Aerogel composite material, preparation method thereof and thermal insulation energy storage material

Abstract

The invention provides an aerogel composite material, a preparation method thereof and a thermal insulation energy storage material, the aerogel composite material has a porous skeleton structure, the porous skeleton structure comprises phase change material particles and a polymer, and the polymer coats at least part of the surface of the phase change material particles; the phase change enthalpy value of the aerogel composite material is not lower than 200J / g, and the heat conductivity coefficient is not higher than 0.16 W / (m.K); the phase change material particles and the polymer are jointly assembled to form an aerogel skeleton structure, the aerogel composite material is obtained, a base body of the aerogel composite material is composed of the phase change material particles and a polymer network, the aerogel composite material has excellent heat insulation performance, meanwhile, the phase change material serves as a functional phase to provide phase change heat storage capacity, and the phase change heat storage capacity is improved. The synergistic effect of the phase change material and the polymer not only constructs a stable skeleton structure, but also improves the low thermal conductivity and high energy storage density of the aerogel composite material, and meets the dual requirements for efficient heat insulation and energy storage in practical application.

Description

Technical Field

[0001] The present invention belongs to the technical field of phase-change aerogel composite materials, and in particular relates to an aerogel composite material and a preparation method thereof, and a heat-insulating energy storage material. Background Art

[0002] The building constant temperature thermal management industry is a key area of ​​rapid development in recent years. As people's demand for high-quality, comfortable and energy-saving living environment continues to increase, the demand for building energy conservation and temperature control management market is also continuing to grow.

[0003] Aerogel is a traditional building insulation material with advantages such as light weight and thermal insulation. However, it is brittle, easy to break, has poor mechanical bearing capacity, and its heat storage performance needs to be improved. It has poor stability in high-intensity, long-cycle applications and is therefore only suitable for thermal insulation applications in specific environments.

[0004] Therefore, in view of the actual engineering needs in the field of building constant temperature thermal management, it is urgent to develop new insulation and energy storage materials. Summary of the invention

[0005] The invention provides an aerogel composite material and a preparation method thereof, and a heat-insulating energy storage material, which are used to solve the problems of high thermal conductivity, low energy storage density, and low stability of aerogel materials in the prior art in high-strength and long-cycle applications.

[0006] In a first aspect, the present invention provides an aerogel composite material having a porous skeleton structure, wherein the porous skeleton structure comprises phase change material particles and a polymer, wherein the polymer is coated on at least a portion of the surface of the phase change material particles; The phase change enthalpy value of the aerogel composite material is not less than 200 J / g, and the thermal conductivity coefficient is not higher than 0.16 W / (m·K).

[0007] Compared with the prior art, the advantages of the present invention are as follows: the skeleton structure of aerogel is formed by assembling phase change material particles and polymers together to obtain an aerogel composite material, whose matrix is ​​composed of phase change material particles and polymer network and has excellent thermal insulation performance. At the same time, the phase change material provides phase change heat storage capacity as a functional phase. The synergistic effect of the phase change material and the polymer not only constructs a stable skeleton structure, but also improves the low thermal conductivity and high energy storage density of the aerogel composite material, thereby meeting the dual needs of efficient thermal insulation and energy storage in practical applications.

[0008] Furthermore, the mass ratio of the phase change material particles to the polymer is (1-9): (0.3-1.5).

[0009] Further, the particle size of the phase change material particles is 2-50 μm; and / or, The solid content of the phase change material particles is 80-90%.

[0010] Further, the phase change material particles include at least one of stearic acid, lauryl alcohol, paraffin and methyl palmitate; and / or, The polymer includes at least one of gelatin, chitosan, polyacrylamide, polyvinyl alcohol and sodium alginate.

[0011] Furthermore, the phase change material particles are paraffin, the polymer is polyvinyl alcohol, and the mass ratio of the paraffin to the polyvinyl alcohol is (0.4-0.8): (5-7); and / or, The phase change material particles are paraffin, and the polymer includes polyacrylamide and polyvinyl alcohol in a mass ratio of (2-4): (0.5-1.5).

