A method for preparing biomass material thermal insulation film

Abstract

The present disclosure discloses a method for preparing a biomass material thermal insulation film, comprising: S100: washing, drying, grinding, and sieving a biomass material to obtain a biomass material powder; S200: heat-treating the biomass material powder under a certain atmosphere to obtain a porous graphite powder; S300: mixing a certain amount of polyvinylidene fluoride with the porous graphite powder, grinding it, and then mixing it with a certain amount of N-methylpyrrolidone to obtain a slurry; S400: coating the slurry on a glass substrate or a special base tape at a certain temperature; S500: soaking the glass substrate or the special base tape coated with the slurry in deionized water to obtain a thermal insulation film.

Description

Technical Field

[0001] The present disclosure relates specifically to a method for preparing a biomass material thermal insulation film. Background Art

[0002] With rapid economic growth and the intensifying greenhouse effect, global temperatures are rising, and global energy demand is increasing. Buildings are the largest energy consumer, accounting for 33% of total energy consumption in my country and showing an increasing trend year by year. The most effective and direct way to achieve energy conservation in buildings is through the use of thermal insulation materials. These materials can reduce heat loss from indoor and outdoor environments, significantly reducing energy consumption for air conditioning and heating.

[0003] Currently, the thermal insulation materials commonly used in construction include mineral wool, expanded perlite, foam plastics, and aerogels. Mineral wool contains substances like asphalt and glue, which can easily pollute the environment. Expanded perlite, while offering excellent fire resistance and sound insulation, is highly hydrophilic and easily breakable, making it difficult to transport. Foam plastics are lightweight and offer excellent sound and heat insulation properties, but they are flammable and difficult to construct. Aerogel preparation is complex and expensive.

[0004] Biomass energy is a type of energy stored in natural biomass sources. It has the advantages of low cost, easy access, and convenient storage and transportation. Therefore, it has become a renewable clean energy source that countries around the world are competing to develop and utilize. In my country, the main way to utilize biomass energy is to produce biogas or directly burn it for use as fuel. However, when biomass energy is directly burned as fuel, it not only pollutes the environment but also has a low utilization rate. my country has a rich and diverse renewable biomass energy source, with an annual output of over 5 billion tons. Based on this, a method for preparing thermal insulation film materials using biomass materials has been developed. In addition to low production costs and a wide range of raw material sources, it also effectively reduces the environmental pollution caused by burning biomass such as straw. In addition to being green and environmentally friendly and low cost, the product also has advantages in thermal insulation performance. Summary of the Invention

[0005] In response to the deficiencies in the prior art, the purpose of the present disclosure is to provide a method for preparing a biomass material thermal insulation film. The method uses biomass material as raw material, obtains carbon material through high-temperature pyrolysis, and obtains low-cost, good thermal insulation effect and green and environmentally friendly thermal insulation carbon sheet through means such as scraping and curing.

[0006] To achieve the above objectives, the present disclosure provides the following technical solutions:

[0007] A method for preparing a biomass material thermal insulation film comprises the following steps:

[0008] S100: washing, drying, grinding, and sieving the biomass material to obtain biomass material powder;

[0009] S200: heat-treating the biomass material powder under a certain atmosphere to obtain porous graphite powder;

[0010] S300: A certain amount of polyvinylidene fluoride is mixed with porous graphite powder, and after grinding, a certain amount of N-methylpyrrolidone is mixed to obtain a slurry;

[0011] S400: Coating the slurry on a glass substrate or a special base tape at a certain temperature;

[0012] S500: Soaking the glass substrate or special base tape coated with the slurry in deionized water to obtain a heat insulation film.

[0013] Preferably, in step S200, the heat treatment temperature is 500-850°C.

[0014] Preferably, in step S200, the heating rate of the heat treatment is 5°C / min.

[0015] Preferably, in step S300, the mass ratio of the carbon powder to polyvinylidene fluoride is 16:1.

[0016] Preferably, in step S300, the mass ratio of the carbon powder to N-methylpyrrolidone is 400:1.

[0017] Preferably, in step S400, the coating thickness of the slurry is 100um-500um.

[0018] Preferably, in step S400, the coating temperature of the slurry is 60-80°C.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention utilizes the porosity of biomass materials to prepare thermal insulation materials, which not only improves the utilization rate of biomass materials, but also simplifies the preparation process and does not produce excessive harmful gases. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a flow chart of a method for preparing a biomass material thermal insulation film provided by one embodiment of the present disclosure;

[0022] Figure 2 yes Figure 1 SEM schematic diagram of the thermal insulation film prepared by the method shown;

[0023] Figure 3 Schematic diagram of the flexibility of the thermal insulation film material prepared by carbonizing rice husks at 500°C in the present invention;

[0024] Figure 4 Schematic diagram of the fireproof performance of the thermal insulation film material prepared by carbonizing rice husks at 500°C in the present invention. DETAILED DESCRIPTION

[0025] The following will refer to the attached Figures 1 to 4 Specific embodiments of the present disclosure are described in detail. Although specific embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. Instead, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0026] It should be noted that certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that technicians may use different nouns to refer to the same component. This specification and claims do not use the difference in nouns as a way to distinguish components, but use the difference in the functions of the components as the criterion for distinction. As mentioned throughout the specification and claims, "including" or "comprising" is an open term, so it should be interpreted as "including but not limited to". The subsequent description of the specification is a preferred embodiment of the present disclosure, but the description is based on the general principles of the specification and is not used to limit the scope of the present disclosure. The scope of protection of the present disclosure shall be as defined by the attached claims.

