A composite core material phase change microcapsule and its preparation method

Abstract

The present invention discloses a preparation method of composite core material phase change microcapsules, including the following: (1) mixing molten inorganic hydrated salt, sugar alcohol and polyetheramine in proportion and reacting to obtain a composite phase change core material; then mixing the composite phase change core material with water to obtain an aqueous phase substance; (2) mixing a certain amount of water-insoluble organic solvent and a surfactant to obtain an oil phase substance; (3) slowly dropping the aqueous phase substance into the oil phase substance, and vigorously stirring and reacting to obtain a homogeneous water-in-oil emulsion; (4) slowly adding a soluble barium salt aqueous solution to the water-in-oil emulsion, continuously stirring and reacting at a certain temperature, after the reaction is completed, filtering, washing and drying the reaction material to obtain the composite core material phase change microcapsules. The phase change microcapsules prepared by the present invention have a wider phase change temperature control range and have broad application prospects in aspects such as solar energy heat storage and temperature regulation, functional thermal fluids and temperature control of large electronic devices.

Description

Technical Field

[0001] The present invention belongs to the technical field of phase change energy storage materials, and particularly relates to a composite core material phase change microcapsule and a preparation method thereof. Background Technique

[0002] Phase change microcapsules, also known as microencapsulated phase change energy storage materials (Microencapsulated Phase Change Material, MEPCM), refer to composite phase change energy storage materials with a core-shell structure formed by coating a stable thin film on the surface of solid-liquid phase change energy storage material particles using microcapsule technology. During the phase change process of phase change microcapsules, a solid-liquid phase change occurs inside, while the outer thin film always maintains a solid structure. Therefore, such materials macroscopically appear as solid particles. Phase change microcapsules not only solve the problems of the stability, thermal conductivity, and volume expansion of phase change energy storage materials, but also simplify the use process of phase change energy storage materials and reduce their usage costs.

[0003] However, traditional phase change microcapsules mostly use organic phase change materials (such as paraffin, fatty acids, etc.) as the phase change core material. Although the phase change properties are stable, there are deficiencies such as limited latent heat of phase change value, high cost, low thermal conductivity, and flammability. Therefore, people's attention has turned to inorganic phase change materials with a wider range of raw material sources. As an inorganic phase change material, hydrated salts have advantages such as a high latent heat of phase change value, high thermal conductivity, and non-flammability, and are widely used in technical fields such as solar heating, floor radiant heating, and temperature control of precision components.

[0004] CN102676124A discloses an inorganic hydrated salt phase change energy storage microcapsule and a preparation method thereof. By selecting a suitable organic solvent, supplemented with a surfactant, a uniformly dispersed mixed solution of the core material and the polymer monomer material of the shell material is formed under ultrasonic action; by adding functional additives such as initiators, lubricants, stabilizers, and inhibitors, the polymer monomer is suspension-polymerized and cured in the mixed solution to coat the core material to form a phase change energy storage microcapsule. Among them, the inorganic hydrated salt core material accounts for 50% - 80% of the mass of the microcapsule, and the vinyl monomer polymer shell material accounts for 20% - 50% of the mass of the microcapsule. However, the shell material of the phase change energy storage microcapsule prepared by this method is an organic material, resulting in a not-high thermal conductivity; moreover, relying only on the coating of the shell material cannot completely solve the defects of supercooling and phase separation of the inorganic hydrated salt core material, and these two problems are likely to occur after multiple cycles of use.

[0005] CN106244117A discloses an inorganic hydrated salt phase change energy storage microcapsule and its preparation method. The core material is added to deionized water to prepare a saturated solution of the core material. An emulsifier is added to the saturated solution of the core material, and ultrasonic emulsification is carried out for 20 min to 50 min, and magnetic stirring is carried out in a water bath at 35 °C to 60 °C for a period of time to obtain a uniformly dispersed core material emulsion A. The wall material prepolymer is added to the organic phase, and magnetic stirring is carried out for 30 min to obtain a transparent prepolymer solution B. The uniformly dispersed core material emulsion A is added dropwise to the prepolymer solution B, and magnetic stirring is carried out to form a uniformly dispersed solution. A pH regulator is added to adjust the pH value of the solution to 9.5 to 11, and constant temperature stirring is carried out for 6 h to 10 h to complete the reaction. After centrifugal washing and drying, an inorganic phase change energy storage microcapsule is obtained. For the phase change energy storage microcapsule prepared by this method, due to the fact that the inorganic core material is not treated at all, technical problems of supercooling and phase separation exist after multiple uses. Summary of the Invention

