Polyetherimide / nano-diamond composite material for energy storage dielectric and preparation method of polyetherimide / nano-diamond composite material

Abstract

The invention discloses a polyetherimide / nano-diamond composite material for an energy storage dielectric and a preparation method of the polyetherimide / nano-diamond composite material, and belongs to the technical field of dielectric energy storage. The polyetherimide / nano-diamond composite material comprises polyetherimide and nano-diamond, and the nano-diamond is compounded with the polyetherimide through an in-situ polymerization and coating method. The energy storage density of the polyetherimide / nano-diamond composite material for the energy storage dielectric prepared by the invention is improved compared with that of polyetherimide when the energy storage efficiency is 90% at room temperature. While the polarization performance of the polymer composite dielectric is improved, the dielectric response is reduced by adding the unconventional low-dielectric-constant dielectric material nano-diamond, the breakdown field strength and the energy storage performance of the composite material are finally improved, and the method is simple to operate, efficient in reaction and suitable for industrial production. The method has wide application value in the fields of electronic industry, new energy automobiles and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of dielectric energy storage, and in particular relates to a polyetherimide / nano-diamond composite material for energy storage dielectric and a preparation method thereof. Background Art

[0002] In order to reduce greenhouse gas emissions, many countries have begun to phase out HFCs (and other high-GWP refrigerants) and develop low-GWP alternatives. In addition, the development of compressor-free technology has become an important issue in the current development of new technologies for refrigeration and heat pumps. Therefore, new solid-state technologies such as electrocaloric (EC) refrigeration (based on the electrocaloric effect, ECE) are known for their potential ability to approach low-carbon, high-efficiency refrigeration. EC refrigeration uses the charge and discharge process of dielectric capacitors to achieve a refrigeration cycle with high theoretical efficiency.

[0003] Currently, both ceramic-based and polymer-based EC devices have emerged. These designs can achieve a large temperature span and have the potential to compete with traditional vapor compression refrigeration. Among them, polymer EC devices can be applied to many niche applications where space and weight constraints are very tight and traditional technologies cannot adapt, but EC polymers still require extremely high electric fields to achieve satisfactory refrigeration performance. At present, most ferroelectric inorganic oxide nanoparticles with high dielectric constants (k) are used to modify polymers, resulting in amplified distortion of the electric field at the polymer-oxide interface. The local electric field distortion reduces the service life of the material. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a polyetherimide / nano-diamond composite material for energy storage dielectric and a preparation method thereof.

[0005] In order to achieve the above objectives, the present invention adds low dielectric constant nano-diamond (k=5.7) to polyetherimide, which reduces electric field distortion and improves the breakdown field strength and energy storage density of the composite material. It has great application prospects in polymer EC devices.

[0006] A polyetherimide / nano-diamond composite material for energy storage dielectrics, comprising polyetherimide and nano-diamond, wherein the nano-diamond is composited with the polyetherimide by in-situ polymerization and coating methods;

[0007] The chemical structural formula of the polyetherimide is: Where n≥1.

[0008] A method for preparing a polyetherimide / nano-diamond composite material for energy storage dielectrics is specifically completed by the following steps:

[0009] 1. dissolving nanodiamond in an organic solvent to obtain a nanodiamond dispersion;

[0010] 2. dissolving the diamine monomer in a solvent to obtain a diamine dispersion;

[0011] 3. Evenly mixing the nano-diamond dispersion and the diamine dispersion to obtain a composite solution;

[0012] 4. adding the dianhydride monomers into the composite solution in batches, and stirring with external shear force to obtain a composite sol;

[0013] 5. coating the composite sol on a clean glass substrate into a wet film;

[0014] 6. Performing heat treatment on the wet film to obtain a dielectric film.

[0015] The beneficial effects of the present invention relative to the prior art are:

[0016] First, nanodiamond has a low dielectric constant that ordinary inorganic fillers do not have, but its dielectric constant is slightly higher than that of polyetherimide. Adding nanodiamond to polyetherimide can reduce the organic-inorganic interface distortion while improving the polarization of the composite material and the energy storage density of the composite material. Secondly, nanodiamond is small in size and can be dispersed in polyetherimide more evenly. As an inorganic material, it can improve the breakdown field strength of the composite material. In summary, the simple and easy-to-operate preparation method makes the present invention have broad application prospects and great potential to become an excellent capacitor film.

