Modified bamboo wood and preparation method and application thereof

Abstract

The invention relates to the technical field of cooling filler, in particular to modified bamboo wood and a preparation method and application thereof. The dried bamboos are subjected to vacuum pressure dipping treatment in the modification solution, so that nano silicon dioxide particles and nano aluminum oxide particles can permeate into the cell cavities of the bamboos, meanwhile, the structure and shape of the bamboos are not affected, the nano silicon dioxide particles and the nano aluminum oxide particles are combined with the cell cavities of the bamboos through hydrogen bonds, and therefore the cell cavities of the bamboos can be modified. The method has the advantages that the temperature of the bamboo can be changed by the aid of the temperature of the bamboo, accordingly, binding force among bamboo molecules can be enhanced, vibration and movement of the molecules can be ordered when the bamboo is heated, the temperature of the bamboo can be changed by the aid of more energy, and the specific heat performance of the modified bamboo can be improved. Besides, the nano silicon dioxide particles and the nano aluminum oxide particles permeating into the cell cavities of the bamboo wood can increase heat storage sites, so that the overall heat storage capacity of the modified bamboo wood is improved, the specific heat performance of the modified bamboo wood is improved, and the technical problem that the specific heat performance of existing bamboo wood is insufficient can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of cooling fillers, and specifically relates to a modified bamboo and its preparation method and application. Background Art

[0002] The cooling tower of a power plant is a cooling device with strong heat dissipation ability and energy saving, which is widely used in the industrial field. As the core component of the cooling tower, the cooling filler is responsible for 60% - 70% of the heat dissipation of the cooling tower, and its type has an important impact on its cooling performance. The filler of the power plant cooling tower requires materials to have good specific heat performance, which can quickly cool down hot water for recycling, thus greatly reducing the use cost.

[0003] Currently, the most widely used filler in the market is the PVC film filler. However, it has the disadvantages of short service life, poor anti-pollution performance, and being unfriendly to the environment. Therefore, it is urgent to seek a substitute for the PVC film filler with long service life, low production cost, and environmental friendliness.

[0004] Bamboo fillers are considered to be a kind of cooling filler with great development potential, and there are already examples of using bamboo as the filler of power plant cooling towers. However, the specific heat performance of bamboo currently cannot fully meet the requirements of power plant cooling tower fillers, which limits the application of bamboo in power plant cooling tower fillers. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art, and provide a modified bamboo and its preparation method and application, which solves the technical problem of insufficient specific heat performance of existing bamboo.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions: The present invention provides a preparation method of a modified bamboo, including 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 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 after the second drying, obtaining the modified bamboo; wherein, the silicon dioxide and aluminum oxide are nanoparticles, and the molar ratio of silicon dioxide, aluminum oxide and the silane coupling agent is 1:1:1 - 2, and the molecular weight of the silane coupling agent is 200 - 250.

[0007] Optionally, the moisture content of the dried bamboo is 10wt% - 15wt%.

[0008] Optionally, the mass ratio of the part of the modified solution penetrated into the interior of the modified bamboo in the modified solution is 8% - 10%.

[0009] The moisture content of the dried bamboo will affect the absorption effect of the modification solution. The higher the moisture content, the less the absorption amount of the modification solution.

[0010] Optionally, the vacuum pressure impregnation treatment includes the following steps: placing the dried bamboo in an impregnation device, performing a vacuum treatment and maintaining the pressure for 30 min, adding the modification solution and pressurizing to one atmospheric pressure, and maintaining the pressure for 30 min.

[0011] Optionally, the particle sizes of the silicon dioxide and the aluminum oxide are less than or equal to 100 nm.

[0012] Optionally, the solvent is water.

[0013] The present invention provides a modified bamboo prepared by the above-mentioned preparation method of the modified bamboo.

