MOFs (Metal-Organic Frameworks) modified hollow glass bead, preparation method thereof and application of MOFs modified hollow glass bead in cement-based plate

Abstract

The invention provides MOFs (Metal-Organic Frameworks) modified hollow glass beads, a preparation method and application of the MOFs modified hollow glass beads in cement-based plates. The MOFs modified hollow glass beads are prepared mainly by sequentially carrying out amino modification, carboxylic acid modification and MOFs modification on the hollow glass beads, the surfaces of the hollow glass beads are coated with MOFs porous structures, the MOFs have open pore structures and large specific surface areas, and therefore the thermal insulation performance of the hollow glass beads is guaranteed, and meanwhile the thermal insulation performance of the hollow glass beads is improved. The sound insulation performance of the hollow glass beads is improved to a great extent; the MOFs modified hollow glass beads are applied to preparation of a cement-based plate, so that the cement-based plate has the characteristic of light weight and also has relatively good heat preservation and sound insulation performance, and the compressive strength and breaking strength of the cement-based plate can be improved.

Description

Technical Field

[0001] The present invention relates to the application field of hollow glass microspheres, and particularly to a MOFs modified hollow glass microsphere, a preparation method thereof, and an application thereof in cement-based boards. Background Art

[0002] With the popularization of the concepts of green buildings and energy conservation and environmental protection, the functional requirements for building materials are increasing day by day. Especially in the field of building boards, there is an urgent need for materials with both high-efficiency heat insulation and sound insulation performance. Traditional inorganic boards, as a key component of building infrastructure, although having good strength and durability, have relatively poor performance in heat insulation and sound insulation. Especially in cold regions or noisy environments, traditional inorganic boards often cannot effectively prevent heat loss and noise transmission, thus affecting the living comfort and causing energy consumption. Traditional heat insulation and sound insulation boards mostly adopt a layered composite structure. For example, a heat insulation layer such as polystyrene foam (EPS) or rock wool is embedded in the base material, and a sound insulation felt or sound insulation board is additionally attached. However, such solutions have the following defects: 1) Performance imbalance: Most heat insulation materials are closed-cell structures, which can effectively reduce the thermal conductivity, but their airtightness results in insufficient sound insulation performance; while sound insulation materials can absorb sound energy through porous structures, but have a high thermal conductivity and are difficult to balance the dual performance.

[0003] 2) Thickness and weight problems: The layered design requires stacking different functional layers, resulting in an increase in the thickness and density of the board, which is not conducive to building lightweight.

[0004] 3) Insufficient environmental protection: Organic foam materials are prone to release volatile organic compounds and are difficult to recycle.

[0005] Therefore, the Chinese patent application publication number CN113563771A discloses an anti-cracking sound insulation composite material and a preparation method thereof. The anti-cracking sound insulation composite material includes the following raw materials: 5-20% of hollow glass microspheres, 0.2-0.5% of modified polycarboxylate water reducer, 5-10% of calcium silicate powder, 40-50% of vinyl acetate-ethylene copolymer emulsion, etc.; the silane coupling agent in the composite material has reactivity with the building substrate, enhancing the bonding force between the anti-cracking sound insulation composite material and the building substrate. The prepared anti-cracking sound insulation composite material has excellent sound insulation, heat insulation, strong bonding force, anti-ultraviolet, and is not easy to crack and fall off, etc. However, this material only uses hollow glass microspheres as the sound insulation material, and its closed-cell structure is mainly used for low-frequency sound insulation, and the mid-high frequency sound absorption ability is weak. In addition, the Chinese patent application CN114956716A discloses a lightweight composite building exterior wall heat insulation material and a preparation method thereof. Although the exterior wall heat insulation material is closely combined with the wall interface and has good heat insulation and sound insulation, wear resistance and flame retardancy performance, the mechanical properties of this material are limited, affecting the impact resistance of the exterior wall. Summary of the Invention

[0006] In view of this, an object of the present invention is to provide a method for preparing MOFs (metal-organic frameworks) modified hollow glass microspheres. The MOFs in the MOFs modified hollow glass microspheres have a porous structure and a large specific surface area, which can effectively improve the sound insulation and heat insulation performance of the hollow glass microspheres. While having good heat insulation and sound insulation performance, they can have more contact points with the cement base material, increasing the interfacial bonding strength with cement.

[0007] Another object of the present invention is to provide an application of the above-mentioned MOFs modified hollow glass microspheres in the preparation of cement-based boards, so that the cement-based boards have good heat insulation and sound insulation functions while also having good strength, meeting the mechanical properties and durability requirements of building materials, and satisfying the needs of the construction industry for energy conservation, environmental protection and comfort.

