Phase change microcapsule with zinc tungstate as shell material and preparation method of phase change microcapsule

Abstract

The invention relates to the technical field of phase change materials, in particular to a phase change microcapsule with zinc tungstate as a shell material and a preparation method of the phase change microcapsule. Solid-liquid phase transition of a phase change material easily causes leakage of the phase change material in application, and application of the phase change material in the field of energy storage is seriously affected. In order to solve the technical problems, the invention provides the phase change microcapsule with the zinc tungstate as the shell material, the phase change microcapsule is of a core-shell structure, the core material is a phase change material, the shell material is the zinc tungstate, the mass ratio of the core material to the shell material is 1: (0.5-2), and the phase change microcapsule structure successfully solves the problems that the phase change material is prone to leakage, agglomeration and caking in the application process. The coating rate of the obtained phase change microcapsule can reach 30% or above, the heat storage efficiency can reach 40% or above, and the phase change microcapsule has good application prospects.

Description

Technical Field

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

[0002] In recent years, with the rapid development of economic globalization, the reduction of fossil fuels and the emission of harmful gases have attracted great attention. The use of wind energy, geothermal energy, solar energy and other renewable resources is an effective way to solve the above problems, so thermal energy storage is expected to play a key role in further reducing the consumption of fossil fuels. Latent heat storage in the solid-liquid phase change process has attracted much attention because its energy storage density is higher than that of sensible heat storage and it can absorb or release energy under constant temperature conditions. This feature is used in the fields of insulation, refrigeration and heat transfer.

[0003] The solid-liquid phase transition of phase change materials can easily cause leakage, agglomeration and caking of phase change materials during application, which seriously affects the application of phase change materials in the field of energy storage. Summary of the invention

[0004] The problem in the prior art is that the solid-liquid phase transition of the phase change material easily causes leakage of the phase change material during application, which seriously affects the application of the phase change material in the field of energy storage. In view of the above technical problems, the present invention provides a phase change microcapsule with zinc tungstate as the shell material, which has a core-shell structure, the core material is the phase change material, the shell material is zinc tungstate, and the mass ratio of the core material to the shell material is 1:0.5-2.

[0005] Preferably, the phase change material comprises an organic phase change material, an inorganic phase change material or an organic-inorganic phase change material, or a combination of two or more thereof.

[0006] Preferably, the phase change material is one or more of paraffin, tetradecane, pentadecane, hexadecane, heptadecane, octadecane, nonadecane, eicosane, heneicosane, docosane, tricosane, tetracosane, pentacosane, hexacosane, heptacosane, octacosane.

[0007] Preferably, the phase change material is stearic acid.

[0008] Preferably, the preparation method of the phase change microcapsule with zinc tungstate as the shell material comprises the following steps:

[0009] (1) adding a phase change material into deionized water and stirring at an appropriate temperature so that the phase change material is completely melted in the deionized water to obtain a phase change solution;

[0010] (2) adding a surfactant to the phase change solution, stirring and emulsifying for at least 20 minutes to obtain an emulsion;

[0011] (3) Add zinc nitrate and sodium tungstate into deionized water respectively and fully dissolve them at room temperature to obtain zinc nitrate solution and sodium tungstate solution respectively;

[0012] (4) adding zinc nitrate dropwise to the emulsion while stirring, and continuing to stir for at least 30 minutes after the addition is completed, and then adding sodium tungstate solution dropwise to the emulsion while stirring, and continuing to stir for at least 10 minutes after the addition is completed, thereby obtaining a phase change microcapsule solution;

[0013] (5) The obtained phase change microcapsule solution is washed with anhydrous ethanol and deionized water at least three times respectively, and the obtained solid product is dried at room temperature to obtain a powdered phase change microcapsule.

[0014] Preferably, the surfactant includes at least one of sodium dodecylbenzene sulfonate, sodium dodecylbenzene sulfonate, hexadecyltrimethylammonium bromide and hexadecyltrimethylammonium chloride.

[0015] Preferably, the surfactant is sodium dodecylbenzene sulfonate.

[0016] Preferably, the dosage ratio of phase change material to deionized water in the phase change solution is 0.5-10g:50-400mL, the dosage ratio of surfactant to phase change material in the emulsion is 0.5-2:1-6, the dosage ratio of zinc nitrate to deionized water in the zinc nitrate solution is 1-5g:10-80mL, the dosage ratio of sodium tungstate to deionized water in the sodium tungstate solution is 1-5g:10-80mL, and the dosage ratio of sodium tungstate to zinc nitrate and surfactant in the phase change microcapsule solution is 1-5g:1-5g:0.5-2g.

