Modified bamboo material, preparation method and application thereof

Abstract

The present invention relates to the technical field of cooling fillers, and more specifically to a modified bamboo material, its preparation method, and its application. The present invention subjects dried bamboo material to a vacuum pressure impregnation treatment in a modification solution, allowing nano-silica particles and nano-alumina particles to penetrate into the bamboo cell cavity without affecting the structure and shape of the bamboo material itself. The nano-silica particles and nano-alumina particles hydrogen bond with the bamboo cell cavity to enhance the binding force between the bamboo molecules, making the vibration and movement of the bamboo molecules more orderly when heated, requiring more energy to change its temperature, thereby improving the specific heat performance of the modified bamboo material. Furthermore, the nano-silica particles and nano-alumina particles that penetrate into the bamboo cell cavity increase heat storage sites, thereby increasing the overall heat storage capacity of the modified bamboo material and improving the specific heat performance of the modified bamboo material, thereby resolving the technical problem of insufficient specific heat performance of existing bamboo materials.

Description

Technical Field

[0001] The invention relates to the technical field of cooling fillers, and in particular to a modified bamboo material, a preparation method and an application thereof. Background Art

[0002] Power plant cooling towers are widely used in the industrial sector, offering strong heat dissipation capabilities and energy savings. As a core component of a cooling tower, the cooling filler is responsible for 60% to 70% of the tower's heat dissipation, and its type significantly impacts its cooling performance. Power plant cooling tower filler materials must possess excellent specific heat properties, enabling rapid cooling of hot water for recycling and significantly reducing operating costs.

[0003] Currently, the most widely used PVC film filler on the market is PVC film filler. However, it has disadvantages such as short service life, poor anti-fouling performance, and environmental unfriendliness. Therefore, it is urgent to seek a PVC film filler alternative with long service life, low production cost, and environmental friendliness.

[0004] Bamboo filler is considered a cooling filler with great development potential, and bamboo has already been used as filler in power plant cooling towers. However, bamboo's specific heat capacity currently does not fully meet the requirements for power plant cooling tower fillers, limiting its application in power plant cooling towers. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art, provide a modified bamboo material and a preparation method and application thereof, and solve the technical problem that the prior art bamboo material has insufficient specific heat performance.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The invention provides a preparation method of modified bamboo, comprising the following steps: mixing silicon dioxide, aluminum oxide, a silane coupling agent and a solvent to prepare a modified solution; subjecting the dried bamboo to a vacuum pressure impregnation treatment in the modified solution, allowing part of the silicon dioxide and aluminum oxide to penetrate into the interior of the bamboo; and drying the bamboo for a second time to prepare the modified bamboo. The silicon dioxide and aluminum oxide are nanoparticles, the molar ratio of the silicon dioxide, aluminum oxide and silane coupling agent is 1:1:1-2, and the molecular weight of the silane coupling agent is 200-250.

[0008] Optionally, the moisture content of the dried bamboo material is 10wt% to 15wt%.

[0009] Optionally, the mass proportion of the modified solution that permeates the modified bamboo material in the modified solution is 8% to 10%.

[0010] The moisture content of the dried bamboo will affect the absorption effect of the modified solution. The higher the moisture content, the less the modified solution is absorbed.

[0011] Optionally, the vacuum pressure impregnation treatment comprises the following steps: placing the dried bamboo material in an impregnation device, maintaining the pressure for 30 minutes after vacuum treatment, adding the modified solution and pressurizing it to one atmosphere, and maintaining the pressure for 30 minutes.

[0012] Optionally, the particle size of the silicon dioxide and the aluminum oxide is less than or equal to 100 nm.

[0013] Optionally, the solvent is water.

[0014] The present invention provides a modified bamboo material, which is prepared by adopting the above-mentioned preparation method of the modified bamboo material.

