Straw aerogel composite insulation board and preparation method thereof

Abstract

This invention belongs to the field of thermal insulation materials technology, specifically referring to a straw aerogel composite insulation board and its preparation method. The composite insulation board is prepared from the following raw materials: 80-100 parts of straw modifier, 65-85 parts of aerogel composite, 15-35 parts of antioxidant hydrophobic agent, 30-45 parts of phenolic resin, and 30 parts of silane coupling agent. This invention uses straw modifier and aerogel composite as the main materials. The straw modifier achieves mutual support with the phenolic resin through hydrogen bonding via hydroxyl functional groups. The aerogel composite and phenolic resin synergistically enhance the thermal insulation performance and maintain stability through physical bonding. The straw modifier also forms a toughening-reinforcing complementary structure with the aerogel composite. The silane coupling agent improves the compatibility between materials and partially enhances the cross-linking effect of the phenolic resin. The surface coating with antioxidant hydrophobic agent improves the surface properties of the insulation board. The prepared insulation board has significantly improved strength, thermal insulation, and hydrophobicity compared to existing thermal insulation materials.

Description

Technical Field

[0001] This invention belongs to the field of thermal insulation materials technology, specifically referring to a straw aerogel composite thermal insulation board and its preparation method. Background Technology

[0002] With the continuous development of the construction industry and industrial insulation field, the performance requirements for insulation boards are increasing.

[0003] Among existing insulation boards, some organic insulation boards, while possessing certain insulation properties, often suffer from insufficient strength, susceptibility to aging, poor insulation performance, and inadequate water resistance. This results in poor reliability and safety hazards during long-term use, and their insulation effect decreases significantly when exposed to humid environments. Inorganic insulation boards, despite having better fire resistance and water resistance, are typically brittle and lack toughness, making them prone to damage during installation and use, leading to a decline in insulation performance. Traditional insulation boards have gradually revealed numerous limitations in practical applications, making it difficult to meet diverse usage needs.

[0004] In light of the various shortcomings of existing insulation boards, there is an urgent need to develop a new type of insulation board that can overcome these defects and possesses good strength, excellent thermal insulation performance, and outstanding hydrophobicity. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, the straw aerogel composite insulation board proposed in this invention uses straw modifiers and aerogel composites as the main materials. The straw modifiers support the phenolic resin through hydrogen bonding via hydroxyl functional groups, with the former providing physical support for the latter and making it fill the pores more densely. The aerogel composite and phenolic resin synergistically enhance the insulation performance and maintain stability through physical bonding. The straw modifiers also form a toughening-reinforcing complementary structure with the aerogel composite. Silane coupling agents improve the compatibility between materials and partially enhance the cross-linking effect of phenolic resin. The surface is sprayed with an antioxidant and hydrophobic agent, and the temperature resistance is improved by alumina and the hydrophobicity is ensured by plant wax. This insulation board has significantly improved performance in terms of strength, insulation, and hydrophobicity compared to existing insulation materials.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is a straw aerogel composite insulation board, which is prepared from the following raw materials in parts by weight: 80-100 parts of straw modifier, 65-85 parts of aerogel composite, 15-35 parts of antioxidant hydrophobic agent, 30-45 parts of phenolic resin, and 30 parts of silane coupling agent.

[0007] Furthermore, the method for preparing the antioxidant hydrophobic compound includes the following steps:

[0008] (α) Weigh natural rubber and add it to a mixed solution of tetrahydrofuran and toluene, wherein the mass ratio of natural rubber to the mixed solution is 2-4:25, and the volume percentage of tetrahydrofuran and toluene in the mixed solution is 20%:80%. Heat to 50℃ and stir for 30 min at a speed of 500 r / min to obtain a homogeneous solution.

[0009] (β) Weigh 4-6 parts of alumina and dry them at 65℃ for 2 hours, and grind them to obtain alumina powder. Add the alumina powder to the homogeneous slurry obtained in step (α) and stir for 30 minutes at a speed of 500 r / min to obtain an antioxidant homogeneous slurry.

