A water-resistant bio-based shaped phase change composite material and its preparation method

Abstract

The invention provides a water-resistant bio-based shape-fixed phase-change composite material and a preparation method thereof. Calculated by weight, raw materials for preparing the water-resistant bio-based shape-fixed phase-change composite material include: 20 to 95 parts of organic phase-change material, 1 to 80 parts of biomass material, and 0.1 to 30 parts of modified inorganic micro-nano composite particles; wherein the organic phase-change material includes at least one of paraffin, fatty acid, polyol, and ester; the biomass material is plant fiber; the modified inorganic micro-nano composite particles are compounded by nano-silicon dioxide, ultrafine ceramic powder, and fluorocarbon surfactant; the raw materials for preparing the water-resistant bio-based shape-fixed phase-change composite material also include aminopolydimethylsiloxane and isocyanate; wherein, calculated by molar ratio, aminopolydimethylsiloxane: active end group of organic phase-change material=1:1; calculated by mass ratio, isocyanate: organic phase-change material=0.1 to 2:10.

Description

Technical Field

[0001] The present invention belongs to the field of functional composite materials, and particularly relates to a water-resistant bio-based shaped phase change composite material and a preparation method thereof. Background Art

[0002] Energy is the basis for human development, and thermal energy is an important form of energy. Due to the large losses in the generation, conversion, and utilization of thermal energy, effective management of thermal energy can effectively reduce losses and improve utilization efficiency. In addition, managing and applying thermal energy in a green and environmentally friendly manner is also an important research direction. Organic phase change materials are commonly used thermal energy management materials, which are numerous in variety and can meet the requirements of different temperature regions, and are widely used in fields such as architecture, electronic devices, new energy, and electric power. However, organic phase change materials still face deficiencies such as easy leakage, difficult shaping, and the need for specific containers in applications. To overcome the deficiency of easy leakage, some researchers have proposed methods such as vacuum-assisted adsorption, constructing microcapsules, or physical blending, which can significantly reduce the leakage of organic phase change media. For example, Chinese invention patents CN114672283A, CN109499499A, and CN113617306A, etc., improve the encapsulation ability of the phase change medium to a certain extent by constructing a core-shell structure or a microcapsule structure. However, the organic phase change materials obtained by these methods still have a certain degree of leakage risk, making it difficult for many phase change materials to be repeatedly processed into devices with specific shapes on a large scale.

[0003] On the other hand, in the actual application of organic phase change materials, complex working environments, such as humidity, temperature, stress effects, etc., may cause the phase change materials to deform or even fail. For example, organic phase change materials with strong hydrophilicity are prone to shape instability or even collapse in a humid and hot environment. For scenarios with relatively low humidity, the effect of moisture can be inhibited to a certain extent by improving the hydrophobicity of the material. For example, Chinese invention patents CN103666159B and CN113617306A improve the hydrophobicity of the phase change material by constructing a micro-structure. However, in the face of a high-humidity or even long-term immersion working environment, the currently provided phase change materials with surface hydrophobicity still cannot meet the application requirements under the action of a large amount of moisture or in an immersion operation. Summary of the Invention

[0004] In order to improve the problems of easy deformation, easy leakage, poor water resistance, and poor repeatability of organic phase change materials, the present invention provides a water-resistant bio-based shaped phase change composite material and a preparation method thereof.

[0005] According to one aspect of the present invention, a water-resistant bio-based shaped phase change composite material is provided. Calculated by mass parts, the raw materials for preparing the water-resistant bio-based shaped phase change composite material include: 20 to 95 parts of an organic phase change material, 1 to 80 parts of a biomass material, and 0.1 to 30 parts of a modified inorganic micro-nano composite particle; wherein, the organic phase change material includes at least one of paraffin, fatty acid, polyol, and ester; the biomass material is plant fiber; the modified inorganic micro-nano composite particle is formed by in-situ reaction of nano-silica, ultrafine ceramic powder, and fluorocarbon surfactant; the raw materials for preparing the water-resistant bio-based shaped phase change composite material further include amino polydimethylsiloxane and isocyanate; wherein, calculated by molar ratio, amino polydimethylsiloxane: active end group of the organic phase change material = 1:1; calculated by mass ratio, isocyanate: organic phase change material = 0.1 to 2:10.