[0012] The phase change material particles include paraffin and stearic acid in a mass ratio of (3-5): (1-3), and the polymer includes gelatin and polyvinyl alcohol in a mass ratio of (2-4): (0.5-1.5).

[0013] In a second aspect, the present invention provides a method for preparing an aerogel composite material, which is used to prepare the aerogel composite material described in the first aspect, and is characterized by comprising the following steps: (1) adding a molten phase change material to a polymer solution, performing stirring pre-dispersion treatment and ultrasonic crushing treatment in sequence, and obtaining a phase change material particle emulsion after cooling; (2) pouring the phase change material particle emulsion into a mold and subjecting it to a freeze-thaw cycle treatment, and then freeze-drying treatment to obtain the aerogel composite material; wherein the freeze-thaw cycle treatment includes a freezing treatment and a melting treatment performed in sequence.

[0014] Further, the freezing treatment temperature is -5 to -40°C and the duration is 6 to 48 hours; and / or, The thawing treatment is carried out at room temperature and lasts for 6 to 48 hours; the number of freeze-thaw cycles is 1 to 8 times.

[0015] Furthermore, the stirring pre-dispersion treatment is performed at a temperature of 20 to 90° C. for a time of 1 to 60 minutes; and / or, The ultrasonic treatment is performed at a temperature of 20 to 90° C. for a time of 1 to 30 min; and / or The freeze-drying treatment is carried out at a temperature of -60 to -85°C and for a time of 6 to 72 hours.

[0016] Furthermore, the freeze-drying process also includes a pre-cooling process, wherein the temperature of the pre-cooling process is -10 to -80°C and the time is 10 minutes to 5 hours.

[0017] In a third aspect, the present invention provides a thermal insulation energy storage material, comprising the aerogel composite material described in the first aspect or an aerogel composite material prepared by the preparation method of the aerogel composite material described in the second aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The reliability verification results in the test examples of the present invention; Figure 2 This is a SEM image of the aerogel composite material prepared in Example 4 of the present invention; Figure 3 This is a SEM image of the aerogel composite material prepared in Example 4 of the present invention. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] In a first aspect, the present invention provides an aerogel composite material having a porous skeleton structure, wherein the porous skeleton structure comprises phase change material particles and a polymer, wherein the polymer is coated on at least a portion of the surface of the phase change material particles; The phase change enthalpy value of the aerogel composite material is not less than 200 J / g, and the thermal conductivity is not higher than 0.16 W / (m·K).

[0021] The aerogel composite material provided by the present invention is composed of phase change material particles and polymers assembled together to form the skeleton structure of the aerogel. The polymer forms a coating layer on the surface of the phase change material particles. The phase change material particles and the polymer coating layer on their surface form a microsphere structure. The microspheres are adsorbed by electrostatic effect to form a porous skeleton structure, which has excellent thermal insulation performance. At the same time, the phase change material provides phase change heat storage capacity as a functional phase. The porous structure gives the aerogel excellent thermal insulation performance, and the phase change material realizes the heat storage function by absorbing and releasing latent heat when the temperature changes. The polymer coating prevents the phase change material from flowing or leaking, so that the material has high efficiency in thermal insulation and heat storage capacity while maintaining structural stability.

[0022] The aerogel composite material provided by the present invention is obtained by assembling phase change material particles and polymers together to form an aerogel skeleton structure. The aerogel composite material has a matrix composed of phase change material particles and a polymer network and has excellent thermal insulation performance. At the same time, the phase change material provides phase change heat storage capacity as a functional phase. The synergistic effect of the phase change material and the polymer not only constructs a stable skeleton structure, but also improves the low thermal conductivity and high energy storage density of the aerogel composite material, thereby meeting the dual needs of efficient thermal insulation and energy storage in practical applications.

[0023] Furthermore, the mass ratio of the phase change material particles to the polymer is (1~9):(0.3~1.5).

