Aerogel composite thermal insulation material as well as preparation method and application thereof

Abstract

The invention discloses an aerogel composite thermal insulation material as well as a preparation method and application thereof, and relates to the technical field of thermal insulation materials. Dissolving polyvinyl alcohol and carboxymethyl lignin in the modified filler suspension, adjusting the pH value, stirring, immersing reinforced fibers, and carrying out high-pressure homogenization treatment to obtain an aerogel precursor; adding m-aminophenylboronic acid, epichlorohydrin, ethanol and cystamine into the aerogel precursor, adding triethylamine to adjust pH, stirring, pouring into a mold, naturally cooling, standing and drying to obtain gel, introducing a tannic acid solution into gel pores, standing in a constant-temperature box, and flushing the gel with absolute ethyl alcohol to obtain a crude product gel material; and carrying out solvent gradient water phase replacement on the crude product gel material, transferring to a CO2 supercritical drying kettle, sealing, carrying out supercritical CO2 ethanol replacement and supercritical drying, and thus obtaining the aerogel composite thermal insulation material. The aerogel composite thermal insulation material prepared by the invention has the characteristics of light weight, high toughness, heat conduction / thermal insulation adjustability and environment friendliness.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal insulation materials, and particularly to an aerogel composite thermal insulation material, a preparation method thereof, and an application thereof. Background Art

[0002] Due to its ultra-low density, high porosity, and excellent thermal insulation performance, aerogel materials have attracted much attention in the fields of building insulation, aerospace, and new energy. Traditional aerogels are mostly based on inorganic (such as silica) or organic polymer (such as polyimide) matrices. Although they have a low thermal conductivity, they generally have problems such as poor mechanical properties, high brittleness, and insufficient resistance to wet heat aging. In addition, the design oriented to single function is difficult to balance the scenario requirements of heat preservation and heat conduction. For example, in battery thermal management, both local efficient heat dissipation and overall thermal insulation protection are required, and existing materials are difficult to achieve performance balance.

[0003] In recent years, researchers have tried to improve the mechanical properties by introducing fiber reinforcements (such as carbon fiber, glass fiber) or organic-inorganic hybrid cross-linked networks, but still face the following challenges: the interface between the fiber and the matrix is weakly bonded, the stress transfer efficiency is low, and delamination is likely to occur; most of the cross-linked networks are static covalent bonds (such as epoxy resin), lacking dynamic responsiveness, resulting in the lack of self-healing ability of the material; the dispersion of traditional fillers (such as carbon nanotubes, graphene) is poor, and they are easy to agglomerate under high addition amounts, which instead deteriorates the thermal insulation performance. In addition, most processes rely on toxic cross-linking agents (such as isocyanate) or high-energy-consuming supercritical drying technology, restricting environmental friendliness and large-scale application.

[0004] In view of the above problems, there is an urgent need to develop an aerogel material with the characteristics of lightweight, high strength and toughness, adjustable heat conduction / heat preservation, and environmental friendliness. Through dynamic-static double-network design, bio-based raw material substitution, and multi-scale structure regulation, break through the bottleneck of the existing technology and meet the urgent need for multifunctional integrated aerogel thermal insulation materials. Summary of the Invention

[0005] The purpose of the present invention is to provide an aerogel composite thermal insulation material, a preparation method thereof, and an application thereof, so as to solve the problems raised in the background art.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[0007] An aerogel composite thermal insulation material, comprising the following raw material components in parts by weight:

[0008] 5 - 6.5 parts of carboxymethyl lignin;

[0009] 7.21 - 9.37 parts of reinforcing fiber;

[0010] 0.2 - 0.4 parts of filler;

[0011] 3 - 3.9 parts of polyvinyl alcohol;

[0012] 0.06 - 0.1 part of m - aminophenylboronic acid;

[0013] 0.8 - 1.2 parts of epichlorohydrin;

[0014] 0.5 - 0.8 part of cystamine cross - linker;

[0015] 0.3 - 0.6 part of tannic acid;

[0016] 0.1 - 0.3 part of triethylamine;

[0017] 0.02 - 0.04 part of dispersant;

[0018] 4 - 12 parts of ethanol;

[0019] 10 - 20 parts of deionized water;

[0020] 0.5 - 2 parts of pH regulator.

[0021] Furthermore, the preparation steps of carboxymethyl lignin are as follows:

[0022] Dissolve kraft lignin in a sodium hydroxide solution with a concentration of 1.5 mol / L, stir at 60 °C for 2 - 3 h, add sodium chloroacetate, react at 60 °C for 2 - 3 h, adjust the pH to 4, precipitate, wash with water, and dry to obtain carboxymethyl lignin.

[0023] Furthermore, the dosage ratio of the kraft lignin, sodium hydroxide solution, and sodium chloroacetate is 5 g:10 mL:5 g.

[0024] It should be noted that under alkaline conditions, sodium chloroacetate undergoes nucleophilic substitution on the phenolic hydroxyl group of lignin to introduce carboxymethyl, obtaining carboxymethyl lignin (CA - Lig). The ionization of carboxylic acid groups enhances the hydrophilicity of lignin and forms a dynamic covalent network with the hydroxyl groups of polyvinyl alcohol (PVA) and the boric acid groups of m - aminophenylboronic acid through hydrogen bonds and ionic bonds, significantly improving the cross - link density and anti - swelling property. The introduction of carboxymethyl also enhances the chemical compatibility between lignin and the fiber surface and optimizes the interfacial stress transfer.

[0025] Furthermore, the reinforcing fiber is one of pretreated carbon fiber felt, glass fiber, and basalt fiber.

[0026] Furthermore, the pretreatment steps of the carbon fiber felt are: Immerse the carbon fiber felt in a nitric acid solution with a concentration of 65%, perform water - bath treatment at 60 °C for 30 - 40 min, take it out and rinse with deionized water until neutral, and dry in an oven at 80 °C for 1 - 2 h to obtain the pretreated carbon fiber felt.

[0027] Furthermore, the dosage ratio of the carbon fiber felt to the acid solution is 1 g:10 mL.

[0028] It should be noted that nitric acid oxidation etches microgrooves on the surface of carbon fibers, improves the surface energy, and enhances the interfacial compatibility with the organic matrix.

[0029] Furthermore, the pretreatment steps of the glass fiber are as follows: put the glass fiber into a muffle furnace, heat it to 500 °C at a rate of 5 °C / min, keep it at this temperature for 1 h, then cool it naturally to room temperature. Prepare a 3% silane coupling agent solution, immerse the calcined glass fiber into the 3% silane coupling agent solution, perform ultrasonic treatment for 20 - 30 min, and dry it in an oven at 80 °C for 1 - 2 h to obtain the pretreated glass fiber.

[0030] Furthermore, the dosage ratio of the calcined glass fiber to the 3% silane coupling agent solution is 1 g:10 mL, and the 3% silane coupling agent solution is composed of KH-560 silane coupling agent with a mass fraction of 3% and ethanol with a mass fraction of 97%.

[0031] It should be noted that calcination effectively removes the organic sizing on the surface of the glass fiber, exposing the fresh silica surface.

[0032] Furthermore, the pretreatment steps of the basalt fiber are as follows: immerse the basalt fiber into a hydrochloric acid solution with a concentration of 5%, perform constant-temperature water bath treatment for 15 - 20 min, take it out and rinse it with deionized water until neutral, dry it in an oven at 80 °C for 1 - 2 h. Prepare a 1.5% silane coupling agent solution, immerse the acid-treated basalt fiber into the 1.5% silane coupling agent solution, and the dosage ratio of the acid-treated basalt fiber to the 1.5% silane coupling agent solution is 1 g:8 mL to obtain the pretreated basalt fiber.

