Building heat-insulation energy-saving composite material containing nano aerogel and preparation method of building heat-insulation energy-saving composite material

Abstract

The invention discloses a building heat-insulation energy-saving composite material containing nano aerogel and a preparation method thereof, and belongs to the technical field of building heat-insulation energy-saving materials. The composite material is prepared by preparing aluminum oxide / silicon dioxide composite wet gel by taking tetraethoxysilane and aluminum sec-butoxide as raw materials, dispersing boron-phosphorus dual-modified halloysite nanotubes in the aluminum oxide / silicon dioxide composite wet gel and carrying out glass fiber mat dipping, solvent replacement and supercritical drying. The boron-phosphorus dual-modified halloysite nanotube is prepared by amination, phosphorus modification and boron-phosphorus synergistic modification, and can enhance the mechanical properties of the aerogel skeleton and endow the aerogel skeleton with a flame retardant function. The composite material disclosed by the invention has low heat conductivity coefficient, excellent mechanical strength and high-grade fireproof and flame-retardant properties. The nanotube-shaped structure of the boron-phosphorus dual-modified halloysite nanotube and a gel network form physical crosslinking, so that the mechanical strength is improved, and drying shrinkage is inhibited; aluminum oxide is converted into a flame-retardant ceramic phase at high temperature and cooperates with boron and phosphorus elements to form a barrier layer; rigid groups are introduced to enhance hydrophobicity and interface bonding force and reduce heat conduction.

Description

Technical Field

[0001] The present invention belongs to the technical field of building thermal insulation and energy-saving materials, and in particular relates to a building thermal insulation and energy-saving composite material containing nano aerogel and a preparation method thereof. Background Art

[0002] The construction industry is one of the major sectors of global energy consumption, accounting for approximately 30%-40% of total societal energy consumption. Heating, cooling, and ventilation systems account for a significant portion of building energy consumption. Therefore, improving the thermal insulation performance of building envelopes and reducing indoor-outdoor heat exchange are key technical approaches to reducing building operating energy consumption and achieving energy conservation and emission reduction goals. Currently, widely used building insulation and energy-saving materials include expanded polystyrene (EPS), extruded polystyrene (XPS), polyurethane (PU) foam, rock wool, and glass wool. These materials each have their own advantages and disadvantages: organic insulation materials such as EPS, XPS, and PU have excellent thermal insulation properties and low density, but they are flammable. Once ignited, they burn rapidly and release large amounts of toxic smoke, posing a serious threat to building fire safety. In addition, some organic materials will age and shrink after long-term use, resulting in decreased thermal insulation performance; inorganic insulation materials such as rock wool and glass wool are non-flammable or flame-retardant and have high fire safety, but their thermal conductivity is relatively high. To achieve the same insulation effect, a thicker insulation layer is often required, increasing the building load and construction difficulty. At the same time, they have strong hygroscopicity, and the thermal insulation performance decreases significantly after absorbing water, and the fibers are easy to fall off, which may affect the construction environment and long-term durability.

[0003] In recent years, aerogel, a new type of nanoporous super-insulating material, has shown great potential in the field of building insulation due to its extremely low thermal conductivity, low density, and high porosity. Silica aerogel has become a research hotspot due to its wide range of raw material sources and relatively mature preparation process. However, silica aerogel has poor mechanical properties. Its inherent brittleness and nano-network structure make it extremely susceptible to shrinkage, fragmentation, and pulverization during the drying process and use, making it difficult to produce as a standalone material or withstand construction stress, and its flame retardant properties are insufficient. Although silica itself is non-combustible, the pure aerogel skeleton is prone to structural collapse and sintering at high temperatures, losing its insulating effect; it also lacks active flame retardancy and smoke suppression functions. Therefore, the development of a new building insulation and energy-saving composite material that combines ultra-low thermal conductivity, excellent mechanical strength, high-grade fire retardant properties, and good hydrophobicity is a key issue that needs to be urgently addressed in this field of technology. Summary of the Invention

[0004] In view of the above situation, in order to overcome the defects of the existing technology, the present invention modifies the alumina / silica aerogel by introducing boron-phosphorus dual-modified halloysite nanotubes, and composites it with glass fiber felt to prepare a new type of building thermal insulation and energy-saving composite material with low thermal conductivity, excellent mechanical strength, high-grade fire retardant properties, and good hydrophobicity to meet the needs of building energy conservation and safety.