[0006] In the present invention, at an appropriate ratio, the micro-nano hydrophobic structure constructed by the modified inorganic micro-nano composite particles enhances the water resistance of the organic phase change material, and can meet the application of the phase change composite material under a large dose of moisture or water inlet operation; and, by selecting the biomass material, the mechanical properties of the organic phase change material are effectively enhanced, and the shape stability of the organic phase change material is improved; by using amino polydimethylsiloxane and isocyanate to block the active groups of the organic phase change material, the problem of easy leakage of the organic phase change material can be effectively improved, so as to enhance the repeat processing performance of the phase change material. Therefore, by combining the modified inorganic micro-nano composite particles, the biomass material, and the blocked organic phase change material, a water-resistant bio-based shaped phase change composite material with high shape stability, high water resistance, difficult leakage, and high repeat processing performance can be obtained. In addition, the selected biomass material has the characteristics of being renewable, environmentally friendly and low cost. Therefore, the water-resistant bio-based shaped phase change composite material provided by the present invention has the characteristics of high shape stability, high water resistance, difficult leakage, and high repeat processing performance, and can broaden the application range of the organic phase change composite material.

[0007] Preferably, the polyol includes polyethylene glycol.

[0008] Preferably, the relative molecular mass of polyethylene glycol is 800 to 20000.

[0009] Preferably, the plant fiber includes lignocellulose.

[0010] Preferably, the lignocellulose includes pine fiber.

[0011] Preferably, the isocyanate includes at least one of isophorone diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, and hexamethylene diisocyanate.

[0012] Preferably, by mass ratio, in the modified inorganic micro-nano composite particles, nano-silica: ultrafine ceramic powder = 1 to 10:1.

[0013] Preferably, the particle size of the ultrafine ceramic powder is 10 to 30 μm.

[0014] According to another aspect of the present invention, a method for preparing a water-resistant bio-based shaped phase change composite material is provided. The method includes the following steps: S1. Preparing modified inorganic micro-nano composite particles by in-situ reaction and compounding of nano-silica, ultrafine ceramic powder, and fluorocarbon surfactant; S2. Heating an organic phase change material, amino polydimethylsiloxane, and isocyanate to 60 to 80 °C and mixing to obtain a prefabricated mixture; S3. Blending the prefabricated mixture, modified inorganic micro-nano composite particles, biomass material, and catalyst through melt processing. The processing temperature of the melt processing is 40 to 100 °C, and after reacting for 1 to 30 minutes, a water-resistant bio-based shaped phase change composite material is obtained. The preparation method provided by the present invention first constructs modified inorganic micro-nano composite particles with a micro-nano hydrophobic structure through in-situ reaction; then, the active groups of the organic phase change material are blocked by amino polydimethylsiloxane and isocyanate, effectively improving the problem of easy leakage of the organic phase change material to enhance the repeated processing performance of the phase change material; and, through melt processing, the modified inorganic micro-nano composite particles, biomass material, and organic phase change material can be uniformly mixed, further improving the water resistance and shape stability of the water-resistant bio-based shaped phase change composite material provided by the present invention. In addition, the preparation process and required equipment provided by the present invention are simple, the production cycle is short, and it is convenient to realize industrial production.

[0015] Preferably, in S2, the melt processing is one of screw extrusion processing, internal mixer processing, and open mill processing.

[0016] Preferably, in S3, by mass ratio, catalyst: isocyanate = 0.1 to 1:1.

[0017] Preferably, the catalyst includes at least one of triethylenediamine, dibutyltin dilaurate, diethylcyclohexylamine, and dimethylethanolamine.

[0018] Preferably, in S1, the preparation of the modified inorganic micro-nano composite particles comprises the following steps: Calculated by mass, take 60-150 parts of ethanol, 5-15 parts of ammonia water, 1-10 parts of water, and 0.5-2 parts of ultrafine ceramic powder and mix to form a first reaction solution; Subsequently, add 2-10 parts of silicate compounds to the first reaction solution, and carry out an in-situ reaction at 20-60 °C for 2-10 hours to obtain a second reaction solution containing nano-silica; Add 0.1-10 parts of fluorocarbon surfactant to the second reaction solution, and react at 20-80 °C for 4-24 hours to obtain the modified inorganic micro-nano composite particles. The preparation method of the modified inorganic micro-nano composite particles provided by the present invention first obtains composite particles of ultrafine ceramic powder and nano-silica through an in-situ reaction of silicate compounds in the ultrafine ceramic powder suspension, and then adds a fluorocarbon surfactant to the composite particle suspension for reaction to form a micro-nano hydrophobic structure, thereby obtaining modified inorganic micro-nano composite particles that can enhance the water resistance of the phase change composite material.

