Energy storage phase change thermal insulation foam material and preparation method thereof

Abstract

The present application relates to the technical field of energy storage materials, and particularly relates to an energy storage phase change heat preservation foam material and a preparation method thereof. The preparation method comprises the following steps: mixing a phase change material and an oil phase by melting and heating to obtain a first mixed oil phase; the phase change material is an ester wax substance or a fusible ester substance; the oil phase is a biomass prepolymer; adding nanoparticles and an initiator into the first mixed oil phase to obtain a second mixed oil phase; adding an aqueous phase into the second mixed oil phase, and mechanically stirring and emulsifying to obtain a water-in-oil Pickering emulsion; adding a foaming agent into the water-in-oil Pickering emulsion to obtain a pre-foaming emulsion; pouring the pre-foaming emulsion into a mold for heating and solidification, and drying after solidification to obtain the energy storage phase change heat preservation foam material. The preparation method has the advantages of being green, non-toxic, easy to operate, high in efficiency and low in cost. The prepared energy storage phase change heat preservation foam material is low in thermal conductivity, good in mechanical properties, and large in heat storage capacity, and can be used in various fields.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of energy storage materials, in particular to a kind of energy storage phase change insulation foam material and preparation method thereof. BACKGROUND

[0002] In today's society, the ecological environment is increasingly polluted by petroleum-based insulation foam. Porous foam, porous sponge, aerogel and other products prepared from biomass have become one of the current hotspots in materials science research due to their renewable, degradable and environmentally friendly advantages. With the gradual improvement of people's living standards and the pursuit of health and convenience, the market demand for insulation products is increasing. In particular, in the fields of food preservation, beverage insulation and medical transportation, the pros and cons of insulation effect directly affect the quality and safety of products. However, traditional insulation materials usually rely on thermal insulation materials to reduce heat transfer. This method can maintain temperature in a short time, but in long-term use, the insulation effect often fails to meet the actual demand.

[0003] Phase change materials (PCM) are widely used in temperature regulation due to their ability to absorb or release large amounts of heat during phase change. These materials adjust the ambient temperature through phase transition (such as solid-liquid, liquid-gas, etc.) when the temperature changes, providing stable temperature output when the ambient temperature changes. However, most PCM products on the market still have some drawbacks, such as limited insulation efficiency, volume and weight problems, poor stability and environmental adaptability of PCM.

[0004] Insulation materials prepared from energy storage phase change materials use plant and animal extracts or derivatives such as soybean oil derivatives (epoxy soybean oil acrylate, lignin-based acrylate, etc.), carbohydrates or their derivatives (ethyl cellulose, chitin), phase change materials (palm wax, rice bran wax, beeswax, fatty acid esters, etc.) as raw materials. Through steps such as mixing into emulsion, reaction curing, heating and drying, a foam material with good energy storage effect is finally formed. For example, patent No. CN201910120219.8 provides a filter residue material with phase change energy storage properties by preparing a pre-emulsion and then undergoing a polymerization reaction. Patent No. CN202310118691.4 discloses a phase change energy storage material prepared using paraffin, sodium dodecyl sulfate, dimethyl silicone oil and other raw materials. Although the above methods have certain effects, the preparation methods are complex and tedious, often involving the use of chemical organic reagents, which does not meet the concept of green manufacturing. Therefore, it is particularly important to develop a new type of energy storage phase change insulation foam material that can utilize the heat storage and release characteristics of phase change materials to maintain temperature for a long time and meet the urgent demand for high-performance insulation products in the market. SUMMARY

[0005] To solve or partially solve the problems in the related art, the present application provides a kind of energy storage phase change thermal insulation foam material and preparation method thereof.

[0006] The present application provides a kind of energy storage phase change thermal insulation foam material and preparation method thereof, which comprises:

[0007] Step a), the phase change material is mixed with oil phase melting heating, to obtain the first mixed oil phase;The phase change material is ester wax material or melting ester material;The oil phase is biomass prepolymer;

[0008] Step b), nano particles and initiator are added to the first mixed oil phase to obtain the second mixed oil phase;

[0009] Step c), water phase is added to the second mixed oil phase, and mechanical stirring emulsification is carried out to obtain water-in-oil Pickering emulsion;

[0010] Step d), foaming agent is added to the water-in-oil Pickering emulsion to obtain pre-foaming emulsion;

[0011] Step e), the pre-foaming emulsion is poured into the mold and heated and cured, and after curing, drying is carried out to obtain energy storage phase change thermal insulation foam material.

[0012] Further, the ester wax material is one or more of beeswax, insect wax, palm wax and rice bran wax;The melting ester material is one or more of stearate, hydrogenated castor oil and fatty acid ester.

[0013] Further, the mixing ratio of the phase change material and the oil phase is 1-15:100 by weight.

[0014] Further, the nano particles are organic nano particles and / or inorganic nano particles;The organic nano particles are ethyl cellulose nano particles, chitin nano particles, or phase change nano particles, the phase change nano particles are nano particles made of phase change material with melting temperature higher than 80℃;The inorganic nano particles are silica particles, calcium carbonate particles or zinc oxide particles;The addition amount of the organic nano particles in the first mixed oil phase is 2-12 wt%;The addition amount of the inorganic nano particles in the first mixed oil phase is 0.3-1.8 wt%.

[0015] Further, the initiator is benzoyl peroxide, lauroyl peroxide or tert-butyl peroxybenzoate;The addition amount of the initiator is 2-3 wt% of the first mixed oil phase.

[0016] Further, the foaming agent is a bicarbonate salt, and the foaming agent is added in an amount of 0.1-1.5 wt% of the water-in-oil Pickering emulsion.

[0017] Further, in the step c), the mixing ratio of the second mixed oil phase and the water phase is 6-9:1-4.

[0018] Further, in the step e), the temperature for heating and curing is 70-100℃, and the time is 1.5-6 h; the temperature for drying is 50-60℃, and the time is 6-8 h.

[0019] Further, in the step e), the mold material is polytetrafluoroethylene, high borosilicon or stainless steel.

[0020] The present application also provides a phase change energy storage thermal insulation foam material prepared by the method according to any one of the above.

[0021] The phase change energy storage thermal insulation foam material and the preparation method thereof provided by the present application can have the following beneficial effects:

[0022] 1) The method melts and mixes the phase change material and the oil phase as the mixed oil phase, the phase change material adopts ester wax or melt ester, and the oil phase adopts biomass pre-polymer. On the one hand, the phase change material and the oil phase have better compatibility, and can be more uniformly mixed. Such combination can better combine at the molecular level, avoid separation or performance degradation of the material during phase change, and improve the phase change latent heat and phase change temperature range of the material. On the other hand, the ester wax (such as palm wax) in solid state has high rigidity and toughness. When added to the reaction system, it can not only strengthen the crosslinking process of the material, but also improve the mechanical properties of the material. It improves the mechanical strength and wear resistance of the product prepared by using a single pre-polymer due to low crosslinking degree or insufficient raw material properties, and further improves the impact resistance and durability of the product in application scenarios such as transportation and storage.