[0008] To achieve the above object, the present invention provides the following technical solutions: A method for preparing MOFs modified hollow glass microspheres, comprising the steps of: Amino modification: Modify the hollow glass microspheres with an amino silane coupling agent to obtain amino-modified microspheres; Carboxylic acid modification: Treat the amino-modified microspheres with carboxylic anhydride to obtain carboxylic acid-modified microspheres; MOFs modification: Using metal salts and 2-methylimidazole as raw materials, modify the carboxylic acid-modified microspheres in sequence to form a MOFs layer on the surface of the hollow glass microspheres.

[0009] A MOFs modified hollow glass microsphere prepared by the above preparation method.

[0010] An application of the above-mentioned MOFs modified hollow glass microspheres in the preparation of cement-based boards.

[0011] A cement-based board, the raw materials of which include the following raw materials in parts by mass: 50-70 parts of portland cement, 10-20 parts of fly ash, 20-40 parts of the above-mentioned MOFs modified hollow glass microspheres, 5-10 parts of polypropylene fiber, 4-10 parts of redispersible latex powder, 0.2-0.5 parts of hydroxypropyl methyl cellulose ether, 0.4-0.8 parts of polyacrylic acid water reducer and 30-50 parts of deionized water.

[0012] The present invention provides a manufacturing method of the above-mentioned cement-based board, comprising the following steps: (1) Mix portland cement, fly ash, modified hollow glass microspheres and polypropylene fiber evenly to obtain a solid component; (2) Mix redispersible latex powder, hydroxypropyl methyl cellulose ether, polyacrylic acid water reducer and deionized water evenly to obtain a liquid component; (3) Uniformly mix the solid component and the liquid component to obtain a mixed slurry; (4) Pour the mixed slurry into a mold, and obtain the finished cement-based board after pressing, demolding, curing, and drying.

[0013] Compared with the prior art, the above technical solution provided by the present invention has the following characteristics: First, the present invention generates a MOFs layer with a porous structure on the surface of hollow glass microspheres, which increases the scattering and absorption of sound waves. The closed-cell hollow glass microspheres effectively block low-frequency noise, and the open-pore structure in the MOFs layer realizes the absorption of high-frequency sound waves through the porous sound absorption mechanism. Thus, the MOFs-modified hollow glass microspheres are given good sound insulation effect. In addition, the high specific surface area and porosity of the MOFs layer effectively limit heat conduction and heat radiation, further improving the heat insulation effect of the hollow glass microspheres; The cement-based board prepared by using the modified hollow glass microspheres realizes the integration of heat insulation and sound insulation functions, improving building energy efficiency and comfort; Second, the MOFs layer generated on the surface of the hollow glass microspheres in the present invention has a porous structure and a high specific surface area, providing more contact points with cement. In addition, the carboxyl groups carried by the MOFs layer coordinate with Ca²⁺ in the cement, which also enhances the interfacial bonding and improves the adhesion to cement, thereby improving the strength of the cement-based board; Third, the porous structure and rough surface of MOFs increase the distance between particles, reducing the probability of direct contact between microspheres and avoiding the problem that smooth-surface microspheres are prone to agglomeration due to van der Waals forces or electrostatic interactions. In addition, the combination of the two increases the weight of each other, avoiding the phenomenon of easy upward floating during the preparation of cement-based boards due to light weight. Therefore, the modified hollow glass microspheres of the present invention improve the dispersibility of MOFs materials and hollow glass microspheres in cement. Description of the Drawings

[0014] Figure 1 It is a flowchart for the preparation of MOFs-modified hollow glass microspheres provided in Embodiments 1-3 of the present invention. Detailed Embodiments

[0015] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention.

[0016] In the scope disclosed in the present invention, the endpoints and any values of the scope are not limited to the exact scope or value. These scopes or values should be understood to include values close to these scopes or values. For numerical ranges, the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed in the present invention.

[0017] In the present invention, unless otherwise specified and / or described, all numerical values related to the dosage of components are "weight". Unless otherwise specified, the terms used in the present invention are common terms in the art. For the preparation processes, test methods, etc. used in each embodiment that are not specifically described, they are all conventional means well-known to those skilled in the art, and the raw materials and equipment used can be obtained from public commercial channels.

[0018] The present invention mainly prepares MOF-modified hollow glass microspheres by sequentially performing amino modification, carboxylic acid modification, and MOF modification on hollow glass microspheres, so that the porous structure of MOFs is coated on the surface of the hollow glass microspheres. MOFs have an open pore structure and a large specific surface area. In this way, while ensuring the thermal insulation performance of the hollow glass microspheres, the sound insulation performance of the hollow glass microspheres is greatly improved; applying the MOF-modified hollow glass microspheres to the preparation of cement-based boards can make the cement-based boards have the characteristics of light weight, good thermal insulation and sound insulation performance, and can improve the compressive strength and flexural strength of the cement-based boards.

