CN112390571A - Phase-change composite aerogel and preparation method thereof - Google Patents

Phase-change composite aerogel and preparation method thereof Download PDF

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Publication number
CN112390571A
CN112390571A CN201910743319.6A CN201910743319A CN112390571A CN 112390571 A CN112390571 A CN 112390571A CN 201910743319 A CN201910743319 A CN 201910743319A CN 112390571 A CN112390571 A CN 112390571A
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phase
change
fibers
silicon source
wet gel
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李婧
章伊婷
刘洪丽
李亚静
李洪彦
张忠碧
王旭瑞
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Tianjin Chengjian University
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    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
    • C04B28/005—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing gelatineous or gel forming binders, e.g. gelatineous Al(OH)3, sol-gel binders
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/00017—Aspects relating to the protection of the environment
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/40—Porous or lightweight materials
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2201/00—Mortars, concrete or artificial stone characterised by specific physical values
    • C04B2201/30—Mortars, concrete or artificial stone characterised by specific physical values for heat transfer properties such as thermal insulation values, e.g. R-values
    • C04B2201/32—Mortars, concrete or artificial stone characterised by specific physical values for heat transfer properties such as thermal insulation values, e.g. R-values for the thermal conductivity, e.g. K-factors

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  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Dispersion Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Inorganic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Silicon Compounds (AREA)

Abstract

The invention provides a phase-change composite aerogel and a preparation method thereof, wherein a silicon source 1 and a silicon source 2 are mixed and then dissolved in an ethanol water solution, the mixture is mechanically stirred at room temperature until being uniformly mixed, an acid catalyst is added into the dispersion, the pH value of the dispersion is adjusted to 1-3 to obtain a silica sol, an alkaline catalyst is added into the silica sol prepared in the step 1, the pH value of the silica sol is 7-10, phase-change microcapsules and fibers are added into the sol, the mixture is mechanically stirred at room temperature until being uniformly mixed, the mixed sol is poured into a mold to be kept stand to obtain wet gel, the wet gel is soaked in an absolute ethanol solution to be removed from the mold and aged for 10-40h, and finally the wet gel is dried at 25-65 ℃ for 20-30h to obtain the phase-change composite aerogel. The phase-change microcapsules are loaded in the silicon dioxide aerogel, and the nano fibers with good heat-conducting property are added to enhance the heat-conducting property of the aerogel framework, so that the phase-change microcapsules and the silicon dioxide aerogel are optimized.

Description

Phase-change composite aerogel and preparation method thereof
Technical Field
The invention relates to the field of green energy-saving building materials, in particular to a phase-change composite aerogel and a preparation method thereof.
Background
The phase-change material is a thermal function material capable of absorbing or releasing latent heat, is different from a thermal insulation wall material, is applied to a building and not only can keep warm, but also can participate in storage and utilization of building heat energy, so that the phase-change material can generate thermal insulation and heat preservation effects which are several times as good as those of an equivalent traditional thermal insulation material, meanwhile, the frequency of indoor air temperature fluctuation is reduced through circulation of high-temperature heat absorption and low-temperature heat release, the temperature is kept close to the required temperature within a longer period, the comfort level of a human body is increased, and the energy-saving effect of the building is more remarkable. However, the temperature regulation performance and the heat storage performance of the existing phase-change heat insulation material cannot meet the requirements, and the phase-change material has volume change, so that the problems of phase-change material leakage, phase separation and the like are easy to occur, and the temperature regulation performance of the phase-change material is influenced. Therefore, loading the shaped phase-change microcapsules on other wall materials is an important method for solving the existing problems of the phase-change microcapsules.