[0010] (γ) Weigh 5 parts of plant wax and add them to the antioxidant homogeneous liquid obtained in step (β). Heat the mixture to 90-110℃ using a cooling reflux device and stir for 60 min at a speed of 500 r / min. Seal and store for 5 h to obtain the antioxidant hydrophobic material.

[0011] Furthermore, the preparation method of the aerogel composite includes the following steps:

[0012] (I) Weigh 3.5-5.5 parts of graphene powder and 4.5 parts of nano-silica and add them to 15 parts of anhydrous ethanol. Stir for 30 min at a speed of 300 r / min to obtain a carbon-silicon mixed dispersion.

[0013] (II) Weigh 6-9 parts of methyltrimethoxysilane and add it to the carbon-silicon mixed dispersion obtained in step (I). Add 1-3 parts of acid solution, stir for 40 min at a speed of 500 r / min, seal and let stand at 25℃ for 24 h to obtain the aerogel complex.

[0014] Graphene powder and nano-silica are physically adsorbed through van der Waals forces, and the two are structurally synergistic. Graphene provides a supporting framework for nano-silica, which is conducive to the construction of a stable three-dimensional network structure. Nano-silica and methyltrimethoxysilane undergo hydrolysis and condensation under acid catalysis to form Si-O-Si bonds, thereby modifying the surface of nano-silica. These interactions jointly promote the formation and performance of the aerogel composite.

[0015] Furthermore, the method for preparing the modified straw product includes the following steps:

[0016] (a) Weigh 15-20 parts of straw, dry it at 80℃ for 6 hours, crush it and sieve it with a 20-mesh screen to obtain straw powder. Add the obtained straw powder to 50 parts of deionized water, add salt solution to adjust the pH to neutral, wash it 5 times with deionized water, and dry it at 80℃ for 12 hours to obtain alkalized straw powder. Weigh 8-12 parts of clay, dry it at 110℃ for 12 hours, grind it and sieve it with an 80-mesh screen to obtain fine clay powder.

[0017] (b) Weigh 10-12 parts of epoxy resin, heat to 80°C, and stir for 30 minutes at 500 r / min. Add 3 parts of rosin, heat to 120°C, and stir for 20 minutes at 500 r / min to obtain mixture I.

[0018] (c) Weigh 9-15 parts of graphite powder and add them to the mixture I obtained in step (b). Sonicate for 30 min under a power of 0.5 kW, heat to 110 °C, and stir for 30 min at a speed of 500 r / min to obtain the substrate mixture.

[0019] (d) Add the alkalized straw powder obtained in step (a) to the base mixture, heat to 90°C, and stir for 30 min at a speed of 500 r / min to obtain the straw modified precursor;

[0020] (e) Add the clay powder obtained in step (a) to the straw modified precursor obtained in step (d), heat to 60°C, stir for 2 hours at a speed of 500 r / min, and introduce a gas with a flow rate of 120 ml / min, wherein the gas is either argon or nitrogen, to obtain the straw modified product.

[0021] By filling the pores of straw with clay, the pores are prevented from affecting the strength, while the overall heat insulation performance is improved. Straw contains abundant hydroxyl functional groups, which can form hydrogen bonds with the hydroxyl groups of epoxy resin molecules. The hydrogen bonding helps the resin molecules adhere to the straw surface, thus achieving straw modification.

[0022] This invention also provides a method for preparing a straw aerogel composite insulation board, comprising the following steps:

[0023] Step 1: Weigh 80-100 parts of straw modifier and 65-85 parts of aerogel composite and add them to 30 parts of silane coupling agent. Stir at 1500 r / min for 1 h to obtain mixture I.

[0024] Step 2: Add 55-80 parts of phenolic resin to mixture I obtained in Step 1, and stir for 30 minutes at a speed of 1500 r / min to obtain a paste.

[0025] Step 3: Pour the paste obtained in Step 2 into a mold and cure it at room temperature (25°C) under a cold pressing pressure of 10 MPa for 1 hour to obtain the cured product.

