Preparation method of lignin-based organic phase change material
By adding hexagonal boron nitride and expanded graphite to lignin-based organic phase change materials and using lignin compatibilizers to improve compatibility, the phase separation and enthalpy decay problems of phase change materials were solved, achieving high-efficiency energy storage performance and stability, and simplifying the preparation process.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- QILU UNIVERSITY OF TECHNOLOGY (SHANDONG ACADEMY OF SCIENCES)
- Filing Date
- 2026-02-02
- Publication Date
- 2026-05-08
AI Technical Summary
Existing lignin-based organic phase change materials suffer from phase separation problems, severe decay of phase change enthalpy, difficulty in maintaining stability after multiple cycles of use, and complex preparation processes.
Lignin-based organic phase change materials were prepared by using erythritol as the main phase change component, adding hexagonal boron nitride as a nucleating agent and expanded graphite as a compatibilizer, and by mixing, heating, and ultrasonication. The lignin compatibilizer was used to improve compatibility and stability.
A lignin-based organic phase change material with high phase change enthalpy, low supercooling, and good cycle stability has been developed, which is suitable for thermophysical energy storage and simplifies the preparation process.
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Figure CN121991641A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of organic phase change energy storage and temperature control materials, and relates to a method for preparing a lignin-based organic phase change material. Background Technology
[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.
[0003] Phase change materials (PCMs), with their unique advantages such as high energy density, stable phase change temperature, and near-isothermal heat absorption and release processes, have demonstrated unique application value in various fields, including industrial waste heat recovery, building energy conservation, and temperature control of electronic equipment. They are important materials for promoting the clean and low-carbon transformation of energy systems. However, the current formulation design of PCMs still has many imperfections. For example, inorganic PCMs suffer from severe supercooling and phase separation, organic PCMs have a wide cost range, and composite PCMs have complex preparation processes. These problems directly limit the energy storage performance, service life, and applicable scenarios of the materials, hindering their progress from laboratory research to large-scale application. Therefore, as a core medium for thermal energy storage and management, PCMs are undergoing a paradigm shift from traditional petroleum-based materials to bio-based materials. Lignin-based organic PCMs, with their unique biomass characteristics, have become a key breakthrough in this transformation.
[0004] A study has disclosed a lignin-based energy storage and temperature control material, composed of the following raw materials by mass percentage: 85–97.5% main phase change material, 1–5% nucleating agent, 1–5% water-soluble lignin, and 0.5–5% forming agent. By adding lignin to replace the traditional thickener and adding the forming agent to stabilize its morphology, the phase change temperature of the material is stabilized within the range of 80–90°C. The phase change enthalpy of this material is 234.12 J / g, but phase separation problems still cannot be avoided, and the phase change enthalpy value decays significantly after repeated use.
[0005] A study has disclosed a composite phase change material for long-term thermal storage of supercooled sugar alcohols stabilized by an organic base. This composite phase change material utilizes organic bases including, but not limited to: polyamine compounds (such as diethylenetriamine), nitrogen-containing heterocyclic compounds (such as 1,8-dimethylamine), and organic bases containing organic bases such as ethylenetriamine and dimethylamine. diazabicyclo[5.4.0]undecane 7 One or more of the following compounds (such as potassium tert-butoxide, sodium tert-butoxide, and alkali metal compounds) are used as additives, with erythritol, xylitol, mannitol, and inositol as the main energy storage agents. The organic phase change material prepared by the above formula has a phase change enthalpy of 254.9 J / g, but its phase change performance still needs to be improved. Summary of the Invention
[0006] To address the aforementioned issues and further improve the performance of phase change materials (PCMs), this invention provides a method for preparing lignin-based organic PCMs. This invention enhances the compatibility of the PCM with other components by adding a lignin compatibilizer and improves the overall stability of the material by adjusting the formulation. The energy storage and temperature-controlled PCM provided by this invention exhibits a suitable phase change temperature, high phase change enthalpy, low supercooling, good cycle stability, and no significant phase separation, making it a suitable thermophysical energy storage technology.
