Graphdiyne phase change composite material and preparation method thereof

Abstract

The application provides a graphdiyne phase change composite material and a preparation method thereof. The method constructs a graphdiyne phase change composite material through chemical grafting. The material has good phase change energy storage performance and good mechanical properties. Thanks to the unique chemical structure and excellent physical and chemical properties of graphdiyne, and the controllable phase change temperature and high phase change enthalpy value of the composite material, the composite material has considerable application prospect in the field of energy storage and conversion.

Description

Technical Field

[0001] This invention relates to a method for preparing graphite-diyne-based phase change composite materials synthesized by chemical grafting. Background Technology

[0002] Under the dual pressures of energy shortage and environmental pollution, energy storage and conversion technologies have become a future development trend. Energy storage involves storing energy through physical or chemical changes. Phase change energy storage materials can release / absorb a large amount of heat during liquefaction / solidification, thus maintaining a constant system temperature. Traditional phase change materials are divided into inorganic and organic types: inorganic phase change materials have high energy density and small volume change, but they are prone to supercooling and phase separation; organic phase change materials can achieve temperature adjustability through blending, but they have poor thermal and electrical conductivity and are prone to leakage due to significant volume changes. Therefore, combining inorganic and organic phase change materials can achieve, to a certain extent, excellent properties such as high latent heat, high thermal conductivity, small temperature change, and recyclability.

[0003] Graphitic bisyne is a type of graphitic bisyne composed of sp and sp 2 A novel two-dimensional carbon material composed of hybrid carbon atoms. Due to its unique diyne bond (-C≡CC≡C-), continuous π-conjugated system, and uniformly distributed pore structure, graphitic diyne has broad application potential in energy catalysis, gas separation, and biomedicine. Graphitic diyne is a two-dimensional semiconductor material with a direct band gap of 0.44–1.47 eV and high room-temperature carrier mobility. 4 -10 5 cm 2 ·V -1 ·s -1 This has led to its widespread attention in the fields of electronics, optics, and magnetism. Summary of the Invention

[0004] One of the main objectives of this invention is to chemically graft graphdiyne with organic phase change materials, which can combine the unique chemical structure and excellent physicochemical properties of graphdiyne with the energy storage and temperature control properties of organic phase change materials, thereby enabling energy storage and temperature control applications in energy fields such as batteries and catalysis.

[0005] A primary objective of this invention is to provide a graphitic bis-yne phase change composite material, wherein the composite material is formed by chemically grafting graphitic bis-yne with a phase change polymer.

[0006] According to one embodiment of the present invention, the phase change polymer material is polymerized from phase change polymer monomers.

[0007] Polymers that can undergo a phase change within a certain temperature range, accompanied by endothermic or exothermic phenomena, are called phase change polymers. Substances that can polymerize into phase change polymers through reactions are called phase change polymer monomers.

[0008] According to one embodiment of the present invention, the phase change polymer monomer is one or more of caprolactone, vinyl acetate, polyethylene glycol, and diisocyanate; preferably caprolactone or (polyethylene glycol and diisocyanate). The molecular weight of polyethylene glycol can be selected from 2000, 3000, 4000, 6000, 8000, etc., and the diisocyanate can be selected from hexamethylene diisocyanate, toluene diisocyanate, isoflurane diisocyanate, etc. When the phase change polymer monomer is a mixture of polyethylene glycol and diisocyanate, the mass ratio of hydroxyl-modified graphitic diacetylene powder to polyethylene glycol is between 5:10000 and 1:1000, and the molar ratio of polyethylene glycol to diisocyanate is between 1:1.2 and 1:1.5.

[0009] According to one embodiment of the present invention, the chemical grafting includes hydroxyl modification of the graphdiyne.

[0010] Another main objective of this invention is to provide a method for preparing the above-mentioned composite material, comprising the following steps:

[0011] S1. Preparation of graphitic diacetylene powder dispersion;

[0012] S2. Add catalyst A and hydroxyl-modified compound to the graphite diyne powder dispersion to obtain hydroxyl-modified graphite diyne powder GDY-OH.