[0026] Step 4: Weigh 15-35 parts of antioxidant hydrophobic material and spray it evenly onto the surface of the cured material. At room temperature of 25℃, perform a second cold pressing curing at a pressure of 15MPa for 2 hours to obtain the straw aerogel composite insulation board blank.

[0027] Step 5: Place the straw aerogel composite insulation board blank obtained in Step 4 into a ventilated environment for cross-linking for 72 hours, and then place it in an oven at a temperature of 110-150℃ for 8 hours to obtain the straw aerogel composite insulation board.

[0028] Straw-modified material and aerogel composite were selected as the main materials. The straw-modified material and phenolic resin achieved initial bonding and mutual support through hydrogen bonding. The former provides physical support for the latter, while the latter fills the pores of the former, making it denser. The aerogel composite and phenolic resin synergistically enhance the thermal insulation performance and maintain stability through physical bonding. The straw-modified material, as a toughening thermal insulation material, complements the structure of the thermal insulation material with the aerogel composite. The silane coupling agent plays an interface modification role, improving the compatibility between the straw-modified material, aerogel composite and phenolic resin. At the same time, it can also enhance the cross-linking effect of phenolic resin. In order to improve the oxidation resistance and water resistance of the straw aerogel composite insulation board, an antioxidant and hydrophobic agent is sprayed on the surface. The presence of alumina improves the surface temperature resistance, while plant wax, as a natural hydrophobic material, ensures the surface hydrophobicity.

[0029] The straw aerogel composite insulation board prepared by this invention has significantly improved performance in terms of strength, insulation properties, and hydrophobicity compared to existing insulation materials. Attached Figure Description

[0030] Figure 1 The diagram shows the preparation method of the straw aerogel composite insulation board proposed in this invention.

[0031] Figure 2 This is a plan view of the material distribution of the straw aerogel composite insulation board proposed in this invention;

[0032] Figure 3 Strength test diagrams of the straw aerogel composite insulation boards prepared in the examples and comparative examples;

[0033] Figure 4 The thermal conductivity test results are shown for the straw aerogel composite insulation boards prepared in the examples and comparative examples.

[0034] Figure 5 The loss rate and hydrophobicity test results of the straw aerogel composite insulation boards prepared for the examples and comparative examples are shown in the figure.

[0035] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. Detailed Implementation

[0036] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those familiar to those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to this invention. The preferred embodiments and materials described herein are for illustrative purposes only and do not limit the scope of this application.

[0038] The preparation method and material distribution in the following examples are as follows: Figure 1 and Figure 2 Unless otherwise specified, all methods are conventional. Unless otherwise specified, the materials used in the following examples are calculated by mass, all of which are new materials purchased from the market, and the saturated solutions are prepared according to the solubility of the materials at 25°C.

[0039] Example 1: A straw aerogel composite insulation board is prepared from the following raw materials in parts by weight: 80 parts of straw modifier, 65 parts of aerogel composite, 15 parts of antioxidant hydrophobic material, 30 parts of phenolic resin, and 30 parts of KH550 (γ-aminopropyltriethoxysilane).

[0040] The preparation method of the antioxidant hydrophobic compound includes the following steps:

[0041] (α) Weigh 2 parts of natural rubber and add them to a mixed solution of 25 parts of tetrahydrofuran and toluene, wherein the volume percentage of tetrahydrofuran and toluene in the mixed solution is 20%:80%. Heat the solution to 50°C and stir for 30 minutes at a speed of 500 r / min to obtain a homogeneous solution.

[0042] (β) Weigh 4 parts of alumina and dry them at 65℃ for 2 hours, and grind them to obtain alumina powder. Add the alumina powder to the homogeneous slurry obtained in step (α) and stir for 30 minutes at a speed of 500 r / min to obtain an antioxidant homogeneous slurry.

[0043] (γ) Weigh 5 parts of carnauba wax and add it to the antioxidant homogeneous liquid obtained in step (β). Heat it to 90°C using a cooling reflux device and stir it for 60 min at a speed of 500 r / min. Seal and store for 5 h to obtain the antioxidant hydrophobic material.

