Dispersible aerogel slurry as well as preparation method and application thereof

Abstract

The invention discloses dispersible aerogel slurry as well as a preparation method and application thereof, and belongs to the technical field of aerogel slurry preparation. The preparation method comprises the following steps: S1, dissolving quaternized chitosan in water, then adding aerogel, and uniformly dispersing to obtain an aerogel solution; s2, ammonium polyphosphate is added into the aerogel solution for a reaction, and thick paste is obtained; s3, the paste is granulated and dried, and aerogel particles are obtained; and S4, uniformly mixing the aerogel particles, a binder and water to obtain the dispersible aerogel slurry. The dispersible aerogel slurry has low heat conductivity coefficient and good flame retardance, and can be applied to thermal insulation materials.

Description

Technical Field

[0001] The invention belongs to the technical field of aerogel slurry preparation, and in particular relates to a dispersible aerogel slurry and a preparation method and application thereof. Background Art

[0002] Silica aerogel is a three-dimensional mesh porous nanomaterial with low density, good thermal insulation, high porosity, etc. In addition, in order to reduce the problem of collapse of the pore structure during drying, it is usually necessary to perform hydrophobic modification before drying when preparing aerogels, so most of the prepared aerogels have good hydrophobicity.

[0003] When aerogel is compounded with other inorganic materials, due to its hydrophobic and light characteristics, it will have poor compatibility with other substances. When mixed, it will float on the top 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, thereby preparing aerogel composite materials with stable performance. Summary of the invention

[0004] In order to overcome the shortcomings of the prior art, the first aspect of the present invention provides a method for preparing a dispersible aerogel slurry, comprising the following steps:

[0005] S1, dissolving quaternary ammonium chitosan in water, then adding aerogel to disperse evenly, heating to react, and obtaining an aerogel solution;

[0006] S2, adding ammonium polyphosphate to the aerogel solution to react and obtain a thick paste;

[0007] S3, granulating and drying the paste to obtain aerogel particles;

[0008] S4, stirring and mixing the aerogel particles, the binder and the water to obtain a dispersible aerogel slurry;

[0009] The aerogel described in S1 is a hydrophobic silica aerogel.

[0010] Further, the quaternized chitosan described in S1 is prepared by the following steps:

[0011] Dissolve chitosan in isopropanol, and adjust the pH value of the chitosan solution to 8 with 1M NaOH; add 2,3-epoxypropyltrimethylammonium chloride to the chitosan solution, stir and react at a constant temperature of 60-90°C for 6-10h, then filter, wash with anhydrous ethanol, and dry to obtain quaternized chitosan.

[0012] Furthermore, the mass ratio of chitosan to 2,3-epoxypropyltrimethylammonium chloride is 1:3.

[0013] Further, the mass of aerogel in the aerogel solution described in S1 accounts for 20-30%;

[0014] The amount of quaternized chitosan in S1 is 2-4% of the mass of the aerogel.

[0015] Furthermore, the amount of ammonium polyphosphate in S2 is 3-5% of the mass of the aerogel.

[0016] Furthermore, the reaction temperature in S1 and S2 is 50-60°C, and the reaction time is 1-2h.

[0017] Furthermore, in S3, the drying temperature is 110-120° C., and the drying time is 2-3 h.

[0018] Furthermore, the binder in S4 is one of polyvinyl alcohol, water-based acrylic resin and water-based polyurethane;

[0019] The mass ratio of aerogel particles, binder and water in S4 is 10-20:80-90:0.5-1.

[0020] The second aspect of the present invention provides a dispersible aerogel slurry prepared by the above preparation method.

[0021] The third aspect of the present invention provides a use of the above-mentioned dispersible aerogel slurry in thermal insulation materials;

[0022] The thermal insulation materials are thermal insulation mortar, thermal insulation board and thermal insulation coating.

[0023] Beneficial effects of the present invention:

[0024] The present invention adds quaternized chitosan to the aerogel, and the addition of quaternized chitosan can give the aerogel particles good hydrophilicity, so that the prepared aerogel slurry has good dispersibility and can be evenly dispersed in an aqueous system, which is convenient for better application in thermal insulation materials; the addition of ammonium polyphosphate can give the aerogel slurry good flame retardant performance, and the quaternized chitosan can improve the compatibility of ammonium polyphosphate and aerogel, so that the ammonium polyphosphate is successfully introduced into the aerogel. DETAILED DESCRIPTION

[0025] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only 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.