The silicon dioxide aerogel is an ultra-light heat-insulating building material with good application value. The nano-porous structure is formed by mutually gathering nano-sized colloidal particles and is characterized by large specific surface area, high porosity, low density and low thermal conductivity. Because the thermal conductivity of the silicon dioxide aerogel is lower than that of air, the silicon dioxide aerogel is a solid material with the best heat insulation performance, the phase change microcapsules are loaded on the silicon dioxide aerogel, and under the condition of heat insulation, intelligent temperature adjustment of a building can be further realized through the temperature adjustment function of the phase change material. In addition, the low density characteristic of the composite material meets the trend of the current building towards a multilayer and light structure. And the silicon source species is SiO2The structure and performance of the aerogel have great influence, and the silicon alkoxide is easy to dissolve in common organic solvents, so that high-purity and high-dispersion aerogel can be obtainedAnd high-uniformity sol, the silicon content of the methyl orthosilicate is higher, the hydrolysis rate is higher, and the prepared SiO2The aerogel has narrow pore diameter and uniform distribution, and the cost is low by using water glass, polysiloxane and rice husk as silicon sources, but the prepared SiO is2Aerogel performance has yet to be further improved. The silicon source with certain hydrophobic property, such as methyltrimethoxysilane, is used as a hydrophobic modifier and is directly added when collosol is prepared, so that the hydrophobicity of the aerogel can be effectively improved, the hydrophobic modification process in the preparation step can be omitted, and the preparation flow is simplified. Therefore, through the optimization of different silicon sources, the phase-change and composite silicon source is used as the raw material, the silicon dioxide aerogel phase-change composite material is prepared through the normal pressure drying method, the heat insulation and heat storage are realized in different temperature areas, and the silicon dioxide aerogel phase-change composite material is suitable for buildings.
Disclosure of Invention
The invention overcomes the defects in the prior art, provides a phase-change composite aerogel and a preparation method thereof, and provides a preparation process which is simple to operate and low in cost, and a special aerogel with heat preservation and heat storage performance and heat insulation performance is prepared.
The purpose of the invention is realized by the following technical scheme.
The phase-change composite aerogel and the preparation method thereof are carried out according to the following steps:
step 1, mixing a silicon source 1 and a silicon source 2, dissolving the mixture in an ethanol aqueous solution, mechanically stirring the mixture at room temperature (20-25 ℃) until the mixture is uniformly mixed, adding an acid catalyst into the dispersion liquid, and adjusting the pH of the dispersion liquid to 1-3 to obtain a silicon dioxide sol, wherein the silicon source 1 adopts one or two of tetraethyl orthosilicate, sodium silicate and polysiloxane, the silicon source 2 adopts methyltrimethoxysilane, hexamethyldisilazane or polydivinylsiloxane, and the adding proportion of the silicon source 1 to the silicon source 2 is (3-60): (3-60);
step 2, adding an alkaline catalyst into the silica sol prepared in the step 1, adjusting the pH value of the silica sol to 7-10, adding phase-change microcapsules and fibers into the silica sol, mechanically stirring the mixture at room temperature (20-25 ℃) until the mixture is uniformly mixed, pouring the mixed sol into a mold, standing the mixture to obtain wet gel, removing the wet gel from the mold, soaking the wet gel in an absolute ethyl alcohol solution, aging the wet gel for 10-40 hours, and drying the wet gel at 25-65 ℃ for 20-30 hours to obtain the phase-change composite aerogel, wherein the fibers are quartz fibers, glass fibers, bacterial fibers (namely antibacterial fibers) or high silica fibers, and the adding proportion of the phase-change microcapsules and the fibers is (4-12): (1-3).
In step 1, the addition ratio of the silicon source 1 and the silicon source 2 is (5-50): (5-50), in the ethanol water solution, the mass ratio of absolute ethanol to distilled water is (50-200): (20-100), using hydrochloric acid, nitric acid, phosphoric acid or oxalic acid as an acid catalyst, preferably hydrochloric acid, and adding the acid catalyst to adjust the pH of the dispersion to 1-2.
In the step 2, the addition ratio of the phase-change microcapsules to the fibers is (5-10): (1-2), the diameter of the phase change microcapsule is 10-25 μm, the energy storage density is 120J/g, and the phase change temperature is 25 ℃; the diameter of the fiber is 5-10 μm, and the length is 20-100 μm.