[0044] The preparation method of the aerogel complex includes the following steps:

[0045] (I) Weigh 3.5 parts of graphene powder and 4.5 parts of nano-silica and add them to 15 parts of anhydrous ethanol. Stir at 300 r / min for 30 min to obtain a carbon-silicon mixed dispersion.

[0046] (II) Weigh 6 parts of methyltrimethoxysilane and add them to the carbon-silicon mixed dispersion obtained in step (I). Add 1 part of glacial acetic acid and stir for 40 min at a speed of 500 r / min. Seal and let stand at 25℃ for 24 h to obtain the aerogel complex.

[0047] The preparation method of straw modified materials includes the following steps:

[0048] (a) Weigh 15 parts of corn stalks, dry them at 80℃ for 6 hours, crush them and sieve them through a 20-mesh screen to obtain straw powder. Add the obtained straw powder to 50 parts of deionized water, add saturated sodium carbonate solution to adjust the pH to neutral, wash with deionized water 5 times, and dry them at 80℃ for 12 hours to obtain alkalized straw powder. Weigh 8 parts of kaolin, dry it at 110℃ for 12 hours, grind it and sieve it through an 80-mesh screen to obtain clay powder.

[0049] (b) Weigh 10 parts of epoxy resin, heat to 80°C, and stir for 30 minutes at 500 r / min. Add 3 parts of rosin, heat to 120°C, and stir for 20 minutes at 500 r / min to obtain mixture I.

[0050] (c) Weigh 9 parts of graphite powder and add them to the mixture I obtained in step (b). Sonicate for 30 min under a power of 0.5 kW, heat to 110 °C, and stir for 30 min at a speed of 500 r / min to obtain the substrate mixture.

[0051] (d) Add the alkalized straw powder obtained in step (a) to the base mixture, heat to 90°C, and stir for 30 min at a speed of 500 r / min to obtain the straw modified precursor;

[0052] (e) The clay powder obtained in step (a) is added to the straw modified precursor obtained in step (d), heated to 60°C, and stirred for 2 hours at a speed of 500 r / min. Argon gas with a flow rate of 120 ml / min is introduced to obtain the straw modified product.

[0053] This embodiment also provides a method for preparing a straw aerogel composite insulation board, including the following steps:

[0054] Step 1: Weigh 80 parts of straw modifier and 65 parts of aerogel composite and add them to 30 parts of KH550. Stir at 1500 r / min for 1 h to obtain mixture I.

[0055] Step 2: Add 30 parts of phenolic resin to mixture I obtained in Step 1, and stir for 30 minutes at a speed of 1500 r / min to obtain a paste.

[0056] Step 3: Pour the paste obtained in Step 2 into a mold and cure it at room temperature (25°C) under a cold pressing pressure of 10 MPa for 1 hour to obtain the cured product.

[0057] Step 4: Weigh 15 parts of antioxidant hydrophobic material and spray it evenly onto the surface of the cured material. At room temperature of 25℃, perform a second cold pressing curing at a pressure of 15MPa for 2 hours to obtain the straw aerogel composite insulation board blank.

[0058] Step 5: Place the straw aerogel composite insulation board blank obtained in Step 4 into a ventilated environment for cross-linking for 72 hours, and then place it in an oven at a temperature of 110℃ for 8 hours to obtain the straw aerogel composite insulation board.

[0059] Example 2: A straw aerogel composite insulation board, prepared from the following raw materials in parts by weight: 90 parts straw modifier, 75 parts aerogel composite, 25 parts antioxidant hydrophobic agent, 38 parts phenolic resin, and 30 parts KH550.

[0060] The preparation method of the antioxidant hydrophobic compound includes the following steps:

[0061] (α) Weigh 3 parts of natural rubber and add them to a mixed solution of 25 parts of tetrahydrofuran and toluene, wherein the volume percentage of tetrahydrofuran and toluene in the mixed solution is 20%:80%. Heat the solution to 50°C and stir for 30 minutes at a speed of 500 r / min to obtain a homogeneous solution.

