CN117886539B - Aerogel slurry and its application - Google Patents

Abstract

The invention provides aerogel slurry and application thereof. The aerogel slurry comprises a component A, a component B, a component C and a component D, wherein the component A is hydrophobic aerogel powder, the component B is a nonionic surfactant and is at least one of polyether L62, polyether L63, polyether L65, polyether L42, polyether L43 and Tween 80, the component C is a cationic surfactant and is at least one of cetyltrimethylammonium chloride (CTAC), cetyltrimethylammonium bromide (CTAB), dodecyltrimethylammonium bromide (DTAB), octadecyltrimethylammonium chloride (OTAC) and octadecyltrimethylammonium bromide (OTAB), and the component D is water. According to the invention, the problem of poor compatibility of the aerogel powder with water is solved through the cooperation of the nonionic surfactant and the cationic surfactant, and the prepared aerogel slurry has the advantages of no layering, low thermal conductivity and high hydrophobicity.

Description

Aerogel slurry and its application

Technical Field

The invention belongs to the technical field of aerogel slurry preparation, and in particular relates to aerogel slurry and application thereof.

Background technique

Silica aerogel is a three-dimensional mesh porous nanomaterial with low density, good thermal insulation, hydrophobicity, high porosity, etc. When aerogel is compounded with other inorganic materials, due to its hydrophobic and light characteristics, it will have poor compatibility with other substances and will float on the top when mixed and cannot be mixed evenly. Therefore, in order to better apply aerogel, it is necessary to solve the compatibility problem of aerogel with other materials so that aerogel can be evenly dispersed in the aqueous system, so as to prepare aerogel composite materials with stable performance.

After searching, Chinese invention patent CN113956740A discloses a method for preparing aerogel thermal insulation slurry. In this preparation method, due to the large amount of additives added, the thermal conductivity of the aerogel slurry after drying is very large, and it cannot play a good thermal insulation role. Chinese invention patent CN115676839A also discloses a process for preparing aerogel slurry. In this preparation process, not only a nano-modifier but also a nano-stabilizer is required to prevent the obtained aerogel slurry from stratification. In the above patents, more modifiers, dispersants or stabilizers need to be added, the manufacturing cost of the slurry is high, and it will also greatly affect the performance and structure of the aerogel.

At the same time, the dispersing and wetting effect of using a single surfactant is not ideal, and a binder needs to be added to overcome the technical problem of stratification.

Summary of the invention

The object of the present invention is to provide a nonionic surfactant and a cationic surfactant to synergistically enhance the problem of poor compatibility of aerogel powder with water, and the prepared aerogel slurry is not stratified and has low thermal conductivity.

In order to achieve the above object, the present invention provides an aerogel slurry, comprising:

Component A, wherein component A is a hydrophobic aerogel powder, and the thermal conductivity of component A is 18 to 25 mW/(m·K);

Component B, wherein the component B is a nonionic surfactant, and the component B is selected from at least one of polyether L62, polyether L63, polyether L65, polyether L42, polyether L43, and Tween 80;

Component C, wherein the component C is a cationic surfactant, and the component C is at least one selected from the group consisting of hexadecyltrimethylammonium chloride, hexadecyltrimethylammonium bromide, dodecyltrimethylammonium bromide, octadecyltrimethylammonium chloride, and octadecyltrimethylammonium bromide;

Component D, wherein the component D is water;

The thermal conductivity of the aerogel slurry is 19 to 32 mW/(m·K).

In a specific embodiment, the difference between the thermal conductivity of the aerogel slurry and the thermal conductivity of the component A is NmW/(m·K), where 1≤N≤7.

In a specific embodiment, the component A is a silica aerogel powder having a thermal conductivity of 18 mW/(m·K), and the thermal conductivity of the aerogel slurry is not greater than 25 mW/(m·K).

In a specific embodiment, the silica aerogel powder has a particle size of 15-50 microns and a density of 60-80 kg/m ³ .

In a specific embodiment, based on the weight of component D of the aerogel slurry, component B is 0.1wt% to 0.4wt%, and component C is 0.4wt% to 1.6wt%; based on the total weight of component A, component B, component C and component D, the amount of component A is in the range of 6.8wt% to 20wt%.

