A method for the organic modification of a high mechanical performance nanoporous material

Abstract

The application discloses a method for preparing high-mechanical-property nano-porous material by organic modification, and comprises the following steps: S1, preparing sol: uniformly mixing a silicon source, deionized water and a hydrolysis catalyst in anhydrous ethanol, and then adding an organic polymer and stirring until the organic polymer is dissolved to form sol; S2, adding an auxiliary agent: adding a proper thickening agent and a surfactant into the sol; S3, mixing and stirring: fully mixing the sol and the auxiliary agent; S4, gelation: forming a gel structure through a gel reaction by chemical reaction; S5, solidification: placing the gel sample in a proper condition for solidification; and S6, drying: drying the solidified gel sample. The added organic polymer can act as a crosslinking agent and a thickening agent, and finally forms a crosslinked network structure of silica and the organic polymer with elasticity, so that the flexibility of a silica main chain is improved, and the mechanical strength is also improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of nanometer porous material preparation, and particularly relates to a method for preparing high-mechanical-property nanometer porous material through organic modification. BACKGROUND

[0002] Silica (SiO2) aerogel is a lightweight nanometer porous material with a spatial network structure formed by the cross-linking of colloidal particles or polymer molecules.

[0003] Silica aerogel has the characteristics of high specific surface area and porous structure, can provide a large reactive surface, is conducive to chemical reactions and adsorption processes, has good adsorption performance and mass transfer performance, can effectively insulate, and has good application prospects; it can be applied to the field of environmental governance, effectively absorbing, adsorbing and removing harmful substances; it can be applied to the field of energy, as energy storage material, solar cell panel, fuel cell, etc., to improve the efficiency and utilization rate of energy; it can also be applied to the field of building, as thermal insulation material, for thermal insulation, sound absorption and noise reduction, etc., to improve the energy-saving performance of buildings.

[0004] However, silica aerogel still has the following limitations: the production process of silica aerogel is relatively complex, requiring high temperature and special conditions, resulting in high cost; due to its porous and low-density characteristics, silica aerogel has low mechanical strength and poor flexibility, and is easily broken or fractured. Therefore, a new preparation method is needed to efficiently and at low cost prepare nanometer porous aerogel material with high flexibility and high mechanical strength. SUMMARY

[0005] The present application discloses a method for preparing high-mechanical-property nanometer porous material through organic modification, aiming to solve the technical problems in the background art.

[0006] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0007] A method for preparing high-mechanical-property nanometer porous material through organic modification, comprising the following specific steps:

[0008] S1: preparing sol: adding 40-50% of silicon source, 15-25% of deionized water and 4-6% of hydrolysis catalyst into 10-20% of solvent anhydrous ethanol, mixing and stirring uniformly, then adding 6%-8% of organic polymer, and continuing to stir until the silicon source and the organic polymer are dissolved in the solvent to form sol;

[0009] S2: adding auxiliary agent: adding 1% of thickening agent and 2% of surfactant in the sol to control the viscosity and fluidity of the sol;

[0010] S3: Mixing and stirring: the sol and thickening agent, surfactant are mixed and stirred well, so that the sol is uniformly dispersed in the thickening agent and surfactant;

[0011] S4: Gelation: the components undergo a gel reaction, the sol polymerizes or micelles aggregate, so that the silicon source in the sol forms a three-dimensional network structure, and is crosslinked with the organic polymer, thereby forming a gel network, and then the gel network is crosslinked and exchanged, and crystallization occurs, thereby solidifying the gel to enhance the stability and mechanical strength of the gel. An acid catalyst with a mass percentage of 3-5% is added during the gelation process to accelerate the gelation rate;

[0012] S5: Curing: the gel sample is placed in appropriate conditions and allowed to cure for a period of time to stabilize the gel structure;

[0013] S6: Drying: the cured gel sample is dried to remove the solvent, obtaining the final silica aerogel product.

[0014] During the hydrolysis process, the organic polymer material is added for compounding. The organic polymer material can control the pore structure, act as a crosslinking agent and thickening agent, accelerate the crosslinking and compounding of the silicon source and the organic polymer, and increase the consistency of the sol. Finally, a crosslinked network structure of silica and organic polymer with elasticity is formed, which not only improves the flexibility and mechanical strength of the silica backbone, but also adjusts the pore size distribution, and the prepared nano-porous material silica aerogel has significantly enhanced flexibility and mechanical strength.