[0062] (β) Weigh 5 parts of alumina and dry them at 65℃ for 2 hours, and grind them to obtain alumina powder. Add the alumina powder to the homogeneous slurry obtained in step (α) and stir for 30 minutes at a speed of 500 r / min to obtain an antioxidant homogeneous slurry.

[0063] (γ) Weigh 5 parts of carnauba wax and add it to the antioxidant homogeneous liquid obtained in step (β). Heat it to 100°C using a cooling reflux device and stir it for 60 minutes at a speed of 500 r / min. Seal and store it to obtain the antioxidant hydrophobic material.

[0064] The preparation method of the aerogel complex includes the following steps:

[0065] (I) Weigh 4.5 parts of graphene powder and 4.5 parts of nano-silica and add them to 15 parts of anhydrous ethanol. Stir for 30 min at a speed of 300 r / min to obtain a carbon-silicon mixed dispersion.

[0066] (II) Weigh 7.5 parts of methyltrimethoxysilane and add it to the carbon-silicon mixed dispersion obtained in step (I). Add 2 parts of glacial acetic acid and stir for 40 min at a speed of 500 r / min. Seal and let stand at 25℃ for 24 h to obtain the aerogel complex.

[0067] The preparation method of straw modified materials includes the following steps:

[0068] (a) Weigh 18 parts of corn stalks, dry them at 80℃ for 6 hours, crush them and sieve them through a 20-mesh screen to obtain straw powder. Add the obtained straw powder to 50 parts of deionized water, add saturated sodium carbonate solution to adjust the pH to neutral, wash with deionized water 5 times, and dry them at 80℃ for 12 hours to obtain alkalized straw powder. Weigh 10 parts of kaolin, dry it at 110℃ for 12 hours, grind it and sieve it through an 80-mesh screen to obtain clay powder.

[0069] (b) Weigh 11 parts of epoxy resin, heat to 80°C, and stir for 30 minutes at a speed of 500 r / min. Add 3 parts of rosin, heat to 120°C, and stir for 20 minutes at a speed of 500 r / min to obtain mixture I.

[0070] (c) Weigh 12 parts of graphite powder and add them to the mixture I obtained in step (b). Sonicate for 30 min under a power of 0.5 kW, heat to 110 °C, and stir for 30 min at a speed of 500 r / min to obtain the substrate mixture.

[0071] (d) Add the alkalized straw powder obtained in step (a) to the base mixture, heat to 90°C, and stir for 30 min at a speed of 500 r / min to obtain the straw modified precursor;

[0072] (e) The clay powder obtained in step (a) is added to the straw modified precursor obtained in step (d), heated to 60°C, and stirred for 2 hours at a speed of 500 r / min. Argon gas with a flow rate of 120 ml / min is introduced to obtain the straw modified product.

[0073] This embodiment also provides a method for preparing a straw aerogel composite insulation board, including the following steps:

[0074] Step 1: Weigh 90 parts of straw modifier and 75 parts of aerogel composite and add them to 30 parts of KH550. Stir at 1500 r / min for 1 h to obtain mixture I.

[0075] Step 2: Add 38 parts of phenolic resin to mixture I obtained in Step 1, and stir at 1500 r / min for 30 min to obtain a paste.

[0076] Step 3: Pour the paste obtained in Step 2 into a mold and cure it at room temperature (25°C) under a cold pressing pressure of 10 MPa for 1 hour to obtain the cured product.

[0077] Step 4: Weigh 25 parts of antioxidant hydrophobic material and spray it evenly onto the surface of the cured material. At room temperature of 25℃, perform a second cold pressing curing at a pressure of 15MPa for 2 hours to obtain the straw aerogel composite insulation board blank.

[0078] Step 5: Place the straw aerogel composite insulation board blank obtained in Step 4 into a ventilated environment for cross-linking for 72 hours, and then place it in an oven at a temperature of 130℃ for 8 hours to obtain the straw aerogel composite insulation board.