[0007] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a lignin-based organic phase change material composed of the following raw materials in weight percentages: 86% to 97% erythritol, 2% to 5% hexagonal boron nitride, 0.5% to 2% lignin compatibilizer, and 0.5% to 10% expanded graphite, wherein the sum of the mass percentages of each raw material is 100%.
[0008] Hybrid mechanism: In this composite phase change material system, erythritol serves as the main phase change component, undertaking the core function of heat storage and release. Hexagonal boron nitride, lignin compatibilizer, and expanded graphite serve as functional additives, optimizing the material properties from the dimensions of nucleation, rheology, and molding, respectively.
[0009] Erythritol, as the primary phase change heat storage medium, absorbs and releases a large amount of heat through its own solid-liquid-phase change process, making it the main source of the heat storage capacity of phase change materials. Appropriate addition of hexagonal boron nitride as a nucleating agent can suppress supercooling; its layered crystal structure can serve as heterogeneous nucleation sites, reducing the supercooling of erythritol and improving the reversibility of the phase change. Expanded graphite possesses a unique porous layered structure, which can enhance the mechanical strength and formability of the material, mitigating structural damage caused by volume shrinkage / expansion during the phase change process. However, the poor compatibility among these components makes them prone to phase separation during the solid-liquid conversion process, resulting in a loss of phase change enthalpy. The lignin compatibilizer treated by the method of this invention has high solubility and good dispersibility. At the same time, it can utilize the unique network structure of its natural polymer to ensure that it can still form a viscous three-dimensional network structure after dissolution, which restricts the flow of molten erythritol in local space, effectively inhibits liquid leakage, and avoids the loss of heat storage enthalpy value caused by excessive thickening. In addition, the treated lignin compatibilizer is rich in a variety of polar and non-polar functional groups while retaining its main phenylpropane structural unit. It can improve the interfacial compatibility between the main phase change material and other components while taking into account the anti-leakage effect, and solve the problem of poor compatibility between inorganic additives and organic matrix.
[0010] Figure 1 The Fourier transform infrared spectra of erythritol and that of Example 1 are shown below. Figure 1It can be seen that the infrared spectrum curve of the phase change material is highly consistent with that of erythritol, indicating that no chemical modification occurred between the various formulation components and erythritol during the preparation of the phase change material.
[0011] A second aspect of the present invention provides a method for preparing a lignin-based organic phase change material, comprising: Erythritol, hexagonal boron nitride, and lignin compatibilizer are mixed and heated until completely melted to obtain a molten mixture. Expanded graphite is added to the molten mixture and mixed evenly to obtain a graphite-adsorbed phase change material. The graphite-adsorbed phase change material is poured into a mold, cooled, and shaped to obtain the final product.
[0012] Experimental studies have shown that the phase change enthalpy of the temperature-controlled phase change material in this experiment is between 250 and 350 J / g, exhibiting good cycle stability and excellent energy storage and temperature control capabilities.
[0013] A third aspect of the present invention provides the application of the above-described lignin-based organic phase change materials in the fields of energy, construction, electronics, and transportation.
[0014] Beneficial effects of the present invention (1) This invention improves the compatibility of phase change materials with other components by adding lignin compatibilizers and improves the overall stability of the material by adjusting the formulation. The energy storage temperature-controlled phase change material provided by this invention has a suitable phase change temperature, high phase change enthalpy, low supercooling, good cycle stability, and no obvious phase separation phenomenon, making it a suitable thermophysical energy storage technology.
[0015] (2) The preparation method of the present invention is simple, practical and easy to promote. Attached Figure Description
[0016] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. Exemplary embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.
[0017] Figure 1 The Fourier transform infrared spectrum is of erythritol and that of Example 1. Detailed Implementation
[0018] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.