[0019] Preferably, in S1, the in-situ reaction is a suspension in-situ chemical modification method.

[0020] Preferably, in S1, after the reaction is completed, it is also necessary to go through static treatment, separation treatment, washing treatment, and drying treatment to obtain the modified inorganic micro-nano composite particles.

[0021] Preferably, the silicate compounds include at least one of tetraethyl orthosilicate and tetrapropyl orthosilicate. Specific Embodiments

[0022] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention and the accompanying drawings in the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0023] Example 1

[0024] 1. Preparation of raw materials for water-resistant bio-based shaped phase change composite materials

[0025] This example provides a water-resistant bio-based shaped phase change composite material, and the required raw materials and their mass parts for preparing this water-resistant bio-based shaped phase change composite material are shown in Table 1.

[0026] Table 1. Raw materials required for preparing the water-resistant bio-based shaped phase change composite material in this example

[0027]

[0028] 2. Method for Preparing Water-Resistant Bio-Based Shaped Phase Change Composite Materials

[0029] S1. Prepare the materials required for preparing modified inorganic micro-nano composite particles according to Table 1. Mix ethanol, ammonia water, and water evenly, then add ultrafine ceramic powder and stir to form a uniform first reaction solution. Subsequently, under stirring, slowly drop tetraethyl orthosilicate into the first reaction solution, and carry out an in-situ reaction at 30 °C for 6 hours to obtain a second reaction solution containing nano-silica. Then, add a fluorocarbon surfactant to the second reaction solution under continuous stirring and react at 40 °C for 4 hours. After the reaction, let it stand for 10 hours, separate and wash the precipitate, and dry it to obtain modified inorganic micro-nano composite particles, where the mass ratio of nano-silica to ultrafine ceramic powder is 2:1;

[0030] S2. Prepare the materials required for preparing water-resistant bio-based shaped phase change composite materials according to Table 1. Take polyethylene glycol, amino-polydimethylsiloxane, and isocyanate and heat them to 65 °C to melt all the materials, and stir evenly to obtain a prefabricated mixture;

[0031] S3. Mix the prefabricated mixture, pine fiber powder, and modified inorganic micro-nano composite particles evenly, and add the reactants to an open mill. Rotate and mix at 70 °C and gradually add a catalyst (triethylenediamine). The processing time for the open mill reaction is 15 minutes, and the rotation speed of the open mill is 30 revolutions per minute. Take it out and cool to obtain a water-resistant bio-based shaped phase change composite material.

[0032] Comparative Example 1

[0033] This comparative example prepares a water-resistant bio-based shaped phase change composite material with reference to the formula and method provided in Example 1. The difference from Example 1 is that in this comparative example, polydimethylsiloxane with an equal mass fraction is used to replace amino-polydimethylsiloxane when preparing the phase change composite material. Except for the above difference, the operation steps for preparing the phase change composite material in this comparative example are strictly the same as those in Example 1.

[0034] Comparative Example 2

[0035] This comparative example prepares a water-resistant bio-based shaped phase change composite material with reference to the formula and method provided in Example 1. The difference from Example 1 is that in this comparative example, polyethylene glycol with an equal mass fraction is used to replace amino-polydimethylsiloxane when preparing the phase change composite material. Except for the above difference, the operation steps for preparing the phase change composite material in this comparative example are strictly the same as those in Example 1.

[0036] Comparative Example 3

[0037] This comparative example prepared a water-resistant bio-based shaped phase change composite material with reference to the formula and method provided in Example 1. The difference from Example 1 is that in this comparative example, polyethylene glycol in equal mass parts was used to replace isocyanate when preparing the phase change composite material. Except for the above differences, the operating steps for preparing the phase change composite material in this comparative example were strictly the same as those in Example 1.