[0079] Example 3: A straw aerogel composite insulation board, prepared from the following raw materials in parts by weight: 100 parts straw modifier, 85 parts aerogel composite, 35 parts antioxidant hydrophobic agent, 45 parts phenolic resin, and 30 parts KH550.

[0080] The preparation method of the antioxidant hydrophobic compound includes the following steps:

[0081] (α) Weigh 4 parts of natural rubber and add them to a mixed solution of 25 parts of tetrahydrofuran and toluene, wherein the volume percentage of tetrahydrofuran and toluene in the mixed solution is 20%:80%. Heat the solution to 50°C and stir for 30 minutes at a speed of 500 r / min to obtain a homogeneous solution.

[0082] (β) Weigh 6 parts of alumina and dry them at 65℃ for 2 hours, and grind them to obtain alumina powder. Add the alumina powder to the homogeneous slurry obtained in step (α) and stir for 30 minutes at a speed of 500 r / min to obtain an antioxidant homogeneous slurry.

[0083] (γ) Weigh 5 parts of carnauba wax and add it to the antioxidant homogeneous liquid obtained in step (β). Heat it to 110°C using a cooling reflux device and stir it for 60 min at a speed of 500 r / min. Seal and store for 5 h to obtain the antioxidant hydrophobic material.

[0084] The preparation method of the aerogel complex includes the following steps:

[0085] (I) Weigh 5.5 parts of graphene powder and 4.5 parts of nano-silica and add them to 15 parts of anhydrous ethanol. Stir for 30 min at a speed of 300 r / min to obtain a carbon-silicon mixed dispersion.

[0086] (II) Weigh 9 parts of methyltrimethoxysilane and add them to the carbon-silicon mixed dispersion obtained in step (I). Add 3 parts of glacial acetic acid and stir for 40 min at a speed of 500 r / min. Seal and let stand at 25℃ for 24 h to obtain the aerogel complex.

[0087] The preparation method of straw modified materials includes the following steps:

[0088] (a) Weigh 20 parts of corn stalks, dry them at 80℃ for 6 hours, crush them and sieve them through a 20-mesh screen to obtain straw powder. Add the obtained straw powder to 50 parts of deionized water, add saturated sodium carbonate solution to adjust the pH to neutral, wash with deionized water 5 times, and dry them at 80℃ for 12 hours to obtain alkalized straw powder. Weigh 12 parts of kaolin, dry it at 110℃ for 12 hours, grind it and sieve it through an 80-mesh screen to obtain clay powder.

[0089] (b) Weigh 12 parts of epoxy resin, heat to 80°C, and stir for 30 minutes at a speed of 500 r / min. Add 3 parts of rosin, heat to 120°C, and stir for 20 minutes at a speed of 500 r / min to obtain mixture I.

[0090] (c) Weigh 15 parts of graphite powder and add them to the mixture I obtained in step (b). Sonicate for 30 min under a power of 0.5 kW, heat to 110 °C, and stir for 30 min at a speed of 500 r / min to obtain the substrate mixture.

[0091] (d) Add the alkalized straw powder obtained in step (a) to the base mixture, heat to 90°C, and stir for 30 min at a speed of 500 r / min to obtain the straw modified precursor;

[0092] (e) The clay powder obtained in step (a) is added to the straw modified precursor obtained in step (d), heated to 60°C, and stirred for 2 hours at a speed of 500 r / min. Argon gas with a flow rate of 120 ml / min is introduced to obtain the straw modified product.

[0093] This embodiment also provides a method for preparing a straw aerogel composite insulation board, including the following steps:

[0094] Step 1: Weigh 100 parts of straw modifier and 85 parts of aerogel composite and add them to 30 parts of KH550. Stir at 1500 r / min for 1 h to obtain mixture I.

[0095] Step 2: Add 45 parts of phenolic resin to mixture I obtained in Step 1, and stir for 30 minutes at a speed of 1500 r / min to obtain a paste.