In step 2, the alkaline catalyst is sodium hydroxide or ammonia water, and the pH of the silica sol is adjusted to 7-9 by adding the alkaline catalyst.
In the step 2, the wet gel is aged for 12-36h, dried at 30-60 ℃ for 22-24 h.
The invention adopts two or more than two silicon sources to be compounded as a composite silicon source, prepares the phase-change microcapsule composite silicon dioxide aerogel by using a normal pressure drying method, selects the phase-change microcapsule with the surface compounded with silicon dioxide nano particles, has good affinity with the aerogel by the nano particles on the surface, can be used as an induced nucleation point of the aerogel, and takes the microcapsule as a core to be condensed in situThe gel method is used for preparing the aerogel, good chemical combination between two phases is kept under the condition of not damaging the aerogel network structure, micron-sized fibers (the diameter and the length reach micron-sized) are introduced into the aerogel structure and are enhanced through crosslinking, and the crosslinking agent network and SiO2Covalent bonds between the framework network of the aerogel are cross-linked to enhance the bond strength between the aerogel and the nanocolloid.
The invention has the beneficial effects that: in the preparation process, a toxic organic solvent is not used, so that the generation of a large amount of solvents and waste liquid required to be consumed by solvent replacement is avoided, green production is facilitated, the preparation period is greatly shortened, the production cost and the complexity of operation are reduced, the investment and energy consumption are reduced, and the technical effect of continuous industrial production is easy to realize; the phase-change composite aerogel is used as a building heat-insulation material, has the advantages of large phase-change latent heat, high energy storage capacity, strong temperature regulation capacity and the like, can ensure that the phase-change heat-insulation material has better heat storage and heat insulation performance, and simultaneously utilizes the super heat insulation function of the aerogel when the phase-change temperature range is exceeded through the ultra-light aerogel with the nano porous structure, wherein the gaps are filled with gaseous dispersion media; the preparation method is environment-friendly, nontoxic, environment-friendly and pollution-free, and the phase-change composite aerogel material prepared by synthesizing the composite silicon source without using toxic organic solvents has environment-friendly characteristics and is environment-friendly.
Drawings
FIG. 1 is a macroscopic and microscopic topography of the phase-change composite aerogel prepared by the present invention, wherein (a) is a macroscopic topography, and (b) is a microscopic topography, i.e., a scanning electron microscope;
FIG. 2 is a DSC curve of the phase-change composite aerogel prepared by the present invention;
FIG. 3 is a thermal conductivity curve of the phase-change composite aerogel prepared by the present invention.
Detailed Description
The technical solution of the present invention is further illustrated by the following specific examples. The phase change microcapsule is purchased from Hubei Saimer New energy science and technology Limited, the diameter is 10-25 μm, the energy storage density is 120J/g, and the phase change temperature is 25 ℃; the quartz fiber is purchased from New materials GmbH of Tian navigation in Henan province, the bacterial fiber (i.e. antibacterial fiber) is purchased from Guilin Qihong scientific and technology GmbH, the glass fiber and the high silica fiber are purchased from New materials GmbH in Shanxi Huate, and the micron-sized fiber is selected for use.
In the invention, the adding proportion of the silicon source 1 and the silicon source 2 is the mass ratio of the two, the adding proportion of the phase-change microcapsule and the fiber is the mass ratio of the two, and in the embodiment, the adding proportion is 1g in parts by mass; the volume of each drop of the acid catalyst and the basic catalyst is controlled to be 0.05 ml.
Example 1
(1) Dissolving 15 parts of ethyl orthosilicate and 5 parts of methyltrimethoxysilane in a mixed solution of 100 parts of ethanol and 50 parts of water, stirring at room temperature until the mixture is uniformly mixed, adding a proper amount of 5 drops of hydrochloric acid to adjust the pH value of the solution to 1-2, and hydrolyzing for 20 minutes to form silicon dioxide sol.