[0005] In order to achieve the above object, the following technical solution is adopted: The present invention provides a building thermal insulation and energy-saving composite material containing nano aerogel and a preparation method thereof, wherein the composite material is prepared by the following steps:

[0006] S1. Mix ethyl orthosilicate with anhydrous ethanol, add deionized water at room temperature, and stir at a speed of 200 r / min for 3 min-5 min. Then, add 36% hydrochloric acid with a mass fraction to adjust the pH value of the solution to 3, and continue stirring at a speed of 200 r / min for 1 h to obtain a wet silica gel. Dissolve aluminum sec-butoxide in anhydrous ethanol, add glacial acetic acid and deionized water, and stir at a speed of 150 r / min at 25°C-50°C for 2 h-3 h to obtain a wet alumina gel.

[0007] S2, mixing the silica wet gel and the alumina wet gel to obtain an alumina / silica composite wet gel, dispersing the boron-phosphorus double-modified halloysite nanotubes in ethanol to obtain a dispersion, then slowly adding the dispersion to the alumina / silica composite wet gel, and uniformly dispersing the boron-phosphorus double-modified halloysite nanotubes in the gel solution by ultrasonic treatment, and standing at room temperature for 12-24 hours to obtain a modified nano-alumina / silica wet gel;

[0008] S3. Immerse the glass fiber felt in the modified nano-alumina / silica wet gel for 15-20 minutes, take it out, spread it evenly on a flat plate, repeat 3 times, then immerse the glass fiber felt spread 3 times in a gradient mixture of ethanol and isopropanol, perform solvent replacement treatment, and finally perform supercritical drying to obtain the composite material.

[0009] Furthermore, the boron-phosphorus modified halloysite nanotubes are prepared by the following steps:

[0010] (1) adding halloysite nanotubes to toluene, stirring at a speed of 150 r / min, and ultrasonically dispersing for 30 min, adding N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane after the end of the ultrasonication, increasing the speed to 300 r / min, heating to reflux for 6 h, and after the end of the reaction, washing the reaction product with toluene and anhydrous ethanol three times each, and vacuum drying at 60-100 ° C for 12 h to obtain amino-modified halloysite nanotubes;

[0011] (2) adding 3,9-bis(3-chloro-2,2-dimethylpropoxy)-2,4,8,10-tetrahydro-3,9-diphosphaspiro[5.5]undecane-3,9-dioxide to DMF and stirring at a speed of 200 r / min until completely dissolved, then adding the amino-modified halloysite nanotubes, adjusting the speed to 250 r / min, and reacting at 100° C. for 8 h. After the reaction is completed, the product is washed with DMF and deionized water three times each, and vacuum dried at 60-100° C. for 12 h to obtain phosphorus-modified halloysite nanotubes;

[0012] (3) Phosphorus-modified halloysite nanotubes and 3,3'-carbonylbis(ureadiyl)bis(3,1-phenylene)diboric acid were added to a mixed solvent of toluene and water. Under nitrogen protection, tetrakis(triphenylphosphine)palladium was added as a catalyst and potassium carbonate was added at the same time. The materials were initially mixed at a speed of 180 r / min, then the temperature was raised to 80°C, the speed was adjusted to 220 r / min, and the reaction was continued for 10-15 hours. After the reaction was completed, the product was washed with toluene and deionized water three times each, and vacuum dried at 60-100°C for 12 hours to obtain boron-phosphorus double-modified halloysite nanotubes.

[0013] Furthermore, in step S1, the feeding ratio of ethyl orthosilicate, anhydrous ethanol and deionized water is 100 mL: 200-400 mL: 50-100 mL; and the feeding ratio of aluminum sec-butoxide, anhydrous ethanol, glacial acetic acid and deionized water in step S1 is 50 g: 150-350 mL: 10-40 mL: 30-60 mL.

[0014] Furthermore, in step S2, the feeding ratio of the silica wet gel and the alumina wet gel is 50-100 mL:50 mL; the feeding ratio of the boron-phosphorus double-modified halloysite nanotubes and ethanol in step S2 is 5 g:100-150 mL; and the feeding volume ratio of the dispersion liquid and the alumina / silica composite wet gel in step S2 is 100 mL:150-200 mL.

[0015] Furthermore, the specific steps of the solvent replacement treatment in step S3 are:

[0016] Use a mixture of ethanol and isopropanol with a volume ratio of 2:1 and soak for 12 hours;

[0017] Use a mixture of ethanol and isopropanol with a volume ratio of 1:1 and soak for 12 hours;

[0018] Use a mixture of ethanol and isopropanol with a volume ratio of 1:2 and soak for 12 hours.