[0017] 2. The energy storage density of the polyetherimide / nano-diamond composite material for energy storage dielectric prepared by the present invention when the energy storage efficiency is 90% at room temperature is higher than that of polyetherimide. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a diagram showing the energy storage efficiency and energy storage density of the polyetherimide / nanodiamond composite material for energy storage dielectric prepared in Example 3. DETAILED DESCRIPTION

[0019] Specific implementation method 1: This implementation method is a polyetherimide / nano-diamond composite material for energy storage dielectrics, including polyetherimide and nano-diamonds, wherein the nano-diamonds are composited with the polyetherimide by in-situ polymerization and coating methods;

[0020] The chemical structural formula of the polyetherimide is: Where n≥1.

[0021] Specific embodiment 2: The difference between this embodiment and specific embodiment 1 is that the polyetherimide is obtained by in-situ polymerization of diamine monomers and dianhydride monomers; the diamine monomer is 4,4'-diaminodiphenyl ether, the structural formula is The dianhydride monomer is bisphenol A diether dianhydride, and the structural formula is The other steps are the same as those in the first embodiment.

[0022] Specific implementation method three: This implementation method is a method for preparing a polyetherimide / nano-diamond composite material for energy storage dielectrics, which is specifically completed in the following steps:

[0023] 1. dissolving nanodiamond in an organic solvent to obtain a nanodiamond dispersion;

[0024] 2. dissolving the diamine monomer in an organic solvent to obtain a diamine dispersion;

[0025] 3. Evenly mixing the nano-diamond dispersion and the diamine dispersion to obtain a composite solution;

[0026] 4. adding the dianhydride monomers into the composite solution in batches, and stirring with external shear force to obtain a composite sol;

[0027] 5. coating the composite sol on a clean glass substrate into a wet film;

[0028] 6. Performing heat treatment on the wet film to obtain a dielectric film.

[0029] Specific embodiment 4: This embodiment differs from specific embodiments 1 to 3 in that the diamine monomer in step 2 is 4,4'-diaminodiphenyl ether, and the dianhydride monomer in step 4 is bisphenol A diether dianhydride. The other steps are the same as those in specific embodiments 1 to 3.

[0030] Specific embodiment 5: This embodiment differs from specific embodiments 1 to 4 in that the concentration of the nano-diamond dispersion in step 1 is 4 mg / mL to 21 mg / mL. The other steps are the same as those in specific embodiments 1 to 4.

[0031] Specific embodiment 6: This embodiment differs from specific embodiments 1 to 5 in that the organic solvent in step 1 and step 2 is N,N-dimethylformamide, dimethylacetamide or N-methylpyrrolidone; in step 1, nanodiamonds are added to the organic solvent and magnetically stirred at room temperature for 8h to 12h to obtain a nanodiamond dispersion. The other steps are the same as those in specific embodiments 1 to 5.

[0032] Specific embodiment 7: This embodiment differs from specific embodiments 1 to 6 in that the concentration of the diamine dispersion in step 2 is 91 mg / mL. The other steps are the same as those of specific embodiments 1 to 6.

[0033] Specific embodiment eight: This embodiment differs from specific embodiments one to seven in that: in step three, the nano-diamond dispersion and the diamine dispersion are uniformly mixed at room temperature and under ultrasonic conditions to obtain a composite solution; the mass ratio of nano-diamond to diamine monomer in the composite solution in step three is (0..0126-0.0634):3. The other steps are the same as specific embodiments one to seven.

[0034] Specific embodiment 9: This embodiment differs from specific embodiments 1 to 8 in that: in step 4, the dianhydride monomers are added to the composite solution in batches, and an external mechanical force is used to stir for 2h to 3h to obtain a composite sol; the mass ratio of the dianhydride monomers to the diamine monomers in the composite sol described in step 4 is (3 to 5): 3. The other steps are the same as those of specific embodiments 1 to 8.