[0033] Furthermore, the dosage ratio of the basalt fiber to the hydrochloric acid solution is 1 g:10 mL, and the 3% silane coupling agent solution is composed of KH-550 silane coupling agent with a mass fraction of 1.5% and ethanol with a mass fraction of 98.5%.

[0034] It should be noted that acid treatment dissolves metal oxide components such as CaO and MgO in the basalt fiber, forms a microporous structure and exposes the silica tetrahedron framework.

[0035] It should be noted again that by pretreating the fiber, -COOH and -OH groups are introduced on the oxidized surface, increasing the surface energy of the fiber. After hydrolysis, the silane coupling agent (KH-560 / KH-550) generates Si-OH, which condenses with the hydroxyl groups on the fiber surface to form Si-O-Si bonds, enhancing the fiber-matrix interfacial bonding strength. The rough surface of the pretreated fiber increases the mechanical anchoring effect, inhibits crack propagation, and improves the fracture toughness of the composite material.

[0036] It should be noted that PVA constructs an aerogel skeleton with both mechanical strength, thermal conduction / thermal insulation balance, and environmental stability mainly through three mechanisms: chemical cross-linking, physical entanglement, and interfacial synergy. First, the hydroxyl groups of PVA combine with the carboxyl groups of carboxymethyl lignin through ester bonds, and at the same time form reversible borate ester bonds with the borate groups of 3-aminophenylboronic acid. These dynamic covalent bonds endow the material with self-healing ability. The hydroxyl groups of PVA can undergo ring-opening reaction with the epoxy groups of epichlorohydrin to form ether bonds, forming a permanent cross-linked network, improving the rigidity and solvent resistance of the material. The long-chain molecules of PVA are entangled with carboxymethyl lignin and fillers through hydrogen bonds and van der Waals forces to form an interpenetrating network, inhibiting crack propagation and increasing the tensile strength. Second, hydrogen bonds are formed with the surface oxygen-containing groups of the fillers (B-OH of BN, -COOH of rGO) to promote the uniform dispersion of the fillers, reducing the interfacial thermal resistance. The gelation process of PVA forms a hierarchical pore structure through supercritical drying, reducing gas convection heat conduction. Third, the hydroxyl groups of PVA form a hydrogen bond network with the phenolic hydroxyl groups of tannic acid to capture free radicals and delay the oxidative degradation of the material.

[0037] Furthermore, the preparation steps of the filler are as follows:

[0038] A1. Mix graphene oxide and boron nitride, disperse them in ethanol, and ultrasonicate for 1 h to obtain a suspension;

[0039] Furthermore, in the step A1, the dosage ratio of graphene oxide, boron nitride, and ethanol is 0.1 g:0.3 g:50 mL;

[0040] A2. Transfer the suspension to a stainless-steel hydrothermal reaction kettle lined with polytetrafluoroethylene and seal it. The pressure in the hydrothermal kettle is about 1.5 - 2.0 MPa. Heat it to 120 °C at a rate of 2 °C / min and react for 6 h. Naturally cool it to room temperature, centrifuge, wash with water, filter, and dry to obtain doped BN powder;

[0041] A3. Disperse the doped BN powder in a Tris-HCl buffer solution with a pH of 8.5, add catecholamine, stir at 25 °C for 24 h, centrifuge, wash with water, filter, and dry to obtain the filler.

[0042] Furthermore, in the step A3, the dosage ratio of the doped BN powder, Tris-HCl buffer solution, and catecholamine is 0.4 g:200 mL:0.4 g.

[0043] It should be noted that graphene oxide and boron nitride form a heterostructure through hydrothermal reduction. The hydrothermal reduction partially removes the oxygen-containing groups of GO to form reduced graphene oxide (rGO), restoring sp 2Conjugated structure to enhance electron / phonon conduction ability; the catechol group of catecholamine is anchored on the surface of BN through hydrogen bonding, and its amino group forms an amide bond with the carboxyl group of carboxymethyl lignin, enhancing the filler-matrix interfacial bonding and simultaneously inhibiting phonon scattering.

[0044] It should be noted again that the interfacial micropores between the filler and the matrix and the macropores of the fiber-aerogel form a hierarchical pore structure, inhibiting gas convection and radiative heat transfer, reducing the thermal conductivity under static air, and improving the thermal insulation performance. In addition, the oxygen-containing groups on the surface of the pretreated fiber react with the amino group of catecholamine to form a covalent bond bridge, enhancing the interfacial bonding between the filler and the fiber; the amide bond of catecholamine forms a hydrogen bond network with the hydroxyl group of CA-Lig / PVA, and the dynamic bonds (borate bond, thioether bond) relieve thermal stress and prevent interfacial debonding. The amino group of catecholamine bonds with the carboxylic acid group of carboxymethyl lignin to form a chemical anchoring point at the filler-matrix interface, inhibiting filler migration; the unreacted amino group on the surface of the filler forms a hydrogen bond with the phenolic hydroxyl group of tannic acid, reducing the number of larger pores and the heat loss caused by air convection, further improving the thermal insulation performance.

[0045] Further, the cystamine crosslinking agent is one of cystamine, polyethylene glycolated cystamine, and cystine.

[0046] Further, the dispersant is one of polyethylene glycol octyl phenyl ether, 3-[3-(cholamidopropyl) dimethylammonio] propanesulfonate inner salt, and polyvinylpyrrolidone.

[0047] A preparation method of an aerogel composite thermal insulation material is as follows:

[0048] S1. Disperse the filler in deionized water in an ice-water bath, add the dispersant, ultrasonically homogenize for 15 - 30 min, centrifuge at a speed of 3000 r / min for 10 - 15 min, and take the upper suspension to obtain a modified filler suspension.

[0049] Further, the dosage ratio of the filler, deionized water, and the dispersant in step S1 is (0.2 - 0.4) g: 5 mL: (20 - 40) mg.

[0050] S2. Dissolve polyvinyl alcohol and carboxymethyl lignin in the modified filler suspension at 60 °C, adjust the pH to 8.5 - 9, stir at a speed of 300 - 500 r / min for 5 - 20 min, immerse the reinforcing fiber in the above premixed solution, adjust the pH to 8.5 - 9, and treat it in a 50 MPa high-pressure homogenizer for 30 - 90 min to obtain an aerogel precursor.

[0051] Further, in the step S2, the dosage ratio of polyvinyl alcohol, carboxymethyl lignin, modified filler suspension and reinforcing fiber is (3 - 3.9) g : (5 - 6.5) g : (12.5 - 16.3) mL : (7.21 - 9.37) g.

[0052] S3. Sequentially add 3-aminophenylboronic acid, epichlorohydrin, ethanol and cystamine crosslinking agent to the aerogel precursor, add triethylamine to adjust the pH to 8 - 8.5, stir and react at 60 °C for 2 - 4 h, pour into a mold, naturally cool and stand at room temperature for 12 h, dry at 50 °C for 12 - 24 h to obtain a gel. Introduce a tannic acid solution with a tannic acid mass fraction of 6% into the pores of the gel, place the gel in a constant temperature incubator at 25 °C and a humidity of 25% and stand for 12 h, and rinse the gel with absolute ethanol 3 - 5 times to obtain a crude gel material.

