Light magnesium sulfate plate with mute function and preparation process thereof

Abstract

The application discloses a light magnesium sulfate plate with a mute function and a preparation process thereof, and relates to the technical field of magnesium sulfate plates. The structure of the light magnesium sulfate plate comprises, from top to bottom, a nanofiber felt layer 1, a magnesium sulfate slurry layer 2, a polyurethane foam layer B 3, a magnesium sulfate slurry layer 4, a polyurethane foam layer A 5, a magnesium sulfate slurry layer 6 and a nanofiber felt layer 7. The preparation method of the light magnesium sulfate plate comprises the following steps: preparing polyurethane foam A, preparing polyurethane foam B, preparing polyurethane nanofiber cloth, preparing magnesium sulfate slurry, preparing a plate, curing, demolding, secondary curing, cutting and obtaining the light magnesium sulfate plate.

Description

Technical Field

[0001] This invention relates to the field of magnesium sulfate board technology, specifically a lightweight magnesium sulfate board with sound-silencing function and its preparation process. Background Technology

[0002] In the design and manufacture of building panels, traditionally, to improve the strength and load-bearing capacity of the panels, the thickness of the panels or the use of high-density, high-strength materials are typically increased. For example, materials such as steel or reinforced concrete are often used as building panels to meet structural strength requirements. However, with the increase in thickness and density, these materials bring some significant drawbacks, such as increasing the overall self-weight of the building, leading to excessive structural loads, increasing construction difficulty, and occupying more space.

[0003] In addition, some lightweight materials, such as plywood or blockboard, exist in the market. While these materials are lightweight and easy to handle and install, their strength and load-bearing capacity are relatively weak. Furthermore, due to the properties of wood, they have poor fire and moisture resistance, making them unsuitable for humid or high-temperature environments. At the same time, these materials typically lack good sound insulation, generating significant noise when people walk on their surfaces, making them unsuitable for building environments where quietness and comfort are paramount.

[0004] Therefore, it is of great significance to develop a magnesium sulfate board that combines lightweight, high strength, and sound insulation properties. Summary of the Invention

[0005] The purpose of this invention is to provide a lightweight magnesium sulfate sheet with a sound-silencing function and its preparation process, so as to solve the problems raised in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A lightweight magnesium sulfate board with sound-absorbing function, the structure of the lightweight magnesium sulfate board from top to bottom includes: nanofiber felt layer 1, magnesium sulfate slurry layer 2, polyurethane foam layer B3, magnesium sulfate slurry layer 4, polyurethane foam layer A5, magnesium sulfate slurry layer 6, and nanofiber felt layer 7.

[0008] Furthermore, the nanofiber felt layer 1 and nanofiber felt layer 7 are made of polyurethane nanofiber cloth; the preparation method of the polyurethane nanofiber cloth includes the following steps: adding polyurethane particles to a mixed solution of tetrahydrofuran and N,N-dimethylformamide, stirring evenly, electrospinning, and vacuum drying to obtain polyurethane nanofiber cloth.

[0009] Furthermore, in the preparation process of polyurethane nanofiber cloth, the electrospinning parameters include: applied voltage of 18kV, needle tip to electrode distance of 15cm, and feed rate of 0.5mL / h.

[0010] Furthermore, in the mixed solution of tetrahydrofuran and N,N-dimethylformamide, the volume ratio of tetrahydrofuran to N,N-dimethylformamide is 1:1.

[0011] Furthermore, the magnesium sulfate slurry layer 2, magnesium sulfate slurry layer 4, and magnesium sulfate slurry layer 6 are laid with magnesium sulfate slurry; the preparation method of the magnesium sulfate slurry includes the following steps: mixing magnesium sulfate solution and magnesium oxysulfate modifier evenly, adding lignin fiber and stirring evenly, then adding magnesium oxide, organic fiber, active filler, and foamed inorganic material in sequence, stirring evenly to obtain magnesium sulfate slurry;

[0012] Furthermore, the magnesium sulfate slurry comprises the following components in parts by mass: 80-100 parts magnesium sulfate solution, 0.3-1.6 parts magnesium sulfate oxysulfate modifier, 5-10 parts lignin fiber, 0.5-1.5 parts organic fiber, 80-100 parts magnesium oxide, 12-20 parts active filler, and 4-15 parts foamed inorganic material.

[0013] Furthermore, the magnesium sulfate solution comprises magnesium sulfate heptahydrate;

[0014] Furthermore, the organic fiber includes any one of polypropylene fiber and polyolefin fiber;

[0015] Furthermore, the magnesium oxide includes lightly calcined magnesium oxide;

[0016] Furthermore, the active filler includes any one of silica fume and fly ash;

[0017] Furthermore, the foamed inorganic material includes any one of expanded perlite, expanded vermiculite, and ceramic sand.

[0018] Furthermore, polyurethane foam layer B3 is formed by laying polyurethane foam B; the preparation method of polyurethane foam B includes the following steps:

[0019] S1: Add manganese nitrate tetrahydrate and cobalt nitrate tetrahydrate to ethylene glycol and stir until homogeneous. Add glycerin, preheat to 80-82℃, and stir for 20-30 min until manganese nitrate tetrahydrate and cobalt nitrate tetrahydrate are completely dissolved. Cool the solution to 30-32℃, add 2-propanal and triethylamine, and stir for 20-30 min until a brown gel is formed. Transfer the brown gel to a muffle furnace, heat to 250-255℃, burn for 30-40 min, and grind to obtain MnCo2O4 nanoparticles.

[0020] Furthermore, in the preparation process of MnCo2O4 nanoparticles, the molar ratio of manganese nitrate tetrahydrate to cobalt nitrate tetrahydrate is 1:2.