[0013] S3. Prepare GDY-OH dispersion;

[0014] S4. Add catalyst B and phase change polymer monomer to the GDY-OH dispersion and stir thoroughly until polymer polymerization is complete to obtain the graphite diacetylene phase change composite material.

[0015] According to one embodiment of the present invention, step S1 is to uniformly disperse graphite diacetylene powder into a solution of a certain volume to obtain a graphite diacetylene powder dispersion.

[0016] According to one embodiment of the present invention, the dispersion solvent of the graphite diacetylene powder dispersion is one or more of N-methylpyrrolidone, N,N'-dimethylformamide, N,N'-dimethylacetamide, toluene, acetone, ethanol, and dichloromethane, preferably dichloromethane.

[0017] According to one embodiment of the present invention, the concentration of the graphite diacetylene powder dispersion is 0.5-100 mg / mL.

[0018] According to one embodiment of the present invention, the hydroxyl-modifying compound in step S2 is one or more of ethanol, isopropanol, acetone, mercaptoethanol, and mercaptopropanol; preferably 2-mercaptoethanol.

[0019] According to one embodiment of the present invention, catalyst A in step S2 is a click reaction catalyst; preferably 2,2-bis(hydroxymethyl)propionic acid (DMPA).

[0020] According to one embodiment of the present invention, in step S2 above, the concentration of catalyst A is 0.05 to 10 mg / mL.

[0021] According to one embodiment of the present invention, step S2 further includes: initiating a click reaction with a UV lamp of a certain power under continuous stirring. The power of the UV lamp is 5-150W, preferably 30W. The reaction time is 10min-24h, preferably 2h.

[0022] According to one embodiment of the present invention, step S2 further includes: after the reaction is complete, thoroughly washing, centrifuging, and drying the resulting mixed dispersion.

[0023] According to one embodiment of the present invention, in step S3, the dispersion solvent used for the GDY-OH dispersion is one or more of commonly used organic solvents such as dichloromethane, N,N-dimethylformamide, toluene, ethanol, and acetone, preferably toluene.

[0024] According to one embodiment of the present invention, step S4 further includes: thoroughly washing the initially obtained GDY phase change composite material and centrifuging it to obtain purified GDY phase change composite material.

[0025] According to one embodiment of the present invention, the catalyst B is a phase change polymer monomer polymerization catalyst known in the art.

[0026] According to one embodiment of the present invention, the dispersing equipment used in step S1 or S3 is an ultrasonic device, a high-speed dispersing disc, an emulsifier, a homogenizer, a centrifugal mill, or a combination thereof.

[0027] Beneficial effects

[0028] This invention utilizes a chemical grafting method to prepare graphite-diyne phase change composite materials, resulting in graphite-diyne-based composite phase change materials. By combining the unique chemical structure and excellent physicochemical properties of graphite-diyne materials with the energy storage and temperature control properties of organic phase change materials, the resulting composite material exhibits good mechanical properties, efficient photothermal conversion performance, and phase change temperature control performance, enabling its application in energy storage and temperature control in fields such as batteries and catalysis. Attached Figure Description

[0029] Figure 1This is a schematic diagram of the structure of the graphite-diyne phase change composite material prepared in Example 1;

[0030] Figure 2 This is a photograph of the graphite-diyne phase change composite material prepared in Example 1.

[0031] Figure 3 shows the dispersion of the graphite diacetylene phase change composite material prepared in Example 1 and the actual product after washing and centrifugation; wherein... Figure 3A The dichloromethane dispersion of the graphite diacetylene phase change composite material prepared in Example 1; Figure 3B This is a photograph of the graphite diacetylene phase change composite material prepared in Example 1 after washing and centrifugation.

[0032] Figure 4A , Figure 4B and Figure 4C The images are scanning electron microscope (SEM) characterization images of the graphite diacetylene phase change composite material prepared in Example 1 at different magnifications.

[0033] Figure 5 Raman spectra of the graphitic diyne powder, hydroxyl-modified graphitic diyne powder, and graphitic diyne phase change composite material prepared in Example 1.