[0023] 2) The raw materials involved in the method can be derived from biomass materials except for a small amount of inorganic materials, so the method has the advantages of green, non-toxic, wide source and easy to obtain. The biomass materials also have social and economic benefits of waste utilization, and have the potential of biodegradation, thereby realizing the greenization and safety of the foam material from the source.

[0024] 3) The method adds a foaming agent in the emulsion to further increase the number of emulsion cells. The formed cells can capture and hold air stably, forming an air layer, thereby greatly limiting the flow of heat, reducing the structure density caused by the introduction of phase change materials, reducing the thermal conductivity of the foam material, and improving the thermal insulation performance of the foam material. Further, the foaming agent can be ammonium bicarbonate, sodium bicarbonate, etc. These reagents are widely available, inexpensive and easy to obtain, and the decomposition products produced when heated, such as ammonia, carbon dioxide, and water, are not harmful factors in the environment, which is conducive to environmental protection.

[0025] 4) The method produces energy storage phase change thermal insulation foam material by constructing W / O type Pickering emulsion, using Pickering emulsion as a template, and heating the template (oil phase) to solidify. Only common basic equipment such as mechanical stirrers, water baths, and ovens are involved in the process, avoiding the dependence on special equipment (such as high-pressure reaction devices, high-speed shearing equipment, and freeze-drying equipment) and special reaction conditions (such as high temperature and high pressure, low temperature and negative pressure). The foam forming process is relatively simple, as it involves one-time feeding and molding and one-time heating, avoiding the multiple compounding and complex chemical treatment in traditional foam forming processes such as gel sol-freeze drying method, improving production efficiency and molding yield, and reducing molding cost. Therefore, the preparation method has the advantages of easy operation, high efficiency, and low cost.

[0026] 5) The energy storage phase change thermal insulation foam material prepared by the method has a large number of small pores, low thermal conductivity, good mechanical properties, and large heat storage capacity, and can be used in various fields.

[0027] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present application. BRIEF DESCRIPTION OF DRAWINGS

[0028] The above and other objects, features and advantages of the present application will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which like reference characters refer to like parts throughout the figures, and wherein exemplary embodiments of the application are shown.

[0029] Figure 1 is the DSC graph of the energy storage phase change thermal insulation foam material prepared in Examples 1-6 of the present application;

[0030] Figure 2 is the appearance display graph of the energy storage phase change thermal insulation foam material prepared in Examples 1-6 of the present application;

[0031] Figure 3 is the mechanical property test graph of the energy storage phase change thermal insulation foam material prepared in Examples 1-6 of the present application;

[0032] Figure 4 are appearance display diagrams of the energy storage phase change thermal insulation foam materials prepared in embodiments 13 and 14 of the present application;

[0033] Figure 5 are appearance diagrams of the energy storage phase change thermal insulation foam materials prepared in embodiments 3 and 13 of the present application;

[0034] Figure 6 are scanning electron microscope diagrams of the foam materials prepared in embodiment 3 of the present application Figure 6 a) and the foam materials prepared in comparative example 3 Figure 6 b);

[0035] Figure 7 are appearance display diagrams of the foam materials prepared in embodiment 3 of the present application Figure 7 a), comparative example 1 Figure 7 c) and comparative example 2 Figure 7 b). DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be apparently and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0037] The terms used in the present application are merely for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "an" and "the" used in the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0038] It should be understood that although the terms "first", "second", "third", etc. are used in the present application to describe various information, these information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, the first information can also be referred to as the second information, and similarly, the second information can also be referred to as the first information without departing from the scope of the present application. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0039] The embodiments of the present application provide a preparation method of an energy storage phase change thermal insulation foam material, which comprises the following steps:

[0040] Step a), melt and heat mix the phase change material and the oil phase to obtain a first mixed oil phase; the phase change material is an ester wax or a melt ester; the oil phase is a biomass prepolymer;

[0041] Step b), add nanoparticles and an initiator into the first mixed oil phase to obtain a second mixed oil phase;

[0042] Step c), add an aqueous phase into the second mixed oil phase and mechanically stir to emulsify to obtain a water-in-oil Pickering emulsion;

[0043] Step d), add a foaming agent into the water-in-oil Pickering emulsion to obtain a pre-foaming emulsion;

[0044] Step e), add the pre-foaming emulsion into a mold and heat to solidify, dry after solidification to obtain an energy storage phase change thermal insulation foam material.

[0045] In the above preparation method, step a) is a step of melt mixing the phase change material and the oil phase to uniformly disperse the phase change material in the oil phase and improve the bonding degree by using the similar compatibility principle to obtain the first mixed oil phase. This step can be specifically:

[0046] Heat and melt the phase change material;

[0047] Add the oil phase into the phase change material in a molten state and mix thoroughly;

[0048] Let it stand and cool, and the first mixed oil phase is obtained.

[0049] In this embodiment, the phase change material is an ester wax or a melt ester, which can be one or more of beeswax, insect wax, palm wax, and rice bran wax; the oil phase is a biomass prepolymer, which can be one or more of stearate, hydrogenated castor oil, and fatty acid ester. The phase change material and the oil phase have better compatibility, can be mixed more uniformly, and such a combination can better combine them at the molecular level, avoid separation or performance degradation of the material during phase change, and improve the latent heat of phase change and the phase change temperature range of the material. Moreover, the raw materials of the phase change material come from natural raw materials, and the oil phase material is a soybean oil derivative, a carbohydrate or a derivative thereof, which is of natural origin. Thus, the use of environmentally hazardous chemical raw materials such as petroleum-based derivatives is avoided, and the environmental friendliness of the product is improved. Further, the mixing ratio of the phase change material and the oil phase is 1-15:100 by weight, which ensures that the material has good phase change performance while maintaining sufficient strength and toughness. The mixing ratio of the phase change material and the oil phase is more preferably 5-10:100 by weight.

[0050] The step b) is a step of mixing nanoparticles and initiator into the first mixed oil phase. The nanoparticles act as Pickering emulsifier to stabilize the W / O emulsion, prevent water and oil separation, and ensure the stability of the foam structure. The thermal initiator is used to initiate the curing reaction of the oil phase, so that the oil phase forms a three-dimensional network structure, thereby improving the strength and toughness of the material. The nanoparticles are organic nanoparticles and / or inorganic nanoparticles; the organic nanoparticles are ethyl cellulose nanoparticles, chitin nanoparticles, or phase change nanoparticles, the phase change nanoparticles are nanoparticles made of phase change materials with a melting temperature higher than 80℃; the inorganic nanoparticles are silica particles, calcium carbonate particles or zinc oxide particles. The raw materials of the above-mentioned nanoparticles are all from natural raw materials, thereby further improving the environmental protection of the product and its preparation process. The addition amount of the organic nanoparticles in the first mixed oil phase is preferably 2-12wt%, more preferably 2-4wt%, and most preferably 4wt%; the addition amount of the inorganic nanoparticles in the first mixed oil phase is preferably 0.3-1.8wt%, more preferably 0.6-1.2wt%. The particle size of the above-mentioned nanoparticles is preferably 150-1200 nm. In the above-mentioned organic nanoparticles, if phase change nanoparticles are used, it is more helpful to improve the heat storage performance of the foam product. At present, the inventors have found that if the phase change material of the phase change nanoparticles has a melting temperature lower than 80℃, it will be difficult to form the cured product, or the mechanical properties of the formed product will be too poor. Therefore, the phase change nanoparticles of the present application are nanoparticles made of phase change materials with a melting temperature higher than 80℃. The phase change nanoparticles can be prepared according to the following method: mixing the phase change material with water, heating to melt the phase change material, then adding an emulsifier such as Tween 20, and performing magnetic stirring to obtain a phase change material particle pre-dispersion; then performing ultrasonic treatment to obtain a phase change material nanoparticle water dispersion, and concentrating for use. The mixing mass ratio of the phase change material to water is preferably 1:(55-65), and most preferably 1:50. The speed of magnetic stirring is preferably 700-900r / min, and the time is preferably 20-40min, and most preferably, the speed of magnetic stirring is 800r / min and the time is 30min. The amplitude of ultrasonic treatment is preferably 60%-80%, the ultrasonic treatment is 4-6s, and the interval is 4-6s, and most preferably, the amplitude is 70%, the ultrasonic treatment is 5s, and the interval is 5s. The time of ultrasonic treatment is preferably 4-6min, and most preferably 5min.