[0021] S2: Multi-walled carbon nanotubes were added to a mixture of concentrated sulfuric acid and concentrated nitric acid, ultrasonically dispersed, heated to 140-145℃, acidified for 55-60 min, washed with deionized water, filtered, and dried to obtain acidified multi-walled carbon nanotubes; N,N'-dicyclohexylcarbodiimide was added to N,N-dimethylformamide, stirred evenly, 4-dimethylaminopyridine and acrylic acid were added, stirred evenly, and under a nitrogen atmosphere, the N,N-dimethylformamide solution of acidified multi-walled carbon nanotubes was added, heated to 85-86℃ and reacted for 1 day, washed with deionized water, filtered, and dried to obtain carboxylated multi-walled carbon nanotubes; Carboxylated multi-walled carbon nanotubes were added to N,N-dimethylformamide, ultrasonically dispersed, and under a nitrogen atmosphere, polyethylenepolyamine was added, reacted at room temperature for 1 day, washed with deionized water, filtered, and dried to obtain amination-modified multi-walled carbon nanotubes;

[0022] Furthermore, in the preparation process of acidified multi-walled carbon nanotubes, the volume ratio of concentrated sulfuric acid to concentrated nitric acid in the mixed solution of concentrated sulfuric acid and concentrated nitric acid is 6:4.

[0023] Furthermore, in the preparation of carboxylated multi-walled carbon nanotubes, the mass ratio of acidified multi-walled carbon nanotubes: N,N'-dicyclohexylcarbodiimide: 4-dimethylaminopyridine: acrylic acid is (5-10): (20-40): (1.5-3): (50-100).

[0024] Furthermore, in the preparation process of amino-modified multi-walled carbon nanotubes, the mass ratio of carboxylated multi-walled carbon nanotubes to polyethylene polyamine is 1:2; the relative molecular weight of the polyethylene polyamine is 60-100.

[0025] S3: Add polyol B, foaming agent, crosslinking agent, catalyst, surfactant, and composite nanomaterials to a container, disperse by ultrasonication, add isocyanate, stir evenly, pour into a mold, and let stand to obtain polyurethane foam intermediate B; place polyurethane foam intermediate B in a sealed container and foam dynamically with supercritical carbon dioxide to obtain polyurethane foam B.

[0026] Furthermore, in the polyurethane foam intermediate B, the components, by mass fraction, include: 80-100 parts of polyol B, 0.6-0.8 parts of blowing agent, 4-5 parts of crosslinking agent, 0.9-1 part of catalyst, 1.3-1.4 parts of surfactant, 1.0-1.2 parts of composite nanomaterials, and 55-60 parts of isocyanate.

[0027] Furthermore, the specific operation of the dynamic supercritical carbon dioxide foaming includes the following steps: rinsing the container with low-pressure carbon dioxide to remove air, saturating it at 12MPa and 110℃ for 2-2.5h, opening the exhaust valve, controlling the critical carbon dioxide flow rate to 38mL / min, maintaining a stable flow of carbon dioxide through the container and stabilizing the container pressure, and depressurizing to atmospheric pressure within 3s.

[0028] Furthermore, the polyol B includes PPG6000;

[0029] Furthermore, the foaming agent includes deionized water;

[0030] Furthermore, the crosslinking agent includes diethanolamine;

[0031] Furthermore, the catalyst includes any one or more of DABCO33LV, DABCOBL11, and DBTDL;

[0032] Furthermore, the catalyst comprises a combination of DABCO33LV, DABCOBL11, and DBTDL, with a mass ratio of DABCO33LV:DABCOBL11:DBTDL of 0.72:0.08:0.1.

[0033] Furthermore, the surfactant includes L-3002;

[0034] Furthermore, the isocyanate includes CG-3701S with an NCO index of 1.0;

[0035] Furthermore, the composite nanomaterial comprises a combination of amination-modified multi-walled carbon nanotubes and MnCo2O4 nanoparticles, with a mass ratio of amination-modified multi-walled carbon nanotubes to MnCo2O4 nanoparticles of (40-50):(1-2).

[0036] Furthermore, the polyurethane foam layer A5 is formed by laying polyurethane foam A; the preparation method of the polyurethane foam A includes the following steps:

[0037] PET microspheres were placed in a sealed container and foamed with supercritical carbon dioxide to obtain auxiliary foaming microspheres. Polyol A, foaming agent, crosslinking agent, catalyst, surfactant, and auxiliary foaming microspheres were added to the container, ultrasonically dispersed, isocyanate was added, stirred evenly, injected into a mold, and allowed to stand to obtain polyurethane foam intermediate A. Polyurethane foam intermediate A was placed in a sealed container and foamed with dynamic supercritical carbon dioxide to obtain polyurethane foam A.

[0038] Furthermore, the specific operation of the supercritical carbon dioxide foaming includes the following steps: rinsing the container with low-pressure carbon dioxide to remove air, saturating it in an environment of 9MPa and 40℃ for 4-5 hours, rapidly increasing the temperature and pressure to 20MPa and 240-240.5℃, depressurizing it to atmospheric pressure within 3-5 seconds, and drying it at 160℃ for 4 hours.

[0039] Furthermore, in the polyurethane foam intermediate A, the proportions of each component by mass fraction include: 80-100 parts of polyol A, 0.6-0.8 parts of foaming agent, 4-5 parts of crosslinking agent, 0.9-1 part of catalyst, 1.3-1.4 parts of surfactant, 20-30 parts of auxiliary foaming microspheres, and 55-60 parts of isocyanate.

[0040] Furthermore, the polyol A comprises PPG6000 and TF400, with a mass ratio of PPG6000 to TF400 of 100 to 20.76.

[0041] Furthermore, the polyurethane foam intermediate A contains the same components as polyurethane foam intermediate B, except for polyol A.

[0042] Furthermore, in the preparation process of polyurethane foam A, the specific steps of dynamic supercritical carbon dioxide foaming are the same as those of polyurethane foam B.