[0019] Furthermore, in step S3, the supercritical drying temperature is 32-42° C., the critical pressure is 7.2-8 MPa, and the processing time is 3-6 hours.

[0020] Furthermore, in the step (1), the feeding ratio of halloysite nanotubes, toluene and N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane is 10 g:85-100 mL:5-8 g.

[0021] Furthermore, in the step (2), the feeding ratio of 3,9-bis(3-chloro-2,2-dimethylpropoxy)-2,4,8,10-tetrahydro-3,9-diphosphaspiro[5.5]undecane-3,9-dioxide, DMF and amino-modified halloysite nanotubes is 3 g:50-85 mL:5-8 g.

[0022] Furthermore, in step (3), the feeding ratio of phosphorus-modified halloysite nanotubes, 3,3'-carbonylbis(ureadiyl)bis(3,1-phenylene)diboric acid, toluene, water, tetrakis(triphenylphosphine)palladium and potassium carbonate is 5g:1-3g:50-80mL:20-40mL:0.1-0.2g:3-5g.

[0023] The beneficial effects of the present invention are:

[0024] (1) The present invention uses boron-phosphorus dual-modified halloysite nanotubes as a reinforcing skeleton. Its nanotubular structure forms physical cross-linking points in the wet gel and is tightly combined with the alumina / silica gel network through hydrogen bonds and van der Waals forces. After compounding, the mechanical strength of the aerogel is significantly improved, avoiding structural collapse during drying and use. At the same time, the alumina component can be converted into a flame-retardant alumina ceramic phase at high temperature, and synergistically acts with the boron-phosphorus flame-retardant elements of the nanotubes to give the composite material excellent fire-resistant and flame-retardant properties.

[0025] (2) Halloysite nanotubes are naturally occurring layered silicate minerals that connect the aerogel skeleton through physical bridging, thereby enhancing the aerogel rebound effect. 3,9-bis(3-chloro-2,2-dimethylpropoxy)-2,4,8,10-tetraoxy-3,9-diphosphaspiro[5.5]undecane-3,9-dioxide and 3,3'-carbonylbis(ureadiyl)bis(3,1-phenylene)diboronic acid are introduced through a two-step reaction, introducing nitrogen, phosphorus, and boron elements. The diphosphaspiro ring structure decomposes at high temperature to form polyphosphoric acid, catalyzing the dehydration of the material into carbon. The phenylboronic acid group forms a glassy borate covering layer, isolating oxygen and inhibiting the release of combustible gases. The nitrogen elements of the urea group and the silaneamine group decompose under heat to produce inert gas, diluting the concentration of combustible materials, and forming a ceramic composite barrier layer through a synergistic flame retardant effect.

[0026] (3) The introduction of rigid groups such as diphosphospirocyclic, urea, and phenylboronic acid enhances the rigidity of halloysite nanotubes through steric hindrance effects. During the gel drying process, these groups form strong hydrogen bonds or covalent connections with the silanol / aluminum hydroxyl groups of the aerogel skeleton, resisting the capillary stress of the aerogel, preventing pore collapse, and reducing the drying shrinkage rate. The prepared aerogel has developed and complete pores and has better thermal insulation properties. The above modifications also reduce the surface energy of the aerogel and enhance its hydrophobicity, further inhibiting heat conduction through intermolecular hydrophobic interactions and improving thermal insulation properties.

[0027] (4) Boron-phosphorus dual-modified halloysite nanotubes improve the dispersion and interfacial bonding strength of aerogel on glass fiber mat. Through chemical bonding and mechanical interlocking of nanotubes, they are embedded in the porous structure of fiber mat, thereby enhancing the overall performance of the composite material and improving the durability of glass fiber mat. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A comparison chart of the impact strength test results of the composite materials prepared in various groups of embodiments and comparative examples of the present invention;

[0029] Figure 2 A comparison chart of tensile property test results of composite materials prepared in various groups of embodiments and comparative examples of the present invention;

[0030] Figure 3 A comparison chart of the bending performance test results of the composite materials prepared in various groups of embodiments and comparative examples of the present invention;

[0031] Figure 4 The figure is a comparison chart of the thermal conductivity test results of the composite materials prepared in each group of embodiments and comparative examples of the present invention.