[0035] Specific embodiment 10: This embodiment differs from specific embodiments 1 to 9 in that: the thickness of the wet film in step 5 is 7 μm to 13 μm; the heat treatment in step 6 is: heat treatment for 12 hours in an air atmosphere at a temperature of 80°C to 100°C, and then transfer to a high-temperature drying oven at a temperature of 150°C to 300°C for gradient thermal imidization for 3 hours to 5 hours. The other steps are the same as those in specific embodiments 1 to 9.

[0036] The following examples are used to verify the beneficial effects of the present invention:

[0037] Example 1: A method for preparing a polyetherimide / nano-diamond composite material for energy storage dielectrics, which is specifically completed by the following steps:

[0038] 1. Dissolve 0.0634 g of nanodiamond in 3 mL of organic solvent and stir magnetically for 12 h at room temperature to obtain a nanodiamond dispersion;

[0039] The organic solvent described in step 1 is N,N-dimethylformamide (DMF);

[0040] 2. Dissolve 3.0 g of diamine monomer in 33 mL of organic solvent and perform ultrasonic treatment for 5 min to obtain a diamine dispersion;

[0041] The organic solvent described in step 2 is N,N-dimethylformamide (DMF);

[0042] The diamine monomer described in step 2 is 4,4'-diaminodiphenyl ether;

[0043] 3. At room temperature and under ultrasonic conditions, add the nanodiamond dispersion to the diamine dispersion, perform ultrasonication for 10 minutes, mix well, and obtain a composite solution;

[0044] 4. In an ice water bath, 4 g of dianhydride monomer was added to the composite solution in 4 times, with the amount added each time being 1 g, 1 g, 1 g, and 1 g. After each addition, the stirring time with external shear force was 30 min, 30 min, 30 min, and 60 min to obtain a composite sol;

[0045] The dianhydride monomer described in step 4 is bisphenol A diether dianhydride;

[0046] 5. Coat the composite sol on a clean glass substrate to form a 10 μm wet film;

[0047] 6. Performing heat treatment on the wet film to obtain a dielectric film.

[0048] The heat treatment described in step six is: first heat treatment in air atmosphere at a temperature of 80°C for 12 hours, then heat treatment at 150°C, 200°C, 250°C and 300°C for 1 hour respectively, and after cooling to room temperature, a polyetherimide / nanodiamond composite material for energy storage dielectric is obtained.

[0049] Example 2: The difference between this example and Example 1 is that in step 1, 0.0126 g of nanodiamond is dissolved in 3 mL of organic solvent and magnetically stirred at room temperature for 12 h to obtain a nanodiamond dispersion. The other steps and parameters are the same as those in Example 1.

[0050] Example 3: This example is different from Example 1 in that: in step 1, 0.0316 g of nanodiamond is dissolved in 3 mL of organic solvent and magnetically stirred at room temperature for 12 h to obtain a nanodiamond dispersion. The other steps and parameters are the same as those in Example 1.

[0051] Example 4: The difference between this example and Example 1 is that in step 1, 0.0126 g of nanodiamond is dissolved in 3 mL of organic solvent and magnetically stirred at room temperature for 12 h to obtain a dispersion of nanodiamond; the organic solvent in step 2 is N-methylpyrrolidone (NMP). The other steps and parameters are the same as those in Example 1.

[0052] Embodiment 5: The difference between this embodiment and embodiment 1 is that: in step 1, 0.0316g of nano-diamond is dissolved in 3mL of organic solvent, and magnetic stirring is carried out at room temperature for 12h to obtain a dispersion of nano-diamond; in step 4, 4.05g of dianhydride monomer is added to the composite solution in 4 times under the condition of an ice-water bath, and the amount added each time is 1.05g, 1g, 1g, and 1g, and the time of stirring with external shear force after each addition is 30min, 30min, 30min, and 60min to obtain a composite sol. The other steps and parameters are the same as those in embodiment 1.