[0019] The specific implementation schemes provided by the present invention are as follows: A preparation method of MOF-modified hollow glass microspheres, comprising the following steps: Amino modification: Immerse the hollow glass microspheres in an amino silane coupling agent solution with a concentration of 0.1-1.0 wt% to carry out an amination reaction to obtain amino-modified microspheres; Carboxylic acid modification: Immerse the amino-modified microspheres in a carboxylic anhydride solution with a concentration of 0.1-1.0 mol / L, and carry out an amidation reaction under the action of a catalyst with a concentration of 1-3 wt% to form an amide group on the surface of the hollow glass microspheres and introduce a terminal carboxyl group to obtain carboxylic acid-modified microspheres; MOF modification: First, immerse the carboxylic acid-modified microspheres in a metal salt solution with a concentration of 0.02-0.1 mol / L for a coordination reaction; then add a 2-methylimidazole solution with a concentration of 0.1-0.5 mol / L for reaction to form a MOF layer on the surface of the hollow glass microspheres to obtain the MOF-modified hollow glass microspheres.

[0020] The step of amino modification is carried out by soaking the hollow glass microspheres in the amino silane coupling agent solution to introduce amino groups on the surface of the hollow glass microspheres. The amino groups serve as active sites, providing a connection bridge for the subsequent carboxylation reaction and facilitating the formation of the subsequent MOFs layer. The temperature of the amination reaction is preferably 50-90 °C, such as 50 °C, 60 °C, 70 °C, 80 °C, 90 °C, etc.; the amination reaction time is preferably 2-4 h, such as 2 h, 3 h, 4 h, etc. The amino silane coupling agent is preferably coupling agent KH170 or KH550. The solvent in the amino silane coupling agent solution is preferably toluene, ethanol or acetone. If the concentration of the amino silane coupling agent solution is lower than 0.1 wt%, it is likely to result in insufficient grafting of amino functional groups on the surface of the hollow glass microspheres, further leading to uneven growth or weak binding force of the subsequent MOFs; if the concentration is higher than 1.0 wt%, it may cause excessive accumulation and self-polymerization of the coupling agent on the microsphere surface to form particles, affecting the amino modification effect. Therefore, the concentration of the amino coupling agent solution is preferably 0.1-1.0 wt%, such as 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1.0 wt%, etc.

[0021] The hollow glass microspheres used in the present invention preferably have a true density of 0.18-0.40 g / cm 3 and a particle size of at least one of 40-65 μm, such as one or several of the models HL20 (D50 = 65 μm) and HL38 (D50 = 40 μm) produced by Zhengzhou Shenglaite Hollow Microsphere New Materials Co., Ltd. This is beneficial for the MOFs-modified hollow glass microspheres to have high heat insulation and sound insulation properties at the same time. Among them, the solid-liquid ratio g:mL of the hollow glass microspheres and the amino silane coupling agent solution can be 1:7-10, such as 1:7, 1:8, 1:9, 1:10, etc.

[0022] The carboxylic acid modification step is carried out by soaking the amino-modified microspheres in the carboxylic anhydride solution. Under the action of a catalyst, the carboxylic anhydride in it undergoes ring-opening and an amidation reaction occurs between the surface amino group of the hollow glass microspheres and the carboxylic anhydride to form an amide group, and a terminal carboxyl group is introduced on the surface of the hollow glass microspheres, so that the hollow glass microspheres are modified by carboxyl groups to obtain carboxylic acid-modified microspheres, in order to promote the formation of a MOFs layer on the surface of the hollow glass microspheres later. The temperature of the amidation reaction can be 60-80 °C, such as 60 °C, 65 °C, 70 °C, 75 °C, 80 °C, etc.; the amidation reaction time can be 6-12 h, such as 6 h, 7 h, 8 h, 9 h, 10 h, 11 h, 12 h, etc. The carboxylic anhydride can be succinic anhydride, maleic anhydride or glutaric anhydride. The solvent in the carboxylic anhydride solution can be toluene, acetone or DMF. If the concentration of the carboxylic anhydride solution is too low, it is easy to cause a low amino conversion rate and insufficient carboxylation degree, affecting the subsequent formation of MOFs; if the concentration is too high, it may lead to an increase in solution viscosity, restricted diffusion, self-polymerization of the acid anhydride or reaction with the solvent to generate by-products, etc.; therefore, the concentration of the carboxylic anhydride solution is 0.1-1.0 mol / L, such as 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, 1 mol / L, etc. The main role of the catalyst is to accelerate the ring-opening of the carboxylic anhydride, and triethylamine or pyridine is preferably used. The solid-liquid ratio g:mL of the amino-modified microspheres and the carboxylic anhydride solution can be 1:8-12, such as 1:8, 1:9, 1:10, 1:11, 1:12, etc.