[0015] The present invention provides an application of the modified bamboo material in preparing a filler for a cooling tower in a power plant.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The present invention subjects dried bamboo to a vacuum pressure impregnation treatment in a modification solution, allowing nano-silica and nano-alumina particles to penetrate into the bamboo cell cavities without affecting the structure and shape of the bamboo itself. The nano-silica and nano-alumina particles hydrogen-bond with the bamboo cell cavities, strengthening the binding force between the bamboo molecules. This results in more orderly vibration and movement of the molecules when heated, requiring more energy to change their temperature, thereby improving the specific heat performance of the modified bamboo. Furthermore, the nano-silica and nano-alumina particles, due to their high specific surface area, have a high heat storage capacity. The nano-silica and nano-alumina particles that penetrate into the bamboo cell cavities increase the number of heat storage sites, thereby increasing the overall heat storage capacity of the modified bamboo and improving the specific heat performance of the modified bamboo. Therefore, the preparation method of the present invention can address the technical problem of insufficient specific heat performance of existing bamboo materials.

[0018] The bamboo material of the present invention, after being subjected to vacuum pressure impregnation treatment in a modified solution, can significantly improve its specific heat capacity, with the specific heat capacity being 1.3 to 1.5 times that of the bamboo material before modification, thereby facilitating the cooling of water in a cooling tower. The preparation process of the present invention is simple, low-cost, easy to operate, and suitable for mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a comparison chart of the specific heat performance of bamboo before and after modification provided by the present invention.

[0020] Figure 2 This is a statistical diagram of the quality changes of the bamboo material provided by the present invention before and after vacuum pressure impregnation treatment.

[0021] Figure 3 These are scanning electron microscope images of the modified bamboo material provided by the present invention, wherein a is a scanning electron microscope image of a cross section of the modified bamboo material, and b is a scanning electron microscope image of a tangential section of the modified bamboo material.

[0022] Figure 4 These are scanning electron microscope images of the unmodified bamboo provided by the present invention, wherein a is a scanning electron microscope image of the cross section of the unmodified bamboo, and b is a scanning electron microscope image of the tangential section of the unmodified bamboo.

[0023] Figure 5 This is a comparison chart of the thermal stability of bamboo before and after modification provided by the present invention. Among them, a is the mass temperature curve, and b is the flow rate temperature curve. DETAILED DESCRIPTION

[0024] In order to solve the above technical problems, the present invention provides a modified bamboo material and a preparation method and application thereof. The technical solutions and embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0025] The present invention is described in detail below through specific examples. The examples are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0026] The untreated bamboo blocks in the embodiment of the present invention are selected from 3-year-old moso bamboos produced in Anhui Taiping Forest Farm.

[0027] The silane coupling agent in the embodiment of the present invention is selected from silane coupling agent KH550, Shanghai Yuanye Biotechnology Co., Ltd., model S15028-500ml, English name: AMEO, CAS: 919-30-2, specification: BR, 98%, molecular formula: C9H 23 NO3Si, molecular weight: 221.37.

[0028] The equipment used for microwave-assisted drying in the embodiment of the present invention is a common microwave heating equipment on the market.

[0029] Example 1

[0030] This embodiment provides a modification method for improving the thermal conductivity of bamboo. The modification method includes the following steps:

[0031] 1) Microwave-assisted drying of bamboo blocks to a moisture content of 10%.

[0032] 2) Prepare a modified solution by mixing nano-silica, nano-alumina, a silane coupling agent, and water in a suitable ratio and mechanically stirring for 3 hours to fully mix the solution. The molar ratio of silica, alumina, and silane coupling agent is 1:1:1.

[0033] 3) Treat the dried bamboo blocks with the modification solution. Using a pressure impregnation tank for modification, first place the bamboo blocks in the tank, evacuate the tank, and maintain the pressure for 30 minutes. Then, inject the modification solution and simultaneously pressurize it to 1 atmosphere. This pressure is maintained for 30 minutes. Modification is complete.

[0034] 4) Take out the modified bamboo block, wipe the modified solution on the surface with absorbent paper, and then dry it to a moisture content of 10% to 15%.

[0035] 5) Characterize the modified bamboo blocks to verify that the modified samples meet the requirements for use.

[0036] Example 2

[0037] This embodiment provides a modification method for improving the thermal conductivity of bamboo. The modification method includes the following steps:

[0038] 1) Microwave-assisted drying of bamboo blocks to a moisture content of 11%.