[0024] By further limiting the mass ratio of the phase change material particles to the polymer, the synergistic effect can be further enhanced, the thermal conductivity of the aerogel composite material can be further reduced, the energy storage density can be increased, and the stability of the aerogel composite material can be further improved.

[0025] Specifically, the particle size of the phase change material particles is 2-50 μm; and the solid content of the phase change material particles is 80-90%.

[0026] By further limiting the phase change material particles and the polymer, the synergistic effect can be further enhanced, the thermal conductivity of the aerogel composite material can be further reduced, the energy storage density can be increased, and the stability of the aerogel composite material can be further improved.

[0027] Optionally, the phase change material particles include at least one of stearic acid, lauryl alcohol, paraffin and methyl palmitate; the polymer includes at least one of gelatin, chitosan, polyacrylamide, polyvinyl alcohol and sodium alginate.

[0028] When the phase change material particles or polymers are selected from the above-defined materials, the synergistic effect can be further enhanced, the thermal conductivity of the aerogel composite material can be further reduced, the energy storage density can be increased, and the stability of the aerogel composite material can be further improved.

[0029] In a specific implementation example, the phase change material particles are paraffin, the polymer is polyvinyl alcohol, and the mass ratio of paraffin to polyvinyl alcohol is (5-7): (0.4-0.8).

[0030] In another specific embodiment, the phase change material particles are paraffin; the polymers are polyacrylamide and polyvinyl alcohol, and the mass ratio is (2-4): (0.5-1.5).

[0031] In another specific embodiment, the phase change material particles are paraffin and stearic acid in a mass ratio of (3-5):(1-3); the polymer is gelatin and polyvinyl alcohol in a mass ratio of (2-4):(0.5-1.5).

[0032] The inventors have found that when the phase change material particles and the polymer are combined as described above and in a special ratio, the thermal conductivity of the aerogel composite material can be further reduced, the energy storage density can be increased, and the stability of the aerogel composite material can be further improved.

[0033] In a second aspect, the present invention provides a method for preparing an aerogel composite material, which is used to prepare the aerogel composite material of the first aspect, comprising the following steps: (1) adding a molten phase change material to a polymer solution, performing stirring pre-dispersion treatment and ultrasonic crushing treatment in sequence, and obtaining a phase change material particle emulsion after cooling; (2) After the phase change material particle emulsion is poured into a mold, a freeze-thaw cycle treatment is performed, and then a freeze-drying treatment is performed to obtain an aerogel composite material; wherein the freeze-thaw cycle treatment includes a freezing treatment and a melting treatment performed in sequence.

[0034] In step (1), the molten phase change material particles are added into a completely dissolved uniform and transparent polymer solution, and the polymer is coated on the surface of the phase change material particles through stirring pre-dispersion treatment and ultrasonic crushing treatment, and a stable phase change material particle emulsion is obtained after cooling; in step (2), the phase change material particle emulsion is poured into a mold and subjected to a freeze-thaw cycle treatment, and then subjected to a freeze-drying treatment to form an aerogel composite material with a porous skeleton structure.

[0035] The preparation method of the aerogel composite material provided by the present invention can form an excellent porous skeleton structure by subjecting a stably dispersed phase change material particle emulsion coated with a polymer to a freeze-thaw cycle treatment and then to a freeze-drying treatment, so that a good interface is formed between the phase change material particle microspheres coated with the polymer, and the aerogel composite material with a phase change enthalpy value of not less than 200 J / g and a thermal conductivity coefficient of not more than 0.16 W / (m·K) can be prepared, and the aerogel composite material has good stability.

[0036] In a specific embodiment, the molten phase change material particles are obtained by melting in a 50° C. constant temperature oven.

[0037] In one specific embodiment, the concentration of the polymer solution is 40-80 g / L.

[0038] Furthermore, the freezing treatment temperature is -5~-40°C and the duration is 6~48h; the thawing treatment is carried out at room temperature and lasts for 6~48h; the number of freeze-thaw cycles is 1~8 times.