[0053] Figure 1 The energy storage efficiency and energy storage density diagram of the polyetherimide / nano-diamond composite material for energy storage dielectric prepared in Example 3;

[0054] from Figure 1 It can be seen that the energy storage density of the polyetherimide / nano-diamond composite material for energy storage dielectric prepared in Example 3 is higher than that of polyetherimide when the energy storage efficiency is 90% at room temperature.

Claims

1. A polyetherimide / nano-diamond composite material for energy storage dielectric, characterized in that The polyetherimide / nano-diamond composite material comprises polyetherimide and nano-diamond, wherein the nano-diamond is compounded with the polyetherimide by in-situ polymerization and coating; The chemical structural formula of the polyetherimide is: Where n≥1.

2. The polyetherimide / nano-diamond composite material for energy storage dielectric according to claim 1, characterized in that The polyetherimide is obtained by in-situ polymerization of diamine monomers and dianhydride monomers; the diamine monomer is 4,4'-diaminodiphenyl ether, and the structural formula is The dianhydride monomer is bisphenol A diether dianhydride, and the structural formula is 3. The method for preparing a polyetherimide / nano-diamond composite material for energy storage dielectric according to claim 1, characterized in that The preparation method is specifically completed according to the following steps:

1. dissolving nanodiamond in an organic solvent to obtain a nanodiamond dispersion; 2. dissolving the diamine monomer in an organic solvent to obtain a diamine dispersion; 3. Evenly mixing the nano-diamond dispersion and the diamine dispersion to obtain a composite solution; 4. adding the dianhydride monomers into the composite solution in batches, and stirring with external shear force to obtain a composite sol; 5. coating the composite sol on a clean glass substrate into a wet film; 6. Performing heat treatment on the wet film to obtain a dielectric film.

4. The method for preparing a polyetherimide / nano-diamond composite material for energy storage dielectric according to claim 3, characterized in that The diamine monomer described in step 2 is 4,4'-diaminodiphenyl ether; and the dianhydride monomer described in step 4 is bisphenol A diether dianhydride.

5. The method for preparing a polyetherimide / nano-diamond composite material for energy storage dielectric according to claim 3, characterized in that The concentration of the nano-diamond dispersion described in step 1 is 4 mg / mL to 21 mg / mL.

6. The method for preparing a polyetherimide / nano-diamond composite material for energy storage dielectric according to claim 3, characterized in that The organic solvent described in step 1 and step 2 is N,N-dimethylformamide, dimethylacetamide or N-methylpyrrolidone; in step 1, nanodiamond is added to the organic solvent and magnetically stirred at room temperature for 8h to 12h to obtain a nanodiamond dispersion.

7. The method for preparing a polyetherimide / nano-diamond composite material for energy storage dielectric according to claim 3, characterized in that The concentration of the diamine dispersion described in step 2 is 91 mg / mL.

8. The method for preparing a polyetherimide / nano-diamond composite material for energy storage dielectric according to claim 3, characterized in that In step 3, the nano-diamond dispersion and the diamine dispersion are uniformly mixed at room temperature and under ultrasonic conditions to obtain a composite solution; the mass ratio of the nano-diamond to the diamine monomer in the composite solution in step 3 is (0.0126-0.0634):

3.

9. The method for preparing a polyetherimide / nano-diamond composite material for energy storage dielectric according to claim 3, characterized in that In step 4, the dianhydride monomers are added to the composite solution in batches, and the composite solution is stirred for 2h to 3h by applying external mechanical force to obtain a composite sol; the mass ratio of the dianhydride monomers to the diamine monomers in the composite sol described in step 4 is (3 to 5):

3.

10. The method for preparing a polyetherimide / nano-diamond composite material for energy storage dielectric according to claim 3, characterized in that The thickness of the wet film described in step five is 7 μm to 13 μm; the heat treatment described in step six is: heat treatment for 12 hours in an air atmosphere at a temperature of 80°C to 100°C, and then transferred to a high-temperature drying oven at a temperature of 150°C to 300°C for gradient thermal imidization for 3 hours to 5 hours.

Images