[0053] It should be noted that the boronic acid group of 3-aminophenylboronic acid forms a dynamic (reversible) borate ester bond with the hydroxyl group of PVA; the amino group of 3-aminophenylboronic acid undergoes a ring-opening reaction with the epoxy ring in epichlorohydrin under alkaline conditions to generate a stable C-N bond, forming a permanent crosslinked network. This static crosslinking point complements the dynamic borate ester bond, balancing the rigidity and toughness of the material. The hydroxyl group in the generated β-amino alcohol structure forms a hydrogen bond with the carboxyl group of carboxymethyl lignin or the hydroxyl group of PVA, enhancing the interfacial binding. The crosslinked network significantly improves the mechanical strength of the material. The -SH of the cystamine crosslinking agent attacks the epoxy ring of epichlorohydrin to generate a thioether bond crosslinked network. The flexibility of the thioether bond relieves stress concentration and inhibits brittle fracture. On the other hand, the remaining -SH groups are oxidized to dynamic (reversible) disulfide bonds under the catalysis of oxygen or triethylamine. The disulfide bonds dissipate stress energy and can be broken under mechanical force or thermal stimulation. After breaking, they can be recombined through a thiol-disulfide exchange reaction to achieve self-healing. In summary, the dual-mode crosslinked network (dynamic + static) significantly improves the fatigue resistance. The coexistence of dynamic bonds and covalent networks endows the material with a high elastic modulus and self-healing ability, maintaining the overall strength of the material and improving the fracture toughness.

[0054] Further, in the step S3, the dosage ratio of 3-aminophenylboronic acid, epichlorohydrin, ethanol, cystamine crosslinking agent, aerogel precursor and triethylamine is (0.06 - 0.1) g : (0.8 - 1.2) g : (5 - 15) mL : (0.5 - 0.8) g : (4 - 7.2) g : (0.01 - 0.3) g.

[0055] Further, in step S3, the solvent of the tannic acid solution is ethanol and the pH is 5.5; the method for introducing the tannic acid solution into the gel pores includes any one of injection pump injection and vacuum-assisted penetration; the injection rate of the injection pump injection operation is 0.5 mL / min, and the dosage ratio of the tannic acid solution to the gel is 1 mL:(5-10) g; the operation steps of the vacuum-assisted penetration method are as follows: immerse the gel in the tannic acid solution, evacuate to -0.08 MPa and hold for 20 min;

[0056] It should be noted that tannic acid is rich in phenolic hydroxyl groups, which form multiple hydrogen bonds with the carboxylic acid groups of carboxymethyl lignin, the hydroxyl groups of PVA, and the oxygen-containing groups on the fiber surface, enhancing the interfacial bonding strength between the pore wall and the matrix, inhibiting pore collapse, and maintaining the stability of the hierarchical pore structure; the phenolic hydroxyl groups of tannic acid scavenge reactive oxygen species and free radicals in the environment through an electron transfer mechanism, delaying oxidative degradation. At the same time, the phenolic hydroxyl groups of tannic acid form hydrogen bonds with the thiol groups of cystamine, assisting the stability of the thioether bond and improving the heat and humidity resistance of the cross-linked network; tannic acid is adsorbed on the surface of the filler through π-π stacking, inhibiting filler agglomeration, and at the same time its polar hydroxyl groups enhance the interfacial heat transfer efficiency between the filler and the matrix; tannic acid forms a phenolic hydroxyl coating on the fiber surface and binds to the silane coupling agent (such as KH-550) of the pretreated fiber through hydrogen bonds, enhancing the interfacial shear strength between the fiber and the matrix.

[0057] S4. Immerse the crude gel material in 50%, 70%, 90%, and 100% ethanol in sequence to displace the aqueous phase, let it stand for 6 h at each gradient, and transfer it to a CO 2 supercritical drying autoclave for sealing, and continuously introduce supercritical CO 2 at a flow rate of 10 mL / min. Under the conditions of 45°C and 10.5 MPa, maintain the CO 2 flow for 12 h, close the CO 2 valve, let it stand for 6 h under the conditions of 45°C and 10.5 MPa, and gradually reduce the pressure to atmospheric pressure at a rate of 0.2 MPa / min under the condition of 45°C until the CO 2 is completely vaporized and discharged, and wait for the CO 2 supercritical drying autoclave to cool to room temperature to obtain the aerogel composite thermal insulation material.

[0058] It should be noted that the ethanol gradient displaces the aqueous phase to gradually replace the water molecules in the gel pores, avoiding the capillary force caused by the surface tension of water during direct drying from damaging the pore structure; CO 2In the supercritical state, it has both gas diffusivity and liquid dissolving power, with surface tension approaching zero, and can remove ethanol in pores without damage. Gradient replacement and supercritical drying work together to eliminate internal stress. The resulting aerogel composite thermal insulation material retains high porosity and high specific surface area, and has the characteristics of low density and high specific strength. The multi-level pores inhibit gas convection and radiative heat transfer, and control the thermal conductivity of static air.

[0059] Applications of an aerogel composite thermal insulation material in the fields of new energy battery thermal management, heat dissipation and thermal shielding of electronic devices, and special clothing and outdoor equipment.

[0060] Compared with the prior art, the present invention has the following beneficial effects:

[0061] (1) The cross-linking network of carboxymethyl lignin, polyvinyl alcohol, m-aminophenylboronic acid, epichlorohydrin and cystamine cross-linking agent is combined by multi-level dynamic bonds - static bonds, significantly improving the mechanical strength and fatigue resistance of the material.

[0062] (2) The heterogeneous structure of the filler and the oriented arrangement of the fiber reinforcement construct a three-dimensional heat conduction path, improving the axial thermal conductivity. At the same time, the multi-level pores inhibit gas convection and reduce the thermal conductivity under static air, realizing the regulation of heat preservation - heat dissipation.

[0063] (3) The cystamine cross-linking agent and tannic acid form a sulfur ether bond - phenolic hydroxyl composite interface, enhancing the environmental stability and moisture and heat aging resistance of the material.

[0064] (4) The chemical anchoring effect of fiber pretreatment and silane coupling agent optimizes the interfacial stress transfer between the fiber and the matrix, and the impact resistance is improved.

[0065] (5) The carboxylic acid groups of carboxymethyl lignin, the hydroxyl groups of polyvinyl alcohol, the boric acid groups of m-aminophenylboronic acid, the sulfur ether bonds and disulfide bonds generated by the reaction of the cystamine cross-linking agent form a three-dimensional interpenetrating network through dynamic covalent bonds and hydrogen bonds, endowing the material with high cross-linking density and self-healing ability; the synergistic effect of pretreated fibers and fillers optimizes the thermal management efficiency while improving the mechanical properties; the post-treatment of tannic acid enhances the pore stability through multiple interfacial bondings, making the material have both high specific surface area and low density. The chemical compatibility and microstructural design among the components achieve the synergistic enhancement of the mechanical, heat preservation and weather resistance of the aerogel composite thermal insulation material. Specific embodiments

[0066] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0067] (1) The preparation steps of carboxymethyl lignin are as follows:

[0068] Dissolve 5 g of kraft lignin in 10 mL of sodium hydroxide solution with a concentration of 1.5 mol / L, stir at 60 °C for 2 - 3 h, add 5 g of sodium chloroacetate, react at 60 °C for 2 - 3 h, adjust the pH to 4, precipitate, wash with water, and dry to obtain carboxymethyl lignin.