[0032] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as those familiar to those skilled in the art. Furthermore, any methods and materials similar or equivalent to those described herein can be applied to the present invention. The preferred embodiments and materials described herein are for illustrative purposes only and are not intended to limit the scope of this application.

[0035] The experimental methods in the following examples, unless otherwise specified, are conventional methods. The experimental materials used in the following examples, unless otherwise specified, were either homemade or purchased from commercial channels. Among them, 3,9-bis(3-chloro-2,2-dimethylpropoxy)-2,4,8,10-tetrahydro-3,9-diphosphaspiro[5.5]undecane-3,9-dioxide, CAS: 61090-88-8.

[0036] Example 1: A building thermal insulation and energy-saving composite material containing nano-aerogel and a preparation method thereof, wherein the composite material is prepared by the following steps:

[0037] S1. Mix 100 mL of ethyl orthosilicate with 200 mL of anhydrous ethanol, add 50 mL of deionized water at room temperature, stir at 200 r / min for 3 min, then add 36% hydrochloric acid to adjust the pH of the solution to 3, and continue stirring at 200 r / min for 1 h to obtain a wet silica gel. Dissolve 50 g of aluminum sec-butoxide in 150 mL of anhydrous ethanol, add 10 mL of glacial acetic acid and 30 mL of deionized water, and stir at 25°C at 150 r / min for 2 h to obtain a wet alumina gel.

[0038] S2, 50 mL of silica wet gel and 50 mL of alumina wet gel were mixed to obtain an alumina / silica composite wet gel, 5 g of boron-phosphorus double-modified halloysite nanotubes were dispersed in 100 mL of ethanol to obtain a dispersion, and then 100 mL of the dispersion was slowly added to 150 mL of the alumina / silica composite wet gel, and the boron-phosphorus double-modified halloysite nanotubes were uniformly dispersed in the gel solution by ultrasonic treatment, and the mixture was allowed to stand at room temperature for 12 h to obtain a modified nano-alumina / silica wet gel;

[0039] S3. Immerse the glass fiber felt in the modified nano-alumina / silica wet gel, take it out after immersion for 15 minutes, spread it evenly on a flat plate, repeat 3 times, then immerse the glass fiber felt spread 3 times in a gradient mixture of ethanol and isopropanol, perform solvent replacement treatment, and finally perform supercritical drying at a temperature of 32°C, a critical pressure of 7.2 MPa, and a processing time of 3 hours to obtain the composite material.

[0040] The specific steps of solvent replacement treatment are as follows:

[0041] Use a mixture of ethanol and isopropanol with a volume ratio of 2:1 and soak for 12 hours;

[0042] Use a mixture of ethanol and isopropanol with a volume ratio of 1:1 and soak for 12 hours;

[0043] Use a mixture of ethanol and isopropanol with a volume ratio of 1:2 and soak for 12 hours.

[0044] The boron-phosphorus double-modified halloysite nanotubes are prepared by the following steps:

[0045] (1) 10 g of halloysite nanotubes were added to 85 mL of toluene, stirred at a speed of 150 r / min, and ultrasonically dispersed for 30 min. After the ultrasonication, 5 g of N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane was added, the speed was increased to 300 r / min, and the mixture was heated to reflux for 6 h. After the reaction, the reaction product was washed with toluene and anhydrous ethanol three times each, and vacuum dried at 60 ° C for 12 h to obtain amino-modified halloysite nanotubes;

[0046] (2) 3 g of 3,9-bis(3-chloro-2,2-dimethylpropoxy)-2,4,8,10-tetrahydro-3,9-diphosphaspiro[5.5]undecane-3,9-dioxide was added to 50 mL of DMF and stirred at a speed of 200 r / min until completely dissolved, and then 5 g of the amino-modified halloysite nanotubes was added, and the speed was adjusted to 250 r / min. The reaction was carried out at 100° C. for 8 h. After the reaction was completed, the product was washed with DMF and deionized water 3 times each, and vacuum dried at 60° C. for 12 h to obtain phosphorus-modified halloysite nanotubes;

[0047] (3) 5 g of phosphorus-modified halloysite nanotubes and 1 g of 3,3'-carbonylbis(ureadiyl)bis(3,1-phenylene)diboric acid were added to a mixed solvent of 50 mL of toluene and 20 mL of water. Under nitrogen protection, 0.1 g of tetrakis(triphenylphosphine)palladium was added as a catalyst, and 3 g of potassium carbonate was added at the same time. The materials were preliminarily mixed at a speed of 180 r / min, then the temperature was raised to 80 °C, the speed was adjusted to 220 r / min, and the reaction was continued for 10 h. After the reaction was completed, the product was washed with toluene and deionized water 3 times each, and vacuum dried at 60 °C for 12 h to obtain boron-phosphorus double-modified halloysite nanotubes.