In a specific embodiment, based on the weight of component D of the aerogel slurry, the component B is 0.2wt% to 0.3wt%, and the component C is 0.6wt% to 1.2wt%; based on the total weight of components A, B, C and D, the amount of component A is in the range of 7wt% to 14wt%, and in each case, the total amount of components A, B, C and D always adds up to 100wt%.

In a specific embodiment, the mass ratio of the component D to the component B is 1:(0.002-0.003), and the mass ratio of the component B to the component C is 1:(2-4).

In a specific embodiment, the mass ratio of the component D to the component A is 1:(0.08-0.2).

In a specific embodiment, the aerogel slurry is prepared by the following method, comprising:

Add water, nonionic surfactant and cationic surfactant into a mechanical stirrer in sequence, and stir at a speed of 500-1000 r/min for 3-5 minutes at normal temperature and pressure to form a mixed solution;

The hydrophobic aerogel powder is added to the mixed solution, and then stirred at a speed of 400-5000 r/min for 3-20 minutes at normal temperature and pressure to mix evenly to form a non-stratified aerogel slurry.

The present invention also provides a use of the aerogel slurry described above in a thermal insulation material.

The beneficial effects of the present invention include at least:

1. The present invention provides an aerogel slurry, comprising component A, component B, component C and component D, wherein component A is a hydrophobic aerogel powder, component B is a nonionic surfactant, component C is a cationic surfactant, and component D is water; specific nonionic surfactants and cationic surfactants are added to the aerogel slurry provided by the present invention for synergistic enhancement, and mixed micelles can be formed in the solution to enhance the wettability and dispersibility of the aerogel powder during the preparation of the aerogel slurry, thereby improving the stability of the aerogel slurry, so that the prepared aerogel slurry has good stability (no stratification), which is convenient for long-term storage and use; and the prepared aerogel slurry has low thermal conductivity and belongs to Class A non-combustible material, and the thermal insulation product prepared using the aerogel slurry has better thermal insulation performance.

Second, the surfactants obtained by compounding nonionic surfactants and cationic surfactants synergistically improve the hydrophobicity of aerogel powders, so that the thermal conductivity of the prepared aerogel slurry is only slightly higher than the thermal conductivity of the aerogel powder raw material (that is, the difference between the thermal conductivity of the aerogel slurry and the thermal conductivity of the hydrophobic aerogel powder raw material is small). In this way, the technical problem of high thermal conductivity of aerogel slurry caused by adding other additives such as adhesives to the existing aerogel slurry can be solved.

Second, the present invention uses less raw materials to prepare aerogel slurry, the preparation method is simple, and has the advantages of low cost, short production cycle, and convenient mass production.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a hydrophobic test diagram of aerogel slurry prepared in Example 4 of the present invention;

FIG2 is a scanning electron microscope image of the aerogel slurry prepared in Example 4 of the present invention;

FIG3 is a hydrophobic test of the aerogel slurry prepared in Example 3 of the present invention;

FIG4 is a scanning electron microscope image of the aerogel slurry prepared in Example 8 of the present invention;

FIG5 is a scanning electron microscope image of the aerogel slurry prepared in Example 18 of the present invention.

Detailed ways

The present invention is described in detail below with reference to the accompanying drawings and embodiments, but the present invention can be implemented in many different ways as limited and covered by the claims.

The present invention generally relates to aerogel slurry, preparation method and application thereof.

The prior art discloses that hydrophilic aerogel can be obtained by treating the hydrophobicity of aerogel with a surfactant, and then a single surfactant can improve the wettability and dispersibility of aerogel powder. However, there is still a problem of poor stability (stratification after 24 hours), and a binder needs to be added to overcome the stratification problem. The addition of a binder will increase the thermal conductivity of the aerogel slurry.

The aerogel slurry disclosed in the present invention enhances the wettability and dispersibility of aerogel powder in the aerogel slurry preparation process through the synergistic enhancement of nonionic surfactant and cationic surfactant, so that the prepared aerogel slurry has the advantages of good stability (no stratification) and low thermal conductivity.