[0006] In view of the deficiencies of the prior art, the present invention provides a composite core material phase change microcapsule and its preparation method. The composite core material phase change microcapsule of the present invention has a wider phase change temperature control range, and improves the supercooling and phase separation problems of the inorganic hydrated salt core material; an inorganic shell material is obtained through a targeted deposition reaction, which not only improves the coating rate and coating integrity, but also effectively overcomes the disadvantage of low thermal conductivity of the organic shell material.

[0007] The preparation method of the composite core material phase change microcapsule of the present invention includes the following contents:

[0008] (1) Mix and react molten inorganic hydrated salt, sugar alcohol and polyetheramine in proportion to obtain a composite phase change core material; then the composite phase change core material is mixed with water to obtain an aqueous phase substance;

[0009] (2) Mix a certain amount of water-insoluble organic solvent and a surfactant to obtain an oil phase substance;

[0010] (3) Slowly drip the aqueous phase substance into the oil phase substance, and carry out vigorous stirring reaction to obtain a homogeneous water-in-oil emulsion;

[0011] (4) Slowly add a soluble barium salt aqueous solution to the water-in-oil emulsion, continuously stir and react at a certain temperature. After the reaction is completed, the reaction material is filtered, washed and dried to obtain a composite core material phase change microcapsule.

[0012] In step (1), the inorganic hydrated salt is selected from one or more of zinc nitrate hexahydrate, disodium hydrogen phosphate dodecahydrate or sodium sulfate decahydrate. The sugar alcohol is selected from one or more of xylitol, erythritol or sorbitol. The polyetheramine is a polyetheramine with an average molecular weight of 1000 to 2000.

[0013] In step (1), the mass ratio of the inorganic hydrated salt, sugar alcohol, and polyetheramine is 1: 0.01-0.08: 0.001-0.008, preferably 1: 0.03-0.06: 0.003-0.006.

[0014] In step (1), the mixing reaction conditions of the inorganic hydrated salt, sugar alcohol, and polyetheramine are as follows: the reaction temperature is 90 °C to 150 °C, preferably 110 °C to 130 °C, the reaction time is 15 to 45 minutes, preferably 25 to 35 minutes; the reaction is generally carried out under stirring conditions.

[0015] In step (1), the mass ratio of the composite phase change core material to water is 1: 0.5-1.2, preferably 1: 0.7-1.

[0016] In step (1), during the mixing stage of the composite phase change core material, the reaction temperature is 60 °C to 95 °C, preferably 75 °C to 85 °C; the reaction time is 10 to 30 minutes, preferably 15 to 25 minutes. The mixing is carried out under stirring conditions.

[0017] In step (2), the non-water-soluble organic solvent is selected from one or more of cycloheptane, cyclooctane, and cyclodecane, preferably cyclodecane. The surfactant is selected from a composition of an anionic surfactant and a non-ionic surfactant, where the anionic surfactant is selected from one or more of sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, and sodium dodecylnaphthalenesulfonate; the non-ionic surfactant is selected from one or several of octylphenol polyoxyethylene ether-10, nonylphenol polyoxyethylene ether-10, and Tween 20.

[0018] In step (2), the mass ratio of the non-water-soluble organic solvent to the surfactant is 1: 0.05-0.5, preferably 1: 0.08-0.25. Among them, the mass ratio of the anionic surfactant to the non-ionic surfactant is 1: 0.04-0.1, preferably 1: 0.06-0.08.

[0019] In step (2), the mixing temperature is 30 °C to 70 °C, preferably 45 °C to 55 °C, the mixing time is 5 to 25 minutes, preferably 10 to 15 minutes. The mixing is carried out under stirring conditions.

[0020] In step (3), the dropping rate of the aqueous phase material is 0.5 g / min to 3 g / min, preferably 1 g / min to 2 g / min.

[0021] In step (3), the violent stirring reaction temperature is 70 °C to 115 °C, preferably 90 °C to 105 °C, the reaction time is 25 to 55 minutes, preferably 35 to 45 minutes; the stirring speed is 3000 rpm to 8000 rpm, preferably 5000 rpm to 6000 rpm.