[0043] A process for preparing a lightweight magnesium sulfate board with sound-absorbing function includes the following steps: preparing polyurethane foam A, preparing polyurethane foam B, preparing polyurethane nanofiber cloth, preparing magnesium sulfate slurry, preparing the board, curing, demolding, secondary curing, cutting, and obtaining the lightweight magnesium sulfate board.

[0044] Furthermore, the steps for preparing the board include: forming a nanofiber felt layer 7 using polyurethane nanofiber cloth as a base layer; laying magnesium sulfate slurry on the nanofiber felt layer 7 to form a magnesium sulfate slurry layer 6; laying polyurethane foam A on the magnesium sulfate slurry layer 6 to form a polyurethane foam layer A5; laying magnesium sulfate slurry on the polyurethane foam layer A5 to form a magnesium sulfate slurry layer 4; laying polyurethane foam B on the magnesium sulfate slurry layer 4 to form a polyurethane foam layer B3; laying magnesium sulfate slurry on the polyurethane foam layer B3 to form a magnesium sulfate slurry layer 2; and laying polyurethane nanofiber cloth on the magnesium sulfate slurry layer 2 to form a nanofiber felt layer 1.

[0045] Compared with the prior art, the beneficial effects of the present invention are:

[0046] 1. This invention prepares polyurethane nanofiber cloth through electrospinning, using it as a nanofiber felt layer. Sound absorption is improved by adding micron- and nano-scale voids. These voids act as sound traps, increasing the surface area for sound wave interaction. The nanofibers form a multilayer structure where sound waves must pass through different material layers, losing energy at each interface. This process enhances sound attenuation, making the foam more effective at reducing noise.

[0047] 2. This invention uses PET microspheres, after foaming, as an auxiliary foaming agent to prepare polyurethane foam A through secondary foaming with supercritical carbon dioxide. This foaming agent helps form a fine honeycomb structure in polyurethane foam and other materials. The high pressure and controlled expansion during the foaming process produce a uniform closed-cell foam structure. When supercritical carbon dioxide penetrates the polymer matrix and is released under controlled conditions, it forms microbubbles. These bubbles improve thermal insulation by reducing heat transfer, and the fine honeycomb structure increases sound absorption due to the scattering and dissipation of sound waves within the foam matrix.

[0048] 3. This invention introduces amination-modified multi-walled carbon nanotubes and MnCo2O4 nanoparticles as composite nanoparticles into polyurethane foam, and prepares polyurethane foam B through dynamic supercritical carbon dioxide secondary foaming. On the one hand, by controlling the amount of amination-modified multi-walled carbon nanotubes added and the molecular weight of polyethylenepolyamines in the preparation process of amination-modified multi-walled carbon nanotubes, the pore size distribution and apparent density of polyurethane foam B can be controlled. On the other hand, the introduction of composite nanoparticles into polyurethane foam improves sound absorption and mechanical strength, and works synergistically with polyurethane foam A. Because the front layer (polyurethane foam A) has highly open porosity to dissipate high-frequency waves, and the back layer (polyurethane foam B) has small cavities to diffract low-frequency waves, the sound absorption coefficient is greatly improved. In the dynamic supercritical carbon dioxide foaming method, the intramolecular stress relaxation generated by the supercritical carbon dioxide flow field induces molecular chain distortion on the surface of the pores, forming a wrinkled structure, which enhances the internal sound wave scattering. The magnetic properties of MnCo2O4 nanoparticles interact with the foam matrix to generate vibration damping, thereby achieving the purpose of enhancing the sound absorption coefficient by disrupting the transmission of sound waves.

[0049] 4. The magnesium sulfate slurry of the present invention is the bonding layer between the layers. By adding foamed inorganic materials, lignin fibers, organic fibers and active fillers to it, the prepared magnesium sulfate board can reduce the density of the board to achieve the purpose of lightweight, while having good impact strength and flexural strength. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of the structure of a lightweight magnesium sulfate sheet with a sound-silencing function according to the present invention.

[0051] Among them, 1. Nanofiber felt layer, 2. Magnesium sulfate slurry layer, 3. Polyurethane foam layer B, 4. Magnesium sulfate slurry layer, 5. Polyurethane foam layer A, 6. Magnesium sulfate slurry layer, 7. Nanofiber felt layer. Detailed Implementation

[0052] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0053] In the following examples, the PET microspheres were CB602, purchased from Far East Industries (Shanghai) Co., Ltd.; PPG6000 specifications: OH value: 28±2, Mw: 6000, average functional groups: 3, 1200cps (25℃); TF400 specifications: OH value: 400±15, Mw: 400, average functional groups: 3, 350cps (25℃); DABCO33LV and DABCOBL11 were purchased from Air Products, Inc.; silicone surfactant L-3002 was purchased from Momentive, Inc.; CG-3701S specifications: %NCO: 37, 15cps (25℃); polyurethane particles specifications: Mw: 1100000, purchased from Cardio Tech, Japan; the remaining raw materials were commercially available.

[0054] The following embodiments describe a method for preparing MnCo2O4 nanoparticles, comprising the following steps: adding manganese nitrate tetrahydrate and cobalt nitrate tetrahydrate in a molar ratio of 1:2 to ethylene glycol, stirring until homogeneous, preparing a 0.025M solution, adding 20 mL of glycerol, preheating to 80°C, stirring for 20 min until the manganese nitrate tetrahydrate and cobalt nitrate tetrahydrate are completely dissolved, cooling the solution to 30°C, adding 8 mL of 2-propanal and 7 mL of triethylamine, stirring for 20 min until a brown gel is formed, transferring the brown gel to a muffle furnace, heating to 250°C, burning for 30 min, and grinding to obtain MnCo2O4 nanoparticles.