[0069] (2) The preparation steps of the filler are as follows:

[0070] A1. Mix 0.1 g of graphene oxide and 0.3 g of boron nitride, disperse them in 50 mL of ethanol, and ultrasonicate for 1 h to obtain a suspension;

[0071] A2. Transfer the suspension to a stainless-steel hydrothermal reaction kettle lined with polytetrafluoroethylene and seal it. The pressure in the hydrothermal kettle is about 1.5 MPa. Heat it to 120 °C at a rate of 2 °C / min, react for 6 h, naturally cool to room temperature, centrifuge, wash with water, filter, and dry to obtain doped BN powder;

[0072] A3. Disperse 0.4 g of doped BN powder in 200 mL of Tris-HCl buffer solution with a pH of 8.5, add 0.4 g of catecholamine, stir at 25 °C for 24 h, centrifuge, wash with water, filter, and dry to obtain the filler.

[0073] (3) The pretreatment step of the carbon fiber felt is: Immerse 1 g of carbon fiber felt in 10 mL of nitric acid solution with a concentration of 65%, treat it in a water bath at 60 °C for 30 min, take it out, rinse it with deionized water until neutral, and dry it in an oven at 80 °C for 2 h to obtain the pretreated carbon fiber felt.

[0074] (4) The pretreatment step of the glass fiber is: Put the glass fiber into a muffle furnace, heat it to 500 °C at a rate of 5 °C / min, keep it warm for 1 h, naturally cool to room temperature, prepare a 3% silane coupling agent solution composed of 3% KH-560 silane coupling agent and 97% ethanol by mass fraction. Immerse 1 g of the calcined glass fiber in 10 mL of the 3% silane coupling agent solution, ultrasonicate for 20 min, and dry it in an oven at 80 °C for 2 h to obtain the pretreated glass fiber.

[0075] (5) The pretreatment steps of basalt fiber are as follows: Immerse the basalt fiber in a hydrochloric acid solution with a concentration of 5%, perform a water bath treatment at room temperature for 15 minutes, take it out and rinse it with deionized water until neutral, dry it in an oven at 80 °C for 2 hours, prepare a 1.5% silane coupling agent solution composed of 1.5% KH-550 silane coupling agent and 98.5% ethanol by mass fraction, immerse 1 g of the acid-treated basalt fiber in 10 mL of the 1.5% silane coupling agent solution, and the dosage ratio of the acid-treated basalt fiber to the 1.5% silane coupling agent solution is 1 g:8 mL to obtain the pretreated basalt fiber.

[0076] Example 1

[0077] Aerogel composite thermal insulation material, comprising the following raw material components by weight:

[0078] 5.7 parts of carboxymethyl lignin;

[0079] 8.3 parts of carbon fiber felt;

[0080] 0.3 part of filler;

[0081] 3.6 parts of polyvinyl alcohol;

[0082] 0.08 part of m-aminophenylboronic acid;

[0083] 1 part of epichlorohydrin;

[0084] 0.65 part of cystamine;

[0085] 0.45 part of tannic acid;

[0086] 0.2 part of triethylamine;

[0087] 0.03 part of polyethylene glycol octyl phenyl ether;

[0088] 8 parts of ethanol;

[0089] 14 parts of deionized water;

[0090] 1.5 parts of pH regulator.

[0091] The preparation method of an aerogel composite thermal insulation material is as follows:

[0092] S1. Disperse 0.6 g of filler in 10 mL of deionized water in an ice-water bath, add 0.06 g of polyethylene glycol octyl phenyl ether, perform ultrasonic homogenization for 20 minutes, centrifuge at a speed of 3000 r / min for 10 minutes, and take the upper suspension to obtain a modified filler suspension;

[0093] S2, dissolving 7.2 g of polyvinyl alcohol and 11.5 g of carboxymethyl lignin in 32 mL of modified filler suspension at 60°C, adjusting the pH to 9, stirring at 300 r / min for 15 min, immersing 16.5 g of carbon fiber felt in the premixed solution, adjusting the pH to 8.5, and treating in a 50 MPa high-pressure homogenizer for 60 min to obtain an aerogel precursor;

[0094] S3, 0.16g of m-aminophenylboronic acid, 2g of epichlorohydrin, 16mL of ethanol and 1.3g of cystamine were added to 11.2g of aerogel precursor in sequence, 0.4g of triethylamine was added to adjust the pH to 8, the reaction was stirred at 60°C for 2h, poured into a mold, naturally cooled and allowed to stand at room temperature for 12h, and dried at 50°C for 24h to obtain a gel, 2mL of a tannic acid / ethanol solution with a pH of 5.5 and a mass fraction of 6% tannic acid was injected into the pores of 10g of the gel at an injection rate of 0.5mL / min, the gel was placed in a thermostat at a temperature of 25°C and a humidity of 25% for 12h, and the gel was rinsed 3 times with anhydrous ethanol to obtain a crude gel material;

[0095] S4. Sequentially immerse the crude gel material in 50%, 70%, 90%, and 100% ethanol to replace the aqueous phase. Each gradient is allowed to stand for 6 hours and then transferred to 45°C, 8MPa CO 2 The supercritical drying reactor was sealed and supercritical CO was continuously introduced at a flow rate of 10 mL / min. 2 , at 45℃, 10.5MPa, maintain CO 2 Flow for 12 hours, turn off CO 2 The valve was placed at 45°C and 10.5 MPa for 6 h, and the pressure was gradually reduced to normal pressure at a rate of 0.2 MPa / min at 45°C until the CO 2 Completely gasified and discharged, waiting for CO 2 The supercritical drying kettle is cooled to room temperature to obtain an aerogel composite thermal insulation material.

[0096] Example 2

[0097] An aerogel composite thermal insulation material comprises the following raw material components by weight:

[0098] 5 parts of carboxymethyl lignin;

[0099] Glass fiber 7.21 parts;

[0100] 0.2 parts of filler;

[0101] 3 parts of polyvinyl alcohol;

[0102] 0.06 parts of m-aminophenylboronic acid;

[0103] 0.8 parts of epichlorohydrin;

[0104] 0.5 parts of cystamine;

[0105] 0.3 parts of tannic acid;

[0106] 0.1 parts of triethylamine;

[0107] 0.02 parts of polyethylene glycol octyl phenyl ether;

[0108] 6 parts of ethanol;

[0109] 12.5 parts of deionized water;

[0110] 0.8 parts of pH regulator.

[0111] A preparation method of an aerogel composite thermal insulation material is as follows:

[0112] S1. Disperse 0.6 g of filler in 10 mL of deionized water in an ice-water bath, add 0.06 g of polyethylene glycol octyl phenyl ether, ultrasonically homogenize for 20 min, centrifuge at a speed of 3000 r / min for 10 min, take the upper suspension to obtain a modified filler suspension;

[0113] S2. Dissolve 7.2 g of polyvinyl alcohol and 11.5 g of carboxymethyl lignin in 32 mL of the modified filler suspension at 60 °C, adjust the pH to 9, stir at a speed of 300 r / min for 15 min, immerse 16.5 g of glass fiber in the above premixed solution, adjust the pH to 8.5, and treat in a high-pressure homogenizer at 50 MPa for 60 min to obtain an aerogel precursor;

[0114] S3. Add 0.16 g of m-aminophenylboronic acid, 2 g of epichlorohydrin, 16 mL of ethanol and 1.3 g of cystamine to 11.2 g of the aerogel precursor in sequence, add 0.4 g of triethylamine to adjust the pH to 8, stir and react at 60 °C for 2 h, pour into a mold, naturally cool and stand at room temperature for 12 h, dry at 50 °C for 24 h to obtain a gel. Inject 2 mL of a tannic acid / ethanol solution with a tannic acid mass fraction of 6% and a pH of 5.5 into the pores of 10 g of the gel at an injection rate of 0.5 mL / min. Place the gel in a constant temperature box at 25 °C and a humidity of 25% and stand for 12 h. Rinse the gel 3 times with absolute ethanol to obtain a crude gel material;

[0115] S4. Immerse the crude gel material in 50%, 70%, 90%, and 100% ethanol in sequence to displace the water phase, stand for 6 h at each gradient, transfer to a supercritical drying autoclave at 45 °C and 8 MPa and seal it, continuously introduce supercritical CO 2 at a flow rate of 10 mL / min, and maintain the CO 2 flowing at 45 °C and 10.5 MPa for 12 h, and then close the CO 2 flow. 2The valve is left standing for 6 h at 45 °C and 10.5 MPa, and the pressure is gradually reduced to atmospheric pressure at a rate of 0.2 MPa / min under the temperature condition of 45 °C until CO 2 is completely vaporized and discharged, and wait for CO 2 The supercritical drying kettle is cooled to room temperature to obtain the aerogel composite thermal insulation material.