The invention provides an aerogel slurry, wherein the thermal conductivity of the aerogel slurry is 19-32 mW/(m·K), and the aerogel slurry comprises component A, component B, component C and component D, wherein the component A is a hydrophobic aerogel powder, and the thermal conductivity of the component A is 18-25 mW/(m·K); the component B is a nonionic surfactant, which is selected from at least one of polyether L62, polyether L63, polyether L65, polyether L42, polyether L43 and Tween 80; the component C is a cationic surfactant, which is selected from at least one of cetyltrimethylammonium chloride (CTAC), cetyltrimethylammonium bromide (CTAB), dodecyltrimethylammonium bromide (DTAB), octadecyltrimethylammonium chloride (OTAC) and octadecyltrimethylammonium bromide (OTAB); and the component D is water.

It should be noted that, in the present invention, the thermal conductivity of the aerogel slurry refers to the thermal conductivity of the powder obtained by drying the aerogel slurry.

The surfactant obtained by compounding a nonionic surfactant and a cationic surfactant in the present invention synergistically improves the hydrophobicity of the aerogel powder, so that the thermal conductivity of the prepared aerogel slurry is only slightly higher than the thermal conductivity of the aerogel powder raw material (that is, the difference between the thermal conductivity of the aerogel slurry and the thermal conductivity of the hydrophobic aerogel powder raw material is small). In this way, the technical problem of high thermal conductivity of the aerogel slurry caused by adding other additives such as adhesives to the existing aerogel slurry can be solved.

Preferably, the difference between the thermal conductivity of the aerogel slurry and the thermal conductivity of the component A is NmW/(m·K), where 1≤N≤7.

More preferably, the component B is polyether L62 and the component C is CTAC, and the difference between the thermal conductivity of the aerogel slurry and the thermal conductivity of the component A is NmW/(m·K), wherein 1≤N≤4.

More preferably, the hydrophobic aerogel powder is silica aerogel powder with a particle size of 15-50 microns, a density of 60-80 kg/m ³ , a thermal conductivity of 18 mW/(m·K), and the thermal conductivity of the aerogel slurry is no more than 25 mW/(m·K).

In the present invention, the component D is deionized water.

Preferably, based on the weight of component D of the aerogel slurry, component B is 0.1wt% to 0.4wt%, and component C is 0.4wt% to 1.6wt%; based on the total weight of component A, component B, component C and component D, the amount of component A is in the range of 6.8wt% to 20wt%.

More preferably, based on the weight of component D of the aerogel slurry, component B is 0.2wt% to 0.3wt%, and component C is 0.6wt% to 1.2wt%; based on the total weight of component A, component B, component C and component D, the amount of component A is in the range of 7wt% to 14wt%.

More preferably, in each case the total amount of component A, component B, component C and component D always adds up to 100 wt%.

In the embodiments provided by the present invention, the total amount of component A, component B, component C, and component D in each case always adds up to 100 wt%. However, the total amount of component A, component B, component C, and component D always adds up to 100 wt% is only a preferred solution. In other embodiments, the addition of other substances that do not affect the stability and thermal conductivity of the aerogel slurry is also within the scope of protection of the present invention.

Preferably, the mass ratio of the component D to the component B is 1:(0.002-0.003).

Preferably, the mass ratio of the component B to the component C is 1:(2-4).

Preferably, the mass ratio of the component D to the component A is 1:(0.008-0.2).

More preferably, the component B is selected from at least one of polyether L62, polyether L63, polyether L65, polyether L42, polyether L43, and Tween 80, the component C is CTAC or CTAB, the hydrophobic angle of the aerogel slurry is greater than or equal to 140°, and the surface tension is less than 30 mN/m.

Preferably, the aerogel slurry is prepared by the following method, comprising:

Add water, nonionic surfactant and cationic surfactant into a mechanical stirrer in sequence, and stir at a speed of 500-1000 r/min for 3-5 minutes at normal temperature and pressure to form a mixed solution;

The hydrophobic aerogel powder is added to the mixed solution, and then stirred at a speed of 400-5000 r/min for 3-20 minutes at normal temperature and pressure to mix evenly to form a non-stratified aerogel slurry.