[0022] In step (4), the soluble barium salt is selected from barium chloride and / or barium nitrate. The mass ratio of the soluble barium salt to the anionic surfactant is 1:0.55 - 0.95, preferably 1:0.68 - 0.83.

[0023] In step (4), the mass percentage concentration of the aqueous solution of the soluble barium salt is 30% - 70%, preferably 50% - 60%. The dropping rate is 0.5 g / min - 3 g / min, preferably 1 g / min - 2 g / min.

[0024] In step (4), the reaction temperature is 70°C - 115°C, preferably 90°C - 105°C; the reaction time is 2.5 - 8.5 hours, preferably 5 - 6.5 hours.

[0025] In step (4), the washing is carried out with an ethanol aqueous solution, and the mass percentage concentration of the ethanol aqueous solution is 30% - 50%. The drying temperature is 50°C - 100°C, preferably 70°C - 80°C. The drying time is 10 - 30 hours, preferably 15 - 20 hours.

[0026] The present invention also provides a composite core material phase change microcapsule, the average particle size of the composite core material phase change microcapsule is 200 nm - 400 nm, the latent heat of fusion value is 105 J / g - 122 J / g, the coating rate is 65% - 75%, and the thermal conductivity is 0.68 W·m -1 ·k -1 ~0.83 W·m -1 ·K -1 , and the compressive strength is 1.35 MPa - 1.86 MPa.

[0027] The composite core material phase change microcapsule prepared by the present invention can be used in multiple technical fields such as solar energy heat storage and temperature regulation, functional thermal fluids, and temperature control of large electronic devices.

[0028] Compared with the prior art, the present invention has the following advantages:

[0029] (1) The present invention uses an inorganic hydrated salt and a sugar alcohol compounded as the phase change core material. The sugar alcohol can form a hydrogen bond with the inorganic hydrated salt matrix, promoting the nucleation of the matrix; adding polyetheramine can increase the consistency of the matrix, enabling the nucleating agent to be stably distributed in the matrix material, so that the nucleating agent can effectively play the nucleating role, effectively overcoming the adverse phenomena of easy supercooling and phase separation when the inorganic hydrated salt is used as the phase change core material; at the same time, by adjusting the ratio between the inorganic hydrated salt and the sugar alcohol, composite core materials with different phase change temperatures can be obtained, broadening the applicable range of the phase change temperature of the product;

[0030] (2) The present invention uses sugar alcohol as part of the composite phase change core material. During the titration of the aqueous phase material to the oil phase material, it forms a compound surfactant synergistic effect together with an anionic surfactant and a non-ionic surfactant, and at the same time, the compound surfactant obtained makes the solution system more stable;

[0031] (3) The present invention obtains an inorganic wall material by chemical deposition. The surfactant component distributed around the aqueous phase material during the wall material deposition and prepolymerization stages can play a targeted navigation role, so that the obtained inorganic wall material has uniform thickness and excellent texture, and extends the service life of the composite core material phase change microcapsule. Description of the Drawings

[0032] Figure 1 Cooling curves after 100 cycles of the phase change microcapsules prepared in Example 1 and Comparative Example 2.

[0033] Figure 2 Scanning electron microscope photograph (SEM) of the phase change microcapsules prepared in Example 1. Detailed Embodiments

[0034] The preparation method and effect of the composite core material phase change microcapsule of the present invention will be further described below through examples. The examples are implemented on the premise of the technical solution of the present invention, and detailed implementation methods and specific operation processes are given, but the protection scope of the present invention is not limited to the following examples.

[0035] In the following examples, the experimental methods, unless otherwise specified, are all conventional methods in the art. The experimental materials used in the following examples, unless otherwise specified, are all purchased from conventional biochemical reagent stores.