[0051] The initiator used in this step is preferably benzoyl peroxide, lauroyl peroxide or tert-butyl benzene peroxide; the addition amount of the initiator is 2-3wt% of the first mixed oil phase, and most preferably benzoyl peroxide is used, and the addition amount is 3wt% of the first mixed oil phase; the above-mentioned proportion of crosslinking agent can effectively control the speed and degree of curing reaction, avoid excessive crosslinking or incomplete crosslinking of the material, and thereby ensure the performance of the product.

[0052] The step c) is to mix and emulsify the water phase and the second mixed oil phase to form a stable water-in-oil Pickering emulsion, which provides a template for subsequent foaming and solidification. In this step, the mixing ratio of the second mixed oil phase and the water phase is preferably 6-9:1-4, and most preferably 6:4. The emulsification method in this step is mechanical stirring emulsification, and the stirring rate is preferably 100-300 r / min, and the stirring time is preferably 15-30 min, to ensure the stability of the emulsion and the uniformity of the foam structure.

[0053] For the case where the mixing ratio of the phase change material and the oil phase in the first mixed oil phase is greater than 5:100, conventional mixing will result in too large viscosity of the mixed oil phase to form an emulsion due to crystallization behavior. Therefore, steps b) and c) need to be compensated by heating, i.e. carried out under heating. The heating temperature is preferably 40-50℃, and more preferably 45℃, as follows:

[0054] Step b) softens the second mixed oil phase under the condition of water bath heating; then solid nanoparticles and an initiator are sequentially added to the second mixed oil phase, stirred and uniformly mixed to obtain the second mixed oil phase;

[0055] Step c), under the condition of water bath heating, the water phase is added to the second mixed oil phase, and mechanical stirring emulsification is carried out to obtain a water-in-oil Pickering emulsion;

[0056] The above step d) is the step of adding a foaming agent to the water-in-oil Pickering emulsion. The inventors of the present application found through research that the product obtained by directly pouring and solidifying the water-in-oil Pickering emulsion still has unsatisfactory thermal insulation performance, and further analysis may be related to the addition of phase change materials, which causes the product internal structure to be too dense. In order to further improve the thermal insulation performance, the inventors consider that the number of bubbles in the emulsion is increased, which can capture and maintain air stably to form an air layer, thereby greatly limiting the flow of heat. Therefore, the energy storage phase change thermal insulation foam material preparation method provided by the present application adds a foaming agent to the Pickering emulsion. For the selection of the foaming agent, the present application preferably uses a bicarbonate salt, such as ammonium bicarbonate, sodium bicarbonate or calcium bicarbonate; the addition amount of the bicarbonate salt is 0.1-1.5wt% of the water-in-oil Pickering emulsion, which can effectively control the porosity and thermal insulation performance of the foam structure. The foaming agent has a heat requirement synchronized with the solidification reaction, i.e. can be thermally decomposed to generate gas to promote the formation of pores at the heating and solidification temperature. The foaming agent is most preferably ammonium bicarbonate, which generates carbon dioxide and ammonia gas to promote the formation of pores during the heating and solidification process, and the decomposition products do not affect the environment, which helps to improve the environmental performance.

[0057] The step e) is a step of pouring, heating curing and drying. The heating process can make the oil phase cured to form a foam structure. After the curing reaction, there is still a large amount of water vapor (aqueous phase) in the reaction mold, and the thermal insulation material is in a highly humid state. The thermal insulation material is dried and cured to remove the water, and finally the energy storage phase change thermal insulation foam material is obtained. In this step, the temperature of the heating curing is preferably 70-100℃, and the time can be 1.5-6h. The drying temperature is preferably 50-60℃, and the time is 8-10h, so as to ensure the forming quality and mechanical properties of the material. More preferably, the temperature of the heating curing is 80℃, and the time is 3h. The drying temperature is 55℃, and the time is 8h.

[0058] The mold material used in this step is preferably polytetrafluoroethylene, high borosilicon or stainless steel. Using different molds can produce different materials with oil film wrapping. In the polytetrafluoroethylene mold, due to its low surface energy, the liquid droplets on the mold surface will form a large contact angle, showing significant repulsion, which makes it difficult for the water phase to wet or spread on the surface of the mold, and thus no uniform water layer is formed on the surface of the mold, so no oil film is produced. The surface energy of the high borosilicon mold makes the water phase easy to spread on the surface of the mold, so that the oil phase in the emulsion is wrapped by the water phase and pushed to the surface of the mold. During the curing process, the oil phase gradually accumulates on the surface of the mold and solidifies to form an oil film.

[0059] During the pouring process, in order to provide the space required for the volume expansion of the foamed emulsion, the pouring volume of the pre-foamed emulsion is preferably 30-70% of the volume fraction of the mold. The mold preferably has a pressure relief mechanism for ensuring that the pressure in the mold is slightly higher than the external pressure, so as to constrain the bubble formation and growth of the emulsion.

[0060] Another embodiment of the present application also provides an energy storage phase change thermal insulation foam material prepared according to the method described in the foregoing embodiments. The energy storage phase change thermal insulation foam material has a large number of small pores, low thermal conductivity, good mechanical properties, and large heat storage capacity, and can be used in various fields.

[0061] From the above, it can be seen that the energy storage phase change thermal insulation foam material and the preparation method thereof provided by the embodiments of the present application have the following advantages:

[0062] 1) The method melts and mixes the phase change material and the oil phase as a mixed oil phase. The phase change material is an ester wax or a molten ester substance, and the oil phase is a biomass prepolymer. On the one hand, the phase change material and the oil phase have better compatibility, and can be more uniformly mixed. Such a combination can better combine at the molecular level, avoid separation or performance degradation of the material during the phase change process, and improve the latent heat of phase change and the phase change temperature range of the material. On the other hand, the ester wax (such as palm wax) has high hardness characteristics. Adding it to the reaction system can not only strengthen the crosslinking process of the material, but also improve the mechanical properties of the material. It improves the mechanical strength and wear resistance of the product prepared by using a single prepolymer, which is caused by low crosslinking degree or insufficient raw material properties, and further improves the impact resistance and durability of the product in application scenarios such as transportation and storage.