[0027] To facilitate understanding of the embodiments of the present disclosure, further explanation will be given below using specific embodiments as examples in conjunction with the accompanying drawings, and the accompanying drawings do not constitute a limitation on the embodiments of the present disclosure.

[0028] In one embodiment, Figure 1 As shown, the present disclosure provides a method for preparing a biomass material thermal insulation film, comprising the following steps:

[0029] 1. The rice husks were repeatedly ultrasonically cleaned with ultrapure water and alcohol to remove dust and impurities. After drying, the rice husks were ground and sieved with 60 mesh to obtain rice husk powder.

[0030] 2. The rice husk powder was heat-treated in a tube furnace at 500° C. for 1 h under an argon atmosphere to obtain carbon powder, wherein the heating rate during the heat treatment was 5° C. / min.

[0031] 3. Mix carbon powder and polyvinylidene fluoride (PVDF) at a mass ratio of 16:1 evenly (if the ratio is less than this, it will not form a thermal insulation film; if it is greater than this, although a thermal insulation film can be prepared, the thermal conductivity will be greatly increased, thereby reducing the thermal insulation). After grinding for 1 hour, add N-methylpyrrolidone (NMP) at a mass ratio of 400:1 to carbon powder to make the polyvinylidene fluoride more evenly dispersed. Mix again to obtain a uniform slurry. In this step, polytetrafluoroethylene can act as a binder, and the thermal conductivity of polytetrafluoroethylene itself is relatively low, at 0.17, which can play a good bonding role with the carbon powder without making the thermal conductivity of the obtained slurry too high.

[0032] 4. Use a casting machine to coat the slurry on a special base tape at 60°C, or use a coater to coat the slurry on a glass substrate at 60°C. During the coating process, N-methylpyrrolidone is removed (N-methylpyrrolidone is only used as a film-forming auxiliary agent to enable polyvinylidene fluoride to react quickly to form a slurry, and it will evaporate at high temperatures). The coating thickness is 100um.

[0033] 5. Soak the special base tape or glass substrate after removing N-methylpyrrolidone in deionized water to obtain the thermal insulation film material. The SEM image of the thermal insulation film material is as follows: Figure 2 As shown by Figure 2 It can be seen that the thermal insulation film material prepared by the above method has a uniform pore structure.

[0034] In another embodiment, a method for preparing a biomass material thermal insulation film comprises the following steps:

[0035] 1. The corn straw was repeatedly ultrasonically cleaned with ultrapure water and alcohol to remove dust and impurities. After drying, the corn straw was ground and sieved with 60 mesh to obtain corn straw powder.

[0036] 2. The corn straw powder was heat-treated in a tube furnace at 700° C. for 1 h under an argon atmosphere to obtain carbon powder, wherein the heating rate during the heat treatment process was 5° C. / min.

[0037] 3. Mix carbon powder and polyvinylidene fluoride (PVDF) in a mass ratio of 16:1, grind for 1 hour, add N-methylpyrrolidone (NMP) in a mass ratio of 400:1 to carbon powder, and mix to obtain a uniform slurry.

[0038] 4. Use a tape casting machine to coat the slurry on a special base tape at 70°C, or use a coater to coat the slurry on a glass substrate at 70°C, with a coating thickness of 300um.

[0039] 5. Soak the special base tape or glass substrate after removing N-methylpyrrolidone in deionized water to obtain the thermal insulation film material.

[0040] In another embodiment, a method for preparing a biomass material thermal insulation film comprises the following steps:

[0041] 1. The wheat straw was repeatedly ultrasonically cleaned with ultrapure water and alcohol to remove dust and impurities. After drying, the rice husk was ground and sieved with 60 mesh to obtain wheat straw powder.

[0042] 2. The wheat straw was heat-treated in a tubular furnace at 850°C for 1 h under a nitrogen atmosphere to obtain carbon powder, wherein the heating rate during the heat treatment process was 5°C / min.

[0043] 3. Mix carbon powder and polyvinylidene fluoride (PVDF) in a mass ratio of 16:1 evenly. After grinding for 1 hour, add N-methylpyrrolidone (NMP) in a mass ratio of 400:1 to carbon powder to make the polyvinylidene fluoride more evenly dispersed. Mix again to obtain a uniform slurry.

[0044] 4. Use a tape casting machine to coat the slurry on a special base tape at 80°C, or use a coater to coat the slurry on a glass substrate at 80°C, with a coating thickness of 500um.

[0045] 5. Soak the special base tape or glass substrate after removing N-methylpyrrolidone in deionized water to obtain the thermal insulation film material.