(2) 5 drops of alkaline catalyst are added to adjust the pH value of the silica sol to 7-9, so that the sol is properly gelled to reach a certain viscosity. Adding 5 parts of phase change microcapsules and 1 part of quartz fibers, stirring at room temperature for 20min, standing, pouring the mixed sol into a mold, standing to obtain wet gel with certain strength, removing the wet gel from the mold, soaking in an absolute ethyl alcohol solution, and aging for 24 h. And finally, drying for 24 hours at 40 ℃ under normal pressure to obtain the phase change microcapsule composite silicon dioxide aerogel.
As shown in fig. 1, a is a macroscopic view of the aerogel prepared in example 1, and it can be seen that the aerogel has good formability and does not generate chalking; b is a scanning electron microscope picture of the aerogel prepared in example 1, and it can be seen from the picture that the aerogel maintains a better pore structure after the phase change microcapsule is added.
As shown in figure 2, the crystallization enthalpy of the phase-change composite aerogel is 60.72J/g, the phase-change temperature of the crystallization is 12.0 ℃, the melting enthalpy of the phase-change composite aerogel is 57.78J/g, and the melting phase-change temperature is 24.5 ℃.
As shown in FIG. 3, the addition of the phase-change microcapsules to the silica sol increases the thermal conductivity of the aerogel, and the thermal conductivity fluctuates between 0.03 and 0.06W/(m.K), so the addition of the phase-change microcapsules has little influence on the thermal insulation effect.
Example 2
(1) Dissolving 15 parts of ethyl orthosilicate and 5 parts of methyltrimethoxysilane in a mixed solution of 120 parts of ethanol and 30 parts of water, stirring at room temperature until the mixture is uniformly mixed, adding a proper amount of 5 drops of hydrochloric acid to adjust the pH value of the solution to 1-3, and hydrolyzing for 40 minutes to form silicon dioxide sol.
(2) 5 drops of alkaline catalyst are added to adjust the pH value of the silica sol to 7-10, so that the sol is properly gelled to reach a certain viscosity. Adding 10 parts of phase-change microcapsules and 1 part of quartz fibers, stirring at room temperature for 20min, standing, pouring the mixed sol into a mold, standing to obtain wet gel with certain strength, removing the wet gel from the mold, soaking in an absolute ethyl alcohol solution, and aging for 10 h. And finally, drying for 30 hours at 25 ℃ under normal pressure to obtain the phase change microcapsule composite silicon dioxide aerogel.
Example 3
(1) Dissolving 10 parts of ethyl orthosilicate and 10 parts of methyltrimethoxysilane in a mixed solution of 100 parts of ethanol and 50 parts of water, stirring at room temperature until the mixture is uniformly mixed, adding a proper amount of 5 drops of hydrochloric acid to adjust the pH value of the solution to 2-3, and hydrolyzing for 20 minutes to form silicon dioxide sol.
(2) 5 drops of alkaline catalyst are added to adjust the pH value of the silica sol to 8-10, so that the sol is properly gelled to reach a certain viscosity. Adding 5 parts of phase-change microcapsules and 2 parts of antibacterial fibers, stirring at room temperature for 20min, standing, pouring the mixed sol into a mold, standing to obtain wet gel with certain strength, removing the wet gel from the mold, soaking in an absolute ethanol solution, and aging for 36 h. And finally, drying for 22 hours at 60 ℃ under normal pressure to obtain the phase change microcapsule composite silicon dioxide aerogel.
Example 4
(1) Dissolving 10 parts of ethyl orthosilicate and 10 parts of methyltrimethoxysilane in a mixed solution of 120 parts of ethanol and 30 parts of water, stirring at room temperature until the mixture is uniformly mixed, adding a proper amount of 5 drops of hydrochloric acid to adjust the pH value of the solution to 1-2, and hydrolyzing for 40 minutes to form silicon dioxide sol.