[0055] The following examples illustrate the preparation method of amination-modified multi-walled carbon nanotubes, comprising the following steps: adding 10g of multi-walled carbon nanotubes to a mixture of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 6:4, ultrasonically dispersing, heating to 140°C, acidifying for 55 min, washing with deionized water, filtering, and drying to obtain acidified multi-walled carbon nanotubes; adding 20g of N,N'-dicyclohexylcarbodiimide to N,N-dimethylformamide, stirring evenly, and adding 1.5g of 4-dimethylaminopyridine and 5g of... 0g of acrylic acid was stirred until homogeneous. Under a nitrogen atmosphere, 5g of an N,N-dimethylformamide solution containing acidified multi-walled carbon nanotubes was added. The mixture was heated to 85°C and reacted for 1 day. After washing with deionized water, the solution was filtered and dried to obtain carboxylated multi-walled carbon nanotubes. 2g of carboxylated multi-walled carbon nanotubes were added to N,N-dimethylformamide and ultrasonically dispersed. Under a nitrogen atmosphere, 4g of polyethylenepolyamine was added and reacted at room temperature for 1 day. After washing with deionized water, the solution was filtered and dried to obtain amination-modified multi-walled carbon nanotubes. The molecular weight of the polyethylenepolyamine was 100.

[0056] In the following embodiments, the preparation method of polyurethane nanofiber cloth includes the following steps: adding polyurethane particles to a mixed solution of tetrahydrofuran and N,N-dimethylformamide in a volume ratio of 1:1, stirring evenly, electrospinning, and vacuum drying to obtain polyurethane nanofiber cloth. The electrospinning parameters include: an applied voltage of 18 kV, a needle tip to electrode distance of 15 cm, and a feed rate of 0.5 mL / h.

[0057] In the following embodiments, the preparation method of the magnesium sulfate slurry includes the following steps: mixing 100 parts of magnesium sulfate solution and 1 part of magnesium oxysulfate modifier evenly, adding 5 parts of lignin fiber and stirring evenly, then adding 100 parts of magnesium oxide, 1 part of organic fiber, 12 parts of active filler, and 10 parts of foamed inorganic material in sequence, stirring evenly to obtain magnesium sulfate slurry.

[0058] Example 1: A method for preparing a lightweight magnesium sulfate board with sound-absorbing function: S1: PET microspheres are placed in a sealed container and foamed with supercritical carbon dioxide to obtain auxiliary foaming microspheres; 1000 parts of polyol A, 0.7 parts of foaming agent, 4 parts of crosslinking agent, 0.9 parts of catalyst, 1.3 parts of surfactant, and 20 parts of auxiliary foaming microspheres are added to the container, ultrasonically dispersed, 55 parts of isocyanate are added, stirred evenly, injected into a mold, and allowed to stand to obtain polyurethane foam intermediate A; polyurethane foam intermediate A is placed in a sealed container and foamed with dynamic supercritical carbon dioxide to obtain polyurethane foam A;

[0059] S2: Add 100 parts of polyol B, 0.7 parts of foaming agent, 4 parts of crosslinking agent, 0.9 parts of catalyst, 1.3 parts of surfactant, and 1 part of composite nanomaterial to a container, disperse by ultrasonication, add isocyanate, stir evenly, pour into a mold, and let stand to obtain polyurethane foam intermediate B; place polyurethane foam intermediate B in a sealed container and foam dynamically with supercritical carbon dioxide to obtain polyurethane foam B; wherein, in the composite nanomaterial, the mass ratio of amino-modified multi-walled carbon nanotubes:MnCozO:nanoparticles is 50:1;

[0060] S3: Prepare polyurethane nanofiber cloth, prepare magnesium sulfate slurry, prepare board, cure, demold, perform secondary curing, cut, and obtain lightweight magnesium sulfate board.

[0061] Example 2: A method for preparing a lightweight magnesium sulfate board with sound-silencing function: The preparation method of amination-modified multi-walled carbon nanotubes includes the following steps: 10g of multi-walled carbon nanotubes are added to a mixture of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 6:4, ultrasonically dispersed, heated to 140℃, acidified for 55min, washed with deionized water, filtered, and dried to obtain acidified multi-walled carbon nanotubes; 20g of N,N'-dicyclohexylcarbodiimide is added to N,N-dimethylformamide, stirred evenly, and then 1.5g of... 4-Dimethylaminopyridine and 50g of acrylic acid were stirred until homogeneous. Under a nitrogen atmosphere, 5g of an acidified multi-walled carbon nanotube solution in N,N-dimethylformamide was added, and the mixture was heated to 85℃ and reacted for 1 day. The mixture was then washed with deionized water, filtered, and dried to obtain carboxylated multi-walled carbon nanotubes. 2g of carboxylated multi-walled carbon nanotubes were added to N,N-dimethylformamide and ultrasonically dispersed. Under a nitrogen atmosphere, 4g of polyethylenepolyamine was added, and the mixture was reacted at room temperature for 1 day. The mixture was then washed with deionized water, filtered, and dried to obtain amination-modified multi-walled carbon nanotubes. The molecular weight of the polyethylenepolyamine was 60.