[0048] Example 2: A building thermal insulation and energy-saving composite material containing nano-aerogel and a preparation method thereof, wherein the composite material is prepared by the following steps:

[0049] S1. Mix 100 mL of ethyl orthosilicate with 400 mL of anhydrous ethanol, add 100 mL of deionized water at room temperature, stir at 200 r / min for 5 min, then add 36% hydrochloric acid to adjust the pH of the solution to 3, and continue stirring at 200 r / min for 1 h to obtain a wet silica gel. Dissolve 50 g of aluminum sec-butoxide in 350 mL of anhydrous ethanol, add 40 mL of glacial acetic acid and 60 mL of deionized water, and stir at 50°C at 150 r / min for 3 h to obtain a wet alumina gel.

[0050] S2, 100 mL of silica wet gel and 50 mL of alumina wet gel were mixed to obtain an alumina / silica composite wet gel, 5 g of boron-phosphorus double-modified halloysite nanotubes were dispersed in 150 mL of ethanol to obtain a dispersion, and then 100 mL of the dispersion was slowly added to 200 mL of the alumina / silica composite wet gel, and the boron-phosphorus double-modified halloysite nanotubes were uniformly dispersed in the gel solution by ultrasonic treatment, and the mixture was allowed to stand at room temperature for 24 h to obtain a modified nano-alumina / silica wet gel;

[0051] S3. Immerse the glass fiber felt in the modified nano-alumina / silica wet gel, take it out after immersion for 20 minutes, spread it evenly on a flat plate, repeat 3 times, then immerse the glass fiber felt spread 3 times in a gradient mixture of ethanol and isopropanol, perform solvent replacement treatment, and finally perform supercritical drying at a temperature of 42°C, a critical pressure of 8 MPa, and a processing time of 6 hours to obtain the composite material.

[0052] The specific steps of solvent replacement treatment are as follows:

[0053] Use a mixture of ethanol and isopropanol with a volume ratio of 2:1 and soak for 12 hours;

[0054] Use a mixture of ethanol and isopropanol with a volume ratio of 1:1 and soak for 12 hours;

[0055] Use a mixture of ethanol and isopropanol with a volume ratio of 1:2 and soak for 12 hours.

[0056] The boron-phosphorus double-modified halloysite nanotubes are prepared by the following steps:

[0057] (1) 10 g of halloysite nanotubes were added to 100 mL of toluene, stirred at a speed of 150 r / min, and ultrasonically dispersed for 30 min. After the ultrasonication, 8 g of N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane was added, the speed was increased to 300 r / min, and the mixture was heated to reflux for 6 h. After the reaction, the reaction product was washed with toluene and anhydrous ethanol three times each, and vacuum dried at 100 ° C for 12 h to obtain amino-modified halloysite nanotubes;

[0058] (2) 3 g of 3,9-bis(3-chloro-2,2-dimethylpropoxy)-2,4,8,10-tetrahydro-3,9-diphosphaspiro[5.5]undecane-3,9-dioxide was added to 85 mL of DMF and stirred at a speed of 200 r / min until completely dissolved, and then 8 g of the amino-modified halloysite nanotubes was added, and the speed was adjusted to 250 r / min. The reaction was carried out at 100° C. for 8 h. After the reaction was completed, the product was washed with DMF and deionized water 3 times each, and vacuum dried at 100° C. for 12 h to obtain phosphorus-modified halloysite nanotubes;

[0059] (3) 5 g of phosphorus-modified halloysite nanotubes and 3 g of 3,3'-carbonylbis(ureadiyl)bis(3,1-phenylene)diboric acid were added to a mixed solvent of 80 mL of toluene and 40 mL of water. Under nitrogen protection, 0.2 g of tetrakis(triphenylphosphine)palladium was added as a catalyst, and 5 g of potassium carbonate was added at the same time. The materials were preliminarily mixed at a speed of 180 r / min, then the temperature was raised to 80 °C, the speed was adjusted to 220 r / min, and the reaction was continued for 15 h. After the reaction was completed, the product was washed with toluene and deionized water 3 times each, and vacuum dried at 100 °C for 12 h to obtain boron-phosphorus double-modified halloysite nanotubes.