[0039] 2) Prepare a modified solution by mixing nano-silica, nano-alumina, a silane coupling agent, and water in a suitable ratio and mechanically stirring for 3 hours to fully mix the solution. The molar ratio of silica, alumina, and silane coupling agent is 1:1:1.

[0040] 3) Treat the dried bamboo blocks with the modification solution. Using a pressure impregnation tank for modification, first place the bamboo blocks in the tank, evacuate the tank, and maintain the pressure for 30 minutes. Then, inject the modification solution and simultaneously pressurize it to 1 atmosphere. This pressure is maintained for 30 minutes. Modification is complete.

[0041] 4) Take out the modified bamboo block, wipe the modified solution on the surface with absorbent paper, and then dry it to a moisture content of 10% to 15%.

[0042] 5) Characterize the modified bamboo blocks to verify that the modified samples meet the requirements for use.

[0043] Example 3

[0044] This embodiment provides a modification method for improving the thermal conductivity of bamboo. The modification method includes the following steps:

[0045] 1) Microwave-assisted drying of bamboo blocks to a moisture content of 12%.

[0046] 2) Prepare a modified solution by mixing nano-silica, nano-alumina, a silane coupling agent, and water in a suitable ratio and mechanically stirring for 3 hours to fully mix the solution. The molar ratio of silica, alumina, and silane coupling agent is 1:1:1.

[0047] 3) Treat the dried bamboo blocks with the modification solution. Using a pressure impregnation tank for modification, first place the bamboo blocks in the tank, evacuate the tank, and maintain the pressure for 30 minutes. Then, inject the modification solution and simultaneously pressurize it to 1 atmosphere. This pressure is maintained for 30 minutes. Modification is complete.

[0048] 4) Take out the modified bamboo block, wipe the modified solution on the surface with absorbent paper, and then dry it to a moisture content of 10% to 15%.

[0049] 5) Characterize the modified bamboo blocks to verify that the modified samples meet the requirements for use.

[0050] Example 4

[0051] This embodiment provides a modification method for improving the thermal conductivity of bamboo. The modification method includes the following steps:

[0052] 1) Microwave-assisted drying of bamboo blocks to a moisture content of 13%.

[0053] 2) Prepare a modified solution by mixing nano-silica, nano-alumina, a silane coupling agent, and water in a suitable ratio and mechanically stirring for 3 hours to fully mix the solution. The molar ratio of silica, alumina, and silane coupling agent is 1:1:1.

[0054] 3) Treat the dried bamboo blocks with the modification solution. Using a pressure impregnation tank for modification, first place the bamboo blocks in the tank, evacuate the tank, and maintain the pressure for 30 minutes. Then, inject the modification solution and simultaneously pressurize it to 1 atmosphere. This pressure is maintained for 30 minutes. Modification is complete.

[0055] 4) Take out the modified bamboo block, wipe the modified solution on the surface with absorbent paper, and then dry it to a moisture content of 10% to 15%.

[0056] 5) Characterize the modified bamboo blocks to verify that the modified samples meet the requirements for use.

[0057] Example 5

[0058] This embodiment provides a modification method for improving the thermal conductivity of bamboo. The modification method includes the following steps:

[0059] 1) Microwave-assisted drying of bamboo blocks to a moisture content of 14%.

[0060] 2) Prepare a modified solution by mixing nano-silica, nano-alumina, a silane coupling agent, and water in a suitable ratio and mechanically stirring for 3 hours to fully mix the solution. The molar ratio of silica, alumina, and silane coupling agent is 1:1:1.

[0061] 3) Treat the dried bamboo blocks with the modification solution. Using a pressure impregnation tank for modification, first place the bamboo blocks in the tank, evacuate the tank, and maintain the pressure for 30 minutes. Then, inject the modification solution and simultaneously pressurize it to 1 atmosphere. This pressure is maintained for 30 minutes. Modification is complete.

[0062] 4) Take out the modified bamboo block, wipe the modified solution on the surface with absorbent paper, and then dry it to a moisture content of 10% to 15%.

[0063] 5) Characterize the modified bamboo blocks to verify that the modified samples meet the requirements for use.