[0038] Test Example 1

[0039] 1. Test Object

[0040] The phase change composite materials prepared in Example 1 and Comparative Examples 1 to 3.

[0041] 2. Test Method

[0042] (1) Leakage of phase change medium and shape stability: After heating on a heating table at 60 °C for 4 hours, observe whether the shape of the sample is deformed and whether there is leakage of the sample.

[0043] (2) Water resistance: ① Take 2 g of the prepared material and soak it in 500 mL of water at 50 °C for 12 hours, and observe the changes of the material every 30 minutes; ② Use a contact angle measuring instrument to measure the static water contact angle of the sample.

[0044] (3) Melting enthalpy: Use differential scanning calorimetry to measure the melting enthalpy of the sample, and use a model DSC 200 F3 (NETZSCH, Germany) to measure the melting enthalpy (J / g) of the sample. Weigh 6 - 10 mg of the sample and place it in an aluminum crucible. Under nitrogen protection, the sample is heated from 25 °C to 100 °C at a rate of 10 °C per minute.

[0045] (4) Recyclability: After heating on a heating table at 60 °C for 4 hours and then cooling, repeat the heating and cooling operations 3 times, and observe whether the material is deformed or leaked.

[0046] 3. Test Results and Analysis

[0047] The test results of this test example are shown in Table 2. Among them, this test example explored the effects of amino-polydimethylsiloxane and isocyanate on the performance of the phase change composite material.

[0048] In Comparative Example 1, polydimethylsiloxane was used to replace amino-polydimethylsiloxane. Since there is no amino group, it cannot react with polyethylene glycol, and thus the active end groups of polyethylene glycol cannot be capped, resulting in a decrease in the structural stability of the phase change composite material, and obvious deformation and leakage will occur at the working temperature. Similarly, in Comparative Examples 2-3, amino-polydimethylsiloxane and isocyanate were not added respectively. That is, in the phase change composite materials prepared in Comparative Examples 2-3, the active end groups of polyethylene glycol were not completely blocked. Therefore, at the working temperature of 60 °C, obvious deformation and leakage occurred in the shapes of the samples in Comparative Examples 2-3.

[0049] Table 2. Test results of Test Example 1

[0050]

[0051] Example 2

[0052] 1. Preparation of raw materials for water-resistant bio-based shaped phase change composite materials

[0053] This example provides a water-resistant bio-based shaped phase change composite material. The required raw materials and their mass fractions for preparing this water-resistant bio-based shaped phase change composite material are shown in Table 3.

[0054] Table 3. Raw materials required for preparing the water-resistant bio-based shaped phase change composite material in this example

[0055]

[0056] 2. Method for preparing the water-resistant bio-based shaped phase change composite material

[0057] S1. Prepare the materials required for preparing the modified inorganic micro-nano composite particles according to Table 3. Mix ethanol, ammonia water, and water evenly and then add ultrafine ceramic powder and stir to form a uniform first reaction solution. Subsequently, under stirring, slowly drop tetraethyl orthosilicate into the first reaction solution and carry out an in-situ reaction at 30 °C for 6 hours to obtain a second reaction solution containing nano-silica. Subsequently, under continuous stirring, add a fluorocarbon surfactant to the second reaction solution and react at 40 °C for 4 hours. After the reaction is completed, let it stand for 10 hours, separate and wash the precipitate, and dry it to obtain the modified inorganic micro-nano composite particles, where the mass ratio of nano-silica to ultrafine ceramic powder is 2:1;

[0058] S2. Prepare the materials required for preparing the water-resistant bio-based shaped phase change composite material according to Table 3. Take polyethylene glycol, amino-polydimethylsiloxane, and isocyanate and heat them to 65 °C to melt all the materials, and stir evenly to obtain a prefabricated mixture;

[0059] S3. Mix the prefabricated mixture, pine fiber powder and modified inorganic micro-nano composite particles evenly, add the reactants into a kneader, rotate and mix at 65 °C, and gradually add the catalyst (triethylenediamine). The kneading reaction processing time is 10 minutes, and the kneader rotation speed is 50 revolutions per minute; take it out and cool to obtain a water-resistant bio-based shaped phase change composite material.

