Phase change microcapsule material and preparation method thereof

Abstract

The invention relates to the technical field of phase-change materials, in particular to a phase-change microcapsule material and a preparation method thereof.The preparation method of the phase-change microcapsule material comprises the following steps that S1, hexadecyl sodium sulfate is dissolved in deionized water, and a water phase is obtained; s2, dissolving sodium hexadecyl sulfate in deionized water, and then adding the modified carbon nanotubes to obtain modified carbon nanotube sol; s3, mixing methyl methacrylate, propyl ethylene, n-octadecane and azodiisobutyronitrile together to obtain an oil phase; s4, slowly adding the oil phase obtained in the step S3 into the water phase obtained in the step S1 to obtain an emulsion; s5, slowly adding the modified carbon nanotube sol prepared in the step S2 into the emulsion obtained in the step S4 to obtain a suspension; and S6, treating the suspension obtained in the step S5 to obtain the phase change microcapsule material. The phase-change microcapsule material prepared by the invention is very excellent in heat-conducting property and compression strength, can cope with a low-temperature environment, and is long in service life.

Description

Technical Field

[0001] The present invention relates to the technical field of phase change materials, and in particular to a phase change microcapsule material and a preparation method thereof. Background Art

[0002] With the increasing environmental pollution and energy crisis, the development of clean energy is particularly important. Solar energy as a clean energy has attracted widespread attention. In the past few decades, the photovoltaic industry has also developed rapidly, but the photoelectric conversion efficiency is still very low and the utilization rate of solar energy is not high. Most of the sunlight shining on the earth is converted into heat energy. If this part of heat energy can be fully utilized, the utilization rate of solar energy will be greatly improved. Phase change materials collect solar energy and use this energy only when there is demand, which can effectively solve the contradiction between supply and demand of solar energy and further promote the development of solar energy technology.

[0003] Phase change materials can absorb or release a large amount of latent heat during the phase change process, and can be widely used in the fields of heat storage and temperature control. They are energy storage materials with great development potential. Phase change materials are generally composed of an outer shell and a core material, and the outer shell serves to wrap the core material. Existing phase change capsule materials have some defects. For example, the outer shell that wraps the core material sometimes breaks due to insufficient strength, which reduces the service life of the phase change capsule material; in addition, the thermal conductivity of the outer shell is low, especially in a low temperature environment, this problem is more likely to be highlighted. To this end, in response to the problems raised in the above background technology, those skilled in the art have proposed a phase change microcapsule material and a preparation method thereof. Summary of the invention

[0004] The present invention provides a phase change microcapsule material and a preparation method thereof to solve the problems raised in the above background technology.

[0005] A method for preparing a phase change microcapsule material comprises the following steps:

[0006] S1. Dissolve sodium hexadecyl sulfate in deionized water to obtain an aqueous phase for later use;

[0007] S2, dissolving sodium hexadecyl sulfate in deionized water, then adding the modified carbon nanotubes, and dispersing by ultrasonic for 2-4 hours to obtain a modified carbon nanotube sol for later use;

[0008] S3, methyl methacrylate, propylene glycol, n-octadecane and azobisisobutyronitrile are mixed together, and the mixture is stirred at a speed of 400-600 r / min for 20-40 min to obtain a uniformly mixed oil phase;

[0009] S4, slowly adding the oil phase obtained in step S3 to the water phase in step S1, and continuing to stir at a speed of 200-400 r / min for 30-70 min to obtain an emulsion;

[0010] S5, slowly adding the modified carbon nanotube sol prepared in step S2 to the emulsion obtained in step S4, and continuing to stir at a speed of 800-1200 r / min for 5-8 hours, and heating in a water bath during stirring at a temperature of 70-90° C. to obtain a phase change microcapsule suspension;

[0011] S6, filtering the phase change microcapsule suspension obtained in step S5, washing with deionized water, and drying to obtain a phase change microcapsule material;

[0012] The modified carbon nanotubes are prepared by the following method:

[0013] S101, slowly adding DMF dropwise to aluminum chloride in an ice bath, and then heating until the aluminum chloride is completely dissolved to obtain solution A;

[0014] S102, adding carbon nanotubes and polyvinyl alcohol into DMF, stirring and mixing to obtain solution B;

[0015] S103, slowly adding solution B into solution A, stirring and reacting at 50-70° C. for 4-8 hours, filtering, and drying to obtain modified carbon nanotubes.