[0064] Example 6

[0065] This embodiment provides a modification method for improving the thermal conductivity of bamboo. The modification method includes the following steps:

[0066] 1) Microwave-assisted drying of bamboo blocks to a moisture content of 15%.

[0067] 2) Prepare a modified solution by mixing nano-silica, nano-alumina, a silane coupling agent, and water in a suitable ratio and mechanically stirring for 3 hours to fully mix the solution. The molar ratio of silica, alumina, and silane coupling agent is 1:1:1.

[0068] 3) Treat the dried bamboo blocks with the modification solution. Using a pressure impregnation tank for modification, first place the bamboo blocks in the tank, evacuate the tank, and maintain the pressure for 30 minutes. Then, inject the modification solution and simultaneously pressurize it to 1 atmosphere. This pressure is maintained for 30 minutes. Modification is complete.

[0069] 4) Take out the modified bamboo block, wipe the modified solution on the surface with absorbent paper, and then dry it to a moisture content of 10% to 15%.

[0070] 5) Characterize the modified bamboo blocks to verify that the modified samples meet the requirements for use.

[0071] Example 7

[0072] This embodiment provides a modification method for improving the thermal conductivity of bamboo. The modification method includes the following steps:

[0073] 1) Microwave-assisted drying of bamboo blocks to a moisture content of 10%.

[0074] 2) Prepare a modified solution by mixing nano-silica, nano-alumina, a silane coupling agent, and water in a suitable ratio and mechanically stirring for 3 hours to fully mix the solution. The molar ratio of silica, alumina, and silane coupling agent is 1:1:2.

[0075] 3) Treat the dried bamboo blocks with the modification solution. Using a pressure impregnation tank for modification, first place the bamboo blocks in the tank, evacuate the tank, and maintain the pressure for 30 minutes. Then, inject the modification solution and simultaneously pressurize it to 1 atmosphere. This pressure is maintained for 30 minutes. Modification is complete.

[0076] 4) Take out the modified bamboo block, wipe the modified solution on the surface with absorbent paper, and then dry it to a moisture content of 10% to 15%.

[0077] 5) Characterize the modified bamboo blocks to verify that the modified samples meet the requirements for use.

[0078] Specific heat performance test

[0079] The untreated samples were compared with the samples treated in Example 1 and were directly cut into 2×2 cm samples.

[0080] Test instrument name and model: Hot Disk thermal constant analyzer, model TPS2500S.

[0081] The specific test steps are as follows:

[0082] 1. Place the sample. Clamp the Hot Disk probe between two samples or place one side against the sample, applying slight pressure to ensure close contact. Avoid air bubbles or gaps between the probe and the sample.

[0083] 2. Start the test. Initiate the test through the software. The probe will apply a transient heat pulse and record the temperature response curve. Keep the instrument and sample stationary during the test.

[0084] 3. The data acquisition instrument automatically records the temperature changes over time and calculates the thermal parameters through the mathematical model TPS theory.

[0085] Test results: Figure 1 As shown in the figure, the specific heat capacity of bamboo before and after modification is 0.6 MJ / m 3 K and 0.85MJ / m 3 K, the specific heat capacity of the modified bamboo material is about 1.4 times that of the unmodified bamboo material. This shows that the specific heat capacity of the modified bamboo material prepared in Example 1 is significantly improved compared to the unmodified bamboo material.

[0086] Immersion absorption test

[0087] Weight Gain Test Method: Weigh directly before and after treatment using a scale, and calculate the weight gain. Samples are air-dried to a moisture content between 10% and 12%. The weight change before and after immersion for a total of 60 samples is statistically analyzed, with the weight gain representing the extent of absorption of the modified solution.

[0088] Test results: Figure 2The present invention provides a statistical diagram of the quality change of bamboo before and after vacuum pressure impregnation treatment. Figure 2 As shown in FIG, compared with the bamboo material before vacuum pressure impregnation treatment, the weight of the bamboo material after vacuum pressure impregnation treatment is significantly increased, indicating that the vacuum pressure impregnation treatment can make the bamboo material impregnate and absorb part of the modified solution.