[0063] 2) The raw materials involved in the method can be derived from biomass materials except for a small amount of inorganic substances. Therefore, the method has the advantages of being green, non-toxic, widely available, and easy to obtain. The biomass prepolymer material also has social and economic benefits of waste utilization and potential for biodegradation, thereby realizing the greenization and safety of the foam material from the source.

[0064] 3) The method adds a foaming agent to the emulsion to improve the bubble number of the emulsion. The formed bubble can capture and hold air stably to form an air layer, thereby greatly limiting the flow of heat, reducing the densification of the microstructure caused by the introduction of the phase change material, reducing the thermal conductivity of the foam material, and improving the thermal insulation performance of the foam material. Further, the foaming agent can be ammonium bicarbonate, sodium bicarbonate, etc. These reagents are widely available, inexpensive and easy to obtain, and the decomposition products produced when heated, such as ammonia, carbon dioxide, and water, are not harmful factors in the environment, which is conducive to environmental protection.

[0065] 4) The method produces energy storage phase change thermal insulation foam material by constructing a W / O type Pickering emulsion, using the Pickering emulsion as a template, and heating the template (oil phase) to solidify. Only common basic equipment such as mechanical stirrers, water baths, and ovens are involved in the process, avoiding the dependence on special equipment (such as high-pressure reaction devices, high-speed shearing equipment, and freeze-drying machines) and special reaction conditions (such as high temperature and high pressure, low temperature and negative pressure). The foam forming process is simple. By adding the mold once and heating to form once, the process avoids the multiple compounding and complex chemical treatment in traditional foam forming processes such as gel sol-frozen drying method, improves the production efficiency and forming yield, and reduces the forming cost. Therefore, the preparation method has the advantages of easy operation, high efficiency, and low cost.

[0066] 5)、The energy storage phase change thermal insulation foam material prepared by the method has a large number of cells and small pore size, low thermal conductivity, good mechanical properties, and large heat storage capacity, and can be used in various fields.

[0067] The technical solutions of the present application will be further described below in combination with specific examples:

[0068] The raw materials used in the following examples are as follows:

[0069] Palm wax: purchased from Shanghai Jiexie Industry Co., Ltd. (origin: Brazil);

[0070] Beeswax: purchased from Henan Xuchang Yiheng Bee Industry Co., Ltd.;

[0071] Castor wax: purchased from Global (Hong Kong) Trading Co., Ltd. (origin: Thailand);

[0072] Rice bran wax: purchased from Chongqing Hecai Chemical Technology Co., Ltd.;

[0073] Fatty acid ester: purchased from Guangzhou Huayu Biological Technology Co., Ltd.; Epoxy soybean oil acrylate: purchased from Wuhan Lanna Bai Pharmaceutical Chemical Co., Ltd., biomass content > 90%, epoxy value 6.28;

[0074] Ethyl cellulose nanoparticles: purchased from Shanghai Sigma Co., Ltd.;

[0075] Silicon dioxide nanoparticles: purchased from Shanghai Sigma Co., Ltd.

[0076] Example 1

[0077] (1) 0.171 g of palm wax and 17.0 g of epoxy soybean oil acrylate were mixed, heated to melt at 90℃, and stirred uniformly to obtain a first mixed oil phase;

[0078] (2) 4 wt% of ethyl cellulose with an average particle size of 150 nm and 3 wt% of benzoyl peroxide were added to the first mixed oil phase and mixed uniformly to obtain a second mixed oil phase;

[0079] (3) The water phase (distilled water) was added to the second mixed oil phase, and the oil-water mass ratio was 6:4. After mechanical stirring at 200 r / min for 30 min, emulsification was carried out to obtain a W / O type Pickering emulsion. 1 wt% of ammonium bicarbonate was added to the emulsion and continuously stirred to obtain a pre-foaming emulsion;

[0080] (4) The pre-foaming emulsion was poured into a polytetrafluoroethylene cylindrical mold, heated and cured at 80℃ for 3 h, and after demolding, dried at 55℃ for 8 h to obtain an energy storage phase change thermal insulation foam material.

[0081] (5) The physical property analysis results of the obtained energy storage phase change insulation foam material are as follows: the apparent density is 0.198 g / cm 3 , the thermal conductivity is 0.067 W / , the thermal diffusivity is 0.21 mm 2 / s, the compressive strength is 0.35 MPa, and the heat storage capacity is 1.18 J / g.

[0082] The method of physical property analysis is as follows, and the following examples are the same:

[0083] 1-Apparent density:

[0084] The sample is processed into a cylinder with a size of Φ480x20 mm, an analytical balance (accuracy of 0.001 g) is used to weigh the sample mass, and the sample apparent density is obtained by dividing the mass by the volume. It is expressed by the formula:

[0085]

[0086] Wherein, ρ represents the sample apparent density, g / cm 3 ; m represents the sample mass, g; v represents the sample volume, cm 3 .

[0087] 2-Performance test

[0088] The transient plane heat source method is used to test the normal temperature thermal conductivity of the sample; the specific test process is as follows: first, put the assembled sample and probe into the furnace body, then vacuumize, until the pressure in the furnace body is reduced to 10 Pa and maintained for 1 h to fully desorb the gas adsorbed by the sample, finally, slowly put air into the furnace body, when the set pressure is reached and stabilized for 2 h, start testing the thermal conductivity under the specified pressure.

[0089] 3-Mechanical strength

[0090] According to GB / T8813-2008 "Determination of Compressive Properties of Rigid Foamed Plastics", the compressive properties of the porous material are tested. The WDW model 100 electronic universal testing machine is used to test the compressive strength of the sample. The porous material is a cylinder with a pressure area of 314 mm 2 high 48 mm, a 5000 N load cell is used for mechanical compression test of the porous material, the experiment is carried out at a constant strain rate of 5 mm / min, until the sample is crushed. Each kind of porous material is measured for 3 times to get the average, finally the stress-strain curve of the material is obtained, and the maximum compressive strength is calculated. The calculation formula is as follows:

[0091]

[0092] wherein σ max represents the maximum compressive strength, Pa; represents the maximum force the sample withstands during compression, N; A represents the cross-sectional area of the sample, m 2 .

[0093] 4. Enthalpy change determination

[0094] Differential scanning calorimetry (DSC) is used to determine the enthalpy change of a material during a phase change. 5-15 mg of a dried sample is accurately weighed and placed in a suitable DSC crucible. The temperature range of the phase change material is set, and the test is performed at a heating rate of 5 °C / min. The calculation formula is as follows:

[0095]

[0096] wherein, represents the enthalpy change of the sample in the temperature range, J / g; represents the heat flow density of the DSC curve, mW / mg; T1 and T2 represent the temperature range.

[0097] (6) The apparent density of the obtained energy storage phase change insulation foam material is 0.192 g / cm 3 , the thermal conductivity is 0.065 W / , the thermal diffusivity is 0.19 mm 2 / s, the compressive strength is 0.213 MPa, and the heat storage capacity is 0.046 J / g.