[0036] Example 1

[0037] Take 50 g of zinc nitrate hexahydrate, 2.5 g of xylitol and 0.25 g of polyetheramine D-2000 and mix them. Stir and react at 120 °C for 30 minutes to obtain a composite phase change core material. Take 10 g of the composite phase change core material, add 8 g of deionized water thereto, and stir and react at 80 °C for 20 minutes to obtain an aqueous phase material. Add 7 g of sodium dodecyl sulfate and 0.5 g of octylphenol polyoxyethylene ether-10 to 50 g of cyclodecane, stir and react at 50 °C for 12 minutes to obtain an oil phase material. Drop the aqueous phase material into the oil phase material at a rate of 1.5 g / min, and stir and react vigorously at 100 °C for 40 minutes to obtain a homogeneous water-in-oil emulsion. Drop 17.6 g of barium chloride aqueous solution into the emulsion at a rate of 1.5 g / min, stir and react at 100 °C for 6 hours. After the obtained suspension is filtered, it is washed with an ethanol aqueous solution with a mass concentration of 40% and dried at 75 °C for 18 hours to obtain the composite core material phase change microcapsule.

[0038] Example 2

[0039] 50 g of zinc nitrate hexahydrate, 1.5 g of xylitol and 0.15 g of polyetheramine D-2000 were mixed and stirred at 110 °C for 25 minutes to obtain a composite phase change core material. 10 g of the composite phase change core material was taken, 7 g of deionized water was added thereto, and the mixture was stirred at 75 °C for 15 minutes to obtain an aqueous phase material. 3.77 g of sodium dodecyl sulfate and 0.23 g of octylphenol polyoxyethylene ether-10 were added to 50 g of cyclodecane, and the mixture was stirred at 45 °C for 10 minutes to obtain an oil phase material. The aqueous phase material was added dropwise to the oil phase material at a rate of 1 g / min, and the mixture was vigorously stirred at 90 °C for 35 minutes to obtain a homogeneous water-in-oil emulsion. 10 g of barium chloride aqueous solution was added dropwise to the emulsion at a rate of 1 g / min, and the mixture was stirred at 90 °C for 5 hours. The resulting suspension was filtered and washed with an aqueous ethanol solution with a mass concentration of 30%, and dried at 70 °C for 15 hours to obtain composite core material phase change microcapsules.

[0040] Example 3

[0041] 50 g of zinc nitrate hexahydrate, 3 g of xylitol and 0.3 g of polyetheramine D-2000 were mixed and stirred at 130 °C for 35 minutes to obtain a composite phase change core material. 10 g of the composite phase change core material was taken, 10 g of deionized water was added thereto, and the mixture was stirred at 85 °C for 25 minutes to obtain an aqueous phase material. 11.57 g of sodium dodecyl sulfate and 0.93 g of octylphenol polyoxyethylene ether-10 were added to 50 g of cyclodecane, and the mixture was stirred at 55 °C for 15 minutes to obtain an oil phase material. The aqueous phase material was added dropwise to the oil phase material at a rate of 2 g / min, and the mixture was vigorously stirred at 105 °C for 45 minutes to obtain a homogeneous water-in-oil emulsion. 25.3 g of barium chloride aqueous solution was added dropwise to the emulsion at a rate of 2 g / min, and the mixture was stirred at 105 °C for 6.5 hours. The resulting suspension was filtered and washed with an aqueous ethanol solution with a mass concentration of 50%, and dried at 80 °C for 20 hours to obtain composite core material phase change microcapsules.

[0042] Example 4

[0043] Same as Example 1, except that disodium hydrogen phosphate dodecahydrate was used instead of zinc nitrate hexahydrate, and other reaction conditions and material compositions remained unchanged, to obtain composite core material phase change microcapsules.

[0044] Example 5

[0045] Same as Example 1, except that sodium sulfate decahydrate was used instead of zinc nitrate hexahydrate, and other reaction conditions and material compositions remained unchanged, to obtain composite core material phase change microcapsules.

[0046] Example 6

[0047] Same as Example 1, except that erythritol is used instead of xylitol, and other reaction conditions and material compositions remain unchanged, to obtain the composite core material phase change microcapsules.

[0048] Example 7

[0049] Same as Example 1, except that sorbitol is used instead of xylitol, and other reaction conditions and material compositions remain unchanged, to obtain the composite core material phase change microcapsules.

[0050] Example 8

[0051] Same as Example 1, except that 10 g of the composite phase change core material is taken, and 5 g of deionized water is added thereto, and other reaction conditions and material compositions remain unchanged, to obtain the composite core material phase change microcapsules.

[0052] Example 9

[0053] Same as Example 1, except that cycloheptane is used instead of cyclodecane, and other reaction conditions and material compositions remain unchanged, to obtain the composite core material phase change microcapsules.