[0116] Example 3

[0117] An aerogel composite thermal insulation material comprises the following raw material components by weight:

[0118] 6.5 parts of carboxymethyl lignin;

[0119] 9.37 parts of basalt fiber;

[0120] 0.4 part of filler;

[0121] 3.9 parts of polyvinyl alcohol;

[0122] 0.1 part of m-aminophenylboronic acid;

[0123] 1.2 parts of epichlorohydrin;

[0124] 0.8 part of cystamine;

[0125] 0.6 part of tannic acid;

[0126] 0.3 part of triethylamine;

[0127] 0.04 part of polyethylene glycol octyl phenyl ether;

[0128] 12 parts of ethanol;

[0129] 16.3 parts of deionized water;

[0130] 1.8 parts of pH regulator.

[0131] A preparation method of the aerogel composite thermal insulation material is as follows:

[0132] S1. Disperse 0.6 g of filler in 10 mL of deionized water in an ice-water bath, add 0.06 g of polyethylene glycol octyl phenyl ether, homogenize by ultrasonic for 20 min, centrifuge at a speed of 3000 r / min for 10 min, and take the upper suspension to obtain a modified filler suspension;

[0133] S2. Dissolve 7.2 g of polyvinyl alcohol and 11.5 g of carboxymethyl lignin in 32 mL of the modified filler suspension at 60 °C, adjust the pH to 9, stir at a speed of 300 r / min for 15 min, immerse 16.5 g of basalt fiber in the above premixed solution, adjust the pH to 8.5, and treat in a 50 MPa high-pressure homogenizer for 60 min to obtain an aerogel precursor;

[0134] S3. Add 0.16 g of 3-aminophenylboronic acid, 2 g of epichlorohydrin, 16 mL of ethanol, and 1.3 g of cystamine to 11.2 g of the aerogel precursor in sequence. Add 0.4 g of triethylamine to adjust the pH to 8. Stir and react at 60 °C for 2 h, pour into a mold, and let it cool and stand naturally at room temperature for 12 h. Dry at 50 °C for 24 h to obtain a gel. Inject 2 mL of a tannic acid / ethanol solution with a tannic acid mass fraction of 6% and a pH of 5.5 into the pores of 10 g of the gel at an injection rate of 0.5 mL / min. Place the gel in a constant temperature box at 25 °C and 25% humidity and let it stand for 12 h. Rinse the gel with absolute ethanol three times to obtain a crude gel material;

[0135] S4. Immerse the crude gel material in 50%, 70%, 90%, and 100% ethanol in sequence to displace the aqueous phase. Let it stand for 6 h at each gradient, transfer it to a supercritical drying autoclave at 45 °C and 8 MPa and seal it. Continuously introduce supercritical CO 2 at a flow rate of 10 mL / min. 2 Under the conditions of 45 °C and 10.5 MPa, maintain the CO 2 flow for 12 h, close the CO 2 valve, and let it stand for 6 h under the conditions of 45 °C and 10.5 MPa. Gradually reduce the pressure to atmospheric pressure at a rate of 0.2 MPa / min at 45 °C until the CO 2 is completely vaporized and discharged. Wait for the CO 2 supercritical drying autoclave to cool to room temperature to obtain the aerogel composite thermal insulation material.

[0136] Comparative Example 1

[0137] An aerogel composite thermal insulation material includes the following raw material components by weight:

[0138] 5.7 parts of lignin;

[0139] 8.3 parts of carbon fiber felt;

[0140] 0.3 part of filler;

[0141] 3.6 parts of polyvinyl alcohol;

[0142] 0.08 part of 3-aminophenylboronic acid;

[0143] 1 part of epichlorohydrin;

[0144] 0.65 part of cystamine;

[0145] 0.45 part of tannic acid;

[0146] 0.2 part of triethylamine;

[0147] 0.03 part of polyethylene glycol octyl phenyl ether;

[0148] 8 parts of ethanol;

[0149] 14 parts of deionized water;

[0150] 1.5 parts of pH adjuster.

[0151] A method for preparing an aerogel composite thermal insulation material is as follows:

[0152] S1. Disperse 0.6 g of filler in 10 mL of deionized water in an ice-water bath, add 0.06 g of polyethylene glycol octylphenyl ether, homogenize by ultrasonication for 20 min, centrifuge at 3000 r / min for 10 min, take the upper suspension, and obtain a modified filler suspension;

[0153] S2, dissolving 7.2 g of polyvinyl alcohol and 11.5 g of lignin in 32 mL of modified filler suspension at 60°C, adjusting the pH to 9, stirring at 300 r / min for 15 min, immersing 16.5 g of carbon fiber felt in the premixed solution, adjusting the pH to 8.5, and treating in a 50 MPa high-pressure homogenizer for 60 min to obtain an aerogel precursor;

[0154] S3, 0.16g of m-aminophenylboronic acid, 2g of epichlorohydrin, 16mL of ethanol and 1.3g of cystamine were added to 11.2g of aerogel precursor in sequence, 0.4g of triethylamine was added to adjust the pH to 8, the reaction was stirred at 60°C for 2h, poured into a mold, naturally cooled and allowed to stand at room temperature for 12h, and dried at 50°C for 24h to obtain a gel, 2mL of a tannic acid / ethanol solution with a pH of 5.5 and a mass fraction of 6% tannic acid was injected into the pores of 10g of the gel at an injection rate of 0.5mL / min, the gel was placed in a thermostat at a temperature of 25°C and a humidity of 25% for 12h, and the gel was rinsed 3 times with anhydrous ethanol to obtain a crude gel material;

[0155] S4. Sequentially immerse the crude gel material in 50%, 70%, 90%, and 100% ethanol to replace the aqueous phase. Each gradient is allowed to stand for 6 hours and then transferred to 45°C, 8MPa CO 2 The supercritical drying reactor was sealed and supercritical CO was continuously introduced at a flow rate of 10 mL / min. 2 , at 45℃, 10.5MPa, maintain CO 2 Flow for 12 hours, turn off CO 2 The valve was placed at 45°C and 10.5 MPa for 6 h, and the pressure was gradually reduced to normal pressure at a rate of 0.2 MPa / min at 45°C until the CO 2 Completely gasified and discharged, waiting for CO 2 The supercritical drying kettle is cooled to room temperature to obtain an aerogel composite thermal insulation material.

[0156] The difference between this comparative example and Example 1 is that instead of adding carboxymethyl lignin, unmodified sulfate lignin was added.

