising 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; characterized in that, The preparation method includes the following steps: S1. Prepare epoxy hyperbranched polyester amine: S11. Dry the raw materials, dissolve dimethylolpropionic acid in N,N-dimethylformamide, add p-toluenesulfonic acid, stir at 110-120 °C for 4-6 h, then dropwise add ethylenediamine solution, continue to react for 6-8 h and then cool to room temperature, and obtain hyperbranched polyester amine by vacuum distillation; S12. Under a nitrogen atmosphere, dissolve hyperbranched polyester amine in tetrahydrofuran and add sodium hydroxide, dropwise add allyl glycidyl ether at 50-60 °C, continue to react for 4-6 h, pour the reaction system into water, and obtain epoxy hyperbranched polyester amine after washing and drying the precipitated product; S2. Prepare graphene dispersant: S21. Dry perylene-3,4,9,10-tetracarboxylic dianhydride and then dissolve it in N,N-dimethylformamide, dropwise add triethylenetetramine at 45-50 °C under stirring, react for 3-6 h, add epoxy hyperbranched polyester amine and potassium carbonate, raise the temperature to 60-70 °C and react for 6-8 h, cool to room temperature, and adjust the pH with formic acid to obtain a graphene dispersant precursor; S22. Add an adhesion enhancer to the graphene dispersant precursor, continuously stir at 50-60 °C for 2-3 h, then add polyvinylpyrrolidone, raise the temperature to 65-70 °C and continuously react for 4-6 h, and obtain the graphene dispersant by vacuum distillation; the adhesion enhancer is composed of diethylenetriaminepropylmethyldimethoxysilane and methoxypolyethylene glycol amine with a molar ratio of 1:1-3; S3. Prepare a solvent-based graphene dispersion: Uniformly disperse graphite and the graphene dispersant in ethanol, and obtain a solvent-based graphene dispersion by liquid-phase mechanical exfoliation.

2. The preparation method of the solvent-based graphene dispersion according to claim 1, characterized in that, 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.

3. The preparation method of the solvent-based graphene dispersion according to claim 1, characterized in that, In step S11, the mass fraction of the ethylenediamine solution is 60-65%.

4. The preparation method of the solvent-based graphene dispersion according to claim 1, characterized in that, In step S12, the mass ratio of hyperbranched polyester amine, tetrahydrofuran, sodium hydroxide, and allyl glycidyl ether is 10:50-60:0.1-0.4:1-3.

5. The preparation method of the solvent-based graphene dispersion according to claim 1, characterized in that, In 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.

6. The preparation method of the solvent-based graphene dispersion according to claim 1, characterized in that, In step S21, adjust the pH to 4-6 with formic acid.

7. The preparation method of the solvent-based graphene dispersion according to claim 1, characterized in that, In step S22, it is 1-2 parts by weight of adhesion enhancer, 5-7 parts by weight of graphene dispersant precursor, and 2-4 parts by weight of polyvinylpyrrolidone.

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