[0039] It can be understood that the freeze-thaw cycle treatment includes a freezing treatment and a thawing treatment performed in sequence, and further limiting the parameters of the freezing treatment and the thawing treatment and the number of cycle treatments can further enable the aerogel composite material to have an excellent structure, further reduce the thermal conductivity of the aerogel composite material, increase the energy storage density, and further improve the stability of the aerogel composite material.

[0040] Optionally, the stirring pre-dispersion treatment is performed at a temperature of 20 to 90° C. for 1 to 60 minutes; The temperature of ultrasonic crushing treatment is 20~90℃, and the time is 1~30min; The temperature of freeze-drying treatment is -60~-85℃ and the time is 6~72h.

[0041] In a specific embodiment, the freeze-drying process further includes a pre-cooling process, the pre-cooling process temperature is -10 to -80°C, and the time is 10 minutes to 5 hours.

[0042] The pre-cooling treatment can further enhance the effect of the freeze-drying treatment, further make the aerogel composite material have an excellent structure, further reduce the thermal conductivity of the aerogel composite material, increase the energy storage density, and further improve the stability of the aerogel composite material.

[0043] In a third aspect, the present invention provides a thermal insulation energy storage material, comprising the aerogel composite material of the first aspect or an aerogel composite material prepared by the preparation method of the aerogel composite material of the second aspect.

[0044] The heat-insulating energy storage material provided by the present invention has low thermal conductivity, high energy storage density, and high stability in high-intensity, long-cycle applications, providing a new solution for the development of constant-temperature thermal management in the field of thermal management.

[0045] Hereinafter, an aerogel composite material provided by the present invention is described in detail through specific embodiments. Example 1

[0046] (1) Heat and stir a certain amount of polymer (gelatin) under magnetic stirring conditions until it is completely dissolved to obtain a uniform and transparent polymer solution; (2) Placing the phase change material (paraffin) in a 50°C constant temperature oven to melt and obtain molten phase change material particles; (3) Take a 25 ml small beaker, add the polymer solution, and then add the molten phase change material particles into the beaker; wherein the mass ratio of the phase change material particles to the polymer is 7:0.4; then, the mixed solution of the phase change material and the polymer solution is stirred and pre-dispersed in a 50°C water bath for 5 minutes, transferred to an ultrasonic cell disruptor for cell disruption for 5 minutes, and cooled to obtain a phase change material particle emulsion; (4) Pour the cooled paraffin emulsion into the mold, seal it with an acrylic cover and place it in a fresh-keeping bag; freeze it at -20°C for 12 hours and thaw it at room temperature for 12 hours, which is one freeze-thaw cycle; repeat the freeze-thaw cycle three times; (5) The samples after freeze-thaw cycles were pre-frozen at -50~-80℃ for 60min and then transferred to a freeze dryer for freeze drying for 24h to obtain an aerogel composite material. Example 2

[0047] The difference between this embodiment and embodiment 1 is that the polymer is replaced by chitosan. Example 3

[0048] The difference between this embodiment and embodiment 1 is that the polymer is replaced by polyacrylamide. Example 4

[0049] The difference between this embodiment and embodiment 1 is that the polymer is replaced by polyvinyl alcohol. Example 5

[0050] The difference between this embodiment and embodiment 1 is that the polymer is replaced by sodium alginate. Example 6

[0051] The difference between this embodiment and embodiment 1 is that the polymer includes polyacrylamide and polyvinyl alcohol in a mass ratio of 3:1. Example 7

[0052] The difference between this embodiment and Embodiment 1 is that the phase change material includes paraffin and stearic acid in a mass ratio of 3:1, and the polymer includes gelatin and polyvinyl alcohol in a mass ratio of 5:1. Example 8

[0053] The difference between this embodiment and embodiment 1 is that in step (4), the freeze-thaw cycle treatment is repeated 5 times. Example 9

[0054] The difference between this embodiment and embodiment 1 is that in step (4), the freeze-thaw cycle treatment is repeated 8 times. Example 10

[0055] The difference between this embodiment and embodiment 1 is that the phase change material is replaced by lauryl alcohol.