[0023] The main purpose of the MOFs modification step is to introduce MOFs onto the surface of hollow glass microspheres, so that the hollow glass microspheres have good heat insulation effect while also having good sound insulation effect. Among them, the main role of the metal salt is to provide sufficient metal ions for the formation of MOFs, so as to coordinate with the carboxyl groups on the surface of the carboxyl acid modified microspheres to form a stable core, preferably zinc nitrate or cobalt nitrate; if the concentration of the metal salt solution is too low, it may lead to insufficient ligand sites, slow nucleation of MOFs, and it is difficult to form a dense coating layer; if the concentration is too high, it may lead to supersaturation, forming large particles with disordered aggregation, affecting the dispersibility; the concentration of the metal salt solution is preferably 0.02 - 0.1 mol / L, such as 0.02 mol / L, 0.04 mol / L, 0.06 mol / L, 0.08 mol / L, 0.1 mol / L, etc.; the solid-liquid ratio g:mL of the carboxyl acid modified microspheres and the metal salt solution can be 1:18 - 22, such as 1:18, 1:19, 1:20, 1:21, 1:22, etc. 2-methylimidazole is used as an organic ligand, and its main role is to ensure the integrity of the growth of MOFs crystals. If the concentration of the 2-methylimidazole solution is too low, it will lead to slow formation of MOFs, incomplete growth, and a sparse coating layer; if the concentration is too high, it may lead to rapid nucleation of MOFs but limited growth, forming small particles and affecting the stability. Therefore, the concentration of the 2-methylimidazole solution is preferably 0.1 - 0.5 mol / L, such as 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, etc.; the molar ratio of the metal salt to 2-methylimidazole can be 1:4 - 6, such as 1:4, 1:5, 1:6, etc.

[0024] The preparation method of MOFs is a prior art. In the present invention, the steps of the MOFs modification specifically include: first, soaking the carboxyl acid modified microspheres into the metal salt solution, stirring at 60 - 80 °C for 2 - 4 h to carry out a coordination reaction to form stable coordination bonds; then adding the 2-methylimidazole organic ligand solution, stirring at room temperature for 6 - 10 h, reacting to form a MOFs layer, and after washing and drying, the MOFs modified hollow glass microspheres can be obtained. Among them, the solvents in the metal salt solution and the 2-methylimidazole organic ligand solution are preferably methanol or ethanol.

[0025] The present invention also provides MOFs-modified hollow glass microspheres prepared by the above preparation method. By generating a MOFs layer with a porous structure on the surface of the hollow glass microspheres, the scattering and absorption of sound waves are increased, endowing the hollow glass microspheres with good sound insulation performance. In addition, the high specific surface area and porosity of the MOFs layer effectively limit heat conduction and thermal radiation, further enhancing the heat preservation effect of the hollow glass microspheres and providing more contact points with cement. The carboxyl groups carried by the MOFs layer coordinate with Ca²⁺ in the cement, which can enhance the interfacial bonding strength between the microspheres and the cement substrate, facilitating the improvement of the strength of the cement-based board.

[0026] In addition, the porous structure and rough surface of the MOFs layer in the MOFs-modified hollow glass microspheres increase the distance between particles, reducing the probability of direct contact between the hollow glass microspheres and avoiding the problem that the smooth-surfaced hollow glass microspheres are prone to agglomeration due to van der Waals forces or electrostatic interactions. Moreover, the combination of the two increases the weight of each other, avoiding the phenomenon of easy upward floating during the preparation of the board due to light weight. Therefore, the MOFs-modified hollow glass microspheres of the present invention can improve the dispersibility of the MOFs material and the hollow glass microspheres in the cement, promoting the uniform dispersion of the MOFs-modified hollow glass microspheres in the cement matrix.

[0027] Therefore, the present invention also provides an application of the above MOFs-modified hollow glass microspheres in the preparation of cement-based boards. The cement-based board thus prepared realizes the integration of light weight, heat preservation and sound insulation functions, improves building energy efficiency and comfort, and at the same time enables the cement-based board to have high compressive strength and flexural strength.

[0028] Furthermore, the present invention also provides a cement-based board, which comprises the following raw materials in parts by mass: 50-70 parts of portland cement, 10-20 parts of fly ash, 20-40 parts of the above MOFs-modified hollow glass microspheres, 5-10 parts of polypropylene fiber, 4-10 parts of redispersible latex powder, 0.2-0.5 part of hydroxypropyl methylcellulose ether, 0.4-0.8 part of polyacrylic acid water reducer, and 30-50 parts of deionized water.