[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of skill in the art. The reagents and raw materials used in this invention are readily available through conventional means, and unless otherwise specified, they are used in accordance with conventional methods in the art or product instructions. Similarly, unless otherwise specified, the test methods of this invention are performed in accordance with conventional methods in the art or industry-standard methods or practices. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to the methods of this invention. The preferred embodiments and materials described herein are for illustrative purposes only.
[0020] This invention mainly proposes a lignin-based organic phase change material, which is composed of the following raw materials in weight percentage: 86% to 97% erythritol, 2% to 5% hexagonal boron nitride, 0.5% to 2% lignin compatibilizer and 0.5% to 10% expanded graphite, and the sum of the mass percentages of each raw material is 100%.
[0021] The type of lignin compatibilizer affects its effect on improving the compatibility and phase change properties of each component. Therefore, this invention studies and screens the types of lignin compatibilizers. Preferably, the lignin raw material is mixed with a treatment agent and heated, followed by filtration, concentration, and drying to obtain the lignin compatibilizer. The treatment agent is prepared by mixing n-hexanol with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) at a molar ratio of 1:10 to 10:1, mixing the mixture with water at a molar ratio of 1:10 to 10:1, and then introducing CO2 into the mixture. The lignin compatibilizer prepared by the above process can better improve the compatibility and phase change properties of the system.
[0022] The present invention does not impose any special limitation on the source of lignin raw materials. Preferably, the lignin raw materials are selected from at least one of wood chips, wheat straw, straw, and industrial lignin raw materials containing lignin components. More preferably, the industrial lignin raw materials are selected from at least one of Klassen lignin, sodium lignin sulfonate, alkali lignin, and dealkali-reduced lignin, so as to better improve the performance of lignin compatibilizers.
[0023] The dosage, temperature, and time of the treatment agent affect the performance of the lignin compatibilizer. Therefore, this invention studies the solid-liquid ratio of lignin raw material and treatment agent, the heating temperature, and the treatment time. Preferably, the solid-liquid ratio of lignin raw material and treatment agent is 1:5 to 1:50, the heating temperature is 80 to 150°C, and the treatment time is 2 to 24 hours to obtain better lignin compatibilizer performance.
[0024] Furthermore, a sand core filter funnel is used during filtration to remove filter residue and retain filtrate, thereby improving filtration efficiency and simplifying operation.
[0025] Furthermore, the concentration method involves adding an antisolvent to the filtrate, allowing it to stand, and removing the supernatant. The antisolvent is acetone, and the concentration of the filtrate is achieved by adding the antisolvent.
[0026] Furthermore, the volume ratio of filtrate to antisolvent is 1:10 to 10:1, and the standing time is 2 to 24 hours. By adjusting the volume ratio, the concentration efficiency is improved. Furthermore, the drying conditions are 40~150 °C for 2~24 h to remove the solvent.
[0027] Phase transition temperature is the temperature at which a material changes from one physical state to another, and it has a significant impact on material properties. Therefore, preferably, the phase transition temperature of the lignin-based organic phase transition material is 80~140℃ to obtain better phase transition performance.
[0028] The present invention does not impose any special limitation on the specific type of expanded graphite. Preferably, the expanded graphite is in the form of flakes, worms, porous, fibrous or nanoscale to obtain better phase change performance.
[0029] The present invention also studied the specific preparation method of worm-shaped expanded graphite. Preferably, the preparation method of worm-shaped expanded graphite is microwave treatment with a power of 200-1000 W and a heating time of 5-10 min, so as to obtain worm-shaped expanded graphite with better performance.
[0030] This invention also provides a method for preparing a lignin-based organic phase change material, comprising: Erythritol, hexagonal boron nitride, and lignin compatibilizer are mixed and heated until completely melted to obtain a molten mixture. Expanded graphite is added to the molten mixture and mixed evenly to obtain a graphite-adsorbed phase change material. The graphite-adsorbed phase change material is poured into a mold, cooled, and shaped to obtain the final product.