[0014] The present invention provides an application of the above-mentioned modified bamboo in the preparation of a filler for a power plant cooling tower.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: In the present invention, the dried bamboo is subjected to vacuum pressure impregnation treatment in a modification solution, so that nano-silicon dioxide particles and nano-aluminum oxide particles can penetrate into the bamboo cell cavity, and at the same time, the structure and shape of the bamboo itself are not affected. The nano-silicon dioxide particles and nano-aluminum oxide particles are combined with the bamboo cell cavity through hydrogen bonds to enhance the intermolecular binding force of the bamboo, making the vibration and movement of the molecules more orderly when the bamboo is heated, and more energy is required to change its temperature, thereby improving the specific heat performance of the modified bamboo. In addition, the nano-silicon dioxide particles and nano-aluminum oxide particles have a high heat storage capacity due to their high specific surface area. The nano-silicon dioxide particles and nano-aluminum oxide particles penetrating into the bamboo cell cavity can increase the heat storage sites, thereby increasing the overall heat storage capacity of the modified bamboo to improve the specific heat performance of the modified bamboo. Therefore, the preparation method of the present invention can solve the technical problem of insufficient specific heat performance of the existing bamboo.

[0016] After the bamboo of the present invention is subjected to vacuum pressure impregnation treatment in a modification solution, the specific heat performance of the bamboo can be significantly improved, and the specific heat capacity is 1.3 to 1.5 times that before modification, which is convenient for cooling the water in the cooling tower. The preparation process of the present invention is simple, low in cost, convenient to operate, and suitable for batch production. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a comparison chart of the specific heat performance of the bamboo before and after the modification treatment provided by the present invention.

[0018] Figure 2 It is a statistical chart of the mass change of the bamboo provided by the present invention before and after the vacuum pressure impregnation treatment.

[0019] Figure 3 Scanning electron microscope images of the modified bamboo provided by the present invention. Among them, a is the scanning electron microscope image of the cross-section of the modified bamboo, and b is the scanning electron microscope image of the tangential section of the modified bamboo.

[0020] Figure 4 Scanning electron microscope images of the unmodified bamboo provided by the present invention. Among them, a is the scanning electron microscope image of the cross-section of the unmodified bamboo, and b is the scanning electron microscope image of the tangential section of the unmodified bamboo.

[0021] Figure 5 Comparison chart of the thermal stability performance of bamboo before and after the modification treatment provided by the present invention. Among them, a is the mass-temperature curve, and b is the flow rate-temperature curve. Detailed implementation manners

[0022] To solve the above technical problems, the present invention provides a modified bamboo and its preparation method and application. Now, the technical solutions and embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0023] The present invention will be described in detail below through specific embodiments. The embodiments are exemplary and are intended to explain the present invention, but should not be construed as limiting the present invention.

[0024] In the embodiment of the present invention, the untreated bamboo blocks are selected from 3-year-old Moso bamboo, and the origin is Taiping Forest Farm in Anhui.

[0025] In the embodiment of the present invention, the silane coupling agent is selected from silane coupling agent KH550, Shanghai Yuanye Bio-Technology Co., Ltd., model number S15028-500ml, English name: AMEO, CAS: 919-30-2, specification: BR, 98%, molecular formula: C 9 H 23 NO 3 Si, molecular weight: 221.37.

[0026] In the embodiment of the present invention, the equipment used for microwave-assisted drying is a common microwave heating equipment on the market.

[0027] Example 1 This embodiment provides a modification method that can improve the thermal conductivity of bamboo. The modification method includes the following steps: 1) Microwave-assisted dry the bamboo blocks until the moisture content is 10%.

[0028] 2) Prepare a modified solution by mixing nano-silica, nano-alumina, silane coupling agent and water in proportion and mechanically stirring for 3 hours to fully mix the solution to obtain a modified solution. Among them, the molar ratio of silica, alumina, and silane coupling agent is 1:1:1.

[0029] 3) Treat the dried bamboo blocks with the modified solution. Use a pressure impregnation tank for modification treatment. First, put the bamboo blocks into the impregnation tank, evacuate the air, maintain the pressure for 30 minutes, then inject the modified solution, and at the same time pressurize to one atmosphere and maintain the pressure for 30 minutes. The modification is completed.

[0030] 4) Take out the modified bamboo blocks above, wipe the modified solution on the surface with absorbent paper, and then dry to a moisture content of 10% - 15%.