[0060] Comparative Example 4

[0061] This comparative example prepares a water-resistant bio-based shaped phase change composite material with reference to the formula and method provided in Example 2. The difference from Example 2 is that in this comparative example, carboxymethyl cellulose with an equal mass fraction is used to replace pine fiber to prepare the water-resistant bio-based shaped phase change composite material. Except for the above differences, the operating steps for preparing the phase change composite material in this comparative example are strictly the same as those in Example 2.

[0062] Comparative Example 5

[0063] This comparative example prepares a water-resistant bio-based shaped phase change composite material with reference to the formula and method provided in Example 2. The difference from Example 2 is that in this comparative example, polyethylene glycol with an equal mass fraction is used to replace pine fiber to prepare the water-resistant bio-based shaped phase change composite material. Except for the above differences, the operating steps for preparing the phase change composite material in this comparative example are strictly the same as those in Example 2.

[0064] Comparative Example 6

[0065] This comparative example prepares a water-resistant bio-based shaped phase change composite material with reference to the formula and method provided in Example 2. The difference from Example 2 is that in this comparative example, an equal amount of polyethylene glycol is used to replace the modified inorganic micro-nano composite particles when preparing the phase change composite material. Except for the above differences, the operating steps for preparing the phase change composite material in this comparative example are strictly the same as those in Example 2.

[0066] Test Example 2

[0067] 1. Test objects

[0068] The phase change composite materials prepared in Example 2 and Comparative Examples 4 - 6.

[0069] 2. Test methods

[0070] Conduct tests according to the test method in Test Example 1.

[0071] 3. Test results and analysis

[0072] The test results of this test example are shown in Table 4. This test example explores the influence of modified inorganic micro-nano composite particles and biomass materials on the performance of the phase change composite material.

[0073] Among them, in Comparative Example 4, carboxymethyl cellulose was selected to replace pine fiber for compounding with the phase change material. However, through testing, it was found that when heated at 60 °C for 4 hours, the phase change composite material prepared in Comparative Example 4 would deform. Similarly, in Comparative Example 5, since no biomass material was introduced to enhance the phase change material, the phase change composite material prepared in Comparative Example 3 deformed when heated at 60 °C for 1 hour.

[0074] In Comparative Example 6, without adding the modified inorganic micro-nano composite particles, the water resistance of the corresponding prepared phase change composite material decreased significantly. In the water resistance experiment, it began to swell after soaking for 1 hour, and only plant fibers and inorganic substances remained floating in the water after soaking for 2 hours.

[0075] Table 4. Test results of Test Example 2

[0076]

[0077] Example 3

[0078] 1. Preparation of raw materials for the water-resistant bio-based shaped phase change composite material

[0079] This example provides a water-resistant bio-based shaped phase change composite material. The required raw materials and their mass fractions for preparing this water-resistant bio-based shaped phase change composite material are shown in Table 5.

[0080] Table 5. Raw materials required for preparing the water-resistant bio-based shaped phase change composite material in this example

[0081]

[0082] 2. Method for preparing the water-resistant bio-based shaped phase change composite material

[0083] S1. Prepare the materials required for preparing the modified inorganic micro-nano composite particles according to Table 5. Mix ethanol, ammonia water, and water evenly, then add ultrafine ceramic powder and stir to form a uniform first reaction solution. Subsequently, under stirring, slowly drop tetraethyl orthosilicate into the first reaction solution and carry out an in-situ reaction at 30 °C for 10 hours to obtain a second reaction solution containing nano-silica. Subsequently, under continuous stirring, add a fluorocarbon surfactant to the second reaction solution and react at 40 °C for 6 hours. After the reaction is completed, let it stand for 24 hours, separate and wash the precipitate, and dry it to obtain the modified inorganic micro-nano composite particles, where the mass ratio of nano-silica to ultrafine ceramic powder is 1:1;

[0084] S2. Prepare the materials required for preparing the water-resistant bio-based shaped phase change composite material according to Table 5. Take polyethylene glycol, amino-polydimethylsiloxane, and isocyanate and heat them to 80 °C to melt all the materials, and stir evenly to obtain a prefabricated mixture;

[0085] S3. Mix the prefabricated mixture, pine fiber powder, and modified inorganic micro-nano composite particles evenly, and add the reactants to a small twin-screw extruder. Let the materials be mixed at 80 °C, and gradually add the catalyst (triethylenediamine) through the side feeding port in the melting section to cause the materials to react. The rotational speed of the internal mixer is 35 revolutions per minute; the extrudate is air-cooled and pelletized to obtain a water-resistant bio-based shaped phase change composite material.