[0062] S1: PET microspheres are placed in a sealed container and foamed with supercritical carbon dioxide to obtain auxiliary foaming microspheres; 1000 parts of polyol A, 0.7 parts of foaming agent, 4 parts of crosslinking agent, 0.9 parts of catalyst, 1.3 parts of surfactant, and 20 parts of auxiliary foaming microspheres are added to the container, ultrasonically dispersed, 55 parts of isocyanate are added, stirred evenly, injected into a mold, and allowed to stand to obtain polyurethane foam intermediate A; polyurethane foam intermediate A is placed in a sealed container and foamed with dynamic supercritical carbon dioxide to obtain polyurethane foam A;

[0063] S2: Add 100 parts of polyol B, 0.7 parts of foaming agent, 4 parts of crosslinking agent, 0.9 parts of catalyst, 1.3 parts of surfactant, and 1 part of composite nanomaterial to a container, disperse by ultrasonication, add isocyanate, stir evenly, pour into a mold, and let stand to obtain polyurethane foam intermediate B; place polyurethane foam intermediate B in a sealed container and foam dynamically with supercritical carbon dioxide to obtain polyurethane foam B; wherein, in the composite nanomaterial, the mass ratio of amino-modified multi-walled carbon nanotubes:MnCozO:nanoparticles is 50:1;

[0064] S3: Prepare polyurethane nanofiber cloth, prepare magnesium sulfate slurry, prepare board, cure, demold, perform secondary curing, cut, and obtain lightweight magnesium sulfate board.

[0065] Example 3: A method for preparing a lightweight magnesium sulfate board with sound-absorbing function: S1: PET microspheres are placed in a sealed container and foamed with supercritical carbon dioxide to obtain auxiliary foaming microspheres; 1000 parts of polyol A, 0.7 parts of foaming agent, 4 parts of crosslinking agent, 0.9 parts of catalyst, 1.3 parts of surfactant, and 30 parts of auxiliary foaming microspheres are added to the container, ultrasonically dispersed, 55 parts of isocyanate are added, stirred evenly, injected into a mold, and allowed to stand to obtain polyurethane foam intermediate A; polyurethane foam intermediate A is placed in a sealed container and foamed with dynamic supercritical carbon dioxide to obtain polyurethane foam A;

[0066] S2: Add 100 parts of polyol B, 0.7 parts of foaming agent, 4 parts of crosslinking agent, 0.9 parts of catalyst, 1.3 parts of surfactant, and 1 part of composite nanomaterial to a container, disperse by ultrasonication, add isocyanate, stir evenly, pour into a mold, and let stand to obtain polyurethane foam intermediate B; place polyurethane foam intermediate B in a sealed container and foam dynamically with supercritical carbon dioxide to obtain polyurethane foam B; wherein, in the composite nanomaterial, the mass ratio of amino-modified multi-walled carbon nanotubes:MnCozO:nanoparticles is 50:1;

[0067] S3: Prepare polyurethane nanofiber cloth, prepare magnesium sulfate slurry, prepare board, cure, demold, perform secondary curing, cut, and obtain lightweight magnesium sulfate board.

[0068] The preparation method of the amino-modified multi-walled carbon nanotubes is the same as that in Example 2.

[0069] Example 4: A method for preparing a lightweight magnesium sulfate board with sound-absorbing function: S1: PET microspheres are placed in a sealed container and foamed with supercritical carbon dioxide to obtain auxiliary foaming microspheres; 1000 parts of polyol A, 0.7 parts of foaming agent, 4 parts of crosslinking agent, 0.9 parts of catalyst, 1.3 parts of surfactant, and 30 parts of auxiliary foaming microspheres are added to the container, ultrasonically dispersed, 55 parts of isocyanate are added, stirred evenly, injected into a mold, and allowed to stand to obtain polyurethane foam intermediate A; polyurethane foam intermediate A is placed in a sealed container and foamed with dynamic supercritical carbon dioxide to obtain polyurethane foam A;

[0070] S2: Add 100 parts of polyol B, 0.7 parts of foaming agent, 4 parts of crosslinking agent, 0.9 parts of catalyst, 1.3 parts of surfactant, and 1.2 parts of composite nanomaterials to a container, disperse by ultrasonication, add isocyanate, stir evenly, pour into a mold, and let stand to obtain polyurethane foam intermediate B; place polyurethane foam intermediate B in a sealed container and foam dynamically with supercritical carbon dioxide to obtain polyurethane foam B; wherein, in the composite nanomaterials, the mass ratio of amino-modified multi-walled carbon nanotubes:MnCozO:nanoparticles is 50:1;

[0071] S3: Prepare polyurethane nanofiber cloth, prepare magnesium sulfate slurry, prepare board, cure, demold, perform secondary curing, cut, and obtain lightweight magnesium sulfate board.

[0072] The preparation method of the amino-modified multi-walled carbon nanotubes is the same as that in Example 2.

[0073] Comparative Example 1: A method for preparing a lightweight magnesium sulfate board with sound-absorbing function: S1: PET microspheres are placed in a sealed container and foamed with supercritical carbon dioxide to obtain auxiliary foaming microspheres; 1000 parts of polyol A, 0.7 parts of foaming agent, 4 parts of crosslinking agent, 0.9 parts of catalyst, 1.3 parts of surfactant, and 35 parts of auxiliary foaming microspheres are added to the container, ultrasonically dispersed, 55 parts of isocyanate are added, stirred evenly, injected into a mold, and allowed to stand to obtain polyurethane foam intermediate A; polyurethane foam intermediate A is placed in a sealed container and foamed with dynamic supercritical carbon dioxide to obtain polyurethane foam A;

[0074] S2: Add 100 parts of polyol B, 0.7 parts of foaming agent, 4 parts of crosslinking agent, 0.9 parts of catalyst, 1.3 parts of surfactant, and 1 part of composite nanomaterial to a container, disperse by ultrasonication, add isocyanate, stir evenly, pour into a mold, and let stand to obtain polyurethane foam intermediate B; place polyurethane foam intermediate B in a sealed container and foam dynamically with supercritical carbon dioxide to obtain polyurethane foam B; wherein, in the composite nanomaterial, the mass ratio of amino-modified multi-walled carbon nanotubes:MnCozO:nanoparticles is 50:1;

[0075] S3: Prepare polyurethane nanofiber cloth, prepare magnesium sulfate slurry, prepare boards, cure, demold, perform secondary curing, cut, and obtain lightweight magnesium sulfate boards.