[0026] Example 1

[0027] This embodiment provides a dispersible aerogel slurry, which is prepared by the following steps:

[0028] S1, dissolving 0.6 g of quaternized chitosan in 80 g of water, then adding 30 g of hydrophobic silica aerogel and dispersing evenly, heating to 50° C. for reaction for 2 h to obtain an aerogel solution;

[0029] S2, adding 0.9 g of ammonium polyphosphate to the aerogel solution, heating to 50° C. and reacting for 2 h to obtain a thick paste;

[0030] S3, granulating the paste and drying it at 120°C for 2h to obtain aerogel particles with a diameter of 1-2mm;

[0031] S4. 10 g of aerogel particles, 0.5 g of binder and 80 g of water were mixed uniformly at 500 rpm for 30 min to obtain a dispersible aerogel slurry.

[0032] The quaternized chitosan described in S1 is prepared by the following steps:

[0033] 1.5 g of chitosan was dissolved in 100 mL of isopropanol, and the pH of the chitosan solution was adjusted to 8 with 1 M NaOH; 4.5 g of 2,3-epoxypropyltrimethylammonium chloride was added to the chitosan solution, and the mixture was stirred at a constant temperature of 70° C. for 10 h, and then filtered, washed with anhydrous ethanol, and dried to obtain quaternized chitosan.

[0034] Example 2

[0035] Compared with Example 1, the difference between this example is that the "0.6 g quaternary ammonium chitosan" in S1 is changed to "0.9 g quaternary ammonium chitosan"; the other raw materials and preparation process remain the same as those in Example 1.

[0036] Example 3

[0037] Compared with Example 1, the difference between this example is that the "0.6 g quaternary ammonium chitosan" in S1 is changed to "1.2 g quaternary ammonium chitosan"; the other raw materials and preparation process remain the same as those in Example 1.

[0038] Example 4

[0039] The difference between this embodiment and embodiment 3 is that the "0.9 g ammonium polyphosphate" in S2 is changed to "0.9 g ammonium polyphosphate" to "1.2 g ammonium polyphosphate"; the remaining raw materials and preparation process remain the same as those in embodiment 3.

[0040] Example 5

[0041] The difference between this embodiment and Embodiment 3 is that the "0.9 g ammonium polyphosphate" in S2 is changed to "0.9 g ammonium polyphosphate" to "1.5 g ammonium polyphosphate"; the remaining raw materials and preparation process remain the same as those in Embodiment 3.

[0042] Comparative Example 1

[0043] The difference between this comparative example and Example 1 is that "chitosan" is used to replace "quaternized chitosan"; the other raw materials and preparation process remain the same as those in Example 1.

[0044] Comparative Example 2

[0045] The difference between this comparative example and Example 1 is that no quaternary ammonium chitosan is added to S1; the other raw materials and preparation process remain the same as those in Example 1.

[0046] Comparative Example 3

[0047] The difference between this comparative example and Example 1 is that ammonium polyphosphate is not added to S2; the remaining raw materials and preparation process remain the same as those in Example 1.

[0048] Application Examples

[0049] The application example provides a method for preparing thermal insulation mortar, comprising the following steps:

[0050] Take 3 parts of the dispersible aerogel slurry prepared in Examples 1 to 5 and Comparative Examples 1 to 3, respectively, add 30 parts of cement, 25 parts of slag, 17 parts of perlite, 3 parts of polypropylene fiber and 10 parts of water, and stir and mix for 20 minutes to obtain thermal insulation mortar.

[0051] The aerogel slurry was left to stand for 15 days to observe whether there was stratification and sedimentation; the thermal conductivity of the aerogel slurry was tested after it was dried; the flame retardant properties of the thermal insulation mortar were tested according to the GB 8624-2012 standard, and the flame retardant grades were divided into: Grade A: non-combustible building materials, almost no combustion; Grade B1: flame-retardant building materials, with good flame retardant effect; Grade B2: combustible building materials, with certain flame retardant effect; Grade B3: flammable building materials, extremely easy to burn, with high fire risk. The test results are shown in Table 1.