[0086] Example 4

[0087] This example refers to the formula for preparing the water-resistant bio-based shaped phase change composite material provided in Example 3 and the method for preparing the modified inorganic micro-nano composite particles. The difference from Example 3 is that this example uses a one-pot method to prepare the water-resistant bio-based shaped phase change composite material. Except for the above differences, the formula for preparing the phase change composite material and the method for preparing the modified inorganic micro-nano composite particles in this example are strictly the same as those in Example 3. Specifically, the operating steps of this example are as follows:

[0088] S1. Prepare the modified inorganic micro-nano composite particles according to Example 3.

[0089] S2. Prepare the materials required to prepare the water-resistant bio-based shaped phase change composite material according to the formula provided in Example 3. Take polyethylene glycol, amino polydimethylsiloxane, isocyanate, pine fiber powder, and modified inorganic micro-nano composite particles and heat them to 75 °C to melt all the materials to obtain a mixture. Then add the mixture to an open mill, rotate and mix at 70 °C, and gradually add the catalyst (triethylenediamine). The processing time for the open mill reaction is 15 minutes, and the rotational speed of the open mill is 30 revolutions per minute; take it out and cool to obtain a water-resistant bio-based shaped phase change composite material.

[0090] Comparative Example 7

[0091] This comparative example refers to the formula and method provided in Example 3 to prepare the water-resistant bio-based shaped phase change composite material. The difference from Example 3 is that this comparative example does not add a fluorocarbon surfactant when preparing the modified inorganic micro-nano composite particles. Except for the above differences, the operating steps for preparing the phase change composite material in this comparative example are strictly the same as those in Example 3. Specifically, the operating steps for preparing the modified inorganic micro-nano composite particles in this comparative example are as follows:

[0092] Prepare the materials required to prepare the modified inorganic micro-nano composite particles according to the formula provided in Example 3. Mix ethanol, ammonia water, and water evenly, and then add ultrafine ceramic powder and stir to form a uniform suspension; then, under stirring, slowly drop tetraethyl orthosilicate into the suspension and carry out an in-situ reaction at 30 °C for 10 hours; after the reaction is completed, let it stand for 10 hours, separate and wash the precipitate, and dry to obtain the modified inorganic micro-nano composite particles.

[0093] Comparative Example 8

[0094] In this comparative example, modified inorganic micro-nano composite particles are not used in the preparation of the phase change composite material, and the active groups of the organic phase change material are not subjected to a blocking treatment. Specifically, the operating steps for preparing the phase change composite material in this comparative example are as follows:

[0095] Calculated by mass fraction, 0.5 parts of silane coupling agent are taken to perform surface treatment on a mixture of 8 parts of pine wood fiber and 4 parts of inorganic substance (nitrate), wherein the reaction conditions are 30 °C and the reaction time is 6 hours; subsequently, under the molten state, the surface-modified pine wood fiber and inorganic substance mixture adsorb 100 parts of polyethylene glycol (relative molecular weight is 10,000) through the vacuum-assisted method, wherein the reaction temperature is 75 °C and the reaction time is 10 hours; the unadsorbed polyethylene glycol is removed by the vacuum-assisted filtration method to obtain the phase change composite material.

[0096] Test Example 3

[0097] 1. Test object

[0098] The water-resistant bio-based shaped phase change composite materials prepared in Examples 3-4 and Comparative Examples 7-8.

[0099] 2. Test method

[0100] The test is carried out according to the test method of Test Example 1.

[0101] 3. Test results and analysis

[0102] The test results of this test example are shown in Table 6. This test example mainly explores the influence of the preparation method on the performance of the prepared water-resistant bio-based shaped phase change composite material.

[0103] In Example 4, the water-resistant bio-based shaped phase change composite material is prepared by the one-pot method. Since the amino polydimethylsiloxane and isocyanate do not completely block the active end groups of polyethylene glycol, in the repeated experiment, the phase change composite material prepared in Example 4 leaks.