[0031] To ensure uniform mixing of materials, the present invention employs shaking and / or ultrasonic mixing methods. Preferably, the solid mixing time is 5 to 15 minutes to achieve better mixing results.
[0032] The heating temperature affects the melting effect and efficiency of the material. Therefore, this invention has studied the heating temperature and time. Preferably, the material is heated to 150–170°C and held for 10–30 minutes. More preferably, the solid mixture is heated to 150–170°C in a metal bath under stirring conditions, held for 10–30 minutes, and the heating time is 10–20 minutes, so that the material is completely melted, facilitating subsequent processing.
[0033] Ultrasonic mixing is a technique that utilizes the cavitation effect and acoustic flow of ultrasound to achieve efficient dispersion, mixing, or reaction of substances in liquid or solid-liquid systems. It offers advantages such as non-contact operation and high efficiency. Therefore, preferably, the expanded graphite and the molten mixture are mixed under ultrasonic stirring conditions, with an ultrasonic power of 200–1000 W and an ultrasonic time of 5–10 min, to obtain a better mixing effect.
[0034] The cooling temperature affects the shaping effect and subsequent demolding. Therefore, this invention studies the cooling temperature, and preferably, the cooling temperature is: The temperature is 5–0°C, and the cooling time is 5–20 minutes. More preferably, the mold is made of silicone and placed in… Rapid cooling at 5–0°C for 5–20 minutes is used to achieve better shaping results.
[0035] The present invention will be further described in detail below with reference to specific embodiments. It should be noted that the specific embodiments are explanations of the present invention and not limitations thereof.
[0036] In the following examples and comparative examples, the expanded graphite is worm-shaped expanded graphite, and the preparation method is: microwave treatment with a power of 500 W and a heating time of 8 min.
[0037] In the following examples and comparative examples, the phase transition temperature and phase transition enthalpy were measured using a DSC differential scanning calorimeter at a heating and cooling rate of 10°C / min under a N2 atmosphere, and the phase transition enthalpy was calculated accordingly.
[0038] Example 1: Poplar lignin-sugar alcohol-based molding phase change material DBU, n-hexanol, and water were mixed in a molar ratio of 1:1:5, and then CO2 was introduced (pressure 1 MPa, time 1 h) to obtain a treatment agent. Subsequently, poplar wood was used as raw material and heated at 120℃ for 10 h at a solid-liquid ratio of 1:30. The mixture was then filtered, and the filtrate was retained. An antisolvent (acetone) was added at a volume ratio of 1:10 (filtrate to antisolvent), the mixture was allowed to stand to remove the supernatant, and then dried to obtain a poplar lignin compatibilizer.
[0039] 94% erythritol, 2% hexagonal boron nitride, 2% lignin compatibilizer, and 2% expanded graphite were mixed in a shaker for 5 min, then heated and stirred in a metal bath at 160°C for 15 min, and sonicated at 500 W for 5 min until completely melted and mixed. The mixture was then kept at this temperature and stirred for another 15 min. The mixture was poured into a silicone container and cooled at 0°C for 15 min. After complete cooling, Example 1 was obtained.
[0040] The phase transition temperature was measured to be 122.93℃ and the phase transition enthalpy was 323.3 J / g.
[0041] Example 2: Alkali-degraded lignin-sugar alcohol-based molded phase change material DBU, n-hexanol, and water were mixed in a molar ratio of 1:1:4.5, and then CO2 was introduced (pressure 1 MPa, time 1 h) to obtain the treatment agent. Subsequently, alkali-degraded lignin was used as raw material and heated at 110℃ for 14 h at a solid-liquid ratio of 1:35. The filtrate was then filtered and retained. An antisolvent (acetone) was added at a volume ratio of filtrate to antisolvent of 1:10. The mixture was allowed to stand to remove the supernatant and then dried to obtain the alkali-degraded lignin compatibilizer.
