Vibration reduction and heat insulation composite filler as well as preparation process and application thereof

Abstract

The invention discloses a vibration-damping and heat-insulating composite filler as well as a preparation process and application thereof. The preparation process comprises the following steps: dissolving tetraethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane and hexamethyldisilazane in a solution to form a mixed colloidal solution; dissolving a surfactant in water to form a surfactant solution; adding hollow glass microspheres into the surfactant solution to obtain a dispersion solution; adding the precursor mixed colloidal solution into the dispersion solution, and stirring and mixing; adding ammonia water to gelatinize the precursor on the surfaces of the hollow glass microspheres; cleaning and drying to obtain the aerogel coated hollow glass microsphere material. The surfaces of the hollow glass microspheres are coated with the aerogel to form the vibration reduction and heat insulation composite filler, integrated preparation of the vibration reduction and heat insulation composite material is achieved, the prepared material is small in size, has the filling characteristic and can be secondarily compounded with other materials, and the heat insulation and vibration reduction performance of a body material is improved.

Description

Technical Field

[0001] The invention relates to the technical field of vibration-damping and heat-insulating materials, and in particular to a vibration-damping and heat-insulating composite filler and a preparation process and application thereof. Background Art

[0002] With the development of economy and science and technology, human beings have more and more demands in industrial production. The rapid consumption of energy has forced people to pay attention to the thermal insulation of materials involved in industrial engineering, and materials with vibration reduction characteristics have a promoting effect on extending the service life of engineering equipment. In various engineering fields, the demand for materials with good vibration reduction and thermal insulation performance is getting higher and higher. For example: nuclear power facilities are rich in criss-crossing high-temperature, high-pressure, high-flow rate current-carrying pipelines (high-temperature fluid pipelines, fan pipelines, etc.), and their local over-temperature and vibration exceeding the standard problems are more prominent. Better thermal insulation performance can reduce heat transfer and avoid local over-temperature problems, and further reduction of heat loss can also help reduce energy consumption; and vibration reduction materials can reduce vibration transmission and avoid equipment damage caused by mechanical fatigue of materials. Therefore, the demand for thermal insulation and vibration reduction of high-temperature and high-vibration equipment is very urgent.

[0003] In current engineering application practices, ceramic porous insulation materials are often used to meet the insulation requirements of buildings or equipment, and ceramic hollow ball fillers are used to form cavities to improve the thermal insulation performance of the materials, and polymer damping materials are used to meet the vibration reduction (isolation) requirements. Therefore, functional materials need to be added separately, and it is impossible to achieve materials with good thermal insulation and vibration reduction characteristics at the same time.

[0004] The composite material of the protective layer, upper insulation layer, medium and low damping layer, lower insulation layer and damping alloy layer stacked in CN111923542A "A high temperature resistant heat insulation and vibration reduction composite material" has a complex preparation process and has the problem of large material thickness. CN207241052U "A composite material board" also uses the method of stacking insulation material and damping material to prepare the composite material. Although the thickness of the material is reduced, the stacking of multiple layers of materials leads to a complex preparation process and is not suitable for large-scale industrial production. The lightweight multifunctional composite material prepared with cork particles as the main raw material and polyurethane as the foaming agent proposed in CN114133759A "A light multifunctional composite material made of polyurethane and cork particles and its preparation method and application" realizes the integrated preparation of heat insulation and vibration reduction materials, but the prepared material does not have filling properties and cannot be used as a filling material for secondary compounding with other materials.

[0005] At present, there is no systematic report on the structural design and preparation process of vibration reduction / heat insulation integrated materials, and there is no report on fillers that can simultaneously improve the heat insulation and damping properties in the prior art.

[0006] In view of this, this application is hereby filed. Summary of the invention

[0007] In order to solve the above technical problems, the present invention provides a vibration-damping and heat-insulating composite filler, a preparation process and application thereof, in which aerogel is coated on the surface of hollow glass microspheres to constitute a vibration-damping and heat-insulating composite filler, thereby realizing the integrated preparation of composite materials with vibration-damping and heat-insulating properties. The prepared material is small in size and has filling properties, and can be secondary composited with other materials to improve the heat insulation and vibration-damping properties of the main material, thereby solving the difficulty in preparing the integrated vibration-damping / heat-insulating composite filling material.