[0031] 5) Characterize the modified bamboo blocks to verify that the modified samples meet the usage requirements.

[0032] Example 2 This example provides a modification method that can improve the thermal conductivity of bamboo. The modification method includes the following steps:

[0033] 1) Microwave-assisted dry the bamboo blocks to a moisture content of 11%.

[0034] 2) Prepare the modified solution. Mix nano-silica, nano-alumina, silane coupling agent and water in proportion, and mechanically stir for 3 hours to fully mix the solution to obtain the modified solution. Among them, the molar ratio of silica, alumina, and silane coupling agent is 1:1:1.

[0035] 3) Treat the dried bamboo blocks with the modified solution. Use a pressure impregnation tank for modification treatment. First, put the bamboo blocks into the impregnation tank, evacuate the air, maintain the pressure for 30 minutes, then inject the modified solution, and at the same time pressurize to one atmosphere and maintain the pressure for 30 minutes. The modification is completed.

[0036] 4) Take out the modified bamboo blocks above, wipe the modified solution on the surface with absorbent paper, and then dry to a moisture content of 10% - 15%.

[0037] 5) Characterize the modified bamboo blocks to verify that the modified samples meet the usage requirements.

[0038] Example 3 This example provides a modification method that can improve the thermal conductivity of bamboo. The modification method includes the following steps: 1) Microwave-assisted dry the bamboo blocks to a moisture content of 12%.

[0039] 2) Prepare the modified solution. Mix nano-silica, nano-alumina, silane coupling agent and water in proportion, and mechanically stir for 3 hours to fully mix the solution to obtain the modified solution. Among them, the molar ratio of silica, alumina, and silane coupling agent is 1:1:1.

[0040] 3) Treat the dried bamboo blocks with the modified solution. Use a pressure impregnation tank for modification treatment. First, put the bamboo blocks into the impregnation tank, evacuate the air, maintain the pressure for 30 minutes, then inject the modified solution, and at the same time pressurize to one atmosphere and maintain the pressure for 30 minutes. The modification is completed.

[0041] 4) Take out the above-mentioned modified bamboo blocks, wipe the modified solution on the surface with blotting paper, and then dry to a moisture content of 10% - 15%.

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

[0043] Example 4 This example provides a modification method that can improve the thermal conductivity of bamboo. The modification method includes the following steps:

[0044] 1) Microwave-assisted dry the bamboo blocks to a moisture content of 13%.

[0045] 2) Prepare the modified solution by mixing nano-silica, nano-alumina, silane coupling agent and water in proportion and mechanically stirring for 3 hours to fully mix the solution to obtain the modified solution. Among them, the molar ratio of silica, alumina, and silane coupling agent is 1:1:1.

[0046] 3) Treat the dried bamboo blocks with the modified solution. Use a pressure impregnation tank for modification treatment. First, put the bamboo blocks into the impregnation tank, evacuate the air, maintain the pressure for 30 minutes, then inject the modified solution, and at the same time pressurize to one atmosphere and maintain the pressure for 30 minutes. The modification is completed.

[0047] 4) Take out the above-mentioned modified bamboo blocks, wipe the modified solution on the surface with blotting paper, and then dry to a moisture content of 10% - 15%.

[0048] 5) Characterize the modified bamboo blocks to verify that the modified samples meet the usage requirements.

[0049] Example 5 This example provides a modification method that can improve the thermal conductivity of bamboo. The modification method includes the following steps: 1) Microwave-assisted dry the bamboo blocks to a moisture content of 14%.

[0050] 2) Prepare the modified solution by mixing nano-silica, nano-alumina, silane coupling agent and water in proportion and mechanically stirring for 3 hours to fully mix the solution to obtain the modified solution. Among them, the molar ratio of silica, alumina, and silane coupling agent is 1:1:1.

[0051] 3) Treat the dried bamboo blocks with the modified solution. Use a pressure impregnation tank for modification treatment. First, put the bamboo blocks into the impregnation tank, evacuate the air, maintain the pressure for 30 minutes, then inject the modified solution, and at the same time, pressurize to one atmosphere and maintain the pressure for 30 minutes to complete the modification.