(2) 5 drops of alkaline catalyst are added to adjust the pH value of the silica sol to 7-9, so that the sol is properly gelled to reach a certain viscosity. Adding 10 parts of phase change microcapsules and 2 parts of glass fiber, stirring at room temperature for 20min, standing, pouring the mixed sol into a mold, standing to obtain wet gel with certain strength, removing the wet gel from the mold, soaking in an absolute ethyl alcohol solution, and aging for 12 h. And finally, drying for 20 hours at 65 ℃ under normal pressure to obtain the phase change microcapsule composite silicon dioxide aerogel.
Example 5
(1) Dissolving 5 parts of ethyl orthosilicate and 15 parts of methyltrimethoxysilane in a mixed solution of 50 parts of ethanol and 100 parts of water, stirring at room temperature until the mixture is uniformly mixed, adding a proper amount of 5 drops of hydrochloric acid to adjust the pH value of the solution to 2-3, and hydrolyzing for 20 minutes to form silicon dioxide sol.
(2) 5 drops of alkaline catalyst are added to adjust the pH value of the silica sol to 8-10, so that the sol is properly gelled to reach a certain viscosity. Adding 5 parts of phase change microcapsules and 1 part of quartz fibers, stirring at room temperature for 20min, standing, pouring the mixed sol into a mold, standing to obtain wet gel with certain strength, removing the wet gel from the mold, soaking in an absolute ethyl alcohol solution, and aging for 40 h. And finally, drying for 24 hours at 50 ℃ under normal pressure to obtain the phase change microcapsule composite silicon dioxide aerogel.
Example 6
(1) Dissolving 3 parts of ethyl orthosilicate and 60 parts of methyltrimethoxysilane in a mixed solution of 200 parts of ethanol and 100 parts of water, stirring at room temperature until the mixture is uniformly mixed, adding a proper amount of 5 drops of hydrochloric acid to adjust the pH value of the solution to 1-2, and hydrolyzing for 20 minutes to form silicon dioxide sol.
(2) 5 drops of alkaline catalyst are added to adjust the pH value of the silica sol to 8-9, so that the sol is properly gelled to reach a certain viscosity. Adding 4 parts of phase change microcapsules and 1 part of high silica fibers, stirring at room temperature for 20min, standing, pouring the mixed sol into a mold, standing to obtain wet gel with certain strength, removing the wet gel from the mold, soaking in an absolute ethanol solution, and aging for 24 h. And finally, drying for 24 hours at 60 ℃ under normal pressure to obtain the phase change microcapsule composite silicon dioxide aerogel.
Example 7
(1) Dissolving 60 parts of ethyl orthosilicate and 3 parts of methyltrimethoxysilane in a mixed solution of 50 parts of ethanol and 20 parts of water, stirring at room temperature until the mixture is uniformly mixed, adding a proper amount of 5 drops of hydrochloric acid to adjust the pH value of the solution to 2-3, and hydrolyzing for 20 minutes to form silicon dioxide sol.
(2) 5 drops of alkaline catalyst are added to adjust the pH value of the silica sol to 7-8, so that the sol is properly gelled to reach a certain viscosity. Adding 12 parts of phase change microcapsules and 3 parts of high silica fibers, stirring at room temperature for 20min, standing, pouring the mixed sol into a mold, standing to obtain wet gel with certain strength, removing the wet gel from the mold, soaking in an absolute ethyl alcohol solution, and aging for 12 h. And finally, drying the phase-change microcapsule composite silica aerogel for 32 hours at the temperature of 45 ℃ under normal pressure.
According to the invention, the preparation of the phase-change microcapsule composite silica aerogel can be realized by adjusting the process parameters, and tests show that the crystallization enthalpy value of the phase-change microcapsule composite silica aerogel is 60-62J/g, the crystallization phase-change temperature is 12 +/-2 ℃, the melting enthalpy value of the phase-change composite aerogel is 56-58J/g, the melting phase-change temperature is 24 +/-2 ℃, and the addition of the phase-change microcapsule into the silica sol can increase the thermal conductivity of the aerogel, and the thermal conductivity floats between 0.03-0.06W/(m.K).