[0054] Example 10

[0055] Same as Example 1, except that cyclooctane is used instead of cyclodecane, and other reaction conditions and material compositions remain unchanged, to obtain the composite core material phase change microcapsules.

[0056] Example 11

[0057] Same as Example 1, except that sodium dodecylbenzenesulfonate is used instead of sodium dodecyl sulfate, and other reaction conditions and material compositions remain unchanged, to obtain the composite core material phase change microcapsules.

[0058] Example 12

[0059] Same as Example 1, except that sodium dodecylnaphthalenesulfonate is used instead of sodium dodecyl sulfate, and other reaction conditions and material compositions remain unchanged, to obtain the composite core material phase change microcapsules.

[0060] Example 13

[0061] Same as Example 1, except that nonylphenol polyoxyethylene ether-10 is used instead of octylphenol polyoxyethylene ether-10, and other reaction conditions and material compositions remain unchanged, to obtain the composite core material phase change microcapsules.

[0062] Example 14

[0063] Same as Example 1, except that Tween 20 is used instead of octylphenol polyoxyethylene ether-10, and other reaction conditions and material compositions remain unchanged, to obtain the composite core material phase change microcapsules.

[0064] Example 15

[0065] Same as Example 1, except that the dropping rate of the aqueous phase material is increased to 3 g / min, and other reaction conditions and material compositions remain unchanged, to obtain the composite core material phase change microcapsules.

[0066] Example 16

[0067] Same as Example 1, except that barium nitrate is used instead of barium chloride, and other reaction conditions and material compositions remain unchanged, to obtain the composite core material phase change microcapsules.

[0068] Example 17

[0069] Same as Example 1, except that the dropping rate of the barium chloride aqueous solution is reduced to 0.5 g / min, and other reaction conditions and material compositions remain unchanged, to obtain the composite core material phase change microcapsules.

[0070] Example 18

[0071] Same as Example 1, except that the mass concentration of the ethanol aqueous solution for washing is increased to 50%, the drying temperature is reduced to 50 °C, and the drying time is extended to 30 hours, and other reaction conditions and material compositions remain unchanged, to obtain the composite core material phase change microcapsules.

[0072] Comparative Example 1

[0073] Same as Example 1, except that xylitol and polyetheramine D-2000 are omitted, and other reaction conditions and material compositions remain unchanged, to obtain the composite core material phase change microcapsules.

[0074] Comparative Example 2

[0075] Same as Example 1, except that polyetheramine D-2000 is omitted, and other reaction conditions and material compositions remain unchanged, to obtain the composite core material phase change microcapsules.

[0076] Comparative Example 3

[0077] Same as Example 1, except that octylphenol polyoxyethylene ether-10 is omitted, and other reaction conditions and material compositions remain unchanged, to obtain the composite core material phase change microcapsules.

[0078] Comparative Example 4

[0079] Same as Example 1, except that the aqueous phase material is directly poured into the oil phase material, and other reaction conditions and material compositions remain unchanged, to obtain the composite core material phase change microcapsules.

[0080] Comparative Example 5

[0081] Same as Example 1, except that the soluble barium salt aqueous solution is directly poured into the emulsion, and other reaction conditions and material compositions remain unchanged, to obtain the composite core material phase change microcapsules.

[0082] Comparative Example 6

[0083] Same as Example 1, except that the amounts of sodium dodecyl sulfate and octylphenol polyoxyethylene ether - 10 are reduced to 0.93 g and 0.07 g respectively, and other reaction conditions and material compositions remain unchanged, to obtain composite core - material phase - change microcapsules.

[0084] Comparative Example 7

[0085] According to the method described in CN102676124A, weigh 15 g of disodium hydrogen phosphate dodecahydrate and 4.5 g of deionized water, place them in a 100 - mL beaker, and put it in a 37°C constant - temperature water bath. Then add 0.375 g of Span 80 and 50 mL of toluene, stir evenly and ultrasonically crush for 30 min to form an emulsion. Measure 12.5 mL of methyl methacrylate, 2.25 mL of ethyl acrylate, 0.003 g of sodium polyacrylate, 0.0072 g of stearic acid, 0.0036 g of benzoyl peroxide and mix them with 50 mL of acetone, ultrasonically crush for 20 min to form a mixed solution. Drop the mixed solution into the emulsion drop by drop, stir magnetically, control the temperature at 80°C - 90°C, react for 4 h - 5 h to form an emulsion. Add 0.0018 g of methylhydroquinone to the above - mentioned emulsion, mix evenly, and leave it at room temperature for 5 h - 6 h to obtain an emulsion containing microcapsules. Wash the emulsion, centrifuge and separate, and dry to obtain a microcapsule product.