[0008] The present invention is achieved through the following technical solutions:

[0009] In a first aspect, the present invention provides a process for preparing a vibration-damping and heat-insulating composite filler, comprising the following steps:

[0010] (1) Preparation of precursor solution: using tetraethyl orthosilicate, methyltrimethoxysilane / methyltriethoxysilane, dimethyldimethoxysilane and hexamethyldisilazane as precursors, dissolving them in an appropriate amount of solution to form a mixed colloidal solution;

[0011] (2) Preparation of surfactant solution: dissolving the surfactant in an appropriate amount of water to form a surfactant solution;

[0012] (3) Dispersion of hollow glass microspheres: adding a certain amount of hollow glass microspheres to the surfactant solution to uniformly disperse the hollow glass microspheres to obtain a hollow glass microsphere dispersion solution;

[0013] (4) Mixing preparation: adding the precursor mixed colloidal solution to the hollow glass microsphere dispersion solution and stirring to mix the precursor and the hollow glass microspheres thoroughly;

[0014] (5) Gelation and coating: During the stirring process, an appropriate amount of ammonia water is gradually added to adjust the acidity and alkalinity of the system. Under the action of ammonia water, the precursor is gelled on the surface of the hollow glass microspheres to form a thin gel layer, thereby coating the hollow glass microspheres.

[0015] (6) Cleaning and drying to obtain aerogel-coated hollow glass microsphere material.

[0016] In a specific embodiment, in step (1), according to the required performance requirements, the mass content of each component is 30-50% of tetraethyl orthosilicate, 15-30% of methyltrimethoxysilane / methyltriethoxysilane, 10-20% of dimethyldimethoxysilane, and 2% of hexamethyldisilazane.

[0017] In a specific embodiment, in step (2), the surfactant is sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, hexadecyltrimethylammonium bromide or hexadecyltrimethylammonium chloride, and the mass concentration of the surfactant solution is 0.5-1%.

[0018] In a specific embodiment, in step (3), the mass fraction of the hollow glass microspheres is 10-15%.

[0019] In a specific embodiment, in step (4), the ratio of the precursor mixed colloid solution to the hollow glass microsphere dispersion solution is 1 to 2.5:1.

[0020] In a specific embodiment, in step (5), the amount of ammonia water added each time is 0.5 mL.

[0021] In a specific embodiment, the specific steps of step (6) are as follows:

[0022] The mixed solution obtained in step (5) is placed in ethanol for solvent exchange to remove the remaining water and solvent;

[0023] The aerogel-coated hollow glass microspheres were obtained by using ethanol supercritical drying technology and drying under appropriate temperature and pressure conditions.

[0024] In a specific embodiment, the process parameters of supercritical drying are: using gradient heating, the temperature of the drying kettle is increased from room temperature to 255°C, the pressure in the kettle is maintained at 11-12MPa for 2h, and then the pressure is released to atmospheric pressure at a rate of 1-2MPa / h, and cooled to room temperature to obtain aerogel-coated hollow glass microspheres.

[0025] In a second aspect, the present invention further provides a vibration-damping and heat-insulating composite filler, which is prepared by using the preparation process of the vibration-damping and heat-insulating composite filler.

[0026] In a specific embodiment, the structure of the vibration-damping and heat-insulating composite filler includes hollow glass microspheres, and the outer surface of the hollow glass microspheres is coated with an aerogel layer.

[0027] In a third aspect, the present invention also provides an application of a vibration-damping and heat-insulating composite filler, which is used to be added into a base material to improve the heat-insulating and vibration-damping properties of the base material.

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

[0029] 1. A vibration-damping and heat-insulating composite filler and its preparation process and application provided in an embodiment of the present invention, wherein aerogel is coated on the surface of hollow glass microspheres to form a core-shell structure, thereby constituting a vibration-damping and heat-insulating composite filler, so that the filler has both shock-absorbing and heat-insulating properties, thereby realizing the integrated preparation of a composite material having both vibration-damping and heat-insulating properties;

[0030] 2. A vibration-damping and heat-insulating composite filler and its preparation process and application provided in an embodiment of the present invention. The prepared material is small in size and has filling properties. It can be composited and filled with other materials for secondary use, thereby improving the heat insulation and vibration-damping performance of the main material and solving the preparation problem of integrated vibration-damping / heat-insulating composite filling materials.