The invention has been described in an illustrative manner, and it is to be understood that any simple variations, modifications or other equivalent changes which can be made by one skilled in the art without departing from the spirit of the invention fall within the scope of the invention.

Claims (10)

1. A phase change composite aerogel, comprising: the method comprises the following steps:
step 1, mixing a silicon source 1 and a silicon source 2, dissolving the mixture in an ethanol aqueous solution, mechanically stirring the mixture at room temperature (20-25 ℃) until the mixture is uniformly mixed, adding an acid catalyst into the dispersion liquid, and adjusting the pH of the dispersion liquid to 1-3 to obtain a silicon dioxide sol, wherein the silicon source 1 adopts one or two of tetraethyl orthosilicate, sodium silicate and polysiloxane, the silicon source 2 adopts methyltrimethoxysilane, hexamethyldisilazane or polydivinylsiloxane, and the adding proportion of the silicon source 1 to the silicon source 2 is (3-60): (3-60);
step 2, adding an alkaline catalyst into the silica sol prepared in the step 1, adjusting the pH value of the silica sol to 7-10, adding phase-change microcapsules and fibers into the silica sol, mechanically stirring the mixture at room temperature (20-25 ℃) until the mixture is uniformly mixed, pouring the mixed sol into a mold, standing the mixture to obtain wet gel, removing the wet gel from the mold, soaking the wet gel in an absolute ethyl alcohol solution, aging the wet gel for 10-40 hours, and drying the wet gel at 25-65 ℃ for 20-30 hours to obtain the phase-change composite aerogel, wherein the fibers are quartz fibers, glass fibers, bacterial fibers or high silica fibers, and the addition ratio of the phase-change microcapsules to the fibers is (4-12): (1-3).
2. A phase change composite aerogel according to claim 1, wherein: in step 1, the addition ratio of the silicon source 1 and the silicon source 2 is (5-50): (5-50), in the ethanol water solution, the mass ratio of absolute ethanol to distilled water is (50-200): (20-100), using hydrochloric acid, nitric acid, phosphoric acid or oxalic acid as an acid catalyst, preferably hydrochloric acid, and adding the acid catalyst to adjust the pH of the dispersion to 1-2.
3. A phase change composite aerogel according to claim 1, wherein: in the step 2, the addition ratio of the phase-change microcapsules to the fibers is (5-10): (1-2), the diameter of the phase change microcapsule is 10-25 μm, the energy storage density is 120J/g, and the phase change temperature is 25 ℃; the diameter of the fiber is 5-10 μm, and the length is 20-100 μm.
4. A phase change composite aerogel according to claim 1, wherein: in the step 2, the alkaline catalyst adopts sodium hydroxide or ammonia water, the pH value of the silica sol is adjusted to 7-9 by adding the alkaline catalyst, the wet gel aging time is 12-36h, the drying temperature is 30-60 ℃, and the drying time is 22-24 h.
5. A preparation method of the phase-change composite aerogel is characterized by comprising the following steps: the method comprises the following steps:
step 1, mixing a silicon source 1 and a silicon source 2, dissolving the mixture in an ethanol aqueous solution, mechanically stirring the mixture at room temperature (20-25 ℃) until the mixture is uniformly mixed, adding an acid catalyst into the dispersion liquid, and adjusting the pH of the dispersion liquid to 1-3 to obtain a silicon dioxide sol, wherein the silicon source 1 adopts one or two of tetraethyl orthosilicate, sodium silicate and polysiloxane, the silicon source 2 adopts methyltrimethoxysilane, hexamethyldisilazane or polydivinylsiloxane, and the adding proportion of the silicon source 1 to the silicon source 2 is (3-60): (3-60);
step 2, adding an alkaline catalyst into the silica sol prepared in the step 1, adjusting the pH value of the silica sol to 7-10, adding phase-change microcapsules and fibers into the silica sol, mechanically stirring the mixture at room temperature (20-25 ℃) until the mixture is uniformly mixed, pouring the mixed sol into a mold, standing the mixture to obtain wet gel, removing the wet gel from the mold, soaking the wet gel in an absolute ethyl alcohol solution, aging the wet gel for 10-40 hours, and drying the wet gel at 25-65 ℃ for 20-30 hours to obtain the phase-change composite aerogel, wherein the fibers are quartz fibers, glass fibers, bacterial fibers or high silica fibers, and the addition ratio of the phase-change microcapsules to the fibers is (4-12): (1-3).