[0098] Example 2

[0099] (1) 0.43 g of palm wax and 16.74 g of epoxy soybean oil acrylate were mixed, heated to melt at 90 °C, and stirred uniformly to obtain a first mixed oil phase;

[0100] (2) 4 wt% of ethyl cellulose with a particle size of 500 nm and 3 wt% of benzoyl peroxide were added to the first mixed oil phase and mixed uniformly to obtain a second mixed oil phase;

[0101] (3) The water phase (distilled water) was added to the second mixed oil phase, and the oil-water mass ratio was 6:4. The emulsion was obtained by emulsifying under 200 r / min mechanical stirring for 30 min. 1 wt% of ammonium bicarbonate was added to the emulsion and stirred continuously to obtain a pre-foaming emulsion;

[0102] (4) The pre-foaming emulsion was poured into a polytetrafluoroethylene cylindrical mold, heated and cured at 80 °C for 3 h, and then demolded and dried at 55 °C for 8 h to obtain an energy storage phase change insulation foam material.

[0103] (5) The physical properties of the prepared energy storage phase change thermal insulation foam material were analyzed: the apparent density was 0.198 g / cm 3 , the thermal conductivity was 0.067 W / , the thermal diffusivity was 0.21 mm 2 / s, the compressive strength was 0.244 MPa, and the heat storage capacity was 1.18 J / g.

[0104] Example 3

[0105] (1) 0.86 g of palm wax was weighed and mixed with 16.31 g of epoxy soybean oil acrylate, and heated to melt at 90°C, and stirred uniformly to obtain a first mixed oil phase;

[0106] (2) 4 wt% of ethyl cellulose with a particle size of 850 nm and 3 wt% of benzoyl peroxide were added to the first mixed oil phase, and the mixture was heated in a 45°C water bath, and after the mixed oil phase was softened, it was stirred and mixed uniformly to obtain a second mixed oil phase;

[0107] (3) The water phase (distilled water) was added to the second mixed oil phase, and the oil-water mass ratio was 6:4, and emulsified by mechanical stirring at 200 r / min for 30 min to obtain a W / O type Pickering emulsion; 1 wt% of ammonium bicarbonate was added to the emulsion, and the mixture was continuously stirred and mixed uniformly to obtain a pre-foaming emulsion;

[0108] (4) The pre-foaming emulsion was poured into a polytetrafluoroethylene cylindrical mold, and heated and cured at 80°C for 3 h, and then demolded and dried at 55°C for 8 h to obtain an energy storage phase change thermal insulation foam material. The mold used in this example and the following examples was provided with a pressure relief mechanism. When the pressure difference between the inside and outside of the mold was less than a preset value, such as 0.1-0.2 MPa, the pressure relief mechanism was in a closed state; when the pressure difference between the inside and outside of the mold was greater than the preset value, the pressure relief mechanism was opened to reduce the pressure difference between the inside and outside of the mold until the pressure difference was reduced to the preset value. The specific implementation of this example is as follows: a capillary hole was opened at the top of the mold, and an adhesive tape was attached above the capillary hole; when the pressure difference between the inside and outside of the mold was less than the preset value, such as 0.1-0.2 MPa, the adhesive tape completely covered the capillary hole, and the mold was in a completely sealed state; when the emulsion was heated in the mold, the foaming agent decomposed to generate bubble nuclei in the emulsion, and as the bubble nuclei grew, the volume of the emulsion increased, and the pressure in the mold cavity gradually increased; when the pressure difference between the inside and outside of the mold was greater than the preset value, the edge of the adhesive tape was lifted by the gas pressure to form a gas leakage path with the surface of the mold, and the mold was in a slow pressure relief state; until the pressure difference between the inside and outside of the mold was lower than the preset value, the edge of the adhesive tape fell to the state of being attached to the mold.

[0109] (5) The physical property analysis of the prepared energy storage phase change thermal insulation foam material shows that the apparent density is 0.199 g / cm 3 , the thermal conductivity is 0.068 W / , the thermal diffusivity is 0.24 mm 2 / s, the compressive strength is 0.30 MPa, and the heat storage capacity is 1.627 J / g.

[0110] Example 4

[0111] (1) 1.29 g of palm wax and 15.88 g of epoxy soybean oil acrylate were weighed and mixed, heated to melt at 90°C, and stirred uniformly to obtain a first mixed oil phase;

[0112] (2) 4 wt% of ethyl cellulose with a particle size of 850 nm and 3 wt% of benzoyl peroxide were added to the first mixed oil phase, which was heated in a 45°C water bath, and after the mixed oil phase was softened, stirring was performed to obtain a second mixed oil phase;

[0113] (3) The water phase (distilled water) was added to the second mixed oil phase, and the oil-water mass ratio was 6:4. After mechanical stirring at 200 r / min for 30 min, emulsification was performed to obtain a W / O type Pickering emulsion. 1 wt% of ammonium bicarbonate was added to the emulsion, and stirring was continued to obtain a pre-foaming emulsion;

[0114] (4) The pre-foaming emulsion was poured into a polytetrafluoroethylene cylindrical mold, heated and cured at 80°C for 3 h, and after demolding, it was dried at 55°C for 8 h to obtain an energy storage phase change thermal insulation foam material.

[0115] (5) The physical property analysis of the prepared energy storage phase change thermal insulation foam material shows that the apparent density is 0.208 g / cm 3 , the thermal conductivity is 0.072 W / , the thermal diffusivity is 0.25 mm 2 / s, the compressive strength is 0.347 MPa, and the heat storage capacity is 1.897 J / g.

[0116] Example 5

[0117] (1) 1.71 g of palm wax and 15.46 g of epoxy soybean oil acrylate were weighed and mixed, heated to melt at 90°C, and stirred uniformly to obtain a first mixed oil phase;

[0118] (2) 4 wt% of ethyl cellulose with a particle size of 850 nm and 3 wt% of benzoyl peroxide were added to the first mixed oil phase, which was heated in a 45°C water bath, and after the mixed oil phase was softened, stirring was performed to obtain a second mixed oil phase;

[0119] (3) The water phase (distilled water) is added to the second mixed oil phase, the oil-water mass ratio is 6:4, emulsified under 200 r / min mechanical stirring for 30 min, to obtain a W / O type Pickering emulsion; 1 wt% ammonium bicarbonate is added to the emulsion, and stirring is continued until the mixture is uniform, to obtain a pre-foaming emulsion;

[0120] (4) The pre-foaming emulsion is poured into a polytetrafluoroethylene cylindrical mold, heated and solidified at 80℃ for 3 h, and then dried at 55℃ for 8 h after demolding, to obtain an energy storage phase change thermal insulation foam material.

[0121] (5) Physical property analysis is performed on the prepared energy storage phase change thermal insulation foam material: the apparent density is 0.213 g / cm 3 , the thermal conductivity is 0.074 W / , the thermal diffusivity is 0.32 mm 2 / s, the compressive strength is 0.364 MPa, and the heat storage capacity is 2.54 J / g.

[0122] Example 6 (blank control example without phase change material)

[0123] (1) 17.17 g of epoxy soybean oil acrylate is weighed, 4 wt% of ethyl cellulose with a particle size of 850 nm and 3 wt% of benzoyl peroxide are added, and a mixed oil phase is obtained.