The present invention also provides a use of the aerogel slurry described above in a thermal insulation material.

Specifically, gypsum, cement and other materials such as hollow glass microspheres can be added to the aerogel slurry, and the aerogel slurry is mixed with these materials to form a thermal insulation material, which can be mortar, paint and the like.

Example 1

First, 40 parts of deionized water, 0.12 parts of polyether L62, and 0.24 parts of CTAC were added to a beaker in sequence, and stirred at 400 r/min for 3 minutes at room temperature and pressure to form a uniform mixed solution; then 5 parts of silica aerogel powder with a particle size of 50 microns (thermal conductivity of 18 mW/(m·K)) were added to the mixed solution, and then stirred at 4000 r/min for 10 minutes using a high-speed disperser at room temperature and pressure. After uniform mixing, a non-stratified aerogel slurry-1 was formed.

After the prepared aerogel slurry-1 was dried, samples were taken for performance testing, wherein the thermal conductivity was 20.35 mW/(m·K), the hydrophobic angle was 144°, the surface tension was 27.15 mN/m, and it was a Class A non-combustible material.

Among them, the thermal conductivity was measured by XIATECH (China) TC3000E probe using the transient hot wire method according to the standard GB/T 10297-2015.

Embodiments 2 to 6

The nonionic surfactant and cationic surfactant used in Examples 2 to 6 are the same as those in Example 1, and 40 parts of deionized water and 5 parts of aerogel powder are added. The difference is that the number of parts of polyether L62 and/or CTAC added is different. The data and experimental results of component B and component C added in Examples 1 to 6 are shown in Table 1.

Table 1 Performance test results of aerogel slurry prepared by mixing different contents of polyether L62 and CTAC

It can be seen from the experimental data in Table 1 that when the weight of water is 40 parts and the weight of aerogel powder is 5 parts, the amount of nonionic surfactant added is 0.04-0.16 parts and the amount of cationic surfactant added is 0.16-0.64 parts, the thermal conductivity of the prepared aerogel slurry is less than 25mW/(m·K), and the difference between the thermal conductivity of the prepared aerogel slurry and the thermal conductivity of the hydrophobic aerogel powder is less than 3.5mW/(m·K).

Embodiment 7 to Embodiment 16

The cationic surfactant used in Examples 7 to 16 is the same as that in Example 1, and the deionized water added is 40 parts, and the aerogel powder added is 5 parts. The difference is that the nonionic surfactant used is different, and the weight parts added are not exactly the same. The data and experimental results of the components B and C added in Examples 7 to 16 are shown in Table 2.

Table 2 Performance test results of aerogel slurries prepared by mixing different nonionic surfactants and CTAC

It can be seen from the experimental data in Table 2 that when the cationic surfactants are all CTAC, changing the non-ionic surfactant has little effect on the thermal conductivity. The thermal conductivity of the prepared aerogel slurry is within the range defined by the present invention, and when the non-ionic surfactant is Tween 80, the thermal conductivity of the aerogel slurry is the largest.

Example 17 to Example 20

The nonionic surfactant used in Examples 17 to 20 is the same as that in Example 15, and 40 parts of deionized water and 5 parts of aerogel powder are added. The difference is that different cationic surfactants are used.

The data and experimental results of component B and component C added in Examples 17 to 20 are shown in Table 3.

Table 3 Performance test results of aerogel slurry prepared by mixing different cationic surfactants and Tween 80

It can be seen from the experimental data in Table 3 that when the non-ionic surfactant is Tween 80, the thermal conductivity of the prepared aerogel slurry remains basically unchanged by changing the cationic surfactant, and the changes in the surface tension and the hydrophobic angle are also small.

Example 21 to Example 30

The preparation methods of Examples 21 to 25 are the same as those of Example 1, the nonionic surfactant and cationic surfactant used are exactly the same as those of Example 5 and are added in the same amount, and 40 parts of deionized water are added, and the only difference from Example 5 is that the mass of the aerogel powder added is different. The preparation methods of Examples 26 to 30 are the same as those of Example 1, the nonionic surfactant and cationic surfactant used are exactly the same as those of Example 3 and are added in the same amount, and 40 parts of deionized water are added, and the only difference from Example 3 is that the mass of the aerogel powder added is different.