[0060] Example 3: A building thermal insulation and energy-saving composite material containing nano-aerogel and a preparation method thereof, wherein the composite material is prepared by the following steps:

[0061] S1. Mix 100 mL of ethyl orthosilicate with 300 mL of anhydrous ethanol, add 80 mL of deionized water at room temperature, stir at 200 r / min for 4 min, then add 36% hydrochloric acid to adjust the pH of the solution to 3, and continue stirring at 200 r / min for 1 h to obtain a wet silica gel. Dissolve 50 g of aluminum sec-butoxide in 200 mL of anhydrous ethanol, add 25 mL of glacial acetic acid and 45 mL of deionized water, and stir at 40°C at 150 r / min for 2.5 h to obtain a wet alumina gel;

[0062] S2, 50 mL of silica wet gel and 75 mL of alumina wet gel were mixed to obtain an alumina / silica composite wet gel, 5 g of boron-phosphorus double-modified halloysite nanotubes were dispersed in 120 mL of ethanol to obtain a dispersion, and 100 mL of the dispersion was slowly added to 180 mL of the alumina / silica composite wet gel. The boron-phosphorus double-modified halloysite nanotubes were uniformly dispersed in the gel solution by ultrasonic treatment, and the mixture was allowed to stand at room temperature for 18 h to obtain a modified nano-alumina / silica wet gel;

[0063] S3. Immerse the glass fiber felt in the modified nano-alumina / silica wet gel, take it out after immersion for 18 minutes, spread it evenly on a flat plate, repeat 3 times, then immerse the glass fiber felt spread 3 times in a gradient mixture of ethanol and isopropanol, perform solvent replacement treatment, and finally perform supercritical drying at a temperature of 36°C, a critical pressure of 7.5 MPa, and a processing time of 4.5 hours to obtain the composite material.

[0064] The specific steps of solvent replacement treatment are as follows:

[0065] Use a mixture of ethanol and isopropanol with a volume ratio of 2:1 and soak for 12 hours;

[0066] Use a mixture of ethanol and isopropanol with a volume ratio of 1:1 and soak for 12 hours;

[0067] Use a mixture of ethanol and isopropanol with a volume ratio of 1:2 and soak for 12 hours.

[0068] The boron-phosphorus double-modified halloysite nanotubes are prepared by the following steps:

[0069] (1) 10 g of halloysite nanotubes were added to 90 mL of toluene, stirred at a speed of 150 r / min, and ultrasonically dispersed for 30 min. After the ultrasonication, 6 g of N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane was added, the speed was increased to 300 r / min, and the mixture was heated to reflux for 6 h. After the reaction, the reaction product was washed with toluene and anhydrous ethanol three times each, and vacuum dried at 80 ° C for 12 h to obtain amino-modified halloysite nanotubes;

[0070] (2) 3 g of 3,9-bis(3-chloro-2,2-dimethylpropoxy)-2,4,8,10-tetrahydro-3,9-diphosphaspiro[5.5]undecane-3,9-dioxide was added to 60 mL of DMF and stirred at a speed of 200 r / min until completely dissolved, and then 7 g of the amino-modified halloysite nanotubes was added. The speed was adjusted to 250 r / min and the reaction was carried out at 100° C. for 8 h. After the reaction was completed, the product was washed with DMF and deionized water 3 times each and dried in vacuum at 80° C. for 12 h to obtain phosphorus-modified halloysite nanotubes;

[0071] (3) 5 g of phosphorus-modified halloysite nanotubes and 2 g of 3,3'-carbonylbis(ureadiyl)bis(3,1-phenylene)diboric acid were added to a mixed solvent of 60 mL of toluene and 30 mL of water. Under nitrogen protection, 0.15 g of tetrakis(triphenylphosphine)palladium was added as a catalyst, and 4 g of potassium carbonate was added at the same time. The materials were preliminarily mixed at a speed of 180 r / min, then the temperature was raised to 80 ° C, the speed was adjusted to 220 r / min, and the reaction was continued for 12 h. After the reaction was completed, the product was washed with toluene and deionized water 3 times each, and vacuum dried at 80 ° C for 12 h to obtain boron-phosphorus double-modified halloysite nanotubes.

[0072] Comparative Example 1: In this comparative example, the silica wet gel prepared in step S1 is used instead of the modified nano-alumina / silica wet gel in step S3 to impregnate the glass fiber mat to prepare a composite material. The rest is the same as in Example 3.