[0124] (2) The water phase (distilled water) is added to the mixed oil phase, the oil-water mass ratio is 6:4, emulsified under 200 r / min mechanical stirring for 30 min, to obtain a W / O type Pickering emulsion

[0125] (3) 1 wt% ammonium bicarbonate is added to the emulsion, and stirring is continued until the mixture is uniform, to obtain a pre-foaming emulsion;

[0126] (4) The pre-foaming emulsion is poured into a polytetrafluoroethylene cylindrical mold, heated and solidified at 80℃ for 3 h, and then dried at 55℃ for 8 h after demolding, to obtain a biomass foam material.

[0127] (5) Physical property analysis is performed on the prepared foam material: the apparent density is 0.196 g / cm 3 , the thermal conductivity is 0.062 W / , the thermal diffusivity is 0.30 mm 2 / s, the compressive strength is 0.135 MPa, and the heat storage capacity is 0.

[0128] Example 7

[0129] (1) 0.86 g of beeswax is mixed with 16.31 g of epoxy soybean oil acrylate, heated and melted at 90℃, and stirred until uniform, to obtain a first mixed oil phase;

[0130] (2) 4 wt% of ethyl cellulose with a particle size of 850 nm and 3 wt% of benzoyl peroxide were added to the first mixed oil phase, and the mixed oil phase was heated in a 45°C water bath. After the mixed oil phase was softened, stirring was performed to mix the components uniformly, and a second mixed oil phase was obtained;

[0131] (3) The water phase (distilled water) was added to the second mixed oil phase, and the oil-water mass ratio was 6:4. The emulsion was obtained by mechanical stirring at 200 r / min for 30 min. 1 wt% of ammonium bicarbonate was added to the emulsion, and the mixture was stirred to obtain a pre-foaming emulsion;

[0132] (4) The pre-foaming emulsion was poured into a polytetrafluoroethylene cylindrical mold, and the mold was heated at 80°C for 4 h for solidification. After demolding, the mold was dried at 55°C for 8 h to obtain an energy storage phase change thermal insulation foam material.

[0133] (5) The physical properties of the energy storage phase change thermal insulation foam material were analyzed. The apparent density was 0.198 g / cm 3 , the thermal conductivity was 0.068 W / , the thermal diffusivity was 0.26 mm 2 / s, the compressive strength was 0.230 MPa, and the heat storage capacity was 1.437 J / g.

[0134] Example 8

[0135] (1) 0.86 g of rice bran wax and 16.31 g of epoxy soybean oil acrylate were mixed, and the mixture was heated and melted at 90°C. The mixture was stirred uniformly to obtain a first mixed oil phase;

[0136] (2) 4 wt% of ethyl cellulose with a particle size of 850 nm and 3 wt% of benzoyl peroxide were added to the first mixed oil phase, and the mixed oil phase was heated in a 45°C water bath. After the mixed oil phase was softened, stirring was performed to mix the components uniformly, and a second mixed oil phase was obtained;

[0137] (3) The water phase (distilled water) was added to the second mixed oil phase, and the oil-water mass ratio was 6:4. The emulsion was obtained by mechanical stirring at 200 r / min for 30 min. 1 wt% of ammonium bicarbonate was added to the emulsion, and the mixture was stirred to obtain a pre-foaming emulsion;

[0138] (4) The pre-foaming emulsion was poured into a polytetrafluoroethylene cylindrical mold, and the mold was heated at 80°C for 3 h for solidification. After demolding, the mold was dried at 55°C for 8 h to obtain an energy storage phase change thermal insulation foam material.

[0139] (5) Physical property analysis of the prepared energy storage phase change thermal insulation foam material: apparent density 0.201 g / cm 3 , thermal conductivity 0.071 W / , thermal diffusivity 0.33 mm 2 / s, compressive strength 0.281 MPa, and heat storage capacity 1.624 J / g.

[0140] Example 9

[0141] (1) 0.86 g of stearate and 16.31 g of epoxy soybean oil acrylate were weighed and mixed, heated to melt at 90°C, and stirred uniformly to obtain a first mixed oil phase;

[0142] (2) 4 wt% of ethyl cellulose with a particle size of 850 nm and 3 wt% of benzoyl peroxide were added to the first mixed oil phase, which was heated in a 45°C water bath. After the mixed oil phase softened, stirring was performed to mix uniformly, and a second mixed oil phase was obtained;

[0143] (3) The water phase (distilled water) was added to the second mixed oil phase, and the oil-water mass ratio was 6:4. After mechanical stirring at 200 r / min for 30 min, emulsification was performed to obtain a W / O type Pickering emulsion. 1 wt% of ammonium bicarbonate was added to the emulsion, and stirring was continued to mix uniformly to obtain a pre-foaming emulsion;

[0144] (4) The pre-foaming emulsion was poured into a polytetrafluoroethylene cylindrical mold, heated and cured at 80°C for 3 h, and after demolding, it was dried at 55°C for 8 h to obtain an energy storage phase change thermal insulation foam material.

[0145] (5) Physical property analysis of the prepared energy storage phase change thermal insulation foam material: apparent density 0.20 g / cm 3 , thermal conductivity 0.069 W / , thermal diffusivity 0.36 mm 2 / s, compressive strength 0.281 MPa, and heat storage capacity 1.624 J / g.

[0146] Example 10

[0147] (1) 0.86 g of stearate and 16.31 g of epoxy soybean oil acrylate were weighed and mixed, heated to melt at 90°C, and stirred uniformly to obtain a first mixed oil phase;

[0148] (2) 4 wt% of ethyl cellulose with a particle size of 850 nm and 0.6 wt% of silica with a particle size of 200 nm were added to the first mixed oil phase, and 3 wt% of benzoyl peroxide was added. The mixture was heated in a 45°C water bath. After the mixed oil phase softened, stirring was performed to mix uniformly, and a second mixed oil phase was obtained;

[0149] (3) The water phase (distilled water) is added to the second mixed oil phase, the oil-water mass ratio is 6:4, and emulsification is carried out by mechanical stirring at 200 r / min for 30 min to obtain a W / O type Pickering emulsion; 1 wt% ammonium bicarbonate is added to the emulsion, and stirring is continued to obtain a pre-foaming emulsion;

[0150] (4) The pre-foaming emulsion is poured into a polytetrafluoroethylene cylindrical mold, heated and cured at 80°C for 3 h, and then dried at 55°C for 8 h after demolding to obtain an energy storage phase change thermal insulation foam material.