[0016] Furthermore, in step S1, the mass ratio between sodium hexadecyl sulfate and deionized water is 1:(100-200).

[0017] Furthermore, in step S2, the mass ratio of sodium hexadecyl sulfate, carbon nanotubes and deionized water is 1:(0.5-1.2):(50-70).

[0018] Furthermore, in step S3, the mass ratio of azobisisobutyronitrile, propylene glycol, methyl methacrylate and n-octadecane is 1:(8-12):(20-30):(28-36).

[0019] Furthermore, the mass ratio of the modified carbon nanotubes in step S2, the azobisisobutyronitrile in step S3 and the sodium hexadecyl sulfate in step S1 is 1:(2-4):(3-5).

[0020] Furthermore, in the step S101, the mass ratio of aluminum chloride to DMF is 1:(25-40), and in the step S102, the mass ratio of polyvinyl alcohol, carbon nanotubes and DMF is 1:(1-2):(30-50).

[0021] Furthermore, the mass ratio of the DMF used in step S101 to the DMF used in step S102 is 1:3.

[0022] A phase change microcapsule material is prepared by the above-mentioned method for preparing the phase change microcapsule material.

[0023] The advantages and beneficial effects of the present invention are:

[0024] 1. The phase change microcapsule material prepared by the present invention is added with carbon nanotubes, and the carbon nanotubes modify the shell of the phase change material, which can effectively improve the mechanical properties and overall strength of the phase change material, and effectively improve the thermal conductivity of the phase change material;

[0025] 2. The carbon nanotubes used in the present invention are carbon nanotubes modified by polyvinyl alcohol, which effectively improves the dispersion ability of carbon nanotubes in an emulsion based on methyl methacrylate and propylene. At the same time, polyvinyl alcohol is more firmly combined with the product of the emulsification reaction, further enhancing the effect of carbon nanotubes on phase change microcapsules and further improving their mechanical properties and thermal conductivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0027] Figure 1 The process flow chart of preparing phase change microcapsule material in the present invention;

[0028] Figure 2 The process flow chart of preparing modified carbon nanotubes in the present invention is shown in FIG. DETAILED DESCRIPTION

[0029] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings and embodiments. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0030] like Figure 1-2 As shown, the present invention provides:

[0031] Example 1

[0032] A method for preparing a phase change microcapsule material comprises the following steps:

[0033] S1, dissolving 1.5 g of sodium hexadecyl sulfate in 230 g of deionized water to obtain an aqueous phase for later use;

[0034] S2, dissolving 0.4 g of sodium hexadecyl sulfate in 24 g of deionized water, then adding 0.4 g of modified carbon nanotubes, and dispersing by ultrasonic for 3 h to obtain a modified carbon nanotube sol for later use;

[0035] S3, 25g of methyl methacrylate, 11g of propylene, 31g of n-octadecane and 1.0g of azobisisobutyronitrile were mixed together, and the mixture was stirred at a speed of 450r / min for 35min to obtain a uniformly mixed oil phase;

[0036] S4, slowly adding the oil phase obtained in step S3 to the water phase in step S1, and continuing to stir at a speed of 300 r / min for 55 min to obtain an emulsion;

[0037] S5, slowly adding the modified carbon nanotube sol prepared in step S2 to the emulsion obtained in step S4, and continuing to stir at a speed of 1100 r / min for 7 hours. During the stirring process, heating in a water bath at a temperature of 85° C. to obtain a phase change microcapsule suspension;

[0038] S6. Filter the phase change microcapsule suspension obtained in step S5, wash with deionized water, and dry to obtain a phase change microcapsule material.

[0039] The modified carbon nanotubes are prepared by the following method:

[0040] S101, slowly dropwise add 11 g of DMF to 0.4 g of aluminum chloride in an ice bath, and then heat until the aluminum chloride is completely dissolved to obtain solution A;

[0041] S102, adding 1.0 g of carbon nanotubes and 0.8 g of polyvinyl alcohol to 33 g of DMF, stirring and mixing to obtain a solution B;

[0042] S103, slowly adding solution B into solution A, stirring and reacting at 65° C. for 7 h, filtering, and drying to obtain modified carbon nanotubes.