[0015] In a preferred embodiment, in S1, the silicon source uses one of silicate and silicate ester, which provides the source of silica, and forms a silica network structure through the gelation and curing process. The silicate uses one or more of sodium silicate and ammonium silicate, and the silicate ester uses one or more of ethyl tetraethyl silicate and tetra-n-butyl orthosilicate.

[0016] In a preferred embodiment, in S1, the organic polymer uses a polymer and a natural polymer, which is used to combine with the silicon source to form a composite silica aerogel. The polymer uses acrylonitrile-butadiene-styrene copolymer and bismaleimide, and the natural polymer uses one or more of acacia resin, agar and algin.

[0017] By adding acrylonitrile-butadiene-styrene copolymer, the final gel has excellent electrical properties, wear resistance, dimensional stability, chemical resistance and surface gloss. By adding bismaleimide, the final gel has excellent heat resistance, electrical insulation, wave permeability, radiation resistance, flame resistance, good mechanical properties and dimensional stability.

[0018] In a preferred scheme, in the S2, the thickening agent is one or more of gum arabic and agar, and the surfactant is one or more of sodium dodecyl benzene sulfonate, quaternary ammonium compound and fatty acid glyceride.

[0019] By adding the thickening agent, which is gum arabic and agar, the consistency of the sol can be adjusted, and the type of the thickening agent is the same as that of the natural polymer in the organic polymer, so that the final gel structure is not affected by other types of thickening agents, and the strength of the final gel structure is enhanced.

[0020] In a preferred scheme, in the S4, the acid catalyst is one of alumina molecular sieve and ZSM-5 zeolite molecular sieve.

[0021] In a preferred scheme, in the S5, the temperature during the solidification is 5-15℃, the whole process is in a sterile and dust-free environment, and the solidification time is 15-20h.

[0022] In a preferred scheme, in the S6, the drying is vacuum drying or supercritical drying.

[0023] As can be seen from the above, the method for preparing high-mechanical-property nano-porous material by organic modification provided by the application adds organic polymer material for compounding in the hydrolysis process, the organic polymer material can play a role in controlling the pore structure, and can also function as a crosslinking agent and a thickening agent, so that the crosslinking and compounding of the silicon source and the organic polymer material is accelerated, the consistency of the sol is increased, and finally a silica and organic polymer crosslinking network structure with elasticity is formed, the flexibility and mechanical strength of the silica main chain are improved, and the flexibility and mechanical strength of the prepared nano-porous material silica aerogel are obviously enhanced; the acrylonitrile-butadiene-styrene copolymer and the bismaleimide in the organic polymer can make the final gel have excellent electrical properties, wear resistance, dimensional stability, chemical resistance and surface gloss, and also have excellent heat resistance, electrical insulation, wave permeability, radiation resistance, flame resistance and good mechanical properties. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The flow chart of the method for preparing high-mechanical-property nano-porous material by organic modification is provided.

[0025] Figure 2 The silicon source component diagram of the method for preparing high-mechanical-property nano-porous material by organic modification is provided.

[0026] Figure 3 The organic polymer component diagram of the method for preparing high-mechanical-property nano-porous material by organic modification is provided.

[0027] Figure 4 A thickening agent, an acid catalyst, and a surfactant component of a method for preparing a high-mechanical-property nanoporous material by organic modification. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application.

[0029] Embodiment 1

[0030] Reference Figure 1 A method for preparing a high-mechanical-property nanoporous material by organic modification, comprising the following specific steps:

[0031] S1: preparing a sol: adding 40-50% of a silicon source, 15-25% of deionized water, and 4-6% of a hydrolysis catalyst into 10-20% of a solvent, anhydrous ethanol, mixing and stirring uniformly, then adding 6%-8% of an organic polymer, and continuing to stir until the silicon source and the organic polymer are dissolved in the solvent to form a sol;

[0032] S2: adding an additive: adding 1% of a thickening agent and 2% of a surfactant in the sol to control the viscosity and fluidity of the sol;