[0151] (5) Physical property analysis of the prepared energy storage phase change thermal insulation foam material: the apparent density is 0.203 g / cm3, the thermal conductivity is 0.068 W / m·K, the thermal diffusivity is 0.24 mm2 / s, the compressive strength is 0.293 MPa, and the heat storage capacity is 1.627 J / g. 3 2

[0152] Example 11

[0153] (1) 0.86 g of palm wax and 16.31 g of epoxy soybean oil acrylate are weighed and mixed, heated and melted at 90°C, and stirred uniformly to obtain a first mixed oil phase;

[0154] (2) 2 wt% of ethyl cellulose with a particle size of 850 nm, 0.6 wt% of silicon dioxide with a particle size of 250 nm, and 2 wt% of benzoyl peroxide are added to the first mixed oil phase, and the mixture is heated in a 45°C water bath. After the mixed oil phase softens, stirring is carried out to obtain a second mixed oil phase;

[0155] (3) The water phase (distilled water) is added to the second mixed oil phase, the oil-water mass ratio is 6:4, and emulsification is carried out by mechanical stirring at 200 r / min for 30 min to obtain a W / O type Pickering emulsion; 1 wt% sodium bicarbonate is added to the emulsion, and stirring is continued to obtain a pre-foaming emulsion;

[0156] (4) The pre-foaming emulsion is poured into a polytetrafluoroethylene cylindrical mold, heated and cured at 90°C for 2 h, and then dried at 55°C for 8 h after demolding to obtain an energy storage phase change thermal insulation foam material.

[0157] (5) Physical property analysis of the prepared energy storage phase change thermal insulation foam material: the apparent density is 0.198 g / cm3, the thermal conductivity is 0.070 W / m·K, the thermal diffusivity is 0.27 mm2 / s, the compressive strength is 0.294 MPa, and the heat storage capacity is 1.627 J / g.

[0158] ​​​​Example 12

[0159] (1) 0.86 g of palm wax was weighed and mixed with 16.31 g of epoxy soybean oil acrylate, heated to melt at 90°C, and stirred uniformly to obtain a first mixed oil phase;

[0160] (2) 8 wt% of ethyl cellulose with a particle size of 850 nm, 1.2 wt% of silicon dioxide with a particle size of 300 nm, and 2 wt% of benzoyl peroxide were added to the first mixed oil phase, which was heated in a 45°C water bath. After the mixed oil phase softened, stirring was performed to mix uniformly, and a second mixed oil phase was obtained;

[0161] (3) The water phase (distilled water) was added to the second mixed oil phase, and the oil-water mass ratio was 6:4. After mechanical stirring at 200 r / min for 30 min, emulsification was performed to obtain a W / O type Pickering emulsion. 1 wt% of sodium bicarbonate was added to the emulsion, and stirring was continued to mix uniformly to obtain a pre-foaming emulsion;

[0162] (4) The pre-foaming emulsion was poured into a polytetrafluoroethylene cylindrical mold, heated to solidify at 90°C for 2 h, and then demolded and dried at 55°C for 8 h to obtain an energy storage phase change thermal insulation foam material.

[0163] (5) Physical property analysis was performed on the prepared energy storage phase change thermal insulation foam material. The apparent density was 0.221 g / cm 3 , the thermal conductivity was 0.070 W / , the thermal diffusivity was 0.25 mm 2 / s, the compressive strength was 0.301 MPa, and the heat storage capacity was 1.627 J / g.

[0164] Example 13

[0165] (1) 0.86 g of palm wax was weighed and mixed with 16.31 g of epoxy soybean oil acrylate, heated to melt at 90°C, and stirred uniformly to obtain a first mixed oil phase;

[0166] (2) 4 wt% of ethyl cellulose with a particle size of 850 nm and 3 wt% of benzoyl peroxide were added to the first mixed oil phase, which was heated in a 45°C water bath. After the mixed oil phase softened, stirring was performed to mix uniformly, and a second mixed oil phase was obtained;

[0167] (3) The water phase (distilled water) was added to the second mixed oil phase, and the oil-water mass ratio was 6:4. After mechanical stirring at 200 r / min for 30 min, emulsification was performed to obtain a W / O type Pickering emulsion. 1 wt% of sodium bicarbonate was added to the emulsion, and stirring was continued to mix uniformly to obtain a pre-foaming emulsion;

[0168] (4) The pre-foaming emulsion is poured into a high borosilicate cylindrical mold, heated and cured at 80°C for 3 h, and dried at 55°C for 8 h after demolding to obtain the energy storage phase change thermal insulation foam material.

[0169] (5) Physical property analysis of the prepared energy storage phase change thermal insulation foam material: apparent density is 0.202 g / cm 3 , thermal conductivity is 0.069 W / , thermal diffusivity is 0.26 mm 2 / s, compressive strength is 0.303 MPa, and heat storage capacity is 1.627 J / g.

[0170] Example 14

[0171] (1) 0.86 g of palm wax is mixed with 16.31 g of epoxy soybean oil acrylate, heated and melted at 90°C, and stirred uniformly to obtain a first mixed oil phase;

[0172] (2) 2 wt% of palm wax with a particle size of 600 nm, 3 wt% of benzoyl peroxide, and 3 wt% of benzoyl peroxide are added to the first mixed oil phase, and the mixture is heated in a 45°C water bath, stirred after the mixed oil phase is softened, and mixed uniformly to obtain a second mixed oil phase;

[0173] The preparation method of the palm wax nanoparticles is as follows: palm wax is added to distilled water, the wax to water ratio is 1:50, the water bath is heated to the melting point of the palm wax, Tween 20 is then added, and the mixture is stirred at 800 r / min for 30 min; a lipid particle pre-dispersion is obtained; then the mixture is ultrasonically treated (amplitude 70%, ultrasonic treatment 5 s, intermittent 5 s) for 5 min to obtain a palm wax nanoparticle water dispersion, which is concentrated for use.

[0174] (3) The water phase (distilled water) is added to the second mixed oil phase, the oil to water mass ratio is 6:4, and the mixture is emulsified by mechanical stirring at 200 r / min for 30 min to obtain a W / O type Pickering emulsion; 1 wt% of sodium bicarbonate is added to the emulsion, and the mixture is continuously stirred and mixed uniformly to obtain a pre-foaming emulsion;

[0175] (4) The pre-foaming emulsion is poured into a high borosilicate square mold, heated and cured at 80°C for 3 h, and dried at 55°C for 8 h after demolding to obtain the energy storage phase change thermal insulation foam material.

[0176] (5) Physical property analysis of the prepared energy storage phase change thermal insulation foam material: apparent density is 0.203 g / cm 3 , thermal conductivity is 0.074 W / , thermal diffusivity is 0.34 mm 2 / s, compressive strength is 0.185 MPa, and heat storage capacity is 2.236 J / g.

[0177] Comparative Example 1

[0178] Refer to steps (1) to (5) of Example 14, except that the palm wax in step (3) was replaced with beeswax (melting point <80°C). As a result, the expected energy storage phase change material could not be formed. Since the catalytic reaction of the foam needs to be carried out at a temperature greater than 80°C, when exposed to this ambient temperature, the phase change material with a melting point less than 80°C will melt and leak out before the oil phase solidifies, causing the emulsion structure to become unstable and destroyed. The water phase droplets therein will undergo large-scale merger and enlargement, causing the prepared foam pores to expand or collapse.

[0179] Comparative Example 2

[0180] A pre-foamed emulsion was prepared according to steps (1) to (3) of Example 3. The pre-foamed emulsion was then poured into a polytetrafluoroethylene mold, completely sealed (with the pressure relief mechanism closed), and heated at 80°C for curing. As a result, the expected energy storage phase change material could not be formed. This is because in a completely sealed mold, the gas generated by the foaming agent cannot escape, resulting in excessive pressure inside the mold cavity, which inhibits the growth or expansion of the bubble nuclei in the emulsion and the stability of the bubble nuclei.