Table 4 Performance test results of aerogel slurry corresponding to different aerogel powder addition amounts

It can be seen from the experimental data in Table 4 that too little addition of aerogel powder will result in high thermal conductivity of aerogel slurry, but as the amount of aerogel powder added increases, the viscosity of the aerogel slurry will also increase. Thus, limited by the stirring equipment, the mass ratio of water to aerogel powder in the aerogel slurry provided by the present invention is preferably 1: (0.008-0.2). At the same time, when the amount of aerogel powder added is greater than or equal to 4 parts, the aerogel slurry corresponding to each embodiment is not stratified for a long time, and has the advantage of good stability.

It can be seen from FIG. 1 to FIG. 5 that the prepared aerogel slurry has excellent hydrophobicity and the nanoporous skeleton structure of the aerogel is not destroyed during the process of preparing the aerogel slurry.

Example 31 to Example 36

The preparation methods of Examples 31 to 36 are the same as those of Example 1. The difference from Example 1 is that the added components are not exactly the same. Specifically, the added component A is a silica aerogel powder with a particle size of 50 μm (thermal conductivity is 24 mW/(m·K)), and the weight portion is 5 parts; the added component B and component C and their weight portions are shown in Table 5, and the added component D is 40 parts of deionized water.

Table 5 Performance test results of aerogel slurry corresponding to aerogel powders with different thermal conductivities

It can be seen from Table 5 that when the weight of water is 40 parts and the weight of aerogel powder is 5 parts, the amount of nonionic surfactant polyether added is 0.04-0.16 parts and the amount of cationic surfactant added is 0.16-0.64 parts, and the difference between the thermal conductivity of the prepared aerogel slurry and the thermal conductivity of the hydrophobic aerogel powder is less than 3 mW/(m·K).

Comparative Example 1 to Comparative Example 14

The preparation methods of Comparative Examples 1 to 14 are the same as those of Example 1, and the main purpose is to investigate the performance results of aerogel slurries prepared by adding only one surfactant to the aerogel slurry. The specific surfactants added, their amounts, and performance results are detailed in Table 6.

Table 6 Performance results of aerogel slurry corresponding to a single surfactant

The aerogel slurries prepared by using a single-component surfactant in Comparative Examples 1 to 14 will show stratification after 24 hours, and there is a technical problem of high thermal conductivity. At the same time, the difference between the thermal conductivity of the prepared aerogel slurry and the thermal conductivity of the hydrophobic aerogel powder is greater than 8 mW/(m·K).

Comparative Example 15 to Comparative Example 19

The preparation methods of Comparative Examples 15 to 19 are the same as those of Example 1, and the main purpose is to investigate the performance results of aerogel slurries prepared by compounding nonionic surfactants and anionic surfactants. The specific surfactants added, their fractions, and performance results are detailed in Table 7.

Table 7 Performance test results of aerogel slurry prepared by mixing nonionic surfactant and anionic surfactant

From the experimental results of Comparative Examples 15 to 19, it can be seen that the aerogel slurry prepared by compounding a nonionic surfactant and anionic surfactant still has the technical problem of high thermal conductivity. At the same time, the difference between the thermal conductivity of the prepared aerogel slurry and the thermal conductivity of the hydrophobic aerogel powder is greater than 8 mW/(m·K).

Comparative Example 20 to Comparative Example 25

The preparation methods of Comparative Examples 20 to 25 are the same as those of Example 1, and the main purpose is to investigate the performance results of aerogel slurries prepared by compounding cationic surfactants and anionic surfactants. The specific surfactants added, their fractions, and performance results are detailed in Table 8.

Table 8 Performance test results of aerogel slurry prepared by mixing cationic surfactant and anionic surfactant

From the experimental results of Comparative Examples 20 to 25, it can be seen that the aerogel slurry prepared by compounding the cationic surfactant and the anionic surfactant still has the technical problem of high thermal conductivity. At the same time, the difference between the thermal conductivity of the prepared aerogel slurry and the thermal conductivity of the hydrophobic aerogel powder is greater than 9 mW/(m·K).