[0029] In the present invention, the portland cement, fly ash, polypropylene fiber, redispersible latex powder, hydroxypropyl methylcellulose ether and polyacrylic acid water reducer are all existing materials. Specifically, the portland cement can be 425, 425R, etc. The fly ash can be first-class fly ash, second-class fly ash, etc. The length of the polypropylene fiber can be 6-12 mm. The redispersible latex powder can be vinyl acetate-ethylene copolymer powder, vinyl acetate-ethylene-higher fatty acid vinyl ester terpolymer powder, vinyl acetate-higher fatty acid vinyl ester copolymer powder, etc. The viscosity of the hydroxypropyl methylcellulose ether is preferably 100000-200000 mPa·s.

[0030] After testing, the density of the cement-based board is 460 - 650 g / cm 3 , the compressive strength is 8.5 - 14.5 MPa, the tensile strength is 2.7 - 4 MPa, the thermal conductivity is 0.075 - 0.100 W / (m·K), and the sound insulation is 20 - 30 dB.

[0031] The present invention provides a manufacturing method of the above cement-based board, which includes the following steps: (1) Mix and stir evenly portland cement, fly ash, modified hollow glass microspheres, and fibers to obtain a solid component; (2) Mix and stir evenly redispersible latex powder, hydroxypropyl methylcellulose ether, polyacrylic acid water reducer, and deionized water to obtain a liquid component; (3) Mix and stir evenly the solid component and the liquid component to obtain a mixed slurry; (4) Pour the mixed slurry into a mold, and obtain the finished cement-based board after pressing, demolding, curing, and drying.

[0032] The solid component is evenly mixed by an existing method. For example, in step (1), an electric stirrer can be used to stir at a speed of 750 - 900 rpm for 2 - 5 min to obtain the solid component. The liquid component is evenly mixed by an existing method. For example, in step (2), an electric stirrer can be used to stir at a speed of 900 - 1100 rpm for 1.5 - 3 min to obtain the liquid component. The mixed slurry is evenly mixed by an existing method. For example, in step (3), an electric stirrer can be used to stir at a speed of 1100 - 1300 rpm for 1 - 3 min to obtain the mixed slurry. Thus, it can be seen that the manufacturing method of the cement-based board provided by the present invention is relatively simple and easy to operate.

[0033] Next, through specific embodiments, the technical solutions of the present invention will be further described in detail.

[0034] Examples 1 - 4 MOFs Modified Hollow Glass Microspheres and Their Preparation Methods Each of Examples 1 - 4 of the present invention provides a MOFs modified hollow glass microsphere and its preparation method, and the preparation raw materials of the MOFs modified hollow glass microsphere are shown in Table 1: Table 1 Ingredient Table of MOFs Modified Hollow Glass Microspheres Raw materials Example 1 Example 2 Example 3 Example 4 Hollow glass microspheres HL20 HL20 HL20 HL38 Aminosilane coupling agent KH 170 1.0 wt% KH 170 0.5 wt% KH 170 0.1 wt% KH550 1.0 wt% Carboxylic anhydride Succinic anhydride 1.0 mol / L Succinic anhydride 0.5 mol / L Succinic anhydride 0.1 mol / L Maleic anhydride 1.0 mol / L Catalyst Triethylamine 3 wt% Triethylamine 2 wt% Triethylamine 1 wt% Pyridine 2 wt% Metal salt Zinc nitrate 0.1 mol / L Zinc nitrate 0.06 mol / L Zinc nitrate 0.02 mol / L Cobalt nitrate 0.08 mol / L 2-Methylimidazole 0.5 mol / L 0.3 mol / L 0.1 mol / L 0.4 mol / L

[0035] Please refer to Figure 1 , the preparation methods of the MOFs modified hollow glass microspheres provided in Examples 1 - 3 include the following steps: Pretreatment: 70 g of hollow glass microspheres were successively ultrasonically cleaned with acetone, ethanol, and deionized water for 10 min each to remove impurities on the surface of the microspheres; then the cleaned microspheres were placed in 500 mL of a 0.1 mol / L HCl solution for acid treatment, stirred at 60 °C for 2 h, and then dried in a vacuum drying oven at 60 °C for 12 h to obtain pretreated microspheres; Amino modification: KH170 was mixed with anhydrous toluene to prepare an amino-silane coupling agent solution with the concentration shown in Table 1; 50 g of the pretreated microspheres were taken and added to 400 mL of the KH170 solution, and refluxed at 80 °C for 2 h to modify the hollow glass microspheres with amino groups; then the amino-functionalized microspheres were washed 3 times with toluene and ethanol in sequence and dried at 60 °C to obtain amino-modified microspheres; Carboxylic acid modification: Succinic anhydride was dissolved in anhydrous DMF to prepare a succinic anhydride solution with the concentration shown in Table 1, and triethylamine was added as a catalyst. 30 g of the amino-modified microspheres were immersed in 300 mL of the succinic anhydride solution, and stirred at 80 °C for 8 h under nitrogen protection to complete the carboxylation of the microspheres. Then, they were washed alternately with DMF and ethanol and dried at 60 °C to obtain carboxylic acid-modified microspheres; MOFs modification: First, zinc nitrate was dissolved in methanol to prepare a metal salt solution with the concentration shown in Table 1. Then, 20 g of the carboxylic acid-modified microspheres were added to 400 mL of the zinc nitrate solution, and stirred at 60 °C for 2 h to carry out a coordination reaction. The negatively charged carboxyl groups and the positively charged metal ions Zn 2+ formed stable coordination bonds, providing nucleation sites for the growth of MOFs; then 2-methylimidazole was dissolved in methanol to prepare 400 mL of a 2-methylimidazole solution with the concentration shown in Table 1, and the 2-methylimidazole solution was slowly added, and stirred at room temperature for 6 h to form a MOFs layer; finally, the microspheres were washed 3 times with methanol and vacuum dried at 60 °C to obtain hollow glass microspheres coated with ZIF-8 with a porous structure, that is, ZIF-8 modified hollow glass microspheres.