[0017] Preferably, the dosage ratio of phase change material to deionized water in the phase change solution is 6g:260mL, the dosage ratio of surfactant to phase change material in the emulsion is 0.5:6, the dosage ratio of zinc nitrate to deionized water in the zinc nitrate solution is 3g:40mL, the dosage ratio of sodium tungstate to deionized water in the sodium tungstate solution is 3g:40mL, and the dosage ratio of sodium tungstate to zinc nitrate and surfactant in the phase change microcapsule solution is 3g:3g:0.5g.

[0018] The present invention has the following beneficial effects:

[0019] The present invention uses zinc tungstate to wrap the phase change material to obtain a phase change microcapsule with a core-shell structure, which successfully solves the problems of easy leakage, agglomeration and caking of the phase change material during the application process. The coverage rate of the obtained phase change microcapsule can reach more than 30%, and the heat storage efficiency can reach more than 40%, which has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 : is a SEM image of the phase change microcapsule obtained in Example 1 of the present invention. DETAILED DESCRIPTION

[0021] The present invention is described in detail below with reference to the examples. However, it should be understood that the following examples are only illustrative of the embodiments of the present invention, and are not intended to limit the scope of the present invention.

[0022] Example 1

[0023] A phase change microcapsule with zinc tungstate as shell material, the preparation method is as follows:

[0024] (1) Weigh 6.0 g of stearic acid and add it to 260 mL of deionized water, and heat it in a constant temperature water bath at 70° C. with magnetic stirring until the stearic acid is completely melted in the deionized water to obtain a phase change solution;

[0025] (2) weighing 0.5 g of sodium dodecylbenzene sulfonate and adding it to the above phase change solution, stirring and emulsifying at 700 rpm for 20 min to obtain an emulsion;

[0026] (3) Dissolve 3.0 g of zinc nitrate hexahydrate and 3.0 g of sodium tungstate in 40 mL of deionized water to obtain a zinc nitrate solution and a sodium tungstate solution, respectively;

[0027] (4) adding the zinc nitrate solution obtained in step (3) dropwise to the emulsion obtained in step (2) while stirring, stirring at 700 rpm for 30 min after the addition is complete, and then adding the sodium tungstate solution obtained in step (3) dropwise to the reaction system while stirring, stirring at 700 rpm for 10 min after the addition is complete, to obtain a phase change microcapsule solution;

[0028] (5) The obtained phase change microcapsule solution was washed three times with anhydrous ethanol and deionized water respectively, and then dried naturally at room temperature for 24 h to obtain white powder phase change microcapsules.

[0029] Example 2 is the same as Example 1, except that in Example 2, the amount of zinc nitrate hexahydrate added is 6 g, and the amount of sodium tungstate added is 6 g.

[0030] Example 3 is the same as Example 1, except that in Example 3, the added amount of zinc nitrate hexahydrate is 9 g, and the added amount of sodium tungstate is 9 g.

[0031] Example 4 is the same as Example 1, except that in Example 4, the amount of zinc nitrate hexahydrate added is 12 g, and the amount of sodium tungstate added is 12 g.

[0032] Example 5 is the same as Example 1, except that the surfactant in Example 5 is sodium dodecylbenzenesulfonate.

[0033] Example 6 is the same as Example 1, except that the surfactant in Example 6 is hexadecyltrimethylammonium chloride.

[0034] Example 7 is the same as Example 1, except that the surfactant in Example 7 is hexadecyltrimethylammonium bromide.

[0035] Example 8 is the same as Example 7, except that in Example 8, the added amount of zinc nitrate hexahydrate is 6 g, and the added amount of sodium tungstate is 6 g.

[0036] Example 9 is the same as Example 7, except that in Example 9, the amount of zinc nitrate hexahydrate added is 9 g, and the amount of sodium tungstate added is 9 g.

[0037] Example 10 is the same as Example 7, except that in Example 10, the amount of zinc nitrate hexahydrate added is 12 g, and the amount of sodium tungstate added is 12 g.

[0038] Comparative Example 1

[0039] A phase change microcapsule with barium tungstate as shell material, the preparation method is as follows:

[0040] (1) Weigh 6.0 g of stearic acid and add it to 260 mL of deionized water, and heat it in a constant temperature water bath at 70° C. with magnetic stirring until the stearic acid is completely melted in the deionized water to obtain a phase change solution;

[0041] (2) weighing 0.5 g of sodium dodecylbenzene sulfonate and adding it to the above phase change solution, stirring and emulsifying at 700 rpm for 20 min to obtain an emulsion;

[0042] (3) Dissolve 3.0 g of barium nitrate and 3.0 g of sodium tungstate in 40 mL of deionized water to obtain zinc nitrate solution and sodium tungstate solution, respectively;

[0043] (4) adding the zinc nitrate solution obtained in step (3) dropwise to the emulsion obtained in step (2) while stirring, stirring at 700 rpm for 0.5 h after the addition is complete, and then adding the sodium tungstate solution obtained in step (3) dropwise to the reaction system while stirring, stirring at 700 rpm for 10 min after the addition is complete, to obtain a phase change microcapsule solution;

[0044] (5) The obtained phase change microcapsule solution was washed three times with anhydrous ethanol and deionized water respectively, and then dried naturally at room temperature for 24 hours to obtain powdered phase change microcapsules.