[0096] Step 3: Pour the paste obtained in Step 2 into a mold and cure it at room temperature (25°C) under a cold pressing pressure of 10 MPa for 1 hour to obtain the cured product.

[0097] Step 4: Weigh 35 parts of antioxidant hydrophobic material and spray it evenly onto the surface of the cured material. At room temperature of 25℃, perform a second cold pressing curing at a pressure of 15MPa for 2 hours to obtain the straw aerogel composite insulation board blank.

[0098] Step 5: Place the straw aerogel composite insulation board blank obtained in Step 4 into a ventilated environment for cross-linking for 72 hours, and then place it in an oven at a temperature of 150℃ for 8 hours to obtain the straw aerogel composite insulation board.

[0099] The difference between Example 4 and Example 2 is that argon is replaced with nitrogen, and the rest is the same as Example 2.

[0100] Comparative example:

[0101] The difference between Comparative Example 1 and Example 2 is that no straw modifier was added; the rest is the same as Example 2.

[0102] The difference between Comparative Example 2 and Example 2 is that no aerogel complex was added; the rest is the same as Example 2.

[0103] The difference between Comparative Example 3 and Example 2 is that no antioxidant hydrophobic agent was added; the rest is the same as Example 2.

[0104] The performance of the straw aerogel composite insulation boards obtained in the examples and comparative examples was tested respectively. Figure 3 The strength test diagram of the straw aerogel composite insulation board shows that the compressive strength and tensile strength of the straw aerogel composite insulation board prepared in the example are generally better than those of the comparative example. Figure 4 The figures show the thermal conductivity test results of the straw aerogel composite insulation boards prepared in the examples and comparative examples. The overall thermal conductivity of the straw aerogel composite insulation board prepared in the examples is close to 0.01 W / m·K, which shows high thermal insulation performance. The thermal conductivity test was conducted in accordance with GB / T 10294-2008. Figure 5The figures show the loss rate and hydrophobicity test results of the straw aerogel composite insulation boards prepared in the examples and comparative examples. The loss rate was tested by placing the prepared straw aerogel composite insulation boards at 180℃ for 24 hours. It can be seen that the loss rate of the straw aerogel composite insulation boards prepared in the examples remained below 2%, indicating that the material exhibits good performance in heat resistance and oxidation resistance. The hydrophobicity test of the straw aerogel composite insulation boards was conducted according to GB / T 17657-2013. Figure 5 The test data shows that the hydrophobicity of the straw aerogel composite insulation board reaches 99.5%, indicating excellent hydrophobicity. In addition, when argon is replaced with nitrogen, the data analysis and comparison between Example 4 and Example 2 show no significant changes, indicating that nitrogen can be used as an inert gas in the preparation process.

[0105] In summary, it can be seen that the prepared straw aerogel composite insulation board has good performance in terms of strength, heat insulation, oxidation resistance and hydrophobicity.

[0106] Obviously, the above comparative examples and embodiments are only a part of the comparative examples and embodiments of the present invention, and they, along with the comparative examples and embodiments referenced based on such examples, are all within the scope of protection of this invention.

[0107] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

[0108] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention. The actual application is not limited to this. In conclusion, if those skilled in the art are inspired by this description and design similar methods and embodiments without departing from the spirit of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A straw aerogel composite insulation board, characterized in that, It is prepared from the following raw materials in parts by weight: 80-100 parts of straw modifier, 65-85 parts of aerogel complex, 15-35 parts of antioxidant hydrophobic agent, 30-45 parts of phenolic resin and 30 parts of silane coupling agent. The raw materials for preparing the straw modified material include straw, carbon-based materials, clay, epoxy resin and rosin, and the mass ratio of straw, carbon-based materials, clay, epoxy resin and rosin is 15-20:9-15:8-12:10-12:

3. The raw materials for preparing the aerogel composite include graphene powder, nano-silica, and methyltrimethoxysilane, wherein the mass ratio of graphene powder, nano-silica, and methyltrimethoxysilane is 3.5-5.5:4.5:6-9. The raw materials for preparing the antioxidant hydrophobic material include alumina, natural rubber and plant wax, and the mass ratio of alumina, natural rubber and plant wax is 4-6:2-4:

5. The method for preparing the modified straw product includes the following steps: (a) Weigh the straw, dry it, crush it and sieve it to obtain straw powder. Add the obtained straw powder to deionized water, add salt solution to adjust the pH, wash and dry it to obtain alkalized straw powder. Weigh the clay, dry it, grind it and sieve it to obtain fine clay powder. (b) Weigh the epoxy resin, heat and stir, add rosin, heat and stir to obtain mixture I; (c) Weigh out the carbon-based material and add it to the mixture I obtained in step (b), sonicate, heat and stir to obtain the substrate mixture; (d) Add the alkalized straw powder obtained in step (a) to the base mixture, heat and stir to obtain the straw modified precursor; (e) Add the clay powder obtained in step (a) to the straw modified precursor obtained in step (d), heat and stir to obtain the straw modified product.

2. The straw aerogel composite insulation board according to claim 1, characterized in that, The straw mentioned in step (a) is corn straw, the clay is kaolin, the salt solution is saturated sodium carbonate solution, the pH is neutral, the straw sieve mesh is 20 mesh, the clay sieve mesh is 80 mesh, and the carbon-based material mentioned in step (c) is graphite powder.

3. The straw aerogel composite insulation board according to claim 1, characterized in that, The preparation method of the aerogel complex includes the following steps: (I) Weigh graphene powder and nano-silica and add them to anhydrous ethanol. Stir to obtain a carbon-silicon mixed dispersion. (II) Weigh methyltrimethoxysilane and add it to the carbon-silicon mixed dispersion obtained in step (I), add acid solution, stir, seal and let stand to obtain aerogel complex.

4. The straw aerogel composite insulation board according to claim 3, characterized in that, The acid solution in step (II) is glacial acetic acid, and the standing temperature is 25°C and the standing time is 24h.

5. The straw aerogel composite insulation board according to claim 1, characterized in that, The method for preparing the antioxidant hydrophobic material includes the following steps: (α) Weigh natural rubber and add it to a mixed solution of tetrahydrofuran and toluene, heat and stir to obtain a homogeneous solution; (β) Weigh alumina, dry and grind it to obtain alumina powder. Add the alumina powder to the homogeneous liquid obtained in step (α) and stir to obtain an antioxidant homogeneous liquid. (γ) Weigh the plant wax and add it to the antioxidant homogeneous liquid obtained in step (β), heat and stir, seal and store to obtain the antioxidant hydrophobic substance.

6. The straw aerogel composite insulation board according to claim 5, characterized in that, In step (α), the volume percentage of tetrahydrofuran and toluene in the mixed solution is 20%:80%, and the plant wax in step (γ) is carnauba wax.

7. A method for preparing a straw aerogel composite insulation board according to any one of claims 1-6, characterized in that, Includes the following steps: Step 1: Weigh the straw modifier and aerogel complex, add them to the silane coupling agent, and stir to obtain mixture I; Step 2: Add phenolic resin to mixture I obtained in Step 1, stir, and obtain a paste; Step 3: Pour the paste obtained in Step 2 into a mold, cold press to solidify, and obtain the solidified product; Step 4: Weigh out the antioxidant and hydrophobic material and spray it onto the surface of the cured material. Then, perform a second cold pressing to cure the material and obtain the straw aerogel composite insulation board blank. Step 5: Place the straw aerogel composite insulation board blank obtained in Step 4 into a ventilated environment for cross-linking, and then place it in an oven for treatment to obtain the straw aerogel composite insulation board.

8. The method for preparing a straw aerogel composite insulation board according to claim 7, characterized in that, The silane coupling agent mentioned in step one is KH550, the cold pressing pressure mentioned in step three is 10MPa, the cold pressing time is 1h, the secondary cold pressing pressure mentioned in step four is 15MPa, the cold pressing time is 2h, the crosslinking time mentioned in step five is 72h, the oven temperature is 110-150℃, and the heating time is 8h.

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