[0086] Comparative Example 8

[0087] According to the method described in CN106244117A, weigh 15 g of sodium thiosulfate pentahydrate, dissolve it in 20 mL of deionized water, add 0.6 g - 1 g of sodium dodecyl sulfate, ultrasonically disperse for 40 min, place it in a 35°C constant - temperature water bath and stir - react at 800 rpm for 30 min to obtain core - material emulsion A. Add 6 mL - 8 mL of tetraethyl orthosilicate to 25 mL of cyclohexane, stir magnetically at 600 rpm - 1000 rpm for 30 min, dropwise add 5 mL of pentanol, and continue to stir for 10 min to obtain prepolymer solution B. Drop A into B drop by drop, keep the temperature at 60°C, stir magnetically at 600 rpm - 1000 rpm for 30 min, dropwise add 3 - aminopropyldiethoxysilane, adjust the pH value of the solution to 10, and stir constantly at a constant temperature for 8 h - 10 h. After the reaction, centrifuge and separate, wash with deionized water and absolute ethanol respectively, and dry at 40°C for 16 h to obtain inorganic phase - change energy - storage microcapsules.

[0088] Test Example 1

[0089] The physical and chemical properties of the phase change microcapsules in Examples 1-18 and Comparative Examples 1-8 were measured, and the specific results are shown in Table 1. The morphology and particle size of the phase change microcapsules were observed using a Hitachi S-4700 field emission scanning electron microscope (SEM) in Japan. The latent heat of phase change value during the melting process of the phase change microcapsules was measured using a differential scanning calorimeter (DSC), and the instrument model was DSC-60 Plus from Shimadzu Corporation in Japan. Under a nitrogen atmosphere, the temperature test range was -70 °C to 70 °C, the heating rate was 10 °C / min, and the sample weight was approximately 3.5 mg. The thermal conductivity of the phase change microcapsule samples was measured using a DRL-III-P thermal conductivity tester from Xiangyi Instrument Co., Ltd. The compressive strength of the phase change microcapsule samples was measured using a YL-C10K pressure testing machine from Yue Lian Instrument Co., Ltd. in Guangdong. During the supercooling degree test, first, the samples of Example 1 and Comparative Example 2 were inserted into thermocouple sensors and placed in a water bath. They were heated at 85 °C for 30 min, taken out and cooled at room temperature. The average room temperature was 25 °C. The temperature changes were recorded through a data acquisition system, and a cooling curve was plotted. This was repeated 100 times. By comparing the changes in the supercooling degree of different samples, the thermal reliability performance was evaluated.

[0090] The calculation formula for the encapsulation rate of the phase change microcapsules is:

[0091] Encapsulation rate / % = (latent heat of fusion value of microcapsules / latent heat of fusion value of phase change material) × 100%

[0092] Table 1 Properties of the phase change microcapsules prepared in Examples and Comparative Examples

[0093]

[0094] Table 1 (continued) Properties of the phase change microcapsules prepared in Examples and Comparative Examples

[0095]

[0096] From Table 1, Figure 1 - Figure 2 it can be seen that the composite core material phase change microcapsules prepared by the present invention have good physical and chemical properties and regular microscopic morphologies. Since an inorganic hydrated salt and a sugar alcohol are compounded as the phase change core material, the sugar alcohol can form a hydrogen bond with the inorganic hydrated salt matrix, promoting matrix nucleation; adding polyetheramine can increase the matrix consistency, enabling the nucleating agent to be stably distributed in the matrix material, so that the nucleating agent can effectively play a nucleating role, that is, effectively overcoming the adverse phenomena of easy supercooling and phase separation when using an inorganic hydrated salt as the phase change core material. The latent heat of fusion value of the sample in Example 1 was 121.1 J / g. After continuous use for 100 cycles, its supercooling degree was only 0.25 °C, which was significantly lower than that of the samples in the comparative examples. That is, the composite core material phase change microcapsules prepared by the present invention have good thermal stability and reusability.