[0073] Comparative Example 2: In this comparative example, the alumina wet gel prepared in step S1 is used to replace the modified nano-alumina / silica wet gel in step S3 to impregnate the glass fiber mat to prepare a composite material. The rest is the same as in Example 3.

[0074] Comparative Example 3: In this comparative example, the alumina / silica composite wet gel prepared in step S2 is used instead of the modified nano alumina / silica wet gel in step S3 to impregnate the glass fiber mat to prepare a composite material. The rest is the same as in Example 3.

[0075] Comparative Example 4: In this comparative example, unmodified halloysite nanotubes were used instead of the boron-phosphorus dual-modified halloysite nanotubes in step S3 to prepare a composite material. The rest of the steps were the same as those in Example 3.

[0076] Test Example 1: Composite Material Mechanical Properties Test

[0077] The impact strength of the composite materials prepared in each group of embodiments and comparative examples was tested using an XJJC-5 simple supported beam impact tester, and the tensile and flexural properties of the composite materials prepared in each group of embodiments and comparative examples were tested using a WDW-100M universal testing machine. The test results are shown in FIG. Figure 1-3 .

[0078] Test Example 2: Thermal insulation performance test of composite materials

[0079] The thermal conductivity of the composite materials prepared in each group of examples and comparative examples was tested according to GBT17911-2006 "Test methods for refractory ceramic fiber products". The results are shown in Figure 4 .

[0080] Test Example 3: Flame retardant performance test of composite materials

[0081] The combustion performance of the composite materials prepared in each group of examples and comparative examples was graded according to the combustion performance grades and classification criteria for floor covering materials in GB 8624-2012 "Classification of Combustion Performance of Building Materials and Products". The results are shown in Table 1.

[0082] Table 1: Comparison of composite flame retardant test results

[0083] project Combustion performance grade Example 1 A1 Example 2 A1 Example 3 A1 Comparative Example 1 A2 Comparative Example 2 A2 Comparative Example 3 A2 Comparative Example 4 A1

[0084] Result analysis: The composite material prepared by the present invention has excellent impact resistance, tensile strength, and bending resistance, and has a low thermal conductivity and a high flame retardant performance level, indicating that the preparation method of the present invention enables the prepared composite glass fiber felt to have excellent mechanical properties, energy-saving and thermal insulation properties, and flame retardant and fireproof properties.

[0085] While 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 these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

[0086] The present invention and its embodiments are described above. Such description is not restrictive. The drawings show only one embodiment of the present invention, and actual applications are not limited thereto. In short, if a person skilled in the art is inspired by the above, and does not deviate from the purpose of the present invention, any method and embodiment similar to the technical solution without creative design shall fall within the scope of protection of the present invention.

Claims

1. A method for preparing a building thermal insulation and energy-saving composite material containing nano-aerogel, characterized by: Prepared by the following steps: S1. Mix ethyl orthosilicate with anhydrous ethanol, add deionized water at room temperature, and stir at a speed of 200 r / min for 3 min-5 min. Then, add 36% hydrochloric acid with a mass fraction to adjust the pH value of the solution to 3, and continue stirring at a speed of 200 r / min for 1 h to obtain a wet silica gel. Dissolve aluminum sec-butoxide in anhydrous ethanol, add glacial acetic acid and deionized water, and stir at a speed of 150 r / min at 25°C-50°C for 2 h-3 h to obtain a wet alumina gel. S2, mixing the silica wet gel and the alumina wet gel to obtain an alumina / silica composite wet gel, dispersing the boron-phosphorus double-modified halloysite nanotubes in ethanol to obtain a dispersion, then slowly adding the dispersion to the alumina / silica composite wet gel, and uniformly dispersing the boron-phosphorus double-modified halloysite nanotubes in the gel solution by ultrasonic treatment, and standing at room temperature for 12-24 hours to obtain a modified nano-alumina / silica wet gel; S3. Immerse the glass fiber felt in the modified nano-alumina / silica wet gel for 15-20 minutes, take it out, spread it evenly on a flat plate, repeat 3 times, then immerse the glass fiber felt spread 3 times in a gradient mixture of ethanol and isopropanol, perform solvent replacement treatment, and finally perform supercritical drying to obtain the composite material.