6. The method for preparing a phase-change composite aerogel according to claim 5, wherein: in step 1, the addition ratio of the silicon source 1 and the silicon source 2 is (5-50): (5-50), in the ethanol water solution, the mass ratio of absolute ethanol to distilled water is (50-200): (20-100), using hydrochloric acid, nitric acid, phosphoric acid or oxalic acid as an acid catalyst, preferably hydrochloric acid, and adding the acid catalyst to adjust the pH of the dispersion to 1-2.
7. The method for preparing a phase-change composite aerogel according to claim 5, wherein: in the step 2, the addition ratio of the phase-change microcapsules to the fibers is (5-10): (1-2), the diameter of the phase change microcapsule is 10-25 μm, the energy storage density is 120J/g, and the phase change temperature is 25 ℃; the diameter of the fiber is 5-10 μm, and the length is 20-100 μm.
8. The method for preparing a phase-change composite aerogel according to claim 5, wherein: in the step 2, the alkaline catalyst adopts sodium hydroxide or ammonia water, the pH value of the silica sol is adjusted to 7-9 by adding the alkaline catalyst, the wet gel aging time is 12-36h, the drying temperature is 30-60 ℃, and the drying time is 22-24 h.
9. Use of a phase change composite aerogel according to any of claims 1 to 4 for the preparation of thermal insulation materials.
10. Use according to claim 9, characterized in that: the crystallization enthalpy value of the phase-change composite aerogel is 60-62J/g, the crystallization phase-change temperature is 12 +/-2 ℃, the melting enthalpy value of the phase-change composite aerogel is 56-58J/g, the melting phase-change temperature is 24 +/-2 ℃, and the heat conductivity coefficient of the aerogel is improved by adding the phase-change microcapsules into the silica sol and is 0.03-0.06W/(m.K).
CN201910743319.6A 2019-08-12 2019-08-12 Phase-change composite aerogel and preparation method thereof Withdrawn CN112390571A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114181671A (en) * 2021-12-31 2022-03-15 中国科学技术大学先进技术研究院 Preparation method of silicon dioxide aerogel phase-change composite material
CN114538891A (en) * 2022-03-07 2022-05-27 东莞市零度导热材料有限公司 One-step in-situ synthesis fiber-reinforced silica aerogel-based composite phase-change thermal insulation material and preparation method thereof
CN114934393A (en) * 2022-05-24 2022-08-23 河南爱彼爱和新材料有限公司 Phase-change aerogel composite coating, preparation method thereof and heat insulation pad

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114181671A (en) * 2021-12-31 2022-03-15 中国科学技术大学先进技术研究院 Preparation method of silicon dioxide aerogel phase-change composite material
CN114181671B (en) * 2021-12-31 2023-09-26 中国科学技术大学先进技术研究院 Preparation method of silica aerogel phase-change composite material
CN114538891A (en) * 2022-03-07 2022-05-27 东莞市零度导热材料有限公司 One-step in-situ synthesis fiber-reinforced silica aerogel-based composite phase-change thermal insulation material and preparation method thereof
CN114934393A (en) * 2022-05-24 2022-08-23 河南爱彼爱和新材料有限公司 Phase-change aerogel composite coating, preparation method thereof and heat insulation pad
CN114934393B (en) * 2022-05-24 2023-05-23 河南爱彼爱和新材料有限公司 Phase-change aerogel composite coating, preparation method thereof and heat insulation pad

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