Claims

1. A preparation method of a composite core material phase change microcapsule, characterized in that It includes the following: (1) Mixing molten inorganic hydrated salt, sugar alcohol and polyetheramine in proportion and reacting to obtain a composite phase change core material; then mixing the composite phase change core material with water to obtain an aqueous phase substance; (2) Mixing a certain amount of water-insoluble organic solvent and a surfactant to obtain an oil phase substance; (3) Slowly dripping the aqueous phase substance into the oil phase substance, and vigorously stirring and reacting to obtain a homogeneous water-in-oil emulsion; (4) Slowly adding a soluble barium salt aqueous solution to the water-in-oil emulsion, continuously stirring and reacting at a certain temperature, and after the reaction is completed, filtering, washing and drying the reaction material to obtain composite core material phase change microcapsules; the surfactant is selected from a composition of an anionic surfactant and a nonionic surfactant; wherein the anionic surfactant is selected from one or more of sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, and sodium dodecylnaphthalenesulfonate; the nonionic surfactant is selected from one or more of octylphenol polyoxyethylene ether-10, nonylphenol polyoxyethylene ether-10, and Tween 20; the mass ratio of the water-insoluble organic solvent to the surfactant is 1:0.05-0.5; the mass ratio of the anionic surfactant to the nonionic surfactant is 1:0.04-0.1; the average particle size of the composite core material phase change microcapsules is 200nm-400nm, the melting latent heat value is 105J / g-122J / g, the coating rate is 65%-75%, and the thermal conductivity is 0.68W·m -1 ·k -1 ~0.83W·m -1 ·K -1 , and the compressive strength is 1.35MPa-1.86MPa.

2. The method according to claim 1, wherein: The inorganic hydrated salt is selected from one or more of zinc nitrate hexahydrate, disodium hydrogen phosphate dodecahydrate or sodium sulfate decahydrate.

3. The method according to claim 1, characterized in that: The sugar alcohol is selected from one or more of xylitol, erythritol or sorbitol.

4. The method according to claim 1, characterized in that: The average number-average molecular weight of the polyetheramine is 1000 to 2000.

5. The method according to claim 1, wherein: The mass ratio of the inorganic hydrated salt, sugar alcohol and polyetheramine is 1: 0.01 to 0.08: 0.001 to 0.

008.

6. The method according to claim 1, wherein: The reaction conditions for the mixing reaction of the inorganic hydrated salt, sugar alcohol and polyetheramine are: the reaction temperature is 90 to 150 °C, and the reaction time is 15 to 45 minutes.

7. The method according to claim 1, characterized in that: The mass ratio of the composite phase change core material to water is 1: 0.5 to 1.

2.

8. The method according to claim 1, characterized in that: The reaction conditions for mixing the composite phase change core material and water are: the reaction temperature is 60 to 95 °C, and the reaction time is 10 to 30 minutes.

9. The method according to claim 1, wherein: The water-insoluble organic solvent is selected from one or more of cycloheptane, cyclooctane, cyclodecane.

10. The method according to claim 1, wherein: The mixing temperature in step (2) is 30 °C to 70 °C, and the mixing time is 5 to 25 minutes.

11. The method according to claim 1, wherein: In step (3), the dropping rate of the aqueous phase material is 0.5 to 3 g / min.

12. The method according to claim 1, wherein: In step (3), the violent stirring reaction temperature is 70 to 115 °C, the reaction time is 25 to 55 minutes; the stirring speed is 3000 rpm to 8000 rpm.

13. The method according to claim 1, wherein: In step (4), the soluble barium salt is selected from barium chloride and / or barium nitrate; the mass ratio of the soluble barium salt to the anionic surfactant is 1: 0.55 to 0.

95.

14. The method according to claim 1, wherein: In step (4), the mass percentage concentration of the aqueous solution of the soluble barium salt is 30% to 70%; the adding rate is 0.5 g / min to 3 g / min.

15. The method according to claim 1, characterized in that: In step (4), the reaction temperature is 70 °C to 115 °C, and the reaction time is 2.5 to 8.5 hours.

16. Application of the composite core material phase change microcapsule prepared by the method according to any one of claims 1 to 15 in the fields of solar energy heat storage and temperature regulation, functional heat fluid and temperature control of large electronic devices.

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