[0031] 3. A vibration-damping and heat-insulating composite filler, its preparation process and application provided in an embodiment of the present invention, combines the advantages of aerogels and hollow glass microspheres, and has excellent thermal insulation and damping performance improvement effects. It can be applied to a variety of fields, such as composite filling of materials in construction, transportation engineering, aerospace, etc. The preparation method is simple and controllable and can meet different performance requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 A scanning electron microscope image of aerogel-coated hollow glass microspheres provided in an embodiment of the present invention;

[0034] Figure 2 Graph showing the damping performance test results of adding the composite filler of Example 1 of the present invention and without adding filler. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments. The illustrative embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0036] In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present invention. However, it is apparent to one of ordinary skill in the art that these specific details need not be employed to practice the present invention. In other embodiments, in order to avoid confusing the present invention, well-known materials or methods are not specifically described.

[0037] Throughout the specification, references to "one embodiment," "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment of the present invention. Therefore, the phrases "one embodiment," "an embodiment," "an example," or "an example" appearing in various places throughout the specification do not necessarily all refer to the same embodiment or example. In addition, particular features, structures, or characteristics may be combined in one or more embodiments or examples in any suitable combination and / or subcombination. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0038] The "range" disclosed in the present application is defined in the form of a lower limit and an upper limit, and a given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of the particular range. The range defined in this way can be inclusive or exclusive of the end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a range. For example, if a range of 60 to 120 and 80 to 110 is listed for a particular parameter, it is understood that a range of 60 to 110 and 80 to 120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are listed, the following ranges can all be expected: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4 and 2 to 5. In the present application, unless otherwise specified, the numerical range "a to b" represents an abbreviation of any real number combination between a and b, where a and b are both real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0039] If there is no special explanation, all steps of the present application can be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), which means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0040] In a first aspect, the present invention provides a process for preparing a vibration-damping and heat-insulating composite filler, comprising the following steps:

[0041] (1) Preparation of precursor solution: using tetraethyl orthosilicate, methyltrimethoxysilane / methyltriethoxysilane, dimethyldimethoxysilane and hexamethyldisilazane as precursors, dissolving them in an appropriate amount of solution to form a mixed colloidal solution;

[0042] (2) Preparation of surfactant solution: dissolving the surfactant in an appropriate amount of water to form a surfactant solution;

[0043] (3) Dispersion of hollow glass microspheres: adding a certain amount of hollow glass microspheres to the surfactant solution to uniformly disperse the hollow glass microspheres to obtain a hollow glass microsphere dispersion solution;

[0044] (4) Mixing preparation: adding the precursor mixed colloidal solution to the hollow glass microsphere dispersion solution and stirring to mix the precursor and the hollow glass microspheres thoroughly;

[0045] (5) Gelation and coating: During the stirring process, an appropriate amount of ammonia water is gradually added to adjust the acidity and alkalinity of the system. Under the action of ammonia water, the precursor is gelled on the surface of the hollow glass microspheres to form a thin gel layer, thereby coating the hollow glass microspheres.

[0046] (6) Cleaning and drying to obtain aerogel-coated hollow glass microsphere material.

[0047] In a specific embodiment, in step (1), according to the required performance requirements, the mass content of each component is 30-50% of tetraethyl orthosilicate, 15-30% of methyltrimethoxysilane / methyltriethoxysilane, 10-20% of dimethyldimethoxysilane, and 2% of hexamethyldisilazane.

[0048] In a specific embodiment, in step (2), the surfactant is sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, hexadecyltrimethylammonium bromide or hexadecyltrimethylammonium chloride, and the mass concentration of the surfactant solution is 0.5-1%.

[0049] In a specific embodiment, in step (3), the mass fraction of the hollow glass microspheres is 10-15%.

[0050] In a specific embodiment, in step (4), the ratio of the precursor mixed colloid solution to the hollow glass microsphere dispersion solution is 1 to 2.5:1.

[0051] In a specific embodiment, in step (5), the amount of ammonia water added each time is 0.5 mL.

[0052] In a specific embodiment, the specific steps of step (6) are as follows:

[0053] The mixed solution obtained in step (5) is placed in ethanol for solvent exchange to remove the remaining water and solvent;

[0054] The aerogel-coated hollow glass microspheres were obtained by using ethanol supercritical drying technology and drying under appropriate temperature and pressure conditions.