[0104] In Comparative Example 7, the lack of addition of fluorocarbon surfactant during the preparation of the modified inorganic micro-nano composite particles will lead to a decrease in the water resistance of the modified inorganic micro-nano composite particles, and then it is impossible to construct a micro-nano hydrophobic structure, resulting in a significant decrease in the water resistance of the prepared phase change composite material.

[0105] In Comparative Example 8, since modified inorganic micro-nano composite particles are not used and the active groups of the organic phase change material are not subjected to a blocking treatment, the corresponding prepared phase change composite material will undergo obvious deformation and exudation at a working temperature of 60 °C, and the water resistance experiment shows that the material starts to swell after being soaked for 30 minutes, and after being soaked for 1 hour, only plant fibers and inorganic substances are suspended in the solution.

[0106] Table 6. Test Results of Test Example 3

[0107]

[0108] The above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A water-resistant bio-based shaped phase change composite material, characterized in that calculated by mass parts, the raw materials for preparing the water-resistant bio-based shaped phase change composite material include: 10-100 parts of an organic phase change material, 1-8 parts of a biomass material, and 0.5-4 parts of a modified inorganic micro-nano composite particle; wherein, the organic phase change material is a polyol; the biomass material is a plant fiber; the modified inorganic micro-nano composite particle is formed by in-situ reaction of ultrafine ceramic powder, nano-silica, and fluorocarbon surfactant; The raw materials for preparing the water-resistant bio-based shaped phase change composite material further include amino polydimethylsiloxane and isocyanate; wherein, calculated by molar ratio, the amino polydimethylsiloxane: the active end group of the organic phase change material = 1:1; calculated by mass ratio, the isocyanate: the organic phase change material = 0.1-2:

10.

2. The water-resistant bio-based shaped phase change composite material according to claim 1, characterized in that the polyol includes polyethylene glycol.

3. The water-resistant bio-based shaped phase change composite material according to claim 1, characterized in that calculated by mass ratio, in the modified inorganic micro-nano composite particle, the nano-silica: the ultrafine ceramic powder = 1-10:

1.

4. The water-resistant bio-based shaped phase change composite material according to claim 3, characterized in that the particle size of the ultrafine ceramic powder is 10-30 μm.

5. The water-resistant bio-based shaped phase change composite material according to claim 1, characterized in that the isocyanate includes at least one of isophorone diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, and hexamethylene diisocyanate.

6. A method for preparing the water-resistant bio-based shaped phase change composite material according to any one of claims 1-5, characterized in that the method includes the following steps: S1. Using in-situ reaction to compound the nano-silica, the ultrafine ceramic powder, and the fluorocarbon surfactant to prepare the modified inorganic micro-nano composite particle; S2. Heating the organic phase change material, the amino polydimethylsiloxane, and the isocyanate to 60-80 °C and mixing to obtain a prefabricated mixture; S3. Blending the prefabricated mixture, the modified inorganic micro-nano composite particle, the biomass material, and a catalyst through melt processing, and the processing temperature of the melt processing is 40-100 °C, and after reacting for 1-30 minutes, the water-resistant bio-based shaped phase change composite material is obtained.

7. The method according to claim 6, characterized in that in the S3, calculated by mass ratio, the catalyst: the isocyanate = 0.1-1:

1.

8. The method according to claim 7, characterized in that the catalyst includes at least one of triethylenediamine, dibutyltin dilaurate, diethylcyclohexylamine, and dimethylethanolamine.

9. The method according to claim 6, characterized in that In S1, preparing the modified inorganic micro-nano composite particles includes the following steps: calculating by mass, taking 60 to 150 parts of ethanol, 5 to 15 parts of ammonia water, 1 to 10 parts of water, and 0.5 to 2 parts of the ultrafine ceramic powder to mix to form a first reaction liquid; then adding 2 to 10 parts of silicate compounds to the first reaction liquid, reacting in situ at 20 to 60° C., and reacting for 2 to 10 hours to obtain a second reaction liquid containing the nano-silicon dioxide; adding 0.1 to 10 parts of the fluorocarbon surfactant to the second reaction liquid, reacting at 20 to 80° C. for 4 to 24 hours to obtain the modified inorganic micro-nano composite particles.

10. The method according to claim 9, It is characterized in that The silicate compound includes at least one of ethyl orthosilicate and propyl orthosilicate.

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