[0076] Comparative Example 2: A method for preparing a lightweight magnesium sulfate board with sound-absorbing function: S1: PET microspheres are placed in a sealed container and foamed with supercritical carbon dioxide to obtain auxiliary foaming microspheres; 1000 parts of polyol A, 0.7 parts of foaming agent, 4 parts of crosslinking agent, 0.9 parts of catalyst, 1.3 parts of surfactant, and 20 parts of auxiliary foaming microspheres are added to the container, ultrasonically dispersed, 55 parts of isocyanate are added, stirred evenly, injected into a mold, and allowed to stand to obtain polyurethane foam intermediate A; polyurethane foam intermediate A is placed in a sealed container and foamed with dynamic supercritical carbon dioxide to obtain polyurethane foam A;

[0077] S2: Add 100 parts of polyol B, 0.7 parts of foaming agent, 4 parts of crosslinking agent, 0.9 parts of catalyst, 1.3 parts of surfactant, and 1.5 parts of composite nanomaterials to a container, disperse by ultrasonication, add isocyanate, stir evenly, pour into a mold, and let stand to obtain polyurethane foam intermediate B; place polyurethane foam intermediate B in a sealed container and foam dynamically with supercritical carbon dioxide to obtain polyurethane foam B; wherein, in the composite nanomaterials, the mass ratio of amino-modified multi-walled carbon nanotubes:MnCozO:nanoparticles is 50:1;

[0078] S3: Prepare polyurethane nanofiber cloth, prepare magnesium sulfate slurry, prepare board, cure, demold, perform secondary curing, cut, and obtain lightweight magnesium sulfate board.

[0079] Comparative Example 3: A method for preparing a lightweight magnesium sulfate board with sound-absorbing function: S3: Prepare polyurethane nanofiber cloth, prepare magnesium sulfate slurry, prepare board, cure, demold, perform secondary curing, cut, and obtain lightweight magnesium sulfate board.

[0080] The polyurethane foam layer A5 and polyurethane foam layer B3 in the lightweight magnesium sulfate board structure were interchanged, while the experimental method remained the same.

[0081] The remaining steps are the same as in Example 1.

[0082] Comparative Example 4: A method for preparing a lightweight magnesium sulfate board with sound-absorbing function: S1: PET microspheres are placed in a sealed container and foamed with supercritical carbon dioxide to obtain auxiliary foaming microspheres; 1000 parts of polyol A, 0.7 parts of foaming agent, 4 parts of crosslinking agent, 0.9 parts of catalyst, 1.3 parts of surfactant, and 20 parts of auxiliary foaming microspheres are added to the container, ultrasonically dispersed, 55 parts of isocyanate are added, stirred evenly, injected into a mold, and allowed to stand to obtain polyurethane foam intermediate A; polyurethane foam intermediate A is placed in a sealed container and foamed with dynamic supercritical carbon dioxide to obtain polyurethane foam A;

[0083] S2: Add 100 parts of polyol B, 0.7 parts of foaming agent, 4 parts of crosslinking agent, 0.9 parts of catalyst, 1.3 parts of surfactant, and 1 part of composite nanomaterial to a container, disperse by ultrasonication, add isocyanate, stir evenly, pour into a mold, and let stand to obtain polyurethane foam intermediate B; place polyurethane foam intermediate B in a sealed container and foam with supercritical carbon dioxide to obtain polyurethane foam B; wherein, in the composite nanomaterial, the mass ratio of amino-modified multi-walled carbon nanotubes:MnCozO:nanoparticles is 50:1;

[0084] S3: Prepare polyurethane nanofiber cloth, prepare magnesium sulfate slurry, prepare board, cure, demold, perform secondary curing, cut, and obtain lightweight magnesium sulfate board.

[0085] Comparative Example 5: A method for preparing a lightweight magnesium sulfate board with sound-absorbing function: The method for preparing amination-modified multi-walled carbon nanotubes includes the following steps: 10g of multi-walled carbon nanotubes are added to a mixture of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 6:4, ultrasonically dispersed, heated to 140℃, acidified for 55min, washed with deionized water, filtered, and dried to obtain acidified multi-walled carbon nanotubes; 20g of N,N'-dicyclohexylcarbodiimide is added to N,N-dimethylformamide, stirred evenly, and 1.5g of... 4-Dimethylaminopyridine and 50g of acrylic acid were stirred until homogeneous. Under a nitrogen atmosphere, 5g of an N,N-dimethylformamide solution containing acidified multi-walled carbon nanotubes was added. The mixture was heated to 85℃ and reacted for 1 day. After washing with deionized water, the mixture was filtered and dried to obtain carboxylated multi-walled carbon nanotubes. 2g of carboxylated multi-walled carbon nanotubes were added to N,N-dimethylformamide and ultrasonically dispersed. Under a nitrogen atmosphere, 4g of polyethylenepolyamine was added and reacted at room temperature for 1 day. After washing with deionized water, the mixture was filtered and dried to obtain amination-modified multi-walled carbon nanotubes. The molecular weight of the polyethylenepolyamine was 1200.