[0055] In a specific embodiment, the process parameters of supercritical drying are: using gradient heating, the temperature of the drying kettle is increased from room temperature to 255°C, the pressure in the kettle is maintained at 11-12MPa for 2h, and then the pressure is released to atmospheric pressure at a rate of 1-2MPa / h, and cooled to room temperature to obtain aerogel-coated hollow glass microspheres.

[0056] Example 1

[0057] The embodiment of the present invention provides a preparation process of a vibration-damping and heat-insulating composite filler, comprising the following steps:

[0058] (1) Preparation of precursor solution: Take tetraethyl orthosilicate, methyltrimethoxysilane / methyltriethoxysilane, dimethyldimethoxysilane and hexamethyldisilazane as precursors, dissolve them in an appropriate amount of ethanol solution, and stir for 1 hour to form a mixed colloidal solution; wherein the tetraethyl orthosilicate is 40%, methyltrimethoxysilane / methyltriethoxysilane is 20%, dimethyldimethoxysilane is 15%, and hexamethyldisilazane is 2%; the mass concentration of ethanol and water is 12%;

[0059] (2) Preparation of surfactant solution: dissolve the surfactant in an appropriate amount of water and stir for 10 min to form a surfactant solution. The mass concentration of the surfactant solution is 0.8%;

[0060] (3) Dispersion of hollow glass microspheres: adding a certain amount of hollow glass microspheres to the surfactant solution and stirring for 10 minutes to uniformly disperse the hollow glass microspheres to obtain a hollow glass microsphere dispersion solution to form a viscous slurry, wherein the mass ratio of the hollow glass microspheres is 12%;

[0061] (4) Mixing preparation: adding the precursor mixed colloidal solution to the hollow glass microsphere dispersion solution and stirring and mixing for 10 minutes to fully mix the precursor and the hollow glass microspheres; the ratio of the precursor mixed colloidal solution to the hollow glass microsphere dispersion solution is 1:1;

[0062] (5) Gelation and coating: During the stirring process, a pipette is used to gradually add an appropriate amount of ammonia water to the mixture of the precursor and the hollow glass microspheres. The amount of ammonia water added each time is 0.5 mL. The acidity and alkalinity of the solution system are adjusted to make the precursor gradually gel on the surface of the hollow glass microspheres to form a gel layer, thereby coating the hollow glass microspheres.

[0063] (6) placing the mixed solution obtained in step (5) in ethanol for solvent exchange for 4 days, replacing fresh ethanol every 24 hours, removing remaining water and other solvents, and then using ethanol supercritical drying technology, using gradient heating, raising the temperature of the drying kettle from room temperature to 255°C, and maintaining the pressure in the drying kettle at 11-12 MPa for 2 hours, and then releasing the pressure to atmospheric pressure at a rate of 1-2 MPa / h; cooling to room temperature, thereby obtaining aerogel-coated hollow glass microspheres, such as Figure 1 Shown is a scanning electron microscope image of aerogel-coated hollow glass microspheres.

[0064] Example 2

[0065] The embodiment of the present invention provides a preparation process of a vibration-damping and heat-insulating composite filler, comprising the following steps:

[0066] (1) Preparation of precursor solution: Take tetraethyl orthosilicate, methyltrimethoxysilane / methyltriethoxysilane, dimethyldimethoxysilane and hexamethyldisilazane as precursors, dissolve them in appropriate amounts of water and ethanol solution, and stir for 1 hour to form a mixed colloidal solution; wherein the tetraethyl orthosilicate is 45%, the methyltrimethoxysilane / methyltriethoxysilane is 25%, the dimethyldimethoxysilane is 10%, and the hexamethyldisilazane is 2%; the mass concentration of ethanol and water is 8%;

[0067] (2) Preparation of surfactant solution: dissolve the surfactant in an appropriate amount of water and stir for 10 min to form a surfactant solution. The mass concentration of the surfactant solution is 0.5%;

[0068] (3) Dispersion of hollow glass microspheres: adding a certain amount of hollow glass microspheres to the surfactant solution and stirring for 10 min to uniformly disperse the hollow glass microspheres to obtain a hollow glass microsphere dispersion solution to form a viscous slurry, wherein the mass ratio of the hollow glass microspheres is 10%;

[0069] (4) Mixing preparation: adding the precursor mixed colloidal solution to the hollow glass microsphere dispersion solution and stirring and mixing for 10 minutes to fully mix the precursor and the hollow glass microspheres; the ratio of the precursor mixed colloidal solution to the hollow glass microsphere dispersion solution is 1.5:1;

[0070] (5) Gelation and coating: During the stirring process, a pipette is used to gradually add an appropriate amount of ammonia water to the mixture of the precursor and the hollow glass microspheres. The amount of ammonia water added each time is 0.5 mL. The acidity and alkalinity of the solution system are adjusted to make the precursor gradually gel on the surface of the hollow glass microspheres to form a gel layer, thereby coating the hollow glass microspheres.