2. The building thermal insulation and energy-saving composite material containing nano-aerogel according to claim 1, characterized in that: The boron-phosphorus double-modified halloysite nanotubes are prepared by the following steps: (1) adding halloysite nanotubes to toluene, stirring at a speed of 150 r / min, and ultrasonically dispersing for 30 min, adding N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane after the end of the ultrasonication, increasing the speed to 300 r / min, heating to reflux for 6 h, and after the end of the reaction, washing the reaction product with toluene and anhydrous ethanol three times each, and vacuum drying at 60-100 ° C for 12 h to obtain amino-modified halloysite nanotubes; (2) adding 3,9-bis(3-chloro-2,2-dimethylpropoxy)-2,4,8,10-tetrahydro-3,9-diphosphaspiro[5.5]undecane-3,9-dioxide to DMF and stirring at a speed of 200 r / min until completely dissolved, then adding the amino-modified halloysite nanotubes, adjusting the speed to 250 r / min, and reacting at 100° C. for 8 h. After the reaction is completed, the product is washed with DMF and deionized water three times each, and vacuum dried at 60-100° C. for 12 h to obtain phosphorus-modified halloysite nanotubes; (3) Phosphorus-modified halloysite nanotubes and 3,3'-carbonylbis(ureadiyl)bis(3,1-phenylene)diboric acid were added to a mixed solvent of toluene and water. Under nitrogen protection, tetrakis(triphenylphosphine)palladium was added as a catalyst and potassium carbonate was added at the same time. The materials were initially mixed at a speed of 180 r / min, then the temperature was raised to 80°C, the speed was adjusted to 220 r / min, and the reaction was continued for 10-15 hours. After the reaction was completed, the product was washed with toluene and deionized water three times each, and vacuum dried at 60-100°C for 12 hours to obtain boron-phosphorus double-modified halloysite nanotubes.

3. The building thermal insulation and energy-saving composite material containing nano-aerogel according to claim 1, characterized in that: In step S1, the feeding ratio of ethyl orthosilicate, anhydrous ethanol and deionized water is 100 mL: 200-400 mL: 50-100 mL; and the feeding ratio of aluminum sec-butoxide, anhydrous ethanol, glacial acetic acid and deionized water in step S1 is 50 g: 150-350 mL: 10-40 mL: 30-60 mL.

4. The building thermal insulation and energy-saving composite material containing nano-aerogel according to claim 1, characterized in that: In the step S2, the feeding ratio of the silica wet gel and the alumina wet gel is 50-100 mL:50 mL; the feeding ratio of the boron-phosphorus double-modified halloysite nanotubes and ethanol in the step S2 is 5 g:100-150 mL; and the feeding volume ratio of the dispersion liquid and the alumina / silica composite wet gel in the step S2 is 100 mL:150-200 mL.

5. The building thermal insulation and energy-saving composite material containing nano-aerogel according to claim 1, characterized in that: The specific steps of the solvent replacement treatment in step S3 are: Use a mixture of ethanol and isopropanol with a volume ratio of 2:1 and soak for 12 hours; Use a mixture of ethanol and isopropanol with a volume ratio of 1:1 and soak for 12 hours; Use a mixture of ethanol and isopropanol with a volume ratio of 1:2 and soak for 12 hours.

6. The building thermal insulation and energy-saving composite material containing nano-aerogel according to claim 1, characterized in that: In step S3, the supercritical drying temperature is 32-42° C., the critical pressure is 7.2-8 MPa, and the processing time is 3-6 hours.

7. The building thermal insulation and energy-saving composite material containing nano-aerogel according to claim 2, characterized in that: In the step (1), the feeding ratio of halloysite nanotubes, toluene and N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane is 10 g:85-100 mL:5-8 g.

8. The building thermal insulation and energy-saving composite material containing nano-aerogel according to claim 2, characterized in that: In the step (2), the feeding ratio of 3,9-bis(3-chloro-2,2-dimethylpropoxy)-2,4,8,10-tetrahydro-3,9-diphosphaspiro[5.5]undecane-3,9-dioxide, DMF and amino-modified halloysite nanotubes is 3 g:50-85 mL:5-8 g.

9. The building thermal insulation and energy-saving composite material containing nano-aerogel according to claim 2, characterized in that: In the step (3), the feeding ratio of phosphorus-modified halloysite nanotubes, 3,3'-carbonylbis(ureadiyl)bis(3,1-phenylene)diboric acid, toluene, water, tetrakis(triphenylphosphine)palladium and potassium carbonate is 5g:1-3g:50-80mL:20-40mL:0.1-0.2g:3-5g.

10. A nano-aerogel building thermal insulation and energy-saving composite material, characterized by: Prepared by the preparation method according to any one of claims 1 to 9.

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