[0043] Example 2

[0044] A method for preparing a phase change microcapsule material comprises the following steps:

[0045] S1, dissolving 1.2g of sodium hexadecyl sulfate in 120g of deionized water to obtain an aqueous phase for later use;

[0046] S2, dissolving 0.8 g of sodium hexadecyl sulfate in 40 g of deionized water, then adding 0.4 g of modified carbon nanotubes, and dispersing by ultrasonic for 2 h to obtain a modified carbon nanotube sol for later use;

[0047] S3, 16 g of methyl methacrylate, 6.4 g of propylene, 22.4 g of n-octadecane and 0.8 g of azobisisobutyronitrile were mixed together, and the mixture was stirred at a speed of 400 r / min for 20 min to obtain a uniformly mixed oil phase;

[0048] S4, slowly adding the oil phase obtained in step S3 to the water phase in step S1, and continuing to stir at a speed of 200 r / min for 30 min to obtain an emulsion;

[0049] S5, slowly adding the modified carbon nanotube sol prepared in step S2 to the emulsion obtained in step S4, and continuing to stir at a speed of 800 r / min for 5 hours. During the stirring process, heating in a water bath at a temperature of 70° C. to obtain a phase change microcapsule suspension;

[0050] S6. Filter the phase change microcapsule suspension obtained in step S5, wash with deionized water, and dry to obtain a phase change microcapsule material.

[0051] The modified carbon nanotubes are prepared by the following method:

[0052] S101, slowly drop 5 g of DMF into 0.2 g of aluminum chloride in an ice bath, and then heat until the aluminum chloride is completely dissolved to obtain solution A;

[0053] S102, adding 1.0 g of carbon nanotubes and 0.5 g of polyvinyl alcohol to 15 g of DMF, stirring and mixing to obtain a solution B;

[0054] S103, slowly adding solution B into solution A, stirring and reacting at 50° C. for 4 h, filtering, and drying to obtain modified carbon nanotubes.

[0055] Example 3

[0056] A method for preparing a phase change microcapsule material comprises the following steps:

[0057] S1, dissolving 2.0 g of sodium hexadecyl sulfate in 400 g of deionized water to obtain an aqueous phase for later use;

[0058] S2, dissolving 0.33 g of sodium hexadecyl sulfate in 23.1 g of deionized water, then adding 0.4 g of modified carbon nanotubes, and dispersing by ultrasonic for 4 h to obtain a modified carbon nanotube sol for later use;

[0059] S3, 48g of methyl methacrylate, 19.2g of propylene, 57.6g of n-octadecane and 1.6g of azobisisobutyronitrile were mixed together, and the mixture was stirred at a speed of 600r / min for 40min to obtain a uniformly mixed oil phase;

[0060] S4, slowly adding the oil phase obtained in step S3 to the water phase in step S1, and continuing to stir at a speed of 400 r / min for 70 min to obtain an emulsion;

[0061] S5, slowly adding the modified carbon nanotube sol prepared in step S2 to the emulsion obtained in step S4, and continuing to stir at a speed of 1200 r / min for 8 hours. During the stirring process, heating in a water bath at a temperature of 90° C. to obtain a phase change microcapsule suspension;

[0062] S6. Filter the phase change microcapsule suspension obtained in step S5, wash with deionized water, and dry to obtain a phase change microcapsule material.

[0063] The modified carbon nanotubes are prepared by the following method:

[0064] S101, slowly dropwise add 16.7 g of DMF to 0.42 g of aluminum chloride in an ice bath, and then heat until the aluminum chloride is completely dissolved to obtain solution A;

[0065] S102, adding 1.0 g of carbon nanotubes and 1.0 g of polyvinyl alcohol to 50 g of DMF, stirring and mixing to obtain a solution B;

[0066] S103, slowly adding solution B into solution A, stirring and reacting at 70° C. for 8 h, filtering, and drying to obtain modified carbon nanotubes.

[0067] Comparative Example 1

[0068] The difference between Comparative Example 1 and Example 1 is that the preparation step of modified carbon nanotubes is omitted, and ordinary carbon nanotubes are added in step S2 instead. The remaining steps are exactly the same as those in Example 1.

[0069] Comparative Example 2

[0070] The difference between Comparative Example 2 and Comparative Example 1 is that the addition of common carbon nanotubes is further omitted, and the remaining steps are exactly the same as those of Comparative Example 1.