[0071] (6) placing the mixed solution obtained in step (5) in ethanol for solvent exchange for 4 days, replacing fresh ethanol every 24 hours, removing remaining water and other solvents, and then using ethanol supercritical drying technology, using gradient heating, raising the temperature of the drying kettle from room temperature to 255°C, and maintaining the pressure in the drying kettle at 11-12 MPa for 2 hours, and then releasing the pressure to atmospheric pressure at a rate of 1-2 MPa / h; cooling to room temperature, thereby obtaining aerogel-coated hollow glass microspheres, such as Figure 1 Shown is a scanning electron microscope image of aerogel-coated hollow glass microspheres.

[0072] Example 3

[0073] The embodiment of the present invention provides a preparation process of a vibration-damping and heat-insulating composite filler, comprising the following steps:

[0074] (1) Preparation of precursor solution: Take tetraethyl orthosilicate, methyltrimethoxysilane / methyltriethoxysilane, dimethyldimethoxysilane and hexamethyldisilazane as precursors, dissolve them in appropriate amounts of water and ethanol solution, and stir for 1 hour to form a mixed colloidal solution; wherein the tetraethyl orthosilicate is 35%, the methyltrimethoxysilane / methyltriethoxysilane is 30%, the dimethyldimethoxysilane is 20%, and the hexamethyldisilazane is 2%; the mass concentration of ethanol and water is 15%;

[0075] (2) Preparation of surfactant solution: dissolve the surfactant in an appropriate amount of water and stir for 10 min to form a surfactant solution. The mass concentration of the surfactant solution is 1%;

[0076] (3) Dispersion of hollow glass microspheres: adding a certain amount of hollow glass microspheres to the surfactant solution and stirring for 10 minutes to uniformly disperse the hollow glass microspheres to obtain a hollow glass microsphere dispersion solution to form a viscous slurry, wherein the mass ratio of the hollow glass microspheres is 15%;

[0077] (4) Mixing preparation: adding the precursor mixed colloidal solution to the hollow glass microsphere dispersion solution and stirring and mixing for 10 minutes to fully mix the precursor and the hollow glass microspheres; the ratio of the precursor mixed colloidal solution to the hollow glass microsphere dispersion solution is 2:1;

[0078] (5) Gelation and coating: During the stirring process, a pipette is used to gradually add an appropriate amount of ammonia water to the mixture of the precursor and the hollow glass microspheres. The amount of ammonia water added each time is 0.5 mL. The acidity and alkalinity of the solution system are adjusted to make the precursor gradually gel on the surface of the hollow glass microspheres to form a gel layer, thereby coating the hollow glass microspheres.

[0079] (6) placing the mixed solution obtained in step (5) in ethanol for solvent exchange for 4 days, replacing fresh ethanol every 24 hours, removing remaining water and other solvents, and then using ethanol supercritical drying technology, using gradient heating, raising the temperature of the drying kettle from room temperature to 255°C, and maintaining the pressure in the drying kettle at 11-12 MPa for 2 hours, and then releasing the pressure to atmospheric pressure at a rate of 1-2 MPa / h; cooling to room temperature, thereby obtaining aerogel-coated hollow glass microspheres, such as Figure 1 Shown is a scanning electron microscope image of aerogel-coated hollow glass microspheres.

[0080] Example 4

[0081] The embodiment of the present invention provides a preparation process of a vibration-damping and heat-insulating composite filler, comprising the following steps:

[0082] (1) Preparation of precursor solution: Take tetraethyl orthosilicate, methyltrimethoxysilane / methyltriethoxysilane, dimethyldimethoxysilane and hexamethyldisilazane as precursors, dissolve them in appropriate amounts of water and ethanol solution, and stir for 1 hour to form a mixed colloidal solution; wherein the tetraethyl orthosilicate is 50%, methyltrimethoxysilane / methyltriethoxysilane is 15%, dimethyldimethoxysilane is 12%, and hexamethyldisilazane is 2%; the mass concentration of ethanol and water is 10%;