[0033] S3: mixing and stirring: fully mixing and stirring the sol and the thickening agent and the surfactant to make the sol, the thickening agent, and the surfactant uniformly dispersed;

[0034] S4: gelation: the components are subjected to a gel reaction, the sol is polymerized or micellar aggregated, the silicon source in the sol forms a three-dimensional network structure, and is crosslinked with the organic polymer, thereby forming a gel network, and then the gel network is crosslinked, crystallization occurs, thereby solidifying the gel to enhance the stability and mechanical strength of the gel, and 3-5% of an acid catalyst is added in the gelation process to accelerate the gelation rate;

[0035] S5: solidification: placing the gel sample in appropriate conditions to allow it to solidify for a period of time,

[0036] to stabilize the gel structure;

[0037] S6: drying: drying the solidified gel sample to remove the solvent to obtain a final silica aerogel product.

[0038] The organic polymer material is added in the process of hydrolysis to form a complex, the organic polymer material can play a role of cross-linking agent and thickening agent, accelerate the cross-linking and complexing of the silicon source and the organic polymer material, increase the consistency of the sol, and finally form a cross-linked network structure of the silica and the organic polymer material with elasticity, thereby improving the flexibility and mechanical strength of the silica main chain, and the flexibility and mechanical strength of the prepared nano-porous material silica aerogel are obviously enhanced.

[0039] Without the organic polymer, the flexibility of the silica main chain is medium, that is, the silica main chain has a certain flexibility, is not easy to produce obvious deformation, but can still adapt to slight pressure, and the mechanical strength is 0.08-0.1 MPa; after the organic polymer is added, the flexibility of the silica main chain is high, that is, the flexibility is very high, and the silica main chain can produce obvious deformation under slight finger pressure, and the mechanical strength is 0.12-0.14 MPa.

[0040] When the mass percentage of the added organic polymer is 3-6%, the flexibility of the silica main chain is slightly improved, and the mechanical strength is 0.09-0.11 MPa; when the mass percentage of the added organic polymer is 8-12%, the flexibility of the silica main chain does not increase but decreases, and the mechanical strength is 0.13-0.15 MPa, although the mechanical strength increases more, but the flexibility decreases, and therefore the mass percentage of the added organic polymer is preferably 6-8%.

[0041] Reference Figure 2 In one preferred embodiment, in S1, one of silicate and silicate ester is used as the silicon source, and the silicon source provides a source of silica to form a silica network structure through a gelation and solidification process.

[0042] Reference Figure 2 In one preferred embodiment, one or more of sodium silicate and ammonium silicate is used as the silicate, and one or more of tetraethyl ethyl silicate and tetrabutyl orthosilicate is used as the silicate ester.

[0043] Reference Figure 3 In one preferred embodiment, in S1, one of polymer and natural polymer is used as the organic polymer, and the organic polymer is used to combine with the silicon source to form a composite silica aerogel.

[0044] Reference Figure 3 In one preferred embodiment, one or more of acrylonitrile-butadiene-styrene copolymer and bismaleimide is used as the polymer, and one or more of gum arabic, agar and algin is used as the natural polymer.

[0045] By adding acrylonitrile-butadiene-styrene copolymer, the final gel has excellent electrical properties, wear resistance, dimensional stability, chemical resistance and surface gloss. By adding bismaleimide, the final gel has excellent heat resistance, electrical insulation, wave permeability, radiation resistance, flame resistance and good mechanical properties.

[0046] Referring to Figure 4 In a preferred embodiment, in S2, the thickening agent is one or more of gum arabic and agar.

[0047] By adding the thickening agent, which is gum arabic and agar, not only can the consistency of the sol be adjusted, but also the type of thickening agent used is the same as the type of natural polymer in the organic high polymer, which not only avoids the influence of other types of thickening substances on the final gel structure, but also enhances the strength of the final gel structure as an organic high polymer.

[0048] Referring to Figure 4 In a preferred embodiment, in S2, the surfactant is one or more of sodium dodecyl benzene sulfonate, quaternary ammonium compound and fatty acid glyceride.

[0049] Referring to Figure 4 In a preferred embodiment, in S4, the acid catalyst is one of alumina molecular sieve and zeolite ZSM-5 molecular sieve.