[0034] Figure 6 The infrared spectra of the graphite diyne powder, the hydroxyl-modified graphite diyne powder, and the graphite diyne phase change composite material prepared in Example 1 are shown.

[0035] Figure 7 The XRD patterns of the graphite diyne powder and graphite diyne phase change composite material prepared in Example 1 are shown.

[0036] Figure 8 Thermogravimetric analysis of the graphite diacetylene phase change composite material prepared in Example 1;

[0037] Figure 9 The image shows the DSC analysis results of the graphite-diyne phase change composite material prepared in Example 1.

[0038] Figure 10 This is a photograph of the graphite-diyne phase change composite material prepared in Example 7.

[0039] Figure 11A , Figure 11B and Figure 11C The images are scanning electron microscope (SEM) characterization images of the graphite diacetylene phase change composite material prepared in Example 7 at different magnifications.

[0040] Figure 12 The graph shows the photothermal conversion performance of the graphite-diyne phase change composite material prepared in Example 7. Detailed Implementation

[0041] Typical embodiments embodying the features and advantages of the present invention will be described in detail in the following description. It should be understood that the present invention can have various variations in different embodiments without departing from the scope of the present invention, and the descriptions and illustrations herein are for illustrative purposes only and not intended to limit the present invention.

[0042] The preparation of the graphite diacetylene phase change composite material according to an embodiment of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0043] Example 1

[0044] First stage: 20 mg of graphdiyne powder was added to 2 mL of dichloromethane, and then 20 mg of catalyst DMPA was added. The mixture was then stirred magnetically and ultrasonically dispersed for 20 min to fully disperse and dissolve the graphdiyne powder and catalyst A. 20 μL of 2-mercaptoethanol was added to prepare a hydroxyl-modified reaction mixture of graphdiyne.

[0045] A click reaction apparatus was constructed for hydroxyl modification of graphdiyne. The main components of the system were a 30W UV lamp and a stirrer. The reaction was carried out under continuous stirring and illumination for 2 hours. Hydroxyl-modified graphdiyne powder was obtained, washed with dichloromethane, centrifuged three times, and dried under vacuum at 60°C for 12 hours.

[0046] Second stage: The washed and dried powder was added to 100 μL of ultra-dry toluene solution and thoroughly dispersed by ultrasonication to obtain a toluene dispersion of hydroxyl-modified graphene diyne powder. 10 mg of catalyst 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 4-dimethylaminopyridine, and 200 μL of purified caprolactone were added. The mixture was thoroughly ultrasonicated and stirred at room temperature for approximately 1 hour until the phase change polymer polymerized and solidified. The resulting graphene diyne phase change composite material was obtained.

[0047] The graphite diyne phase change composite material was dissolved in dichloromethane and then ether was added until a precipitate formed. After centrifugation, the purified graphite diyne polycaprolactone composite material was obtained. The above purification operation was repeated three times to finally obtain a pure graphite diyne polycaprolactone composite material.

[0048] The testing methods involved in the examples are as follows: the field emission scanning electron microscope was a FEI Quattro S; the Raman characterization was performed using a LabRAM HR Evolution Raman spectrometer from Horiba Corporation, Japan.

[0049] Figure 2 This is a photograph of the graphite-diyne phase change composite material prepared in Example 1. It can be seen that the graphite-diyne phase change composite material obtained under these conditions exhibits good self-supporting properties.

[0050] Figure 3 shows the purification process of the graphite diacetylene phase change composite material prepared in Example 1. Figure 3A It is dispersed in dichloromethane. Figure 3B By adding diethyl ether to a dichloromethane dispersion, it can be seen that the graphite diyne phase change composite material can be dissolved in the dichloromethane solution and can precipitate out in diethyl ether, thereby achieving the purification of the graphite diyne phase change composite material.

[0051] Figure 4 is a scanning electron microscope (SEM) characterization of the graphite diacetylene phase change composite material prepared in Example 1. Figure 4A It can be seen that the graphite-diyne phase change composite material has a uniform and dense surface of graphite-diyne powder and a uniform composite of polymer phase change material. Figure 4B and 4C As can be seen, the graphite diacetylene phase change composite material has a uniform porous structure with sheets stacked together inside.