[0045] Performance Testing

[0046] Relevant performance tests were performed on the embodiments of the present invention and the comparative examples, and the specific test results are shown in Table 1.

[0047] Table 1

[0048] Test items The mass ratio of core material to shell material Coverage rate (%) Thermal storage efficiency (%) Example 1 1：0.5 30.56 31.33％ Example 2 1：1 45.19 45.04％ Example 3 1：1.5 25.17 24.80％ Example 4 1：2 18.58 18.98％ Example 5 1：0.5 32.43 34.24％ Example 6 1：0.5 30.56 31.33％ Example 7 1：0.5 9.73 9.06％ Example 8 1：1 28.7 29.13％ Example 9 1：1.5 9.63 8.89％ Example 10 1：2 8.09 7.59％ Comparative Example 1 1：0.5 20.15 22.34％

[0049] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A phase change microcapsule with zinc tungstate as shell material, characterized in that: The structure is a core-shell structure, the core material is a phase change material, the shell material is zinc tungstate, and the mass ratio of the core material to the shell material is 1:0.5-2.

2. The phase change microcapsule with zinc tungstate as shell material according to claim 1, characterized in that: The phase change material includes an organic phase change material, an inorganic phase change material or an organic-inorganic phase change material or a combination of two or more thereof.

3. The phase change microcapsule with zinc tungstate as shell material according to claim 2, characterized in that: The phase change material is stearic acid.

4. A phase change microcapsule with zinc tungstate as shell material according to any one of claims 1 to 3, characterized in that: The preparation method comprises the following steps: (1) adding a phase change material into deionized water and stirring at an appropriate temperature so that the phase change material is completely melted in the deionized water to obtain a phase change solution; (2) adding a surfactant to the phase change solution, stirring and emulsifying for at least 20 minutes to obtain an emulsion; (3) Add zinc nitrate and sodium tungstate into deionized water respectively and fully dissolve them at room temperature to obtain zinc nitrate solution and sodium tungstate solution respectively; (4) adding zinc nitrate dropwise to the emulsion while stirring, and continuing to stir for at least 30 minutes after the addition is completed, and then adding sodium tungstate solution dropwise to the emulsion while stirring, and continuing to stir for at least 10 minutes after the addition is completed, thereby obtaining a phase change microcapsule solution; (5) The obtained phase change microcapsule solution is washed with anhydrous ethanol and deionized water at least three times respectively, and the obtained solid product is dried at room temperature to obtain a powdered phase change microcapsule.

5. The phase change microcapsule with zinc tungstate as shell material according to claim 4, characterized in that: The surfactant includes at least one of sodium dodecylbenzene sulfonate, sodium dodecylbenzene sulfonate, hexadecyltrimethylammonium bromide and hexadecyltrimethylammonium chloride.

6. The phase change microcapsule with zinc tungstate as shell material according to claim 5, characterized in that: The surfactant is sodium dodecylbenzene sulfonate.

7. The phase change microcapsule with zinc tungstate as shell material according to claim 4, characterized in that: The dosage ratio of phase change material to deionized water in the phase change solution is 0.5-10g:50-400mL, the dosage ratio of surfactant to phase change material in the emulsion is 0.5-2:1-6, the dosage ratio of zinc nitrate to deionized water in the zinc nitrate solution is 1-5g:10-80mL, the dosage ratio of sodium tungstate to deionized water in the sodium tungstate solution is 1-5g:10-80mL, and the dosage ratio of sodium tungstate to zinc nitrate and surfactant in the phase change microcapsule solution is 1-5g:1-5g:0.5-2g.

8. The phase-change microcapsule with zinc tungstate as shell material according to claim 7, characterized in that: The dosage ratio of phase change material to deionized water in the phase change solution is 6g:260mL, the dosage ratio of surfactant to phase change material in the emulsion is 0.5:6, the dosage ratio of zinc nitrate to deionized water in the zinc nitrate solution is 3g:40mL, the dosage ratio of sodium tungstate to deionized water in the sodium tungstate solution is 3g:40mL, and the dosage ratio of sodium tungstate to zinc nitrate and surfactant in the phase change microcapsule solution is 3g:3g:0.5g.

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