[0036] The preparation method of the MOFs-modified hollow glass microspheres provided in Example 4 is basically the same as the preparation methods provided in Examples 1 to 3. The main differences are as follows: Amino modification: Using KH550 as the amino-silane coupling agent, the reflux temperature was 70 °C, and the reflux time was 4 h. The other methods were basically the same as the corresponding steps; Carboxylic acid modification: Using maleic anhydride as the carboxylic anhydride, the reaction temperature was 65 °C, and the reaction time was 12 h. The other methods were basically the same as the corresponding steps; MOFs modification: Using cobalt nitrate as the metal salt, a coordination reaction occurred at 80 °C to form metal ions Co 2+A stable coordination bond is formed, and the remaining methods are basically the same as the corresponding steps; finally, hollow glass microspheres coated with ZIF-67 with a porous structure are prepared, that is, ZIF-67 modified hollow glass microspheres.

[0037] Examples 5 to 10 Cement-based boards and their preparation methods Examples 5 to 10 each provide a cement-based board with heat insulation and sound insulation functions and a preparation method thereof. The cement-based boards provided in each example include the following raw materials in parts by mass: 50 to 70 parts of 425 Portland cement, 10 to 20 parts of first-class fly ash, 20 to 40 parts of MOFs modified hollow glass microspheres shown in Table 2, 5 to 10 parts of polypropylene fibers about 6 mm long, 4 to 10 parts of vinyl acetate-ethylene copolymer powder, 0.2 to 0.5 parts of hydroxypropyl methyl cellulose ether with a viscosity of 100000 mPa·s, 0.4 to 0.8 parts of polyacrylic acid water reducer, and 30 to 50 parts of deionized water. Specifically, the raw material ratios of the cement-based boards provided in each example are shown in Table 2.

[0038] Table 2 Raw material mass ratio table of cement-based boards Raw materials Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 425 Portland cement 50 70 50 50 50 50 Class I fly ash 20 10 10 20 20 20 MOFs modified hollow glass microspheres Example 130 Example 120 Example 140 Example 230 Example 330 Example 430 Polypropylene fiber 7 7 7 5 8 7 Vinyl acetate-ethylene copolymer powder 6 6 6 6 5 6 Hydroxypropyl methyl cellulose ether 0.4 0.4 0.4 0.3 0.3 0.4 Polyacrylic acid water reducer 0.6 0.6 0.6 0.7 0.5 0.6 Water 40 30 50 37 42 40 The preparation methods of the heat insulation and sound insulation cement-based boards provided in Examples 5 to 10 include the following steps: (1) Mix Portland cement, fly ash, modified hollow glass microspheres, and polypropylene fibers, and use an electric stirrer to stir at a speed of 800 rpm for 3 min to obtain a solid component; (2) Add redispersible latex powder, hydroxypropyl methyl cellulose ether, and polyacrylic acid water reducer to deionized water, and use an electric stirrer to stir at a speed of 1000 rpm for 2 min to obtain a liquid component; (3) Add the solid component prepared in step (1) to the liquid component prepared in step (2), and use an electric stirrer to stir at a speed of 1200 rpm for 2 min to obtain a mixed slurry; (4) Uniformly spread the mixed slurry prepared in step (3) in the mold of a molding press, carry out pressing and molding, and then carry out demolding, curing, and drying to obtain a heat insulation and sound insulation cement-based board.

[0039] Comparative Example 1 This comparative example provides a heat insulation and sound insulation cement-based board, and its preparation method is basically the same as that of the cement-based board obtained in Example 5. The main difference is that: compared with Example 1, the "carboxylic acid modification" step is omitted when modifying the hollow glass microspheres in this comparative example.