[0157] Comparative Example 2

[0158] An aerogel composite thermal insulation material includes the following raw material components by weight:

[0159] 5.7 parts of carboxymethyl lignin;

[0160] 0.3 part of filler;

[0161] 3.6 parts of polyvinyl alcohol;

[0162] 0.08 part of m-aminophenylboronic acid;

[0163] 1 part of epichlorohydrin;

[0164] 0.65 part of cystamine;

[0165] 0.45 part of tannic acid;

[0166] 0.2 part of triethylamine;

[0167] 0.03 part of polyethylene glycol octyl phenyl ether;

[0168] 8 parts of ethanol;

[0169] 14 parts of deionized water;

[0170] 1.5 parts of pH regulator.

[0171] A preparation method of an aerogel composite thermal insulation material is as follows:

[0172] S1. Disperse 0.6 g of filler in 10 mL of deionized water in an ice-water bath, add 0.06 g of polyethylene glycol octyl phenyl ether, perform ultrasonic homogenization for 20 min, centrifuge at a speed of 3000 r / min for 10 min, and take the upper suspension to obtain a modified filler suspension;

[0173] S2. Dissolve 7.2 g of polyvinyl alcohol and 11.5 g of carboxymethyl lignin in 32 mL of the modified filler suspension at 60 °C, adjust the pH to 9, stir at a speed of 300 r / min for 15 min, adjust the pH to 8.5, and process in a 50 MPa high-pressure homogenizer for 60 min to obtain an aerogel precursor;

[0174] S3, 0.16g of m-aminophenylboronic acid, 2g of epichlorohydrin, 16mL of ethanol and 1.3g of cystamine were added to 11.2g of aerogel precursor in sequence, 0.4g of triethylamine was added to adjust the pH to 8, the reaction was stirred at 60°C for 2h, poured into a mold, naturally cooled and allowed to stand at room temperature for 12h, and dried at 50°C for 24h to obtain a gel, 2mL of a tannic acid / ethanol solution with a pH of 5.5 and a mass fraction of 6% tannic acid was injected into the pores of 10g of the gel at an injection rate of 0.5mL / min, the gel was placed in a thermostat at a temperature of 25°C and a humidity of 25% for 12h, and the gel was rinsed 3 times with anhydrous ethanol to obtain a crude gel material;

[0175] S4. Sequentially immerse the crude gel material in 50%, 70%, 90%, and 100% ethanol to replace the aqueous phase. Each gradient is allowed to stand for 6 hours and then transferred to 45°C, 8MPa CO 2 The supercritical drying reactor was sealed and supercritical CO was continuously introduced at a flow rate of 10 mL / min. 2 , at 45℃, 10.5MPa, maintain CO 2 Flow for 12 hours, turn off CO 2 The valve was placed at 45°C and 10.5 MPa for 6 h, and the pressure was gradually reduced to normal pressure at a rate of 0.2 MPa / min at 45°C until the CO 2 Completely gasified and discharged, waiting for CO 2 The supercritical drying kettle is cooled to room temperature to obtain an aerogel composite thermal insulation material.

[0176] The difference between this comparative example and Example 1 is that no carbon fiber felt is added.

[0177] Comparative Example 3

[0178] An aerogel composite thermal insulation material comprises the following raw material components by weight:

[0179] Carboxymethyl lignin 5.7 parts;

[0180] 8.3 parts of carbon fiber felt;

[0181] 3.6 parts of polyvinyl alcohol;

[0182] 0.08 parts of m-aminophenylboronic acid;

[0183] 1 part of epichlorohydrin;

[0184] Cystamine 0.65 parts;

[0185] 0.45 parts of tannic acid;

[0186] 0.2 parts of triethylamine;

[0187] 0.03 parts of polyethylene glycol octylphenyl ether;

[0188] 8 parts of ethanol;

[0189] 14 parts of deionized water;

[0190] 1.5 parts of pH adjuster.

[0191] A method for preparing an aerogel composite thermal insulation material is as follows:

[0192] S1. Dissolve 7.2 g of polyvinyl alcohol and 11.5 g of carboxymethyl lignin in 32 mL of deionized water at 60 ° C, adjust the pH to 9, stir at a speed of 300 r / min for 15 min, immerse 16.5 g of carbon fiber felt in the above premixed solution, adjust the pH to 8.5, and treat in a 50 MPa high-pressure homogenizer for 60 min to obtain an aerogel precursor;

[0193] S2, 0.16g of m-aminophenylboronic acid, 2g of epichlorohydrin, 16mL of ethanol and 1.3g of cystamine were added to 11.2g of aerogel precursor in sequence, 0.4g of triethylamine was added to adjust the pH to 8, the reaction was stirred at 60°C for 2h, poured into a mold, naturally cooled and allowed to stand at room temperature for 12h, and dried at 50°C for 24h to obtain a gel, 2mL of a tannic acid / ethanol solution with a pH of 5.5 and a mass fraction of 6% tannic acid was injected into the pores of 10g of the gel at an injection rate of 0.5mL / min, the gel was placed in a thermostat at a temperature of 25°C and a humidity of 25% for 12h, and the gel was rinsed 3 times with anhydrous ethanol to obtain a crude gel material;

[0194] S3, immerse the crude gel material in 50%, 70%, 90%, and 100% ethanol to replace the aqueous phase, let each gradient stand for 6 hours, and transfer to 45°C, 8MPa CO 2 The supercritical drying reactor was sealed and supercritical CO was continuously introduced at a flow rate of 10 mL / min. 2 , at 45℃, 10.5MPa, maintain CO 2 Flow for 12 hours, turn off CO 2 The valve was placed at 45°C and 10.5 MPa for 6 h, and the pressure was gradually reduced to normal pressure at a rate of 0.2 MPa / min at 45°C until the CO 2 Completely gasified and discharged, waiting for CO 2 The supercritical drying kettle is cooled to room temperature to obtain an aerogel composite thermal insulation material.

[0195] The difference between this comparative example and Example 1 is that no filler is added.

[0196] Comparative Example 4

[0197] An aerogel composite thermal insulation material comprises the following raw material components by weight:

[0198] 5.7 parts of carboxymethyl lignin;

[0199] 8.3 parts of carbon fiber felt;

[0200] 0.3 part of filler;

[0201] 3.6 parts of polyvinyl alcohol;

[0202] 0.08 part of m-aminophenylboronic acid;

[0203] 1 part of epichlorohydrin;

[0204] 0.45 part of tannic acid;

[0205] 0.2 part of triethylamine;

[0206] 0.03 part of polyethylene glycol octyl phenyl ether;

[0207] 8 parts of ethanol;

[0208] 14 parts of deionized water;

[0209] 1.5 parts of pH regulator.