[0052] 4) Take out the above-mentioned modified bamboo blocks, wipe the surface of the modified solution with blotting paper, and then dry to a moisture content of 10% - 15%.

[0053] 5) Characterize the modified bamboo blocks to verify that the modified samples meet the usage requirements.

[0054] Example 6 This example provides a modification method that can improve the thermal conductivity of bamboo. The modification method includes the following steps: 1) Microwave-assisted dry the bamboo blocks to a moisture content of 15%.

[0055] 2) Prepare the modified solution by mixing nano-silica, nano-alumina, silane coupling agent and water in proportion and mechanically stirring for 3 hours to fully mix the solution to obtain the modified solution. Among them, the molar ratio of silica, alumina, and silane coupling agent is 1:1:1.

[0056] 3) Treat the dried bamboo blocks with the modified solution. Use a pressure impregnation tank for modification treatment. First, put the bamboo blocks into the impregnation tank, evacuate the air, maintain the pressure for 30 minutes, then inject the modified solution, and at the same time, pressurize to one atmosphere and maintain the pressure for 30 minutes to complete the modification.

[0057] 4) Take out the above-mentioned modified bamboo blocks, wipe the surface of the modified solution with blotting paper, and then dry to a moisture content of 10% - 15%.

[0058] 5) Characterize the modified bamboo blocks to verify that the modified samples meet the usage requirements.

[0059] Example 7 This example provides a modification method that can improve the thermal conductivity of bamboo. The modification method includes the following steps: 1) Microwave-assisted dry the bamboo blocks to a moisture content of 10%.

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

[0061] 3) Treat the dried bamboo blocks with the modified solution. Use a pressure impregnation tank for modification treatment. First, put the bamboo blocks into the impregnation tank, evacuate the air, maintain the pressure for 30 minutes, then inject the modified solution, and at the same time, pressurize to one atmosphere and maintain the pressure for 30 minutes to complete the modification.

[0062] 4) Take out the above-mentioned modified bamboo blocks, wipe the surface of the modified solution with blotting paper, and then dry them to a moisture content of 10% - 15%.

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

[0064] Specific heat capacity performance test Compare the untreated samples with the samples treated in Example 1, and directly cut them into small samples of 2×2 cm.

[0065] Name and model of the test instrument: Hot Disk Thermal Constants Analyzer, model TPS2500S.

[0066] The specific test steps are as follows: 1. Place the sample. Clamp the Hot Disk probe between two pieces of the sample or closely attach it to one side of the sample, and apply slight pressure to ensure close contact. Avoid the existence of air bubbles or gaps between the probe and the sample.

[0067] 2. Start the test. Start the test through the software, and the probe will apply a transient thermal pulse and record the temperature response curve. Keep the instrument and the sample stationary during the test.

[0068] 3. The data acquisition instrument automatically records the change of temperature with time, and calculates the thermal parameters through the mathematical model TPS theory.

[0069] Test results: As Figure 1 shown, the specific heat capacities of the bamboo before and after the modification treatment are 0.6 MJ / m 3 ·K and 0.85 MJ / m 3 ·K respectively. The specific heat capacity of the modified bamboo is about 1.4 times that of the unmodified bamboo. Thus, compared with the unmodified bamboo, the specific heat capacity of the modified bamboo prepared in Example 1 has been significantly improved.

[0070] Impregnation absorption test Weight gain test method: Weigh the weight directly with a balance before and after the treatment, and then calculate the weight gain rate. The samples are air-dried naturally with a moisture content between 10% - 12%. Statistically analyze the weight changes of a total of 60 samples before and after impregnation, and the weight gain represents the amount of the absorbed modified solution.

[0071] Test results: Figure 2 This is the statistical chart of the mass change of the bamboo provided by the present invention before and after the vacuum pressure impregnation treatment. As Figure 2 shown, compared with the bamboo before the vacuum pressure impregnation treatment, the weight of the bamboo after the vacuum pressure impregnation treatment has increased significantly, indicating that the bamboo can impregnate and absorb part of the modified solution through the vacuum pressure impregnation treatment.