[0040] Comparative Example 2 This comparative example provides a heat-insulating and sound-insulating cement-based board, and its preparation method is basically the same as that of the cement-based board obtained in Example 5. The main difference is that the microbeads used in this comparative example are hollow glass microbeads without any modification treatment.

[0041] Comparative Example 3 This comparative example provides a heat-insulating and sound-insulating cement-based board, and its preparation method is basically the same as that of the cement-based board obtained in Example 5. The main difference is that in this comparative example, unmodified hollow glass microbeads, KH170, succinic anhydride, and MOFs are used as raw materials for the board, and the total mass of the above four raw materials in this comparative example is the same as the mass of the corresponding raw materials used in Example 1.

[0042] Comparative Example 4 This comparative example provides a heat-insulating and sound-insulating cement-based board, and its preparation method is basically the same as that of the cement-based board obtained in Example 5. The main difference is that in this comparative example, KH170-modified microbeads with the same mass as in Example 1 are used to replace MOF-modified hollow glass microbeads, and MOFs prepared with the same raw materials and methods as in Example 1 are used as direct components of the board. That is, the mass of the MOF component in this comparative example is the same as the mass of the MOFs used for modifying hollow glass microbeads in Example 1.

[0043] Performance verification The following tests are carried out on parameters such as the compressive strength, flexural strength, thermal conductivity, and sound insulation of the heat-insulating and sound-insulating cement-based boards obtained in Examples 5 to 10 and Comparative Examples 1 to 4. The test results are shown in Table 3.

[0044] Among them, the test methods for density, compressive strength, and flexural strength: The density, compressive strength, and flexural strength are tested according to "Test Methods for Inorganic Rigid Thermal Insulation Products" GB / T5486-2008.

[0045] The test method for thermal conductivity: The thermal conductivity is tested according to "Determination of Steady-State Thermal Resistance and Related Characteristics of Thermal Insulation Materials - Guarded Hot Plate Method" GB / T10294-2008.

[0046] The test method for sound insulation: The sound insulation is determined according to "Acoustics - Measurement of Sound Insulation of Buildings and Building Elements" GB / T19889.

[0047] Table 3 Performance test results of heat-insulating and sound-insulating cement-based boards Sample <![CDATA[Density / (g / cm 3 )]]> Compressive strength / MPa Flexural strength / MPa Thermal conductivity / W / (m·K) Sound insulation / dB Example 5 580 10.5 3.4 0.081 26 Example 6 645 14.5 3.8 0.098 25 Example 7 470 8.7 2.9 0.078 28 Example 8 565 9.8 3.2 0.084 25 Example 9 540 9.4 3.0 0.086 23 Example 10 630 10.0 3.3 0.083 24 Comparative Example 1 530 8.0 2.4 0.091 21 Comparative Example 2 520 6.8 1.9 0.093 20 Comparative Example 3 585 7.2 2.1 0.097 24 Comparative Example 4 575 7.0 2.0 0.096 24 It can be seen from the test results shown in Table 3 that: 1) Generating an MOF layer on the surface of hollow glass microbeads is beneficial to improving the compressive strength, tensile strength, heat insulation performance, and sound insulation performance of the cement-based board. The density of the finally obtained cement-based board is 470 - 645 g / cm 3, compressive strength of 8.7 - 14.5 MPa, flexural strength of 2.9 - 3.8 MPa, thermal conductivity of 0.078 - 0.098 W / (m·K), and sound insulation of 23 - 28 dB; 2) It can be seen from Examples 5 - 7 that the more the addition amount of MOFs - modified hollow glass microspheres, the better the heat insulation and sound insulation effects of the cement - based board, but the compressive and flexural strengths decrease; 3) By combining Example 5 and Comparative Examples 1 - 2, it can be seen that compared with unmodified microspheres, in Example 5, MOFs - modified hollow glass microspheres are used, and the strength, heat insulation and sound insulation performance of the prepared board are improved; when modifying the microspheres, the treatment steps of carboxylic acid modification are significantly better than those of microspheres without carboxyl treatment in improving various properties of the cement - based board. This shows that: the coordination ability of carboxyl is stronger than that of amino, effectively fixing metal ions on the surface of the microspheres and enabling the stable and uniform growth of MOFs along the surface of the microspheres; 4) From the experimental data of Example 5 and Comparative Examples 3 and 4, it can be seen that when MOFs are loaded on the surface of microspheres and added to the cement - based board, the density of the cement - based board remains basically unchanged, and other properties are improved to varying degrees. This is mainly because: MOFs form a uniform porous coating on the surface of the microspheres. Combining with the hollow structure of the hollow glass microspheres itself, a double - pore structure can be constructed, significantly increasing the thermal resistance and inhibiting heat conduction. At the same time, the two work together to broaden the sound - insulation frequency band and enhance the sound - insulation performance. In addition, the porous structure and hydroxyl groups on the surface of MOFs can better combine with cement, resulting in an increase in the compressive and flexural strengths of the cement - based board.