[0210] A preparation method of an aerogel composite thermal insulation material is as follows:

[0211] S1. Disperse 0.6 g of filler in 10 mL of deionized water in an ice-water bath, add 0.06 g of polyethylene glycol octyl phenyl ether, perform ultrasonic homogenization for 20 min, centrifuge at a speed of 3000 r / min for 10 min, and take the upper suspension to obtain a modified filler suspension;

[0212] S2. Dissolve 7.2 g of polyvinyl alcohol and 11.5 g of carboxymethyl lignin in 32 mL of the modified filler suspension at 60 °C, adjust the pH to 9, stir at a speed of 300 r / min for 15 min, immerse 16.5 g of carbon fiber felt in the above premixed solution, adjust the pH to 8.5, and treat it in a high-pressure homogenizer at 50 MPa for 60 min to obtain an aerogel precursor;

[0213] S3. Add 0.16 g of m-aminophenylboronic acid, 2 g of epichlorohydrin, and 16 mL of ethanol to 11.2 g of the aerogel precursor in sequence, add 0.4 g of triethylamine to adjust the pH to 8, stir and react at 60 °C for 2 h, pour it into a mold, naturally cool and stand still at room temperature for 12 h, dry it at 50 °C for 24 h to obtain a gel, inject 2 mL of a tannic acid / ethanol solution with a tannic acid mass fraction of 6% and a pH of 5.5 into the pores of 10 g of the gel at an injection rate of 0.5 mL / min, place the gel in a constant temperature box at a temperature of 25 °C and a humidity of 25% and stand still for 12 h, and rinse the gel with absolute ethanol 3 times to obtain a crude gel material;

[0214] S4. Immerse the crude gel material successively in 50%, 70%, 90%, and 100% ethanol to displace the aqueous phase. Let it stand for 6 h at each gradient, and then transfer it to a CO 2 supercritical drying autoclave and seal it. Continuously introduce supercritical CO 2 at a flow rate of 10 mL / min. Under the conditions of 45°C and 10.5 MPa, maintain the CO 2 flow for 12 h, and then close the CO 2 valve. Let it stand for 6 h under the conditions of 45°C and 10.5 MPa. Gradually reduce the pressure to atmospheric pressure at a rate of 0.2 MPa / min under the temperature condition of 45°C until the CO 2 is completely vaporized and discharged. Wait for the CO 2 supercritical drying autoclave to cool to room temperature to obtain the aerogel composite thermal insulation material.

[0215] The difference between this comparative example and Example 1 is that cysteamine is not added.

[0216] Comparative Example 5

[0217] An aerogel composite thermal insulation material comprises the following raw material components by weight:

[0218] 5.7 parts of carboxymethyl lignin;

[0219] 8.3 parts of carbon fiber felt;

[0220] 0.3 part of filler;

[0221] 3.6 parts of polyvinyl alcohol;

[0222] 0.08 part of m-aminophenylboronic acid;

[0223] 1 part of epichlorohydrin;

[0224] 0.45 part of tannic acid;

[0225] 0.2 part of triethylamine;

[0226] 0.03 part of polyethylene glycol octyl phenyl ether;

[0227] 7 parts of ethanol;

[0228] 14 parts of deionized water;

[0229] 1.5 parts of pH regulator.

[0230] A preparation method of the aerogel composite thermal insulation material is as follows:

[0231] S1. Disperse 0.6 g of the filler in 10 mL of deionized water in an ice-water bath, add 0.06 g of polyethylene glycol octyl phenyl ether, ultrasonically homogenize for 20 min, centrifuge at a speed of 3000 r / min for 10 min, and take the upper suspension to obtain a modified filler suspension;

[0232] S2. Dissolve 7.2 g of polyvinyl alcohol and 11.5 g of carboxymethyl lignin in 32 mL of the modified filler suspension at 60 °C, adjust the pH to 9, stir at a speed of 300 r / min for 15 min, immerse 16.5 g of carbon fiber felt in the above premixed solution, adjust the pH to 8.5, and treat it in a high-pressure homogenizer at 50 MPa for 60 min to obtain an aerogel precursor;

[0233] S3. Add 0.16 g of m-aminophenylboronic acid, 2 g of epichlorohydrin, 16 mL of ethanol, and 1.3 g of cystamine to 11.2 g of the aerogel precursor in sequence, add 0.4 g of triethylamine to adjust the pH to 8, stir and react at 60 °C for 2 h, pour it into a mold, naturally cool and stand at room temperature for 12 h, dry at 50 °C for 24 h to obtain a gel, place the gel in a constant temperature box at 25 °C and 25% humidity and stand for 12 h, and rinse the gel with absolute ethanol 3 times to obtain a crude gel material;

[0234] S4. Immerse the crude gel material in 50%, 70%, 90%, and 100% ethanol in sequence to displace the aqueous phase, stand for 6 h at each gradient, transfer it to a supercritical drying autoclave at 45 °C and 8 MPa and seal it, continuously introduce supercritical CO at a flow rate of 10 mL / min, under the conditions of 45 °C and 10.5 MPa, maintain the CO flow for 12 h, close the CO valve, stand at 45 °C and 10.5 MPa for 6 h, gradually reduce the pressure to atmospheric pressure at a rate of 0.2 MPa / min at 45 °C until the CO is completely vaporized and discharged, wait for the supercritical drying autoclave to cool to room temperature to obtain an aerogel composite thermal insulation material. 2 supercritical drying autoclave seal, continuously introduce supercritical CO 2 at a flow rate of 10 mL / min, under the conditions of 45 °C and 10.5 MPa, maintain the CO 2 flow for 12 h, close the CO 2 valve, stand at 45 °C and 10.5 MPa for 6 h, gradually reduce the pressure to atmospheric pressure at a rate of 0.2 MPa / min at 45 °C until the CO 2 is completely vaporized and discharged, wait for the CO 2 supercritical drying autoclave to cool to room temperature to obtain an aerogel composite thermal insulation material.

[0235] The difference between this comparative example and Example 1 is that tannic acid / ethanol solution was not introduced into the gel pores.

[0236] Test:

[0237] I. Thermal conductivity at room temperature

[0238] "GB / T 10294-2008 Determination of steady-state thermal resistance and related characteristics of thermal insulation materials - Heat flow meter method"

[0239] The test results are shown in Table 1.

[0240] II. Specific Surface Area

[0241] "Determination of Specific Surface Area of Solid Materials by Gas Adsorption BET Method - GB / T 19587-2017"

[0242] The test results are shown in Table 1.

[0243] III. Porosity

[0244] "Test Methods for Apparent Porosity and Bulk Density of Porous Ceramics - GB / T 1966-2024"

[0245] The test results are shown in Table 1.

[0246] IV. Mechanical Properties

[0247] "Standard Test Method for Tensile Properties of Polymer Matrix Composites - ASTM D3039 / D3039M-07"

[0248] The test results are shown in Table 1.

[0249] V. Damp Heat Aging Resistance (Tensile Strength Retention Rate)

[0250] "Test Method for Damp Heat Aging of Vulcanized Rubber - GB / T 15905-1995" - Alternating test environment - Alternating temperature b;

[0251] Tensile strength change rate = (Tensile strength before test - Tensile strength after test) / Tensile strength before test × 100%.

[0252] The test results are shown in Table 1.

[0253] VI. Result Summary

[0254] Table 1

[0255]

[0256] It can be seen from Table 1 that the aerogel composite thermal insulation materials prepared in Examples 1-3 all have excellent mechanical properties, thermal insulation properties and weather resistance, with high specific surface area, low density and high porosity.

[0257] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

[0258] In the description of the specification, the descriptions referring to terms such as "one embodiment", "example", "specific example", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0259] The above content is only an illustration and explanation of the present invention. Those skilled in the art to which this technology belongs can make various modifications or supplements to the described specific embodiments or use similar ways to substitute, as long as they do not deviate from the invention or exceed the scope defined by this claim book, they should all fall within the protection scope of the present invention.