[0052] Table 1

[0053] project Whether it is stratified or settled Thermal conductivity of aerogel slurry mW / (m·K) Flame retardant Example 1 no 19.1 A Example 2 no 18.3 A Example 3 no 17.4 A Example 4 no 16.5 A Example 5 no 15.3 A Comparative Example 1 yes 23.6 B1 Comparative Example 2 yes 28.5 B1 Comparative Example 3 no 30.6 B2

[0054] As can be seen from Table 1, the aerogel slurries prepared in Examples 1 to 5 were left standing for 15 days without any stratification or sedimentation, indicating that the aerogel slurries had good dispersibility; the thermal conductivity coefficients of the aerogel slurries prepared in Examples 1 to 5 were all low, and the flame retardancy was also good when applied to thermal insulation mortar.

[0055] Compared with Example 1, the aerogel slurry obtained by replacing quaternized chitosan with chitosan in Comparative Example 1 showed stratification and sedimentation after standing for 15 days. The reason is that the water solubility of chitosan is not as good as that of quaternized chitosan, resulting in poor water solubility of the obtained aerogel particles, and thus stratification and sedimentation of the aerogel slurry. Compared with Example 1, Comparative Example 2 does not add quaternized chitosan, resulting in poor water solubility of the obtained aerogel particles, stratification and sedimentation of the aerogel slurry, and the thermal conductivity of the aerogel slurry is high. At the same time, because there is no quaternized chitosan, the flame retardancy of the obtained thermal insulation mortar is also poor, because quaternized chitosan can improve the compatibility of ammonium polyphosphate and aerogel, so that ammonium polyphosphate is successfully introduced into the aerogel. Comparative Example 3 does not add ammonium polyphosphate, and the flame retardancy of the obtained aerogel slurry applied to the thermal insulation mortar is poor.

[0056] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0057] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a dispersible aerogel slurry, characterized in that: The following steps are involved: S1, dissolving quaternary ammonium chitosan in water, then adding aerogel to disperse evenly, heating to react, and obtaining an aerogel solution; S2, adding ammonium polyphosphate to the aerogel solution to react and obtain a thick paste; S3, granulating and drying the paste to obtain aerogel particles; S4, stirring and mixing the aerogel particles, the binder and the water to obtain a dispersible aerogel slurry; The aerogel described in S1 is a hydrophobic silica aerogel.

2. The method for preparing a dispersible aerogel slurry according to claim 1, characterized in that: The quaternized chitosan described in S1 is prepared by the following steps: Dissolve chitosan in isopropanol, and adjust the pH value of the chitosan solution to 8 with 1M NaOH; add 2,3-epoxypropyltrimethylammonium chloride to the chitosan solution, stir and react at a constant temperature of 60-90°C for 6-10h, then filter, wash with anhydrous ethanol, and dry to obtain quaternized chitosan.

3. The method for preparing a dispersible aerogel slurry according to claim 2, characterized in that: The mass ratio of the chitosan to 2,3-epoxypropyltrimethylammonium chloride is 1:

3.

4. The method for preparing a dispersible aerogel slurry according to claim 1, characterized in that: The mass of aerogel in the aerogel solution described in S1 accounts for 20-30%; The amount of quaternized chitosan in S1 is 2-4% of the mass of the aerogel.

5. The method for preparing a dispersible aerogel slurry according to claim 1, characterized in that: The amount of ammonium polyphosphate in S2 is 3-5% of the mass of the aerogel.

6. The method for preparing a dispersible aerogel slurry according to claim 1, characterized in that: The reaction temperature in S1 and S2 is 50-60°C, and the reaction time is 1-2h.

7. The method for preparing a dispersible aerogel slurry according to claim 1, characterized in that: The drying temperature in S3 is 110-120°C and the drying time is 2-3h.

8. The method for preparing a dispersible aerogel slurry according to claim 1, characterized in that: The binder in S4 is one of polyvinyl alcohol, water-based acrylic resin and water-based polyurethane; The mass ratio of aerogel particles, binder and water in S4 is 10-20:80-90:1-2.

9. A dispersible aerogel slurry, characterized in that: The aerogel slurry is prepared by the method for preparing the dispersible aerogel slurry according to any one of claims 1 to 8.

10. Use of the dispersible aerogel slurry according to claim 9 in thermal insulation materials.