[0181] Comparative Example 3

[0182] The emulsion was prepared according to steps (1) to (3) of Example 10, except that no foaming agent was added in step (3). The emulsion was then poured into a polytetrafluoroethylene mold, completely sealed, and heated to 80°C for curing to form a phase change material. This material had few pores and could not meet the application requirements. The apparent density of the phase change material was measured and the result was 0.519 g / cm 3 ; The thermal conductivity was measured and the result was 0.163 W / .

[0183] The temperature and heat flow relationship diagram of the energy storage phase change thermal insulation foam material prepared in Examples 1-6 is as follows: Figure 1 As shown by Figure 1 It can be seen that with the increase of palm wax content, the heat storage capacity of the foam material increases significantly.

[0184] The appearance of the energy storage phase change thermal insulation foam material prepared in Example 1-6 is shown in the figure below: Figure 2 As shown, in the figure, a corresponds to the energy storage phase change thermal insulation foam material prepared in Example 6, and bf correspond to the energy storage phase change thermal insulation foam materials prepared in Examples 1-5 respectively.

[0185] The relationship between the compressive strain and stress of the energy storage phase change thermal insulation foam material prepared in Examples 1-6 is shown in the figure below: Figure 3 As shown by Figure 3It can be seen that the compressive stress of the foam material gradually increases with the increase of the content of palm wax. Since palm wax generally exhibits certain rigidity and toughness in solid state, by introducing palm wax into the system, the compressive stress of the foam material is improved by 2.7 times compared with the blank control example (Example 6) without phase change material.

[0186] The appearance display diagram of the energy storage phase change thermal insulation foam material prepared in Example 13 and Example 14 is shown in Figure 4 . Figure 4 In the figure, a is the energy storage phase change thermal insulation foam material prepared in Example 13 by a high borosilicate cylindrical mold, and b is the energy storage phase change thermal insulation foam material prepared by a high borosilicate square mold. Since the emulsion has high moldability and is filled and foamed, various complex geometries can be manufactured by using different types of molds, so that it can adapt to different application requirements and has high flexibility and pertinence.

[0187] The appearance display diagram of the energy storage phase change thermal insulation foam material prepared in Example 3 and Example 13 is shown in Figure 5 , Figure 5 In the figure, a corresponds to Example 3, and b corresponds to Example 13. Figure 5 It can be seen that the foam has no oil film (a in the figure) using a polytetrafluoroethylene mold; the foam has an oil film (b in the figure) using a high borosilicate mold. The formation of the oil film can help to reduce the surface roughness and improve the surface smoothness of the foam material; secondly, the hydrophobicity of the oil film itself can make the foam have stronger water resistance, thereby improving the durability of the material.

[0188] The scanning electron microscope diagram of the foam material prepared in Example 3 and Comparative Example 3 is shown in Figure 6 . Figure 6 In the figure, a is the scanning electron microscope diagram of the foam material prepared in Example 3, and b is the scanning electron microscope diagram of the foam material prepared in Comparative Example 3. It can be seen that the unfoamed foam has low porosity and dense structure, and the shape and distribution of the pores are uneven; in contrast, the foamed foam material has high porosity and dense pores, and the larger spherical pores are caused by the growth of the bubble nucleus, and the small pores on the surface of the spherical pores are obtained by evaporation of the emulsion water droplets, which significantly reduces the density and thermal conductivity of the foam material. Figure 6 The appearance display diagram of the foam material prepared in Example 3, Comparative Example 1 and Comparative Example 2 is shown in

[0189] , Figure 7 In the figure, a corresponds to Example 3, b corresponds to Comparative Example 2, and c corresponds to Comparative Example 1. Figure 7 Figure 7 ​It can be seen that: a in the figure is formed by normal preparation and foaming of the emulsion, the volume is relatively large, the hole distribution is uniform and the number is relatively large, and the density is low; b in the figure: due to the failure of the bubble nucleus to grow normally, the number of holes of the foam is significantly reduced, and the overall structure is relatively compact; c in the figure: due to the aggregation and coalescence of the water phase droplets of the emulsion, the size of the holes formed by the foam is significantly increased, the number is significantly reduced, and the structure is destroyed.

[0190] The above has described various embodiments of the present application, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those skilled in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles, practical applications, or improvements to the technology in the market of the embodiments, or to enable other ordinary skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for preparing an energy storage phase change thermal insulation foam material, characterized in that: include: Step a), melting, heating and mixing a phase change material and an oil phase to obtain a first mixed oil phase; the phase change material is an ester wax substance or a fusible ester substance; the oil phase is a biomass prepolymer; the ester wax substance is one or more of beeswax, insect wax, palm wax, and rice bran wax; the fusible ester substance is a fatty acid ester; Step b), adding nanoparticles and an initiator to the first mixed oil phase to obtain a second mixed oil phase; the nanoparticles are organic nanoparticles and / or inorganic nanoparticles; the organic nanoparticles are ethyl cellulose nanoparticles, chitin nanoparticles, or phase change nanoparticles, and the phase change nanoparticles are nanoparticles made of a phase change material with a melting temperature higher than 80°C; the inorganic nanoparticles are silicon dioxide particles, calcium carbonate particles, or zinc oxide particles; the amount of the organic nanoparticles added to the first mixed oil phase is 2-12wt%; the amount of the inorganic nanoparticles added to the first mixed oil phase is 0.3-1.8wt%; Step c), adding the aqueous phase to the second mixed oil phase, mechanically stirring and emulsifying to obtain a water-in-oil Pickering emulsion; Step d), adding a foaming agent to the water-in-oil Pickering emulsion to obtain a pre-foamed emulsion; Step e) pouring the pre-foamed emulsion into a mold, heating and curing it, and drying it after curing to obtain an energy storage phase change thermal insulation foam material.

2. The preparation method according to claim 1, characterized in that The mixing ratio of the phase change material to the oil phase is 1-15:100 by weight.

3. The preparation method according to claim 1, wherein The initiator is benzoyl peroxide, lauroyl peroxide or tert-butyl perbenzoate; the amount of the initiator added is 2-3 wt% of the first mixed oil phase.

4. The preparation method according to claim 1, wherein The foaming agent is bicarbonate, and the amount of the foaming agent added is 0.1-1.5 wt % of the water-in-oil Pickering emulsion.

5. The preparation method according to claim 1, characterized in that In the step c), the mixing mass ratio of the second mixed oil phase to the water phase is 6-9:1-4.

6. The preparation method according to claim 1, wherein In the step e), the temperature for heating and curing is 70-100° C. for 1.5-6 h; and the temperature for drying is 50-60° C. for 6-8 h.

7. The preparation method according to claim 1, characterized in that In the step e), the mold material is polytetrafluoroethylene, high borosilicate or stainless steel.

8. The preparation method according to claim 1, characterized in that The fusible ester substance is one or both of stearic acid ester and hydrogenated castor oil.

9. An energy storage phase change thermal insulation foam material, characterized in that: It is prepared according to the method according to any one of claims 1 to 8.

Images