Claims

1. An aerogel composite thermal insulation material, characterized in that: The following raw material components are included by weight: Carboxymethyl lignin 5-6.5 parts; Reinforcement fiber 7.21-9.37 parts; Filler 0.2-0.4 parts; Polyvinyl alcohol 3-3.9 parts; 0.06-0.1 parts of m-aminophenylboronic acid; Epichlorohydrin 0.8-1.2 parts; Cystamine cross-linking agent 0.5-0.8 parts; Tannic acid 0.3-0.6 parts; 0.1-0.3 parts of triethylamine; Dispersant 0.02-0.04 parts; 4-12 parts of ethanol; 10-20 parts of deionized water; pH regulator 0.5-2 parts; The preparation steps of the carboxymethyl lignin are as follows: The kraft lignin was dissolved in a sodium hydroxide solution with a concentration of 1.5 mol / L, stirred at 60°C for 2-3 hours, sodium chloroacetate was added, reacted at 60°C for 2-3 hours, the pH was adjusted to 4, precipitated, washed with water, and dried to obtain carboxymethyl lignin; The usage ratio of the kraft lignin, the sodium hydroxide solution and the sodium chloroacetate is 5g:10mL:5g.

2. The aerogel composite thermal insulation material according to claim 1, characterized in that: The reinforcing fiber is one of pretreated carbon fiber felt, glass fiber and basalt fiber.

3. The aerogel composite thermal insulation material according to claim 2, characterized in that: The pretreatment step of the carbon fiber felt is: immersing the carbon fiber felt in a nitric acid solution with a concentration of 65%, treating it in a water bath at 60° C. for 30-40 minutes, taking it out and rinsing it with deionized water until it is neutral, and drying it in an oven at 80° C. for 1-2 hours to obtain a pretreated carbon fiber felt; The pretreatment step of the glass fiber is as follows: placing the glass fiber in a muffle furnace, heating it to 500° C. at 5° C. / min, keeping it warm for 1 hour, cooling it naturally to room temperature, preparing a 3% silane coupling agent solution, immersing the calcined glass fiber in the 3% silane coupling agent solution, ultrasonically treating it for 20-30 minutes, and drying it in an oven at 80° C. for 1-2 hours to obtain the pretreated glass fiber; The pretreatment steps of the basalt fiber are as follows: immersing the basalt fiber in a 5% hydrochloric acid solution, treating it in a room temperature water bath for 15-20 minutes, taking it out and rinsing it with deionized water until it is neutral, drying it in an oven at 80°C for 1-2 hours, preparing a 1.5% silane coupling agent solution, immersing the acid-treated basalt fiber in the 1.5% silane coupling agent solution, and the dosage ratio of the acid-treated basalt fiber to the 1.5% silane coupling agent solution is 1g:8mL, so as to obtain the pretreated basalt fiber.

4. The aerogel composite thermal insulation material according to claim 1, characterized in that: The preparation steps of the filler are as follows: A1, mixing graphene oxide and boron nitride, dispersing them in ethanol and ultrasonicating them for 1 h to obtain a suspension; A2. The suspension was transferred to a stainless steel hydrothermal reactor lined with polytetrafluoroethylene and sealed. The pressure in the hydrothermal reactor was about 1.5-2.0 MPa. The temperature was raised to 120°C at 2°C / min. The reaction was carried out for 6 hours. The suspension was naturally cooled to room temperature. The suspension was centrifuged, washed with water, filtered and dried to obtain doped BN powder. A3. Disperse the doped BN powder in Tris-HCl buffer at pH 8.5, add catecholamine, stir at 25°C for 24 hours, centrifuge, wash with water, filter, and dry to obtain a filler.

5. The aerogel composite thermal insulation material according to claim 4, characterized in that: In the step A1, the ratio of graphene oxide, boron nitride and ethanol is 0.1 g:0.3 g:50 mL; in the step A3, the ratio of doped BN powder, Tris-HCl buffer and catecholamine is 0.4 g:200 mL:0.4 g.

6. The aerogel composite thermal insulation material according to claim 1, characterized in that: The cystamine cross-linking agent is one of cystamine, pegylated cystamine and cystine.

7. The aerogel composite thermal insulation material according to claim 1, characterized in that: The dispersant is one of polyethylene glycol octylphenyl ether, 3-[3-(cholamidopropyl)dimethylamino]propanesulfonic acid inner salt and polyvinyl pyrrolidone.

8. A method for preparing the aerogel composite thermal insulation material according to any one of claims 1 to 7 is as follows: S1. Disperse the filler in deionized water in an ice water bath, add a dispersant, homogenize by ultrasonication for 15-30 min, centrifuge at a speed of 3000 r / min for 10-15 min, take the upper suspension, and obtain a modified filler suspension; The usage ratio of the filler, deionized water and dispersant is (0.2-0.4) g:5 mL:(20-40) mg; S2, dissolving polyvinyl alcohol and carboxymethyl lignin in a modified filler suspension at 60°C, adjusting the pH to 8.5-9, stirring at a speed of 300-500 r / min for 5-20 min to obtain a premixed solution, immersing the reinforcing fiber in the premixed solution, adjusting the pH to 8.5-9, and treating in a 50 MPa high-pressure homogenizer for 30-90 min to obtain an aerogel precursor; The amount ratio of the polyvinyl alcohol, carboxymethyl lignin, modified filler suspension and reinforcing fiber is (3-3.9) g: (5-6.5) g: (12.5-16.3) mL: (7.21-9.37) g; S3, adding m-aminophenylboronic acid, epichlorohydrin, ethanol and cystamine crosslinking agent to the aerogel precursor in sequence, adding triethylamine to adjust the pH to 8-8.5, stirring the reaction at 60°C for 2-4h, pouring into a mold, naturally cooling and standing at room temperature for 12h, drying at 50°C for 12-24h to obtain a gel, introducing a tannic acid solution with a tannic acid mass fraction of 6% into the gel pores, placing the gel in a thermostat at a temperature of 25°C and a humidity of 25% for 12h, and washing the gel with anhydrous ethanol for 3-5 times to obtain a crude gel material; The amount ratio of the m-aminophenylboronic acid, epichlorohydrin, ethanol, cystamine crosslinking agent, aerogel precursor and triethylamine is (0.06-0.1) g: (0.8-1.2) g: (5-15) mL: (0.5-0.8) g: (4-7.2) g: (0.01-0.3) g; S4. Immerse the crude gel material in 50%, 70%, 90%, and 100% ethanol to replace the aqueous phase in turn, let each gradient stand for 6 hours, transfer to a CO2 supercritical drying kettle at 45°C and 8MPa, seal it, and continuously introduce supercritical CO2 at a flow rate of 10mL / min. At 45°C and 10.5MPa, maintain the CO2 flow for 12 hours, close the CO2 valve, let it stand at 45°C and 10.5MPa for 6 hours, and gradually reduce the pressure to normal pressure at a rate of 0.2MPa / min at a temperature of 45°C until the CO2 is completely gasified and discharged, wait for the CO2 supercritical drying kettle to cool to room temperature, and obtain an aerogel composite thermal insulation material.

9. The method for preparing an aerogel composite thermal insulation material according to claim 8, characterized in that: In step S3, the tannic acid solution solvent is ethanol, and the pH is 5.5; the method of introducing the tannic acid solution into the gel pores includes any one of injection by injection pump and vacuum-assisted infiltration method; the injection rate of the injection pump injection operation is 0.5 mL / min, and the dosage ratio of tannic acid solution to gel is 1 mL: (5-10) g; the operation steps of the vacuum-assisted infiltration method are as follows: immerse the gel in the tannic acid solution, evacuate to -0.08 MPa and maintain for 20 minutes.

10. Application of an aerogel composite thermal insulation material according to any one of claims 1 to 8 in the fields of thermal management of new energy batteries, heat dissipation of electronic devices, thermal shielding of electronic devices, special clothing and outdoor equipment.

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