Other comparison ratios

Based on the technical solution disclosed in CN105038445A, the performance test results of aerogel slurry prepared by aerogel powder + water + cationic surfactant + binder are shown in Table 9. Table 9 shows that the preparation method of each embodiment is the same as that of Example 1, and the only difference is that the composition of the aerogel slurry is different.

Table 9 Performance test results of aerogel slurry with added binder

From the comparison of the experimental data of multiple embodiments shown in Table 8, it can be seen that with the increase in the amount of binder, the thermal conductivity of the prepared aerogel slurry gradually increases. At the same time, the 5 groups of aerogel slurries prepared corresponding to Table 9 did not show stratification, while the aerogel slurry without binder in Comparative Example 6 showed stratification after 24 hours of placement, with the defect of poor stability, indicating that the addition of binder can increase the stability of aerogel slurry, but at the same time it will also lead to an increase in its thermal conductivity. The difference between the thermal conductivity of the prepared aerogel slurry and the thermal conductivity of the hydrophobic aerogel powder is greater than 9mW/(m·K).

It should be noted that the thermal conductivity of the aerogel slurry in all the above examples and comparative examples refers to the thermal conductivity of the powder obtained after the aerogel slurry is dried.

The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions and substitutions can be made without departing from the concept of the present invention, which should be regarded as belonging to the protection scope of the present invention.

Claims (8)

1. An aerogel slurry, characterized in that it consists of component A, component B, component C and component D, wherein: The component A is a hydrophobic aerogel powder, and the thermal conductivity of the component A is 18-25 mW/(m·K); The component B is a nonionic surfactant, and the component B is selected from at least one of polyether L62, polyether L63, polyether L65, polyether L42, polyether L43, and Tween 80; The component C is a cationic surfactant, and the component C is selected from at least one of cetyltrimethylammonium chloride, cetyltrimethylammonium bromide, dodecyltrimethylammonium bromide, octadecyltrimethylammonium chloride, and octadecyltrimethylammonium bromide; The component D is water; Based on the weight of component D of the aerogel slurry, the component B is 0.1 wt% to 0.4 wt%, and the component C is 0.4 wt% to 1.6 wt%; based on the total weight of component A, component B, component C and component D, the amount of component A is in the range of 6.8 wt% to 20 wt%; and the mass ratio of component D to component A is 1:(0.08-0.2); The thermal conductivity of the aerogel slurry is 19-32 mW/(m·K). 2 . The aerogel slurry according to claim 1 , wherein the difference between the thermal conductivity of the aerogel slurry and the thermal conductivity of the component A is NmW/(m·K), wherein 1≤N≤7. 3. The aerogel slurry according to claim 1, characterized in that the component A is a silica aerogel powder with a thermal conductivity of 18 mW/(m·K), and the thermal conductivity of the aerogel slurry is not more than 25 mW/(m·K). 4 . The aerogel slurry according to claim 3 , wherein the silica aerogel powder has a particle size of 15-50 μm and a density of 60-80 kg/m ³ . 5. The aerogel slurry according to claim 1, characterized in that, based on the weight of component D of the aerogel slurry, component B is 0.2 wt%~0.3 wt%, and component C is 0.6 wt%~1.2 wt%; based on the total weight of component A, component B, component C and component D, the amount of component A is in the range of 7 wt% to 14 wt%. 6. The aerogel slurry according to claim 1, characterized in that the mass ratio of the component D to the component B is 1:(0.002-0.003), and the mass ratio of the component B to the component C is 1:(2-4). 7. The aerogel slurry according to claim 1, characterized in that the aerogel slurry is prepared by the following method, comprising: Add water, nonionic surfactant and cationic surfactant into a mechanical stirrer in sequence, and stir at a speed of 500-1000 r/min for 3-5 minutes at normal temperature and pressure to form a mixed solution; The hydrophobic aerogel powder is added to the mixed solution, and then stirred at a speed of 400-5000 r/min for 3-20 minutes at normal temperature and pressure to mix evenly to form a non-stratified aerogel slurry. 8. Use of the aerogel slurry according to any one of claims 1 to 7 in thermal insulation materials.