[0052] Figure 5 The images show the Raman spectra of the graphitic diyne powder, hydroxyl-modified graphitic diyne powder, and graphitic diyne phase change composite material prepared in Example 1. Characterization results show that the characteristic peaks of the Raman spectra of the prepared graphitic diyne phase change composite material still originate from the stretching vibrations of the carbon-carbon triple bonds and carbon-carbon single bonds connecting the carbon-carbon triple bonds and benzene rings in the graphitic diyne powder. The peak is located at 1336.5 cm⁻¹. -1 1524.2cm -1 1563.6cm -1 The peak at 2172 cm⁻¹ originates from the stretching vibration of the carbon-carbon bonds in the benzene ring, similar to that in graphene. However, compared to graphene, due to the introduction of the carbon-carbon triple bond, the peak position of this vibrational mode in alkyne-rich two-dimensional materials is red-shifted and the intensity is lower. -1 The characteristic spectral peak at that location originates from the stretching vibration of the diacetylene bond (-C≡CC≡C-).

[0053] Figure 6 The images show the infrared spectra of the graphitic diyne powder, hydroxyl-modified graphitic diyne powder, and graphitic diyne phase change composite material prepared in Example 1. Characterization results show that the phase change is located at 3200 cm⁻¹. -1 The characteristic peak of hydroxyl groups is absent in GDY powder, while the hydroxyl peak of GDY-OH is stronger and located at 2800 cm⁻¹. -1 The characteristic peaks of the -CS- bonds indicate that 2-mercaptoethanol forms chemical bonds with GDY powder via a click reaction. Furthermore, the original GDY powder has relatively few hydroxyl groups. The hydroxyl-modified GDY powder also achieves polymer-initiated polymerization.

[0054] Figure 7 The image shows the XRD pattern of the graphitic diyne powder and graphitic diyne phase change composite material prepared in Example 1. This pattern indicates that the prepared composite material exhibits good crystallinity.

[0055] Figure 8 The thermogravimetric analysis (TGA) diagram shows the graphite-diyne phase change composite material prepared in Example 1. Characterization analysis reveals that PCL mainly decomposes at 374.3℃, resulting in a weight loss of 61.71%.

[0056] Figure 9 The image shows the DSC analysis of the graphite-diyne phase change composite material prepared in Example 1. Characterization analysis shows that the phase change composite material undergoes a solid-to-liquid phase transition at 51.7℃ with an enthalpy change of 63.8 J / g, and a liquid-to-solid phase transition at 36.5℃ with an enthalpy change of 64.6 J / g.

[0057] Example 2

[0058] Except for the addition of 50 mg of graphitic diacetylene powder in the first stage, the other conditions were the same as in Example 1.

[0059] Example 3

[0060] Except for the addition of 10 μL of 2-mercaptoethanol in the first stage, the other conditions were the same as in Example 1.

[0061] Example 4

[0062] Except for the addition of 30 μL of 2-mercaptoethanol in the first stage, the other conditions were the same as in Example 1.

[0063] Example 5

[0064] Except for the addition of 100 μL of polymer monomer in the second stage, the other conditions were the same as in Example 1.

[0065] Example 6

[0066] Except for the addition of 500 μL of polymer monomer in the second stage, the other conditions were the same as in Example 1.

[0067] Examples 2-6 all yield graphite bis-yne / polycaprolactone composite phase change polymer composites similar to those in Example 1.

[0068] Example 7

[0069] Based on the hydroxyl-modified graphyne (GDY-OH) powder obtained in the first stage of Example 1, this example combines it with polyurethane phase change polymer to obtain a graphyne / polyurethane composite phase change polymer material. The specific implementation method is as follows.

[0070] 0.01 g of GDY-OH powder, 10 g of polyethylene glycol 6000, and 0.4 g of hexamethylene diisocyanate were added to 20 mL of LDM solvent. The mixture was stirred and mixed thoroughly at a low temperature (45°C), then heated to 70°C and stirred continuously until the mixture gelled. The reaction was stopped when the viscosity of the liquid increased. The gel product was removed and heated in a vacuum oven at 110°C for 12 hours to remove the solvent, yielding a graphylene / polyurethane composite phase change polymer material.