[0048] Therefore, the raw materials of the cement - based board provided in the embodiments of the present invention contain MOFs - modified hollow glass microspheres, making the prepared cement - based board not only have excellent heat insulation and sound - insulation functions, but also have relatively high compressive strength and flexural strength, providing an innovative solution for the collaborative optimization of high - efficiency energy conservation and structural safety in green buildings.

[0049] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that: it is still possible to modify the specific implementation manners of the present invention or perform equivalent substitution on some technical features; without departing from the spirit of the technical solutions of the present invention, they should all be covered within the scope of the technical solutions claimed by the present invention.

Claims

1. A preparation method of MOFs-modified hollow glass microspheres, comprising the following steps: Amino modification: Modify the hollow glass microspheres with an amino silane coupling agent to obtain amino-modified microspheres; Carboxylic acid modification: Treat the amino-modified microspheres with a carboxylic anhydride to obtain carboxylic acid-modified microspheres; MOFs modification: Using metal salts and 2-methylimidazole as raw materials, sequentially modify the carboxylic acid-modified microspheres to form a MOFs layer on the surface of the hollow glass microspheres.

2. The preparation method according to claim 1, characterized in that, The step of amino modification includes: Immerse the hollow glass microspheres in an amino silane coupling agent solution with a concentration of 0.1-1.0 wt% to carry out an amination reaction to obtain amino-modified microspheres, wherein the amination reaction temperature is 50-90 °C and the reaction time is 2-4 h.

3. The preparation method according to claim 1 or 2, characterized in that, The true density of the hollow glass microspheres is 0.18 to 0.40 g / cm 3 , and the particle size is 40 to 65 μm.

4. The preparation method according to claim 1 or 2, characterized in that The step of carboxylic acid modification includes: Immerse the amino-modified microspheres in a carboxylic anhydride solution with a concentration of 0.1-1.0 mol / L, and carry out an amidation reaction under the action of a catalyst with a concentration of 1-3 wt% to obtain carboxylic acid-modified microspheres.

5. The preparation method according to claim 4, characterized in that, The amidation reaction temperature is 60-80 °C, the amidation reaction time is 6-12 h, the carboxylic anhydride is succinic anhydride, maleic anhydride or glutaric anhydride, and the catalyst is triethylamine or pyridine.

6. The preparation method according to claim 1 or 2, characterized in that, The step of MOFs modification includes: First, immerse the carboxylic acid-modified microspheres in a metal salt solution with a concentration of 0.02-0.1 mol / L for a coordination reaction; then add a 2-methylimidazole solution with a concentration of 0.1-0.5 mol / L for reaction to form a MOFs layer on the surface of the hollow glass microspheres, and obtain the MOFs-modified hollow glass microspheres.

7. The preparation method according to claim 6, characterized in that, The step of MOFs modification includes: First, immerse the carboxylic acid-modified microspheres in the metal salt solution and stir at 60-80 °C for 2-4 h; then add the 2-methylimidazole organic ligand solution and stir at room temperature for 6-10 h to form a MOFs layer. After washing and drying, the MOFs-modified hollow glass microspheres can be obtained; wherein the metal salt is zinc nitrate or cobalt nitrate.

8. A MOFs-modified hollow glass microsphere prepared by the preparation method according to any one of claims 1-7.

9. An application of the MOFs-modified hollow glass microsphere according to claim 8 in the preparation of cement-based boards.

10. A cement-based board, the raw materials of which include the following parts by mass: 50-70 parts of portland cement, 10-20 parts of fly ash, 20-40 parts of the MOFs-modified hollow glass microspheres according to claim 8, 5-10 parts of polypropylene fiber, 4-10 parts of redispersible latex powder, 0.2-0.5 part of hydroxypropyl methyl cellulose ether, 0.4-0.8 part of polyacrylic acid water reducer, and 30-50 parts of deionized water.

11. A manufacturing method of a cement-based board according to claim 10, comprising the following steps: (1) Mix portland cement, fly ash, modified hollow glass microspheres, and polypropylene fiber evenly to obtain a solid component; (2) Mix the redispersible polymer powder, hydroxypropyl methylcellulose ether, polyacrylic acid water reducer and deionized water evenly to obtain a liquid component; (3) Mix the solid component and the liquid component evenly to obtain a mixed slurry; (4) Pour the mixed slurry into a mold, and obtain a finished cement-based board after pressing, demolding, curing and drying.

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