[0050] In a preferred embodiment, in S5, the temperature during curing is 5-15℃, the whole process is in a sterile and dust-free environment, and the curing time is 15-20h.

[0051] In a preferred embodiment, in S6, drying is performed by vacuum drying or supercritical drying.

[0052] Example 2

[0053] Referring to Figure 1 A method for preparing a high-mechanical-property nano-porous material by organic modification, comprising the following specific steps:

[0054] S1: preparing a sol: adding 46% by mass of a silicon source, 20% by mass of deionized water and 5% by mass of a hydrolysis catalyst into 15% by mass of a solvent, i.e. anhydrous ethanol, mixing and stirring until uniform, then adding 7% by mass of an organic high polymer, and continuing to stir until the silicon source and the organic high polymer are both dissolved in the solvent to form a sol;

[0055] S2: adding an additive: adding 1% by mass of a thickening agent and 2% by mass of a surfactant into the sol to control the viscosity and flowability of the sol;

[0056] S3: Mixing and stirring: the sol and thickening agent, surfactant are mixed and stirred well, so that the sol is uniformly dispersed in the thickening agent and surfactant;

[0057] S4: Gelation: the components undergo a gel reaction, the sol polymerizes or micelles aggregate, so that the silicon source in the sol forms a three-dimensional network structure, and is crosslinked with the organic polymer, thereby forming a gel network, and then the gel network is crosslinked and exchanged, and crystallization occurs, thereby solidifying the gel to enhance the stability and mechanical strength of the gel. An acid catalyst with a mass percentage of 4% is added during the gelation process to accelerate the gelation rate;

[0058] S5: Solidification: the gel sample is placed in appropriate conditions and allowed to solidify for a period of time to stabilize the gel structure;

[0059] S6: Drying: the solidified gel sample is dried to remove the solvent, obtaining the final silica aerogel product.

[0060] During the hydrolysis process, the organic polymer material is added for compounding. The organic polymer material can act as a crosslinking agent and a thickening agent, accelerating the crosslinking and compounding of the silicon source and the organic polymer, increasing the consistency of the sol, and ultimately forming a crosslinked network structure of silica and organic polymer with elasticity, improving the flexibility and mechanical strength of the silica backbone, and significantly enhancing the flexibility and mechanical strength of the prepared nanoporous material silica aerogel.

[0061] Without adding organic polymer, the flexibility of the silica backbone is moderate, that is, it has a certain flexibility and is not easy to produce obvious deformation, but it can still adapt to light pressure, and the mechanical strength is 0.08-0.1 MPa. After adding the organic polymer, the flexibility of the silica backbone is high, that is, the flexibility is very high, and it can produce obvious deformation under light finger pressure, and the mechanical strength is 0.12-0.14 MPa.

[0062] Referring to Figure 2 In a preferred embodiment, in S1, the silicon source uses one of silicate and silicate ester, and the silicon source provides the source of silica, which forms a silica network structure through the gelation and solidification processes.

[0063] Referring to Figure 2 In a preferred embodiment, the silicate uses one or more of sodium silicate and ammonium silicate, and the silicate ester uses one or more of tetraethyl ethyl silicate and tetrabutyl orthosilicate.

[0064] Referring to Figure 3 In a preferred embodiment, in S1, the organic polymer uses a polymer and a natural polymer, and the organic polymer is used to combine with the silicon source to form a composite silica aerogel.

[0065] Referring to Figure 3 In a preferred embodiment, the polymer is acrylonitrile-butadiene-styrene copolymer and bismaleimide, and the natural polymer is one or more of gum arabic, agar and algin.

[0066] By adding acrylonitrile-butadiene-styrene copolymer, the final gel has excellent electrical properties, wear resistance, dimensional stability, chemical resistance and surface gloss, and by adding bismaleimide, the final gel has excellent heat resistance, electrical insulation, wave permeability, radiation resistance, flame resistance and good mechanical properties.

[0067] Referring to Figure 4 In a preferred embodiment, in S2, the thickening agent is one or more of gum arabic and agar.

[0068] By adding the thickening agent, which is gum arabic and agar, not only can the consistency of the sol be adjusted, but also the same type of thickening agent and natural polymer in the organic polymer is used, which not only avoids the influence of other types of thickening substances on the final gel structure, but also enhances the strength of the final gel structure.