[0056] Comparative Example 1 The difference between this comparative example and Example 1 is that step (4) is not performed.

[0057] Test Example 1 Thermal performance characterization, reliability verification and high and low temperature cycle stability tests were performed on the above-mentioned embodiments and comparative examples.

[0058] Among them, the thermal performance characterization was measured by a Q20 differential scanning calorimeter, which was purchased from TA Company in the United States, and the phase change enthalpy value of the sample was finally obtained. The test was carried out in a nitrogen atmosphere, the test temperature range was 20~100℃, and the heating rate was 10℃ / min. The thermal conductivity tests were all measured by a TPS2500S thermal conductivity meter. The test was measured using the Hot-disk method, based on ISO22007-2, at 30℃, and three parallel tests were performed at each temperature point. The test atmosphere was air.

[0059] The reliability verification method includes the following steps: placing the paraffin wax and phase change aerogel samples in a 50°C oven and heating them for 6 hours, with filter paper placed at the bottom of the samples to absorb the leaked paraffin wax during the heating process. Weigh the samples before and after the measurement and observe the state of the samples.

[0060] The method for high and low temperature cycle stability test includes the following steps: placing the aerogel composite material and paraffin phase change material into the American BIO-RAD T100 thermal cycler for testing, performing 500 accelerated hot and cold cycles between 4 and 50°C, maintaining the high and low temperatures for 5 minutes each, and sampling every 100 times. The phase change enthalpy values ​​of the samples after accelerated hot and cold cycles are measured by a Q20 differential scanning calorimeter, which is purchased from TA Company in the United States, and the phase change enthalpy values ​​of the samples are finally obtained. The test is carried out in a nitrogen atmosphere, the test temperature range is 20~100°C, and the heating rate is 10°C / min.

[0061] The above test results are shown in Table 1. Figure 1 As shown, Figure 1 It can be seen that the aerogel provided by the present invention can still maintain its original appearance under a continuous high temperature environment, and there is no phenomenon of paraffin melting or structural damage.

[0062] Table 1 Group Phase change enthalpy (J / g) Thermal conductivity (W / (m·K)) Leakage rate (%) Phase change enthalpy decay rate after 500 hot and cold cycles (%) Example 1 204.6 0.1547 0.464 4.57 Example 2 206.1 0.15875 0.349 2.51 Example 3 209.8 0.1375 1.145 3.67 Example 4 209 0.14265 0.443 3.34 Example 5 216.68 0.1188 0.357 5.96 Example 6 211.4 0.11365 0.771 2.83 Example 7 226.2 0.1055 0.306 4.78 Example 8 200.62 0.1222 0.54 2.74 Example 9 213.7 0.1428 0.38 3.86 Example 10 203.1 0.15425 0.48 7.21 Comparative Example 1 185.4 0.21 85.6 90 paraffin 237.9 0.25 - - As can be seen from Table 1, the phase change enthalpy values ​​of the aerogel composite materials provided by the present invention are all greater than 200 J / g, and the thermal conductivity coefficients are all less than 0.16 W / (m·K), with the highest enthalpy value of 226 J / g and the lowest thermal conductivity of 0.105 W / (m·K). In addition, the phase change material and the polymer together constitute the skeleton structure of the aerogel and the interface bonding state is good, which can effectively prevent the leakage of the phase change material during the phase change process. The aerogel composite material can still maintain its original appearance under continuous high temperature environment, and there is no phenomenon of melting of the phase change material or structural damage. The measurement results show that, except for Example 3, the leakage rates of the remaining samples are all less than 1%. This fully demonstrates the excellent reliability of the composite material and effectively overcomes the pain point problem of traditional phase change materials that are prone to leakage in actual thermal management engineering applications. In addition, the aerogel composite material provided by the present invention still maintains a high heat storage performance after 500 cycles of high and low temperature alternation, with a performance decay of about 5%, which fully demonstrates the excellent durability of the material, effectively solves the pain point problem of traditional phase change materials that are prone to failure after long-term use, and significantly improves its reliability and long-term stability in actual engineering applications of thermal management.