[0071] Figure 10 This is a photograph of the graphite-diyne phase change composite material prepared in Example 7. It can be seen that the graphite-diyne phase change composite material obtained under these conditions exhibits good self-supporting properties.

[0072] Figure 11 is a scanning electron microscope (SEM) characterization of the graphite diacetylene phase change composite material prepared in Example 7. Figure 11A It can be seen that the graphite-diyne phase change composite material has a porous structure. Figure 11B and 11C As can be seen, the graphite diacetylene phase change composite material has a uniform porous structure with sheets stacked together inside.

[0073] Figure 12 The graph shows the photothermal conversion performance of the graphite-diyne phase change composite material prepared in Example 7. Figure 12 It can be seen that this graphite-diyne phase change composite material exhibits performance under light intensity of 100 mw / cm². 2 Under light conditions, it heats up rapidly, reaching 65℃ in 27 minutes, exhibiting a fast heating rate and excellent photothermal conversion performance.

[0074] Example 8:

[0075] Except for the addition of 0.005g of GDY-OH powder, the other conditions were the same as in Example 7.

[0076] Unless otherwise specified, the terms used in this invention have the meanings commonly understood by those skilled in the art.

[0077] The embodiments described in this invention are for illustrative purposes only and are not intended to limit the scope of protection of this invention. Those skilled in the art can make various other substitutions, changes and improvements within the scope of this invention. Therefore, this invention is not limited to the above embodiments, but is only defined by the claims.

Claims

1. A graphitic diacetylene phase change composite material, characterized in that, The composite material is formed by chemically grafting graphdiyne and phase change polymer.

2. The composite material according to claim 1, characterized in that, The phase change polymer material is polymerized from phase change polymer monomers.

3. The composite material according to claim 2, characterized in that, The phase change polymer monomer is one or more of caprolactone, vinyl acetate, polyethylene glycol, and diisocyanate.

4. The composite material according to claim 3, characterized in that, The phase change polymer monomer is a mixture of polyethylene glycol and diisocyanate.

5. The composite material according to claim 1, characterized in that, The chemical grafting includes hydroxyl modification of the graphdiyne.

6. A method for preparing the composite material according to any one of claims 1-5, characterized in that, Includes the following steps: S1. Preparation of graphitic diacetylene powder dispersion; S2. Add catalyst A and hydroxyl-modified compound to the graphite diyne powder dispersion to obtain hydroxyl-modified graphite diyne powder GDY-OH; S3. Prepare GDY-OH dispersion; S4. Add catalyst B and phase change polymer monomer to the GDY-OH dispersion and stir thoroughly until polymer polymerization is complete to obtain the graphite diacetylene phase change composite material.

7. The preparation method according to claim 6, characterized in that, The hydroxyl-modifying compound is one or more of mercaptoethanol and mercaptopropanol.

8. The preparation method according to claim 6, characterized in that, The phase change polymer monomer is a mixture of polyethylene glycol and diisocyanate, and the hydroxyl-modified graphitic diacetylene powder: polyethylene glycol mass ratio is 5:10000 to 1:1000, and the amount of polyethylene glycol to diisocyanate is a molar ratio of 1:1.2 to 1:1.

5.

9. The preparation method according to claim 6, characterized in that, Step S2 further includes: triggering a click reaction with a UV lamp of a certain power while continuously stirring.

10. The preparation method according to claim 6, characterized in that, The dispersion solvent of the graphite diacetylene powder dispersion is one or more of N-methylpyrrolidone, N,N'-dimethylformamide, N,N'-dimethylacetamide, toluene, acetone, ethanol, and dichloromethane; and / or The dispersion solvents for the GDY-OH dispersion are toluene and N,N'-dimethylformamide.

11. The application of the composite material according to any one of claims 1-5 or the composite material prepared by the preparation method according to any one of claims 6-10 in photothermal conversion and energy storage temperature control.

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