[0042] 91% (by mass) of the main phase change material erythritol, 2% hexagonal boron nitride, 2% lignin compatibilizer, and 5% expanded graphite were mixed in a shaker for 5 min. Then, the mixture was heated and stirred in a metal bath at 160°C for 15 min, followed by ultrasonication at 500 W for 5 min until completely melted and mixed. The mixture was then kept at this temperature and stirred for another 15 min. The mixture was poured into a silicone container and cooled at 0°C for 15 min. After complete cooling, Example 2 was obtained.
[0043] After testing, its phase transition temperature was found to be 122.17℃ and its phase transition enthalpy was 301.3 J / g.
[0044] Example 3: Alkali lignin-sugar alcohol-based molded phase change material DBU, n-hexanol, and water were mixed in a molar ratio of 1:1:6, and then CO2 was introduced (pressure 1 MPa, time 1 h) to obtain a treatment agent. Subsequently, alkali lignin was used as a raw material and heated at 120℃ for 12 h at a solid-liquid ratio of 1:15. The mixture was then filtered, and the filtrate was retained. An antisolvent (acetone) was added at a volume ratio of 1:10 (filtrate to antisolvent), the mixture was allowed to stand to remove the supernatant, and then dried to obtain an alkali lignin compatibilizer.
[0045] 91% (by mass) of the main phase change material erythritol, 5% hexagonal boron nitride, 2% lignin compatibilizer, and 2% expanded graphite were mixed in a shaker for 5 min. Then, the mixture was heated and stirred in a metal bath at 160°C for 15 min, followed by ultrasonication at 500 W for 5 min until completely melted and mixed. The mixture was then kept at this temperature and stirred for another 15 min. The mixture was poured into a silicone container and cooled at 0°C for 15 min. After complete cooling, Example 3 was obtained.
[0046] After testing, its phase transition temperature was found to be 121.34℃ and its phase transition enthalpy was 293.6 J / g.
[0047] Example 4: Sulfonated lignin-sugar alcohol-based molding phase change material DBU, n-hexanol, and water were mixed in a molar ratio of 1:1:4, and then CO2 was introduced (pressure 1 MPa, time 1 h) to obtain a treatment agent. Subsequently, sulfonated lignin was used as raw material and heated at 135℃ for 11 h at a solid-liquid ratio of 1:35. The filtrate was then filtered and retained. An antisolvent (acetone) was added at a volume ratio of 1:10 (filtrate to antisolvent), the mixture was allowed to stand to remove the supernatant, and then dried to obtain a sulfonated lignin compatibilizer.
[0048] 91% (w / w) of the main phase change material erythritol, 5% hexagonal boron nitride, 0.5% lignin compatibilizer, and 2% expanded graphite were mixed in a shaker for 5 min, then heated and stirred in a metal bath at 160°C for 15 min, and sonicated at 500 W for 5 min until completely melted and mixed. The mixture was then kept at this temperature and stirred for another 15 min. The mixture was poured into a silica gel container and cooled at 0°C for 15 min. After complete cooling, Example 4 was obtained.
[0049] After testing, its phase transition temperature was found to be 122.24℃ and its phase transition enthalpy was 335.5 J / g.
[0050] Comparative Example 1: Paraffin Phase Change Material Paraffin wax was heated and stirred in a metal bath at 65°C for 15 minutes until completely melted and mixed. Then, it was sonicated at 500 W for 5 minutes, followed by stirring at the same temperature for another 15 minutes. The mixture was then poured into a silicone container and cooled at 0°C for 5 minutes. After complete cooling, Comparative Example 1 was obtained.
[0051] Testing revealed that its phase transition temperature was 52.75℃ and its phase transition enthalpy was 124.8 J / g. Pure paraffin wax, lacking supporting materials, is difficult to mold.