[0072] Characterization of the cross-sectional morphology For a 2×2 cm sample, the surface was planed with a microtome knife, and a transverse SEM image was directly taken on the end face. Then the sample was cut open to take a tangential section image.

[0073] Test results: Figure 3 The SEM images of the modified bamboo provided by the present invention are shown. Among them, a is the SEM image of the cross-section of the modified bamboo, and b is the SEM image of the tangential section of the modified bamboo. Figure 4 The SEM images of the unmodified bamboo provided by the present invention are shown. Among them, a is the SEM image of the cross-section of the unmodified bamboo, and b is the SEM image of the tangential section of the unmodified bamboo. By comparison, it can be seen that the unmodified bamboo has a pore structure, and medicament particles occupying some of the pores can be observed inside the modified bamboo. The medicament particles are nano-silica particles and nano-aluminum oxide particles, which indicates that the nano-silica particles and nano-aluminum oxide particles have successfully penetrated into the bamboo cell cavity, and the modified bamboo has been prepared.

[0074] Thermal stability test Samples before and after treatment were compared, and small samples of 2×2 cm were directly cut.

[0075] Name and model of the test instrument: Hot Disk thermal constant analyzer, model TPS2500S.

[0076] The specific test steps are as follows: 1. Place the sample. Clamp the Hot Disk probe between two samples or closely attach it to one side of the sample, and apply slight pressure to ensure close contact. Avoid air bubbles or gaps between the probe and the sample.

[0077] 2. Start the test. Start the test through the software. The probe will apply a transient thermal pulse and record the temperature response curve. Keep the instrument and the sample stationary during the test.

[0078] 3. The data acquisition instrument automatically records the change of temperature with time, and calculates the thermal parameters through the mathematical model TPS theory.

[0079] Test results: As Figure 5 shown, Figure 5 in a, the mass change rate is used to characterize the thermal stability, Figure 5 in b, the heat flow rate per unit mass is used to characterize the thermal stability, that is, the flow rate W / g on the vertical axis in the figure. The higher the value corresponding to the vertical axis, the less decomposition and the higher the stability. Combining Figure a and Figure b, it can be seen that compared with the bamboo before modification, the initial value of the mass change rate of the modified bamboo obtained after modification is higher, and the heat flow rate per unit mass is significantly better. It shows that the modified bamboo has good thermal stability, thus having a higher heat absorption capacity, and further indicating that the modified bamboo has good specific heat performance.

[0080] The above-described are only the preferred embodiments of the present invention, and the above specific embodiments do not limit the present invention. Within the scope of the technical concept of the present invention, various deformations and modifications can occur. Any retouching, modification or equivalent replacement made by those of ordinary skill in the art according to the above description shall fall within the scope protected by the present invention.

Claims

1. A method for preparing modified bamboo material, characterized in that: The following steps are involved: Mixing silicon dioxide, aluminum oxide, a silane coupling agent and a solvent to prepare a modified solution; The dried bamboo is subjected to vacuum pressure impregnation treatment in a modified solution, so that part of the silicon dioxide and aluminum oxide penetrate into the bamboo, and after a second drying, a modified bamboo is obtained; The 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.

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

3. The method for preparing modified bamboo material according to claim 1, characterized in that: The mass proportion of the modified solution that penetrates into the modified bamboo material in the modified solution is 8% to 10%.

4. The method for preparing modified bamboo material according to claim 1, characterized in that: The vacuum pressure impregnation process comprises the following steps: The dried bamboo is placed in an impregnation device, and after vacuum treatment, the pressure is maintained for 30 minutes. The modified solution is added and the pressure is increased to one atmosphere, and the pressure is maintained for 30 minutes.

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

6. The method for preparing modified bamboo material according to claim 1, characterized in that: The solvent is water.

7. A modified bamboo material, characterized in that: The modified bamboo material is prepared by the preparation method of any one of claims 1 to 6.

8. Use of the modified bamboo material according to claim 7 in preparing fillers for cooling towers in power plants.

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