[0063] Test Example 2 The scanning electron microscope test was performed on Example 4, and the results were as follows: Figure 2 , Figure 3 shown.

[0064] from Figure 2 , Figure 3 It can be seen that paraffin and polyvinyl alcohol together constitute the skeleton structure of the aerogel composite material and the interface bonding state is good, which can effectively prevent the leakage of paraffin during the phase change process.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein by equivalents. If these modifications and variations fall within the scope of the claims of the present invention and their equivalent technologies, they should be considered to be within the protection scope of the present invention.

Claims

1. An aerogel composite material, characterized in that: Having a porous skeleton structure, the porous skeleton structure includes phase change material particles and a polymer, and the polymer is coated on at least a portion of the surface of the phase change material particles; The phase change enthalpy value of the aerogel composite material is not less than 200 J / g, and the thermal conductivity coefficient is not higher than 0.16 W / (m·K).

2. The aerogel composite material according to claim 1, characterized in that: The mass ratio of the phase change material particles to the polymer is (1-9): (0.3-1.5).

3. The aerogel composite material according to claim 1, characterized in that: The particle size of the phase change material particles is 2-50 μm; and / or, The solid content of the phase change material particles is 80-90%.

4. The aerogel composite material according to any one of claims 1 to 3, characterized in that: The phase change material particles include at least one of stearic acid, lauryl alcohol, paraffin and methyl palmitate; and / or, The polymer includes at least one of gelatin, chitosan, polyacrylamide, polyvinyl alcohol and sodium alginate.

5. The aerogel composite material according to claim 4, characterized in that: The phase change material particles are paraffin, the polymer is polyvinyl alcohol, and the mass ratio of the paraffin to the polyvinyl alcohol is (5-7): (0.4-0.8); and / or, The phase change material particles are paraffin, and the polymer comprises polyacrylamide and polyvinyl alcohol in a mass ratio of (2-4): (0.5-1.5); and / or, The phase change material particles include paraffin and stearic acid in a mass ratio of (3-5): (1-3), and the polymer includes gelatin and polyvinyl alcohol in a mass ratio of (2-4): (0.5-1.5).

6. A method for preparing an aerogel composite material, for preparing the aerogel composite material according to any one of claims 1 to 5, characterized in that: The following steps are involved: (1) adding a molten phase change material to a polymer solution, performing stirring pre-dispersion treatment and ultrasonic crushing treatment in sequence, and obtaining a phase change material particle emulsion after cooling; (2) pouring the phase change material particle emulsion into a mold and subjecting it to a freeze-thaw cycle treatment, and then freeze-drying treatment to obtain the aerogel composite material; wherein the freeze-thaw cycle treatment includes a freezing treatment and a melting treatment performed in sequence.

7. The method for preparing an aerogel composite material according to claim 6, characterized in that: The freezing temperature is -5~-40℃ and the duration is 6~48h; and / or, The thawing treatment is carried out at room temperature and lasts for 6 to 48 hours; the number of freeze-thaw cycles is 1 to 8 times.

8. The method for preparing an aerogel composite material according to claim 6 or 7, characterized in that: The stirring pre-dispersion treatment is performed at a temperature of 20 to 90° C. for 1 to 60 minutes; and / or The ultrasonic treatment is performed at a temperature of 20 to 90° C. for a time of 1 to 30 min; and / or The freeze-drying treatment is carried out at a temperature of -60 to -85°C and for a time of 6 to 72 hours.

9. The method for preparing an aerogel composite material according to claim 8, characterized in that: The freeze-drying process also includes a pre-cooling process, wherein the temperature of the pre-cooling process is -10 to -80°C and the time is 10 minutes to 5 hours.

10. A thermal insulation energy storage material, characterized in that: The invention relates to an aerogel composite material comprising the aerogel composite material according to any one of claims 1 to 5 or an aerogel composite material prepared by the preparation method of the aerogel composite material according to any one of claims 6 to 9.

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