[0083] (2) Preparation of surfactant solution: dissolve the surfactant in an appropriate amount of water and stir for 10 min to form a surfactant solution. The mass concentration of the surfactant solution is 0.7%;

[0084] (3) Dispersion of hollow glass microspheres: adding a certain amount of hollow glass microspheres to the surfactant solution and stirring for 10 min to uniformly disperse the hollow glass microspheres to obtain a hollow glass microsphere dispersion solution to form a viscous slurry, wherein the mass ratio of the hollow glass microspheres is 10%;

[0085] (4) Mixing preparation: adding the precursor mixed colloidal solution to the hollow glass microsphere dispersion solution and stirring and mixing for 10 minutes to fully mix the precursor and the hollow glass microspheres; the ratio of the precursor mixed colloidal solution to the hollow glass microsphere dispersion solution is 2.5:1;

[0086] (5) Gelation and coating: During the stirring process, a pipette is used to gradually add an appropriate amount of ammonia water to the mixture of the precursor and the hollow glass microspheres. The amount of ammonia water added each time is 0.5 mL. The acidity and alkalinity of the solution system are adjusted to make the precursor gradually gel on the surface of the hollow glass microspheres to form a gel layer, thereby coating the hollow glass microspheres.

[0087] (6) placing the mixed solution obtained in step (5) in ethanol for solvent exchange for 4 days, replacing fresh ethanol every 24 hours, removing remaining water and other solvents, and then using ethanol supercritical drying technology, using gradient heating, raising the temperature of the drying kettle from room temperature to 255°C, and maintaining the pressure in the drying kettle at 11-12 MPa for 2 hours, and then releasing the pressure to atmospheric pressure at a rate of 1-2 MPa / h; cooling to room temperature, thereby obtaining aerogel-coated hollow glass microspheres, such as Figure 1 Shown is a scanning electron microscope image of aerogel-coated hollow glass microspheres.

[0088] Comparative Example 1

[0089] This comparative example provides a preparation process of a filler, comprising the following steps:

[0090] Add ethyl orthosilicate and methyltrimethoxysilane to a dilute acid solution, stir and hydrolyze, and further adjust the pH value of the solution to 7-8 with ammonia water to obtain SiO2 sol: measure ethyl orthosilicate, methyltrimethoxysilane, 3-aminopropyltriethoxysilane and acetonitrile in volumes of 8.9ml, 4.2ml, 30ml and 30ml respectively, place in a beaker and stir fully, and then add 1ml ammonia water for catalysis. Exchange the SiO2 wet gel with anhydrous ethanol 3 times, and then exchange with acetone solvent 3 times, and ensure a 50℃ temperature control environment throughout the process; then place it in a CO2 low-temperature supercritical drying kettle, maintain pressure at 7-10MPa for 1 day; exchange at 7-10MPa for 8 days; maintain pressure at 40℃ at 9-12MPa for 1 day; exchange process for 1 day, and the degassing time is ~14h. The SiO2 aerogel is crushed by ball milling and sieved to obtain 50-80 micron SiO2 aerogel filler.

[0091] Comparative Example 2

[0092] This comparative example provides a preparation process of a filler, comprising the following steps:

[0093] First, add 6 parts of boiling water to the powder aqueous solution slurry reaction tank, and then add 1 part of boric acid, 2 parts of calcium nitrate, 0.25 parts of magnesium nitrate, 0.25 parts of aluminum nitrate and 0.5 parts of urea. Stir at high speed until completely dissolved, and put all the filter cakes into the reaction tank. After high-speed stirring, add waterproofing agent (10 parts of silane material), coagulant (25 parts of aluminum sulfate) and flocculant (5 parts of polyethylene oxide). For full uniformity, it can be treated with a colloid mill or a homogenizing grinder to form a homogenized coagulated slurry and pump it to the atomizing drying equipment. The inlet temperature of the spray drying equipment is 365℃, and the outlet temperature is 125℃, and 30 micron spherical dry particles can be obtained. The micron-level spherical precursor powder obtained in the second step is sent to the sintering system through the feeding device. The sintering furnace system air-natural gas-powder flow tube burner enters the vitrification gasification sintering system. The maximum temperature of the system is in the range of 750-900℃. Hollow glass microspheres with an average particle size of 30 to 100 microns can be formed.