[0086] S1: PET microspheres are placed in a sealed container and foamed with supercritical carbon dioxide to obtain auxiliary foaming microspheres; 1000 parts of polyol A, 0.7 parts of foaming agent, 4 parts of crosslinking agent, 0.9 parts of catalyst, 1.3 parts of surfactant, and 20 parts of auxiliary foaming microspheres are added to the container, ultrasonically dispersed, 55 parts of isocyanate are added, stirred evenly, injected into a mold, and allowed to stand to obtain polyurethane foam intermediate A; polyurethane foam intermediate A is placed in a sealed container and foamed with dynamic supercritical carbon dioxide to obtain polyurethane foam A;

[0087] S2: Add 100 parts of polyol B, 0.7 parts of foaming agent, 4 parts of crosslinking agent, 0.9 parts of catalyst, 1.3 parts of surfactant, and 1 part of composite nanomaterial to a container, disperse by ultrasonication, add isocyanate, stir evenly, pour into a mold, and let stand to obtain polyurethane foam intermediate B; place polyurethane foam intermediate B in a sealed container and foam dynamically with supercritical carbon dioxide to obtain polyurethane foam B; wherein, in the composite nanomaterial, the mass ratio of amino-modified multi-walled carbon nanotubes:MnCozO:nanoparticles is 50:1;

[0088] S3: Prepare polyurethane nanofiber cloth, prepare magnesium sulfate slurry, prepare board, cure, demold, perform secondary curing, cut, and obtain lightweight magnesium sulfate board.

[0089] Experiment: Noise Reduction Performance: Two impedance tubes (SW420 and SW470, BSWA) were used, each containing two 1 / 4-inch microphones (MPA416, BSWA). The two microphones were used for the low-frequency (63–1,600 Hz) and high-frequency (1,000–6,300 Hz) ranges, respectively. The absorption coefficients for the low, mid, and high-frequency ranges were combined into a single-range graph using VA-Lab software (BSWA).

[0090] The thickness of the lightweight magnesium sulfate board sample is 30mm. According to the ISO 10534-1 standard, the sound absorption coefficient is measured based on the standing wave ratio, and the sound absorption coefficients at 1000Hz and 3000Hz are compared.

[0091] The sound enters through the nanofiber felt layer 7 and passes sequentially through the magnesium sulfate slurry layer 6, the polyurethane foam layer A5, the magnesium sulfate slurry layer 4, the polyurethane foam layer B3, the magnesium sulfate slurry layer 2, and the nanofiber felt layer 1.

[0092] Impact strength and flexural strength: determined in accordance with GB / T 33544-2017.

[0093] The experimental data are shown in Table 1 below.

[0094] Table 1 Experimental Data of Lightweight Magnesium Sulfate Boards

[0095]

[0096] Conclusion: The lightweight magnesium sulfate board prepared by this invention has excellent sound insulation properties and mechanical properties.

[0097] In Comparative Example 1, the excessive amount of auxiliary foaming microspheres led to incomplete pore structure damage, resulting in reduced sound insulation and mechanical properties of the lightweight magnesium sulfate board.

[0098] Comparative Example 2 shows that due to the excessive amount of composite nanomaterials, the pore density is too high and the cross-linking is too tight, which reduces the sound insulation function of the lightweight magnesium sulfate board.

[0099] In Comparative Example 3, due to the structural swap between polyurethane foam layer A and polyurethane foam layer B, the synergistic effect of the front layer dissipating high-frequency waves and the rear layer diffracting low-frequency waves cannot be utilized, resulting in a reduction in the sound-dampening function of the lightweight magnesium sulfate board.

[0100] Comparative Example 4: Polyurethane foam B was foamed using ordinary supercritical carbon dioxide. It lacked a pleated foam structure, resulting in reduced mechanical properties, reduced energy absorption for sound waves, and reduced noise reduction.

[0101] In the preparation of comparative example 5, the polyethylene polyamine was too large (1200), which led to an increase in the pore structure, a decrease in pore density, and a decrease in mechanical properties of the polyurethane foam B. The synergistic effect of the front layer dissipating high-frequency waves and the back layer diffracting low-frequency waves was weakened, and the sound insulation function and mechanical properties of the lightweight magnesium sulfate board were reduced.

[0102] like Figure 1 As shown, this invention provides a lightweight magnesium sulfate sheet with sound-silencing function and a method for preparing the same.

[0103] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A lightweight magnesium sulfate board with sound-silencing function, characterized in that: The structure of the lightweight magnesium sulfate board, from top to bottom, includes: nanofiber felt layer (1), magnesium sulfate slurry layer (2), polyurethane foam layer B (3), magnesium sulfate slurry layer (4), polyurethane foam layer A (5), magnesium sulfate slurry layer (6), and nanofiber felt layer (7). The polyurethane foam layer B (3) is made of polyurethane foam B; the preparation method of the polyurethane foam B includes the following steps: S1: Add manganese nitrate tetrahydrate and cobalt nitrate tetrahydrate to ethylene glycol and stir until homogeneous. Add glycerin, preheat to 80-82℃, and stir for 20-30 min until manganese nitrate tetrahydrate and cobalt nitrate tetrahydrate are completely dissolved. Cool the solution to 30-32℃, add 2-propanal and triethylamine, and stir for 20-30 min until a brown gel is formed. Transfer the brown gel to a muffle furnace, heat to 250-255℃, burn for 30-40 min, and grind to obtain MnCo2O4 nanoparticles. S2: Multi-walled carbon nanotubes were added to a mixture of concentrated sulfuric acid and concentrated nitric acid, ultrasonically dispersed, heated to 140-145℃, acidified for 55-60 min, washed with deionized water, filtered, and dried to obtain acidified multi-walled carbon nanotubes; N,N'-dicyclohexylcarbodiimide was added to N,N-dimethylformamide, stirred evenly, 4-dimethylaminopyridine and acrylic acid were added, stirred evenly, and under a nitrogen atmosphere, the N,N-dimethylformamide solution of acidified multi-walled carbon nanotubes was added, heated to 85-86℃ and reacted for 1 day, washed with deionized water, filtered, and dried to obtain carboxylated multi-walled carbon nanotubes; Carboxylated multi-walled carbon nanotubes were added to N,N-dimethylformamide, ultrasonically dispersed, and under a nitrogen atmosphere, polyethylenepolyamine was added, reacted at room temperature for 1 day, washed with deionized water, filtered, and dried to obtain aminolated multi-walled carbon nanotubes; S3: Add polyol B, foaming agent, crosslinking agent, catalyst, surfactant, and composite nanomaterials to a container, disperse by ultrasonication, add isocyanate, stir evenly, pour into a mold, and let stand to obtain polyurethane foam intermediate B; place polyurethane foam intermediate B in a sealed container and foam dynamically with supercritical carbon dioxide to obtain polyurethane foam B. The composite nanomaterial comprises a combination of aminated multi-walled carbon nanotubes and MnCo2O4 nanoparticles. The polyurethane foam layer A (5) is formed by laying polyurethane foam A; the preparation method of the polyurethane foam A includes the following steps: PET microspheres are placed in a sealed container and foamed with supercritical carbon dioxide to obtain auxiliary foaming microspheres. Polyol A, foaming agent, crosslinking agent, catalyst, surfactant, and auxiliary foaming microspheres are added to the container, ultrasonically dispersed, isocyanate is added, stirred evenly, injected into a mold, and allowed to stand to obtain polyurethane foam intermediate A. Polyurethane foam intermediate A is placed in a sealed container and foamed with dynamic supercritical carbon dioxide to obtain polyurethane foam A.