[0046] It should be noted that in step 2 of the above embodiment, if the heat treatment temperature is less than 500°C, the carbonization effect of the rice husk powder is poor, resulting in difficulty in film formation. If the heat treatment temperature is greater than 850°C, the degree of graphitization of the rice husk powder increases, resulting in an increase in thermal conductivity. Secondly, the heating rate can be adjusted to a certain extent based on 5°C / min. However, experiments have shown that the carbonization rate of the rice husk powder is optimal when the heating rate is 5°C / min.

[0047] It should also be noted that in step 2, polyvinylidene fluoride needs to be added first, and then N-methylpyrrolidone. If the order of adding the two is reversed, the polyvinylidene fluoride and carbon powder will be unevenly mixed during the slurry formation process because N-methylpyrrolidone will evaporate first.

[0048] It should be further explained that in step 4, if the coating temperature is lower than 60°C, incomplete drying will occur; if the coating temperature is higher than 80°C, the final thermal insulation film will crack, thereby affecting the use effect.

[0049] Below, the present disclosure describes the characteristics of the thermal insulation film prepared by the above embodiment in combination with specific experimental data.

[0050] The present disclosure uses an LFA447 laser thermal conductivity analyzer to test the thermal insulation film materials prepared in the above different embodiments. The specific testing method is as follows:

[0051] A laser source or xenon flash lamp instantaneously emits a pulse of light, evenly irradiating the lower surface of the sample. The surface absorbs the light energy, causing a transient temperature rise. This surface, acting as the hot end, transfers the energy to the cold end (upper surface) via one-dimensional heat conduction. An infrared detector continuously measures the corresponding temperature rise at the center of the sample's upper surface. The thermal diffusivity is calculated from the half-temperature rise time. Specific heat is measured simultaneously by comparison with a standard specimen, while density is calculated manually.

[0052] There is the following conversion relationship between thermal conductivity (thermal conductivity) and thermal diffusivity:

[0053] λ(T)=α(T)*Cp(T)*ρ(T)

[0054] The test was conducted at room temperature and the average of three data points was taken.

[0055] The thermal conductivity of the thermal insulation film material prepared in the above embodiment after testing is shown in Table 1:

[0056] Table 1

[0057] Thermal conductivity (W / (m·K), room temperature) Example 1 0.042 Example 2 0.060 Example 3 0.079

[0058] Common insulation materials, such as rock wool, are made primarily from high-quality basalt and dolomite. After being melted at temperatures exceeding 1450°C and then centrifuged into fibers using a four-axis centrifuge, a certain amount of binder, dust-proof oil, and water-repellent agent are sprayed onto the fibers. The fibers are then collected by a collector and processed using a pendulum method. After three-dimensional laying, the fibers are cured and cut to form rock wool products of varying specifications and uses. The thermal conductivity of the rock wool products is approximately 0.040. As shown in Table 1, the thermal conductivity of the biomass-based insulation film is similar to that of rock wool, achieving essentially the same insulation effect. Furthermore, the biomass-based insulation film contains no additives other than a certain amount of polyvinylidene fluoride and a small amount of N-methylpyrrolidine (which volatilizes during the preparation process). This makes the film low-cost and environmentally friendly, requiring no high temperatures and being non-flammable. In addition, the present disclosure also conducted a flexibility test on the thermal insulation film prepared in the above embodiment. At a bending angle of 60 degrees, 100 tests had no effect on its performance. In the fire resistance test, after the thermal insulation film material was placed under the flame of an alcohol lamp for 10 seconds, the sample did not burn, and after the fire source was removed, the flame of the sample disappeared immediately.

[0059] The above general description of the invention and the description of its specific embodiments involved in this application should not be understood as limiting the technical solutions of the invention. Based on the disclosure of this application, those skilled in the art may, without violating the constituent elements of the invention involved, add, subtract, or combine the disclosed technical features in the above general description and / or specific embodiments (including examples) to form other technical solutions within the scope of protection of this application.

Claims

1. A method for preparing a biomass material thermal insulation film, comprising the following steps: S100: washing, drying, grinding, and sieving the biomass material to obtain biomass material powder; S200: heat-treating the biomass material powder under a certain atmosphere to obtain carbon powder, wherein: The heat treatment temperature is 500-850℃; S300: mixing a certain amount of polyvinylidene fluoride with carbon powder, grinding the mixture, and then mixing the mixture with a certain amount of N-methylpyrrolidone to obtain a slurry; S400: Coating the slurry on a glass substrate or a special base tape at a certain temperature; S500: Soaking the glass substrate or special base tape coated with the slurry in deionized water to obtain a heat insulation film.

2. The method according to claim 1, wherein In step S200, the heating rate of the heat treatment is 5°C / min.

3. The method according to claim 1, wherein In step S300 , the mass ratio of the carbon powder to polyvinylidene fluoride is 16:

1.

4. The method according to claim 1, wherein In step S300 , the mass ratio of the carbon powder to N-methylpyrrolidone is 400:

1.

5. The method according to claim 1, wherein In step S400 , the coating thickness of the slurry is 100 μm to 500 μm.

6. The method according to claim 1, wherein In step S400, the coating temperature of the slurry is 60-80°C.

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