[0052] Comparative Example 2: Paraffin-based molded phase change materials 98% paraffin and 2% expanded graphite were mixed in a shaker for 5 min, then heated and stirred in a metal bath at 65°C for 15 min, and sonicated at 500 W for 5 min until completely melted and mixed. The mixture was then kept at the temperature and stirred for another 15 min. The mixture was poured into a silicone container and cooled at 0°C for 5 min. After complete cooling, Comparative Example 2 was obtained.
[0053] The phase transition temperature was found to be 52.38℃ and the phase transition enthalpy was 124.5 J / g.
[0054] Comparative Example 3: Sugar Alcohol Phase Change Materials Erythritol was heated and stirred in a metal bath at 160°C for 15 min until completely melted and mixed. The mixture was then sonicated at 500 W for 5 min, followed by stirring at the same temperature for another 15 min. The mixture was then poured into a silicone container and cooled at 0°C for 15 min. After complete cooling, Comparative Example 3 was obtained.
[0055] Testing revealed that its phase transition temperature was 121.02℃ and its phase transition enthalpy was 329.6 J / g. Pure erythritol, without supporting material, exhibited high brittleness after cooling and setting, making it difficult to demold.
[0056] Comparative Example 4: Sugar alcohol-based molded phase change materials 98% erythritol and 2% expanded graphite were mixed in a shaker for 5 min, then heated and stirred in a metal bath at 160°C for 15 min, and sonicated at 500 W for 5 min until completely melted and mixed. The mixture was then kept at the temperature and stirred for another 15 min. The mixture was poured into a silicone container and cooled at 0°C for 15 min. After complete cooling, Comparative Example 4 was obtained.
[0057] The phase transition temperature was measured to be 121.40℃ and the phase transition enthalpy was 276.7 J / g.
[0058] Comparative Example 5 The difference from Example 1 is that no poplar lignin compatibilizer was added.
[0059] The components of the phase change material were not mixed uniformly. Testing revealed a phase change temperature of 121.48℃ and a phase change enthalpy of 267.7 J / g.
[0060] Comparative Example 6 The difference from Example 1 is that alkaline lignin is used instead of poplar lignin compatibilizer, while the amount of compatibilizer remains the same.
[0061] Alkaline lignin was poorly dispersed in the phase change material, and the components were not mixed uniformly. The phase change temperature was measured to be 120.28℃, and the phase change enthalpy was 274.6 J / g.
[0062] Comparative Example 7 The difference from Example 1 is that sodium lignosulfonate is used instead of poplar lignin compatibilizer, while the amount of compatibilizer remains the same.
[0063] Sodium lignosulfonate is an unsuitable candidate for phase change materials, exhibiting poor homogeneity in the mixing of its components. Its phase change temperature is measured to be 121.58℃, and its phase change enthalpy is 282.2 J / g.
[0064] Table 1 Performance test results of the embodiment serial number Erythritol (%) Boron hexanitride (%) Expanded graphite (%) Lignin compatibilizer (%) Phase transition enthalpy (J / g) Example 1 94 2 2 2 323.3 Example 2 91 2 5 2 301.3 Example 3 91 5 2 2 293.6 Example 4 95.5 2 2 0.5 335.5 As can be seen from the comparison of Examples 1-4, the introduction of lignin compatibilizer effectively improved the compatibility of each component and significantly increased the phase transition enthalpy.
[0065] Table 2 Performance test results of Comparative Examples 1 and 2 serial number paraffin(%) Expanded graphite (%) Phase transition enthalpy (J / g) Comparative Example 1 100 0 124.8 Comparative Example 2 98 2 124.5 As can be seen from the comparison of Comparative Examples 1-2, the phase change enthalpy of pure paraffin or paraffin-based phase change materials is relatively low.