[0089] Cross-section morphology characterization

[0090] For a 2×2cm sample, the surface was flattened with a microtome, and a transverse electron microscope was taken directly on the end face. Then the sample was cut open and the tangential surface was photographed.

[0091] Test results: Figure 3 These are scanning electron microscope images of the modified bamboo material provided by the present invention, wherein a is a scanning electron microscope image of a cross section of the modified bamboo material, and b is a scanning electron microscope image of a tangential section of the modified bamboo material. Figure 4 The following are scanning electron micrographs of the unmodified bamboo provided by the present invention, where a is a scanning electron micrograph of a cross-section of the unmodified bamboo, and b is a scanning electron micrograph of a tangential section of the unmodified bamboo. Comparison shows that the unmodified bamboo has a porous structure, while the modified bamboo contains chemical particles, which are nano-silica and nano-alumina particles, occupying some of the pores. This indicates that the nano-silica and nano-alumina particles have successfully penetrated into the bamboo cell cavity, resulting in the production of modified bamboo.

[0092] Thermal stability test

[0093] Comparison of untreated and treated samples, directly cut into 2×2 cm samples.

[0094] Test instrument name and model: Hot Disk thermal constant analyzer, model TPS2500S.

[0095] The specific test steps are as follows:

[0096] 1. Place the sample. Clamp the Hot Disk probe between two samples or place one side against the sample, applying slight pressure to ensure close contact. Avoid air bubbles or gaps between the probe and the sample.

[0097] 2. Start the test. Initiate the test through the software. The probe will apply a transient heat pulse and record the temperature response curve. Keep the instrument and sample stationary during the test.

[0098] 3. The data acquisition instrument automatically records the temperature changes over time and calculates the thermal parameters through the mathematical model TPS theory.

[0099] Test results: Figure 5 As shown, Figure 5 a in the equation uses the mass change rate to characterize thermal stability. Figure 5The thermal stability is characterized by the heat flow rate per unit mass (the vertical axis in the figure, W / g). Higher values on the vertical axis indicate less decomposition and greater stability. Combining Figures a and b, we can see that the initial mass change rate of the modified bamboo material is higher than that of the unmodified bamboo material, and the heat flow rate per unit mass is significantly better. This indicates that the modified bamboo material has better thermal stability, resulting in higher heat absorption capacity and, in turn, better specific heat properties.

[0100] The above description is merely a preferred embodiment of the present invention, and the above specific embodiment is not intended to limit the present invention. Various variations and modifications are possible within the technical scope of the present invention. Any modifications, alterations, or equivalent substitutions made by a person skilled in the art based on the above description are within the scope of protection of the present invention.

Claims

1. A method for preparing modified bamboo material, characterized in that: The following steps are involved: mixing silica, alumina, a silane coupling agent and a solvent to prepare a modified solution; The dried bamboo is subjected to vacuum pressure impregnation treatment in a modification solution, so that part of the silica and alumina penetrate into the bamboo, and after a second drying, a modified bamboo is obtained; Wherein, silicon dioxide and aluminum oxide are nanoparticles, the molar ratio of silicon dioxide, aluminum oxide and silane coupling agent is 1:1:1-2, and the molecular weight of the silane coupling agent is 200-250; The mass proportion of the modified solution that permeates the modified bamboo material in the modified solution is 8% to 10%; The vacuum pressure impregnation process comprises the following steps: The dried bamboo is placed in an impregnation device, vacuumed and pressure maintained for 30 minutes, the modified solution is added and pressurized to one atmosphere, and the pressure is maintained for 30 minutes.

2. The method for preparing modified bamboo material according to claim 1, wherein: The moisture content of the dried bamboo material is 10 wt % to 15 wt %.

3. The method for preparing modified bamboo material according to claim 1, wherein: The particle sizes of the silicon dioxide and the aluminum oxide are both less than or equal to 100 nm.

4. The method for preparing modified bamboo material according to claim 1, wherein: The solvent is water.

5. A modified bamboo material, characterized in that: The modified bamboo material is prepared by the preparation method of any one of claims 1 to 4.

6. Use of the modified bamboo material according to claim 5 in preparing fillers for cooling towers in power plants.

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