[0071] Four groups of phase change microcapsule materials were prepared through the above-mentioned Examples 1-3 and Comparative Examples 1-2. The thermal conductivity and mechanical strength of the four groups of phase change microcapsule materials were tested. The test results are shown in Table 1 below:

[0072] Table 1: Thermal conductivity and compressive strength test table of phase change microcapsule materials prepared in Examples 1-3 and Comparative Examples 1-2

[0073] Thermal conductivity W / (m·K) Compressive strength(MPa) Example 1 0.21 4.67 Example 2 0.24 4.15 Example 3 0.22 4.28 Comparative Example 1 0.17 3.59 Comparative Example 2 0.15 2.31

[0074] It can be seen from the data of Example 1 and Comparative Example 1 in Table 1 above that after the carbon nanotubes are modified by polyvinyl alcohol, the thermal conductivity and strength of the prepared microcapsule material can be further improved; and it can be seen from the data of Comparative Examples 1 and 2 that even if only ordinary carbon nanotubes are added, the thermal conductivity and compressive strength of the microcapsule material can be effectively improved.

[0075] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a phase change microcapsule material, characterized in that: The steps include: S1. Dissolve sodium hexadecyl sulfate in deionized water to obtain an aqueous phase for later use; S2, dissolving sodium hexadecyl sulfate in deionized water, then adding the modified carbon nanotubes, and dispersing by ultrasonic for 2-4 hours to obtain a modified carbon nanotube sol for later use; S3, methyl methacrylate, propylene glycol, n-octadecane and azobisisobutyronitrile are mixed together, and the mixture is stirred at a speed of 400-600 r / min for 20-40 min to obtain a uniformly mixed oil phase; S4, slowly adding the oil phase obtained in step S3 to the water phase in step S1, and continuing to stir at a speed of 200-400 r / min for 30-70 min to obtain an emulsion; S5, slowly adding the modified carbon nanotube sol prepared in step S2 to the emulsion obtained in step S4, and continuing to stir at a speed of 800-1200 r / min for 5-8 hours, and heating in a water bath during stirring at a temperature of 70-90° C. to obtain a phase change microcapsule suspension; S6, filtering the phase change microcapsule suspension obtained in step S5, washing with deionized water, and drying to obtain a phase change microcapsule material; The modified carbon nanotubes are prepared by the following method: S101, slowly adding DMF dropwise to aluminum chloride in an ice bath, and then heating until the aluminum chloride is completely dissolved to obtain solution A; S102, adding carbon nanotubes and polyvinyl alcohol into DMF, stirring and mixing to obtain solution B; S103, slowly adding solution B into solution A, stirring and reacting at 50-70° C. for 4-8 hours, filtering, and drying to obtain modified carbon nanotubes.

2. The method for preparing a phase change microcapsule material according to claim 1, characterized in that: The mass ratio between sodium hexadecyl sulfate and deionized water in step S1 is 1:(100-200).

3. The method for preparing a phase change microcapsule material according to claim 1, characterized in that: In the step S2, the mass ratio of sodium hexadecyl sulfate, carbon nanotubes and deionized water is 1:(0.5-1.2):(50-70).

4. The method for preparing a phase change microcapsule material according to claim 1, characterized in that: In the step S3, the mass ratio of azobisisobutyronitrile, propylene glycol, methyl methacrylate and n-octadecane is 1:(8-12):(20-30):(28-36).

5. The method for preparing a phase change microcapsule material according to claim 1, characterized in that: The mass ratio of the modified carbon nanotubes in step S2, the azobisisobutyronitrile in step S3 and the sodium hexadecyl sulfate in step S1 is 1:(2-4):(3-5).

6. The method for preparing a phase change microcapsule material according to claim 1, characterized in that: In the step S101, the mass ratio of aluminum chloride to DMF is 1:(25-40), and in the step S102, the mass ratio of polyvinyl alcohol, carbon nanotubes and DMF is 1:(1-2):(30-50).

7. The method for preparing a phase change microcapsule material according to claim 1, characterized in that: The mass ratio of the DMF used in step S101 to the DMF used in step S102 is 1:

3.

8. A phase change microcapsule material, characterized in that: The phase change microcapsule material is prepared by the preparation method of any one of claims 1-7.

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