[0066] Table 3 Performance test results for Comparative Examples 3 and 4 serial number Erythritol (%) Expanded graphite (%) Phase transition enthalpy (J / g) Comparative Example 3 100 0 329.6 Comparative Example 4 98 2 276.7 As can be seen from the comparison of Comparative Examples 3-4, pure erythritol without supporting material exhibits high brittleness after cooling and setting, making it difficult to demold, while the phase change enthalpy of erythritol-based phase change materials is still relatively low.
[0067] Table 4 Performance test results of Comparative Examples 5-7 serial number Erythritol (%) Boron hexanitride (%) Expanded graphite (%) Lignin type Lignin (%) Phase transition enthalpy (J / g) Comparative Example 5 96 2 2 - - 267.7 Comparative Example 6 94 2 2 alkaline lignin 2 274.6 Comparative Example 7 94 2 2 Sodium lignosulfonate 2 282.2 As can be seen from the comparison of Comparative Examples 5-7, the introduction of lignin compatibilizer effectively improved the compatibility of each component and significantly increased the phase transition enthalpy. At the same time, compared with other water-soluble lignins (alkaline lignin, sodium lignin sulfonate), poplar lignin compatibilizer can better improve the compatibility of each component and increase the phase transition enthalpy.
[0068] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A lignin-based organic phase change material, characterized in that, It is composed of the following raw materials by weight percentage: 86%–97% erythritol, 2%–5% hexagonal boron nitride, 0.5%–2% lignin compatibilizer, and 0.5%–10% expanded graphite, with the sum of the mass percentages of each raw material being 100%.
2. The lignin-based organic phase change material as described in claim 1, characterized in that, The lignin raw material is mixed with the treatment agent and heated for treatment. After heating, the mixture is filtered, concentrated, and dried to obtain the lignin compatibilizer. The preparation method of the treatment agent is as follows: n-hexanol and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) are mixed in a molar ratio of 1:10 to 10:1, the mixture is mixed with water in a molar ratio of 1:10 to 10:1, and then CO2 is introduced into it; Alternatively, the lignin raw material is selected from at least one of wood chips, wheat straw, straw, and industrial lignin raw materials containing lignin components; Alternatively, the industrial lignin raw material is selected from at least one of Klassen lignin, sodium lignin sulfonate, alkali lignin, and dealkali-treated lignin.
3. The lignin-based organic phase change material as described in claim 1, characterized in that, The phase transition temperature of the lignin-based organic phase change material is 80~140℃.
4. The lignin-based organic phase change material as described in claim 1, characterized in that, The expanded graphite is in the form of flakes, worms, porous, fibrous or nanoscale.
5. The lignin-based organic phase change material as described in claim 4, characterized in that, The worm-like expanded graphite was prepared by microwave treatment with a power of 200–1000 W and a heating time of 5–10 min.
6. A method for preparing a lignin-based organic phase change material, characterized in that, include: Erythritol, hexagonal boron nitride, and lignin compatibilizer are mixed and heated until completely melted to obtain a molten mixture. Expanded graphite is added to the molten mixture and mixed evenly to obtain a graphite-adsorbed phase change material. The graphite-adsorbed phase change material is poured into a mold, cooled, and shaped to obtain the final product.
7. The method for preparing the lignin-based organic phase change material as described in claim 6, characterized in that, Heat to 150–170°C and hold for 10–30 minutes.
8. The method for preparing the lignin-based organic phase change material as described in claim 6, characterized in that, The expanded graphite and the molten mixture are mixed under ultrasonic stirring conditions, with an ultrasonic power of 200-1000W and an ultrasonic time of 5-10 minutes.
9. The method for preparing the lignin-based organic phase change material as described in claim 6, characterized in that, The cooling temperature is Cooling time is 5 to 0℃, and the cooling time is 5 to 20 minutes.
10. The application of the lignin-based organic phase change material according to any one of claims 1-5 in the fields of energy, construction, electronics, and transportation.