2. The lightweight magnesium sulfate board with sound-silencing function according to claim 1, characterized in that: The mass ratio of amination-modified multi-walled carbon nanotubes to MnCo2O4 nanoparticles is (40-50):(1-2).

3. A lightweight magnesium sulfate board with sound-silencing function according to claim 1, characterized in that: The nanofiber felt layer (1) and nanofiber felt layer (7) are made of polyurethane nanofiber cloth; the preparation method of the polyurethane nanofiber cloth includes the following steps: adding polyurethane particles into a mixed solution of tetrahydrofuran and N,N-dimethylformamide, stirring evenly, electrospinning, and vacuum drying to obtain polyurethane nanofiber cloth. In the preparation of polyurethane nanofiber cloth, the electrospinning parameters include: applied voltage of 18kV, needle tip to electrode distance of 15cm, and feed rate of 0.5mL / h.

4. A lightweight magnesium sulfate board with sound-silencing function according to claim 1, characterized in that: The magnesium sulfate slurry layer (2), magnesium sulfate slurry layer (4), and magnesium sulfate slurry layer (6) are laid with magnesium sulfate slurry. The preparation method of the magnesium sulfate slurry includes the following steps: mixing magnesium sulfate solution and magnesium oxysulfate modifier evenly, adding lignin fiber and stirring evenly, adding magnesium oxide, organic fiber, active filler, and foamed inorganic material in sequence, stirring evenly to obtain magnesium sulfate slurry. The magnesium sulfate slurry comprises, by mass percentage, 80-100 parts magnesium sulfate solution, 0.3-1.6 parts magnesium sulfate oxysulfate modifier, 5-10 parts lignin fiber, 0.5-1.5 parts organic fiber, 80-100 parts magnesium oxide, 12-20 parts active filler, and 4-15 parts foamed inorganic material.

5. A lightweight magnesium sulfate board with sound-silencing function according to claim 1, characterized in that: In the preparation of MnCo2O4 nanoparticles, the molar ratio of manganese nitrate tetrahydrate to cobalt nitrate tetrahydrate is 1:

2. In the preparation of carboxylated multi-walled carbon nanotubes, the mass ratio of acidified multi-walled carbon nanotubes: N,N'-dicyclohexylcarbodiimide: 4-dimethylaminopyridine: acrylic acid is (5-10):(20-40):(1.5-3):(50-100). In the preparation of amino-modified multi-walled carbon nanotubes, the mass ratio of carboxylated multi-walled carbon nanotubes to polyethylene polyamine is 1:2; the relative molecular weight of the polyethylene polyamine is 60-100.

6. A lightweight magnesium sulfate board with sound-silencing function according to claim 1, characterized in that: The polyurethane foam intermediate B comprises the following components by mass fraction: 80-100 parts of polyol B, 0.6-0.8 parts of foaming agent, 4-5 parts of crosslinking agent, 0.9-1 parts of catalyst, 1.3-1.4 parts of surfactant, 1.0-1.2 parts of composite nanomaterial, and 55-60 parts of isocyanate.

7. A lightweight magnesium sulfate board with sound-silencing function according to claim 1, characterized in that: The polyurethane foam intermediate A comprises the following components by mass fraction: 80-100 parts of polyol A, 0.6-0.8 parts of foaming agent, 4-5 parts of crosslinking agent, 0.9-1 part of catalyst, 1.3-1.4 parts of surfactant, 20-30 parts of auxiliary foaming microspheres, and 55-60 parts of isocyanate.

8. The preparation process of a lightweight magnesium sulfate plate with sound-silencing function according to any one of claims 1-7, characterized in that: Includes the following steps: Polyurethane foam A was prepared, polyurethane foam B was prepared, polyurethane nanofiber cloth was prepared, magnesium sulfate slurry was prepared, board was prepared, cured, demolded, secondary cured, and cut to obtain lightweight magnesium sulfate board. The steps for preparing the board include: forming a nanofiber felt layer (7) with polyurethane nanofiber cloth as the base layer; laying magnesium sulfate slurry on the nanofiber felt layer (7) to form a magnesium sulfate slurry layer (6); laying polyurethane foam A on the magnesium sulfate slurry layer (6) to form a polyurethane foam layer A (5); laying magnesium sulfate slurry on the polyurethane foam layer A (5) to form a magnesium sulfate slurry layer (4); laying polyurethane foam B on the magnesium sulfate slurry layer (4) to form a polyurethane foam layer B (3); laying magnesium sulfate slurry on the polyurethane foam layer B (3) to form a magnesium sulfate slurry layer (2); and laying polyurethane nanofiber cloth on the magnesium sulfate slurry layer (2) to form a nanofiber felt layer (1).

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