[0094] Comparative Example 3

[0095] This comparative example provides a preparation process of a filler, comprising the following steps:

[0096] The fly ash and sodium hydroxide are mixed evenly, and then placed in a muffle furnace and calcined at 400°C for 2 hours, and then cooled to room temperature to obtain an alkali-melted mixture, and then the alkali-melted mixture is dissolved in dilute hydrochloric acid, and finally ammonia water is used to adjust the solution to neutrality, and filtered to obtain a silicon solution. The silicon solution is dried to obtain a powder cake, and then ball-milled and sieved to obtain SiO2 aerogel powder. The SiO2 aerogel powder is then mixed with hollow glass microspheres in a 1:1 ratio to form a composite material.

[0097] After the materials obtained in Examples 1-4 and Comparative Examples 1-3 were filled into the polyimide matrix material, the thermal insulation and damping properties of the materials were tested, and the thermal insulation and damping properties of the polyimide matrix without the vibration-damping and thermal-insulating composite filler of the present invention were compared.

[0098] Table 1

[0099]

[0100]

[0101] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A preparation process of a vibration-damping and heat-insulating composite filler, characterized in that: The steps include: (1) Preparation of precursor solution: dissolving tetraethyl orthosilicate, methyltrimethoxysilane / methyltriethoxysilane, dimethyldimethoxysilane and hexamethyldisilazane in an appropriate amount of solution to form a mixed colloidal solution; (2) Preparation of surfactant solution: dissolving the surfactant in an appropriate amount of water to form a surfactant solution; (3) Dispersion of hollow glass microspheres: adding hollow glass microspheres to a surfactant solution and dispersing them evenly to obtain a hollow glass microsphere dispersion solution; (4) Mixing preparation: adding the precursor mixed colloid solution into the hollow glass microsphere dispersion solution and stirring and mixing; (5) Gelation and coating: During the stirring process, ammonia water is added to adjust the acidity and alkalinity of the system so that the precursor is gelled on the surface of the hollow glass microspheres to form a gel layer coating the hollow glass microspheres; (6) Cleaning and drying to obtain aerogel-coated hollow glass microsphere material.

2. The preparation process of a vibration-damping and heat-insulating composite filler according to claim 1, characterized in that: In step (1), the mass contents of the components are 30-50% of ethyl orthosilicate, 15-30% of methyltrimethoxysilane / methyltriethoxysilane, 10-20% of dimethyldimethoxysilane, and 2% of hexamethyldisilazane.

3. The preparation process of a vibration-damping and heat-insulating composite filler according to claim 1, characterized in that: In step (2), the surfactant is sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, hexadecyltrimethylammonium bromide or hexadecyltrimethylammonium chloride, and the mass concentration of the surfactant solution is 0.5-1%.

4. The preparation process of a vibration-damping and heat-insulating composite filler according to claim 1, characterized in that: In step (3), the mass fraction of the hollow glass microspheres is 10-15%.

5. The preparation process of a vibration-damping and heat-insulating composite filler according to claim 1, characterized in that: In step (4), the ratio of the precursor mixed colloid solution to the hollow glass microsphere dispersion solution is 1 to 2.5:

1.

6. The preparation process of a vibration-damping and heat-insulating composite filler according to claim 1, characterized in that: In step (5), the amount of ammonia water added each time is 0.5 mL.

7. The preparation process of a vibration-damping and heat-insulating composite filler according to claim 1, characterized in that: The specific steps of step (6) are as follows: The mixed solution obtained in step (5) is placed in ethanol for solvent exchange to remove the remaining water and solvent; The aerogel-coated hollow glass microspheres were obtained by using ethanol supercritical drying technology and drying under appropriate temperature and pressure conditions.

8. The preparation process of the vibration-damping and heat-insulating composite filler according to claim 7, characterized in that: The process parameters of supercritical drying are as follows: using gradient heating, the temperature of the drying kettle is increased from room temperature to 255°C, the pressure in the kettle is maintained at 11-12MPa for 2h, and then the pressure is released to atmospheric pressure at a rate of 1-2MPa / h, and cooled to room temperature to obtain aerogel-coated hollow glass microspheres.

9. A vibration-damping and heat-insulating composite filler, characterized in that: The invention is prepared by the preparation process described in any one of claims 1 to 8.

10. Application of the vibration-damping and heat-insulating composite filler according to claim 9, characterized in that: Used to add fillers to the main material to improve the heat insulation and vibration reduction properties of the main material.

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