[0069] Referring to Figure 4 In a preferred embodiment, in S2, the surfactant is one or more of sodium dodecyl benzene sulfonate, quaternary ammonium compound and fatty acid glyceride.

[0070] Referring to Figure 4 In a preferred embodiment, in S4, the acid catalyst is one of alumina molecular sieve and zeolite ZSM-5 molecular sieve.

[0071] In a preferred embodiment, in S5, the temperature during curing is 8°C, the whole process is in a sterile and dust-free environment, and the curing time is 18h.

[0072] In a preferred embodiment, in S6, drying is performed by vacuum drying or supercritical drying.

[0073] The above description is only a preferred embodiment of the present application, but the protection scope of the present application is not limited thereto. The alternatives can be partial structure, device, method step alternatives, or complete technical solutions. According to the technical solutions and inventive concepts of the present application, equivalent replacement or changes are covered within the protection scope of the present application.

Claims

1. A method for preparing nanoporous materials with high mechanical properties by organic modification, characterized in that: The specific steps include: S1: preparing a sol: adding 40-50% by mass of a silicon source, 15-25% by mass of deionized water, and 4-6% by mass of a hydrolysis catalyst to 10-20% by mass of anhydrous ethanol as a solvent, stirring the mixture, and then adding 6%-8% by mass of an organic polymer, wherein the organic polymer comprises a polymer and a natural polymer, and the organic polymer is used to combine with the silicon source to form a composite silica aerogel, wherein the polymer comprises acrylonitrile-butadiene-styrene copolymer and bismaleimide, and the natural polymer comprises one or more of arabic resin, agar, and alginate, and continuing stirring until the silicon source and the organic polymer are dissolved in the solvent to form a sol; S2: Addition of additives: 1% by mass of thickener and 2% by mass of surfactant were added to the sol to control the viscosity and fluidity of the sol; S3: Mixing and stirring: The sol, thickener and surfactant are fully mixed and stirred to make the sol, thickener and surfactant uniformly dispersed; S4: Gelation: Each component undergoes a gelation reaction, and the sol polymerizes or micelles aggregate to form a three-dimensional network structure of silicon sources in the sol, and crosslinks with organic polymers to form a gel network. Then, the gel network crosslinks are exchanged and crystallized, thereby solidifying the gel to enhance the stability and mechanical strength of the gel. During the gelation process, an acid catalyst of 3-5% by mass is added to accelerate the gelation rate. S5: Curing: Place the gel sample under appropriate conditions and allow it to cure for a period of time to stabilize the gel structure; S6: Drying: Drying the solidified gel sample to remove the solvent to obtain the final silica aerogel product.

2. The method for preparing nanoporous materials with high mechanical properties by organic modification according to claim 1, characterized in that: In the above-mentioned S1, the silicon source is one of silicate and silicate ester, which provides a source of silicon dioxide and forms a silicon dioxide network structure through gelation and solidification processes.

3. The method for preparing nanoporous materials with high mechanical properties by organic modification according to claim 2, characterized in that: The silicate is one or more of sodium silicate and ammonium silicate, and the silicate ester is one or more of tetraethyl ethyl silicate and tetrabutyl orthosilicate.

4. The method for preparing nanoporous materials with high mechanical properties by organic modification according to claim 1, characterized in that: In S2, the thickener is one or more of gum arabic and agar.

5. The method for preparing nanoporous materials with high mechanical properties by organic modification according to claim 1, characterized in that: In the above S2, the surfactant is one or more of sodium dodecylbenzenesulfonate, quaternary ammonium compounds and fatty acid glycerides.

6. The method for preparing nanoporous materials with high mechanical properties by organic modification according to claim 1, characterized in that: In the S4, the acid catalyst is one of alumina molecular sieve and zeolite ZSM-5 molecular sieve.

7. The method for preparing nanoporous materials with high mechanical properties through organic modification according to claim 1, characterized in that: In the above-mentioned S5, the temperature during curing is 5-15° C., the whole curing process is in a sterile and dust-free environment, and the curing time is 15-20 hours.

8. The method for preparing nanoporous materials with high mechanical properties through organic modification according to claim 1, characterized in that: In S6, the drying is performed by vacuum drying or supercritical drying.

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